Dark-matter decay as a complementary probe of multicomponent dark sectors.

PubMed

Dienes, Keith R; Kumar, Jason; Thomas, Brooks; Yaylali, David

2015-02-06

In single-component theories of dark matter, the 2→2 amplitudes for dark-matter production, annihilation, and scattering can be related to each other through various crossing symmetries. The detection techniques based on these processes are thus complementary. However, multicomponent theories exhibit an additional direction for dark-matter complementarity: the possibility of dark-matter decay from heavier to lighter components. We discuss how this new detection channel may be correlated with the others, and demonstrate that the enhanced complementarity which emerges can be an important ingredient in probing and constraining the parameter spaces of such models.

Single molecule fluorescence imaging as a technique for barium tagging in neutrinoless double beta decay

NASA Astrophysics Data System (ADS)

Jones, B. J. P.; McDonald, A. D.; Nygren, D. R.

2016-12-01

Background rejection is key to success for future neutrinoless double beta decay experiments. To achieve sensitivity to effective Majorana lifetimes of ~ 1028 years, backgrounds must be controlled to better than 0.1 count per ton per year, beyond the reach of any present technology. In this paper we propose a new method to identify the birth of the barium daughter ion in the neutrinoless double beta decay of 136Xe. The method adapts Single Molecule Fluorescent Imaging, a technique from biochemistry research with demonstrated single ion sensitivity. We explore possible SMFI dyes suitable for the problem of barium ion detection in high pressure xenon gas, and develop a fiber-coupled sensing system with which we can detect the presence of bulk Ba++ ions remotely. We show that our sensor produces signal-to-background ratios as high as 85 in response to Ba++ ions when operated in aqueous solution. We then describe the next stage of this R&D program, which will be to demonstrate chelation and fluorescence in xenon gas. If a successful barium ion tag can be developed using SMFI adapted for high pressure xenon gas detectors, the first essentially zero background, ton-scale neutrinoless double beta decay technology could be realized.

Confirmation of the Decay of 283112 and First Indication for Hg-like Behavior of Element 112

NASA Astrophysics Data System (ADS)

Eichler, R.; Aksenov, N. V.; Belozerov, A. V.; Bozhikov, G. A.; Chepigin, V. I.; Dressler, R.; Dmitriev, S. N.; Gäggeler, H. W.; Gorshkov, V. A.; Haenssler, F.; Itkis, M. G.; Lebedev, V. Ya.; Laube, A.; Malyshev, O. N.; Oganessian, Yu. Ts.; Petruschkin, O. V.; Piguet, D.; Rasmussen, P.; Shishkin, S. V.; Shutov, A. V.; Svirikhin, A. I.; Tereshatov, E. E.; Vostokin, G. K.; Wegrzecki, M.; Yeremin, A. V.

2007-05-01

Two gas phase adsorption chemistry experiments aimed at the chemical characterization of element 112 using its isotope 283112 have been performed at the Flerov Laboratory for Nuclear Reactions (FLNR) Dubna, Russia. The applied Insitu-Volatilization and On-line Detection (IVO) technique is a thermochromatographic system combining the determination of the deposition temperature of volatile elements on a surface along a temperature gradient with an efficient detection of the deposited species by event-by-event alpha and SF-fragment spectroscopy. Two possibilities to produce the isotope 283112 were used: 1.) the direct production reaction 238U( 48Ca,3n) 283112; 2.) the reaction 242Pu( 48Ca,3n), where the primary product 287114, decays via alpha emission to 283112 with a half-life of 0.5 s. The chemistry experiments were aimed at a chemical identification of 283112 and an independent confirmation of its decay properties. In the direct reaction no decays related to 283112 were observed. However, two decay chains unambiguously attributed to the decay of 283112 were observed using the second production path. Previously reported observation of 283112 and 279Ds and their decay properties were confirmed. From its thermochromatorgaphic deposition first thermochemical data were deduced for element 112, unveiling it as a typical group 12 element.

Improving Identification of Dijet Resonances at Hadron Colliders

NASA Astrophysics Data System (ADS)

Izaguirre, Eder; Shuve, Brian; Yavin, Itay

2015-01-01

The experimental detection of resonances has played a vital role in the development of subatomic physics. The overwhelming multijet backgrounds at the Large Hadron Collider (LHC) necessitate the invention of new techniques to identify resonances decaying into a pair of partons. In this Letter we introduce an observable that achieves a significant improvement in several key measurements at the LHC: the Higgs boson decay to a pair of b quarks; W±/Z0 vector-boson hadronic decay; and extensions of the standard model (SM) with a new hadronic resonance. Measuring the Higgs decay to b quarks is a central test of the fermion mass generation mechanism in the SM, whereas the W±/Z0 production rates are important observables of the electroweak sector. Our technique is effective in large parts of phase space where the resonance is mildly boosted and is particularly well suited for experimental searches dominated by systematic uncertainties, which is true of many analyses in the high-luminosity running of the LHC.

Improving identification of dijet resonances at hadron colliders.

PubMed

Izaguirre, Eder; Shuve, Brian; Yavin, Itay

2015-01-30

The experimental detection of resonances has played a vital role in the development of subatomic physics. The overwhelming multijet backgrounds at the Large Hadron Collider (LHC) necessitate the invention of new techniques to identify resonances decaying into a pair of partons. In this Letter we introduce an observable that achieves a significant improvement in several key measurements at the LHC: the Higgs boson decay to a pair of b quarks; W±/Z0 vector-boson hadronic decay; and extensions of the standard model (SM) with a new hadronic resonance. Measuring the Higgs decay to b quarks is a central test of the fermion mass generation mechanism in the SM, whereas the W±/Z0 production rates are important observables of the electroweak sector. Our technique is effective in large parts of phase space where the resonance is mildly boosted and is particularly well suited for experimental searches dominated by systematic uncertainties, which is true of many analyses in the high-luminosity running of the LHC.

An innovative technique for the investigation of the 4-fold forbidden beta-decay of 50V

NASA Astrophysics Data System (ADS)

Pattavina, L.; Laubenstein, M.; Nagorny, S. S.; Nisi, S.; Pagnanini, L.; Pirro, S.; Rusconi, C.; Schäffner, K.

2018-05-01

For the first time a Vanadium-based crystal was operated as cryogenic particle detector. The scintillating low temperature calorimetric technique was used for the characterization of a 22g YVO4 crystal aiming at the investigation of the 4-fold forbidden non-unique β- decay of 50V. The excellent bolometric performance of the compound together with high light output of the crystal make it an outstanding technique for the study of such elusive rate process. The internal radioactive contaminations of the crystal are also investigated showing that an improvement on the current status of material selection and purification are needed, 235/238U and 232Th are measured at the level of 28mBq/kg, 1.3 Bq/kg and 28m Bq/kg, respectively. In this work, we also discuss a future upgrade of the experimental set-up which may pave the road for the detection of the rare 50V β- decay.

Imaging and detection of early stage dental caries with an all-optical photoacoustic microscope

NASA Astrophysics Data System (ADS)

Hughes, D. A.; Sampathkumar, A.; Longbottom, C.; Kirk, K. J.

2015-01-01

Tooth decay, at its earliest stages, manifests itself as small, white, subsurface lesions in the enamel. Current methods for detection in the dental clinic are visual and tactile investigations, and bite-wing X-ray radiographs. These techniques suffer from poor sensitivity and specificity at the earliest (and reversible) stages of the disease due to the small size (<100μm) of the lesion. A fine-resolution (600 nm) ultra-broadband (200 MHz) all-optical photoacoustic microscopy system was is used to image the early signs of tooth decay. Ex-vivo tooth samples exhibiting white spot lesions were scanned and were found to generate a larger (one order of magnitude) photoacoustic (PA) signal in the lesion regions compared to healthy enamel. The high contrast in the PA images potentially allows lesions to be imaged and measured at a much earlier stage than current clinical techniques allow. PA images were cross referenced with histology photographs to validate our experimental results. Our PA system provides a noncontact method for early detection of white-spot lesions with a high detection bandwidth that offers advantages over previously demonstrated ultrasound methods. The technique provides the sensing depth of an ultrasound system, but with the spatial resolution of an optical system.

High Spin States in ^24Mg

NASA Astrophysics Data System (ADS)

Schwartz, J.; Lister, C. J.; Wuosmaa, A.; Betts, R. R.; Blumenthal, D.; Carpenter, M. P.; Davids, C. N.; Fischer, S. M.; Hackman, G.; Janssens, R. V. F.

1996-05-01

The ^12C(^16O,α)^24Mg reaction was used at 51.5MeV to populate high angular momentum states in ^24Mg. Gamma-rays de-exciting high spin states were detected in a 20 detector spectrometer (the AYE-ball) triggered by the ANL Fragment Mass Analyser (FMA). Channel selection, through detection of ^24Mg nuclei with the appropriate time of flight, was excellent. All the known decays from high spin states were seen in a few hours, with the exception of the 5.04 MeV γ-decay of the J^π=9^- state at 16.904 MeV footnote A.E.Smith et al., Phys. Lett. \\underlineB176, (1986)292. which could not be confirmed. The potential of the technique for studying the radiative decay of states with very high spin in light nuclei will be discussed.

Detection prospects of the cosmic neutrino background

NASA Astrophysics Data System (ADS)

Li, Yu-Feng

2015-04-01

The existence of the cosmic neutrino background (CνB) is a fundamental prediction of the standard Big Bang cosmology. Although current cosmological probes provide indirect observational evidence, the direct detection of the CνB in a laboratory experiment is a great challenge to the present experimental techniques. We discuss the future prospects for the direct detection of the CνB, with the emphasis on the method of captures on beta-decaying nuclei and the PTOLEMY project. Other possibilities using the electron-capture (EC) decaying nuclei, the annihilation of extremely high-energy cosmic neutrinos (EHECνs) at the Z-resonance, and the atomic de-excitation method are also discussed in this review (talk given at the International Conference on Massive Neutrinos, Singapore, 9-13 February 2015).

Differential die-away analysis system response modeling and detector design

NASA Astrophysics Data System (ADS)

Jordan, K. A.; Gozani, T.; Vujic, J.

2008-05-01

Differential die-away-analysis (DDAA) is a sensitive technique to detect presence of fissile materials such as 235U and 239Pu. DDAA uses a high-energy (14 MeV) pulsed neutron generator to interrogate a shipping container. The signature is a fast neutron signal hundreds of microseconds after the cessation of the neutron pulse. This fast neutron signal has decay time identical to the thermal neutron diffusion decay time of the inspected cargo. The theoretical aspects of a cargo inspection system based on the differential die-away technique are explored. A detailed mathematical model of the system is developed, and experimental results validating this model are presented.

Picosecond time-resolved photoluminescence using picosecond excitation correlation spectroscopy

NASA Astrophysics Data System (ADS)

Johnson, M. B.; McGill, T. C.; Hunter, A. T.

1988-03-01

We present a study of the temporal decay of photoluminescence (PL) as detected by picosecond excitation correlation spectroscopy (PECS). We analyze the correlation signal that is obtained from two simple models; one where radiative recombination dominates, the other where trapping processes dominate. It is found that radiative recombination alone does not lead to a correlation signal. Parallel trapping type processes are found to be required to see a signal. To illustrate this technique, we examine the temporal decay of the PL signal for In-alloyed, semi-insulating GaAs substrates. We find that the PL signal indicates a carrier lifetime of roughly 100 ps, for excitation densities of 1×1016-5×1017 cm-3. PECS is shown to be an easy technique to measure the ultrafast temporal behavior of PL processes because it requires no ultrafast photon detection. It is particularly well suited to measuring carrier lifetimes.

Dark Matter Indirect Detection with Gamma Rays

DOE PAGES

Patrick Harding, J.

2017-07-27

Searches for weakly interacting massive particle (WIMP) dark matter with gamma-ray instruments are a way to get a unique observational handle on the particle nature of dark matter. I will discuss the details of how to perform these searches, both for annihilating and decaying WIMPs. I will discuss the calculation of the gamma-ray flux from possible sources of dark matter annihilation or decay and show examples of limits which have been calculated using these techniques.

Application of environmental DNA to detect an endangered marine skate species in the wild.

PubMed

Weltz, Kay; Lyle, Jeremy M; Ovenden, Jennifer; Morgan, Jessica A T; Moreno, David A; Semmens, Jayson M

2017-01-01

Environmental DNA (eDNA) techniques have only recently been applied in the marine environment to detect the presence of marine species. Species-specific primers and probes were designed to detect the eDNA of the endangered Maugean skate (Zearaja maugeana) from as little as 1 L of water collected at depth (10-15 m) in Macquarie Harbour (MH), Tasmania. The identity of the eDNA was confirmed as Z. maugeana by sequencing the qPCR products and aligning these with the target sequence for a 100% match. This result has validated the use of this eDNA technique for detecting a rare species, Z. maugeana, in the wild. Being able to investigate the presence, and possibly the abundance, of Z. maugeana in MH and Bathurst harbour (BH), would be addressing a conservation imperative for the endangered Z. maugeana. For future application of this technique in the field, the rate of decay was determined for Z. maugeana eDNA under ambient dissolved oxygen (DO) levels (55% saturation) and lower DO (20% saturation) levels, revealing that the eDNA can be detected for 4 and 16 hours respectively, after which eDNA concentration drops below the detection threshold of the assay. With the rate of decay being influenced by starting eDNA concentrations, it is recommended that samples be filtered as soon as possible after collection to minimize further loss of eDNA prior to and during sample processing.

Application of environmental DNA to detect an endangered marine skate species in the wild

PubMed Central

Morgan, Jessica A. T.; Moreno, David A.

2017-01-01

Environmental DNA (eDNA) techniques have only recently been applied in the marine environment to detect the presence of marine species. Species-specific primers and probes were designed to detect the eDNA of the endangered Maugean skate (Zearaja maugeana) from as little as 1 L of water collected at depth (10–15 m) in Macquarie Harbour (MH), Tasmania. The identity of the eDNA was confirmed as Z. maugeana by sequencing the qPCR products and aligning these with the target sequence for a 100% match. This result has validated the use of this eDNA technique for detecting a rare species, Z. maugeana, in the wild. Being able to investigate the presence, and possibly the abundance, of Z. maugeana in MH and Bathurst harbour (BH), would be addressing a conservation imperative for the endangered Z. maugeana. For future application of this technique in the field, the rate of decay was determined for Z. maugeana eDNA under ambient dissolved oxygen (DO) levels (55% saturation) and lower DO (20% saturation) levels, revealing that the eDNA can be detected for 4 and 16 hours respectively, after which eDNA concentration drops below the detection threshold of the assay. With the rate of decay being influenced by starting eDNA concentrations, it is recommended that samples be filtered as soon as possible after collection to minimize further loss of eDNA prior to and during sample processing. PMID:28591215

Temporal and spatial binning of TCSPC data to improve signal-to-noise ratio and imaging speed

NASA Astrophysics Data System (ADS)

Walsh, Alex J.; Beier, Hope T.

2016-03-01

Time-correlated single photon counting (TCSPC) is the most robust method for fluorescence lifetime imaging using laser scanning microscopes. However, TCSPC is inherently slow making it ineffective to capture rapid events due to the single photon product per laser pulse causing extensive acquisition time limitations and the requirement of low fluorescence emission efficiency to avoid bias of measurement towards short lifetimes. Furthermore, thousands of photons per pixel are required for traditional instrument response deconvolution and fluorescence lifetime exponential decay estimation. Instrument response deconvolution and fluorescence exponential decay estimation can be performed in several ways including iterative least squares minimization and Laguerre deconvolution. This paper compares the limitations and accuracy of these fluorescence decay analysis techniques to accurately estimate double exponential decays across many data characteristics including various lifetime values, lifetime component weights, signal-to-noise ratios, and number of photons detected. Furthermore, techniques to improve data fitting, including binning data temporally and spatially, are evaluated as methods to improve decay fits and reduce image acquisition time. Simulation results demonstrate that binning temporally to 36 or 42 time bins, improves accuracy of fits for low photon count data. Such a technique reduces the required number of photons for accurate component estimation if lifetime values are known, such as for commercial fluorescent dyes and FRET experiments, and improve imaging speed 10-fold.

Combination of confocal principle and aperture stop separation improves suppression of crystalline lens fluorescence in an eye model.

PubMed

Klemm, Matthias; Blum, Johannes; Link, Dietmar; Hammer, Martin; Haueisen, Jens; Schweitzer, Dietrich

2016-09-01

Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new technique to detect changes in the human retina. The autofluorescence decay over time, generated by endogenous fluorophores, is measured in vivo. The strong autofluorescence of the crystalline lens, however, superimposes the intensity decay of the retina fluorescence, as the confocal principle is not able to suppress it sufficiently. Thus, the crystalline lens autofluorescence causes artifacts in the retinal fluorescence lifetimes determined from the intensity decays. Here, we present a new technique to suppress the autofluorescence of the crystalline lens by introducing an annular stop into the detection light path, which we call Schweitzer's principle. The efficacy of annular stops with an outer diameter of 7 mm and inner diameters of 1 to 5 mm are analyzed in an experimental setup using a model eye based on fluorescent dyes. Compared to the confocal principle, Schweitzer's principle with an inner diameter of 3 mm is able to reduce the simulated crystalline lens fluorescence to 4%, while 42% of the simulated retina fluorescence is preserved. Thus, we recommend the implementation of Schweitzer's principle in scanning laser ophthalmoscopes used for fundus autofluorescence measurements, especially the FLIO device, for improved image quality.

Demonstration of Single-Barium-Ion Sensitivity for Neutrinoless Double-Beta Decay Using Single-Molecule Fluorescence Imaging.

PubMed

McDonald, A D; Jones, B J P; Nygren, D R; Adams, C; Álvarez, V; Azevedo, C D R; Benlloch-Rodríguez, J M; Borges, F I G M; Botas, A; Cárcel, S; Carrión, J V; Cebrián, S; Conde, C A N; Díaz, J; Diesburg, M; Escada, J; Esteve, R; Felkai, R; Fernandes, L M P; Ferrario, P; Ferreira, A L; Freitas, E D C; Goldschmidt, A; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Guenette, R; Hafidi, K; Hauptman, J; Henriques, C A O; Hernandez, A I; Hernando Morata, J A; Herrero, V; Johnston, S; Labarga, L; Laing, A; Lebrun, P; Liubarsky, I; López-March, N; Losada, M; Martín-Albo, J; Martínez-Lema, G; Martínez, A; Monrabal, F; Monteiro, C M B; Mora, F J; Moutinho, L M; Muñoz Vidal, J; Musti, M; Nebot-Guinot, M; Novella, P; Palmeiro, B; Para, A; Pérez, J; Querol, M; Repond, J; Renner, J; Riordan, S; Ripoll, L; Rodríguez, J; Rogers, L; Santos, F P; Dos Santos, J M F; Simón, A; Sofka, C; Sorel, M; Stiegler, T; Toledo, J F; Torrent, J; Tsamalaidze, Z; Veloso, J F C A; Webb, R; White, J T; Yahlali, N

2018-03-30

A new method to tag the barium daughter in the double-beta decay of ^{136}Xe is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba^{++}) resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (∼2  nm), and detected with a statistical significance of 12.9σ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.

Demonstration of Single-Barium-Ion Sensitivity for Neutrinoless Double-Beta Decay Using Single-Molecule Fluorescence Imaging

NASA Astrophysics Data System (ADS)

McDonald, A. D.; Jones, B. J. P.; Nygren, D. R.; Adams, C.; Álvarez, V.; Azevedo, C. D. R.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carrión, J. V.; Cebrián, S.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Guenette, R.; Hafidi, K.; Hauptman, J.; Henriques, C. A. O.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Johnston, S.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Repond, J.; Renner, J.; Riordan, S.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.; NEXT Collaboration

2018-03-01

A new method to tag the barium daughter in the double-beta decay of Xe 136 is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba++ ) resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (˜2 nm ), and detected with a statistical significance of 12.9 σ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.

Development of Advanced Signal Processing and Source Imaging Methods for Superparamagnetic Relaxometry

PubMed Central

Huang, Ming-Xiong; Anderson, Bill; Huang, Charles W.; Kunde, Gerd J.; Vreeland, Erika C.; Huang, Jeffrey W.; Matlashov, Andrei N.; Karaulanov, Todor; Nettles, Christopher P.; Gomez, Andrew; Minser, Kayla; Weldon, Caroline; Paciotti, Giulio; Harsh, Michael; Lee, Roland R.; Flynn, Edward R.

2017-01-01

Superparamagnetic Relaxometry (SPMR) is a highly sensitive technique for the in vivo detection of tumor cells and may improve early stage detection of cancers. SPMR employs superparamagnetic iron oxide nanoparticles (SPION). After a brief magnetizing pulse is used to align the SPION, SPMR measures the time decay of SPION using Super-conducting Quantum Interference Device (SQUID) sensors. Substantial research has been carried out in developing the SQUID hardware and in improving the properties of the SPION. However, little research has been done in the pre-processing of sensor signals and post-processing source modeling in SPMR. In the present study, we illustrate new pre-processing tools that were developed to: 1) remove trials contaminated with artifacts, 2) evaluate and ensure that a single decay process associated with bounded SPION exists in the data, 3) automatically detect and correct flux jumps, and 4) accurately fit the sensor signals with different decay models. Furthermore, we developed an automated approach based on multi-start dipole imaging technique to obtain the locations and magnitudes of multiple magnetic sources, without initial guesses from the users. A regularization process was implemented to solve the ambiguity issue related to the SPMR source variables. A procedure based on reduced chi-square cost-function was introduced to objectively obtain the adequate number of dipoles that describe the data. The new pre-processing tools and multi-start source imaging approach have been successfully evaluated using phantom data. In conclusion, these tools and multi-start source modeling approach substantially enhance the accuracy and sensitivity in detecting and localizing sources from the SPMR signals. Furthermore, multi-start approach with regularization provided robust and accurate solutions for a poor SNR condition similar to the SPMR detection sensitivity in the order of 1000 cells. We believe such algorithms will help establishing the industrial standards for SPMR when applying the technique in pre-clinical and clinical settings. PMID:28072579

Alphas and surface backgrounds in liquid argon dark matter detectors

NASA Astrophysics Data System (ADS)

Stanford, Christopher J.

Current observations from astrophysics indicate the presence of dark matter, an invisible form of matter that makes up a large part of the mass of the universe. One of the leading theories for dark matter is that it is made up of Weakly Interacting Massive Particles (WIMPs). One of the ways we try to discover WIMPs is by directly detecting their interaction with regular matter. This can be done using a scintillator such as liquid argon, which gives off light when a particle interacts with it. Liquid argon (LAr) is a favorable means of detecting WIMPs because it has an inherent property that enables a technique called pulse-shape discrimination (PSD). PSD can distinguish a WIMP signal from the constant background of electromagnetic signals from other sources, like gamma rays. However, there are other background signals that PSD is not as capable of rejecting, such as those caused by alpha decays on the interior surfaces of the detector. Radioactive elements that undergo alpha decay are introduced to detector surfaces during construction by radon gas that is naturally present in the air, as well as other means. When these surface isotopes undergo alpha decay, they can produce WIMP-like signals in the detector. We present here two LAr experiments. The first (RaDOSE) discovered a property of an organic compound that led to a technique for rejecting surface alpha decays in LAr detectors with high efficiency. The second (DarkSide-50) is a dark matter experiment operated at LNGS in Italy and is the work of an international collaboration. A detailed look is given into alpha decays and surface backgrounds present in the detector, and projections are made of alpha-related backgrounds for 500 live days of data. The technique developed with RaDOSE is applied to DarkSide-50 to determine its effectiveness in practice. It is projected to suppress the surface background in DarkSide-50 by more than a factor of 1000.

Solving real decay and conservation problems of building materials by ultrasounds technique

NASA Astrophysics Data System (ADS)

Alvarez de Buergo, Monica; Fort, Rafael; Gomez-Heras, Miguel; Vazquez-Calvo, Carmen

2010-05-01

In this study a variety of case studies and different building materials in which ultrasounds velocity played a significant role are shown, either to characterize building materials, to measure deterioration, to assess conservation techniques or for preventive purposes. Regarding to materials properties, ultrasounds velocity provided interesting indices such as the quality index (useful when selecting replacing materials, materials for new constructions or either for sculptures); alteration index (very much related to pores and voids, and fissures); mechanical strength (assessing its reduction when materials are affected by several decay processes, being fire one of them) or anisotropy indices, which highly condition the decay of elements and materials in buildings and sculptures, and which vary themselves with decay progress. The technique is also a tool for detecting and locating elements inside structures, like metallic ones, and also to detect and locate discontinuities inside elements, both for consolidation purposes or even in cases of structures movement, which is quite common nowadays. Using some specific software, ultrasounds results can be plotted as iso-areas, which allows to define areas or zones of structures with the highest risk of detachment in a short-time in order to plan the most adequate interventions. Not new is also the aid of ultrasonics to assess consolidation products and to determine the degree of materials decay when submitted to artificial ageing. Much more innovative is the fact that ultrasonics measurement can be also helpful to determine different building periods in a same building, even the fact of determining an element's lifetime. The results obtained by this non destructive and portable technique that will be presented in this session correspond to both real case studies (results that helped to solve a real problem), some of them corresponding to emblematic monuments de España (Royal Palace of Madrid and some other monuments belonging to the Spanish National Heritage or Trust, archaeological structures and sculptures), and also to laboratory research to understand processes and helpful to see the best way of preservation. In some of the cases, other techniques have been used as complementary, such as sclerommetry, magnetometry and IR termography. Acknowledgements: to both MATERNAS (0505/MAT/0094) and GEOMATERIALES (2009-1629) research programmes, funded by the Regional Government of Madrid; and to the CONSOLIDER-INGENIO programme (CSD2007-0058), funded by the Spanish Ministry of Education and Science.

Study of teeth phosphorescence detection technique

NASA Astrophysics Data System (ADS)

Cai, De-Fang; Wang, Shui-ping; Yang, Zhen-jiang; An, Yuying; Huang, Li-Zi; Liang, Yan

1995-05-01

On the basis of research and analysis into optical properties of teeth, this paper introduces the techniques to transform teeth phosphorescence excited by ultraviolet light into electric signals and following steps for data collection, analysis and processing. Also presented are the methods to diagnose pulp-vitality, decayed teeth, and, especially, infant caries and pre-caries diseases. By measurement of a tooth's temperature, other stomatic illnesses can be diagnosed.

Demonstration of Single-Barium-Ion Sensitivity for Neutrinoless Double-Beta Decay Using Single-Molecule Fluorescence Imaging

DOE PAGES

McDonald, A. D.; Jones, B. J. P.; Nygren, D. R.; ...

2018-03-26

A new method to tag the barium daughter in the double beta decay ofmore » $$^{136}$$Xe is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba$$^{++}$$) resolution at a transparent scanning surface has been demonstrated. A single-step photo-bleach confirms the single ion interpretation. Individual ions are localized with super-resolution ($$\\sim$$2~nm), and detected with a statistical significance of 12.9~$$\\sigma$$ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.« less

Combination of confocal principle and aperture stop separation improves suppression of crystalline lens fluorescence in an eye model

PubMed Central

Klemm, Matthias; Blum, Johannes; Link, Dietmar; Hammer, Martin; Haueisen, Jens; Schweitzer, Dietrich

2016-01-01

Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new technique to detect changes in the human retina. The autofluorescence decay over time, generated by endogenous fluorophores, is measured in vivo. The strong autofluorescence of the crystalline lens, however, superimposes the intensity decay of the retina fluorescence, as the confocal principle is not able to suppress it sufficiently. Thus, the crystalline lens autofluorescence causes artifacts in the retinal fluorescence lifetimes determined from the intensity decays. Here, we present a new technique to suppress the autofluorescence of the crystalline lens by introducing an annular stop into the detection light path, which we call Schweitzer’s principle. The efficacy of annular stops with an outer diameter of 7 mm and inner diameters of 1 to 5 mm are analyzed in an experimental setup using a model eye based on fluorescent dyes. Compared to the confocal principle, Schweitzer’s principle with an inner diameter of 3 mm is able to reduce the simulated crystalline lens fluorescence to 4%, while 42% of the simulated retina fluorescence is preserved. Thus, we recommend the implementation of Schweitzer’s principle in scanning laser ophthalmoscopes used for fundus autofluorescence measurements, especially the FLIO device, for improved image quality. PMID:27699092

Detection of colorectal cancer using time-resolved autofluorescence spectrometer

NASA Astrophysics Data System (ADS)

Fu, Sheng; Kwek, Leong-Chuan; Chia, Teck-Chee; Lim, Chu-Sing; Tang, Choong-Leong; Ang, Wuan-Suan; Zhou, Miao-Chang; Loke, Po-Ling

2006-04-01

As we know Quantum mechanics is a mathematical theory that can describe the behavior of objects that are at microscopic level. Time-resolved autofluorescence spectrometer monitors events that occur during the lifetime of the excited state. This time ranges from a few picoseconds to hundreds of nanoseconds. That is an extremely important advance as it allows environmental parameters to be monitored in a spatially defined manner in the specimen under study. This technique is based on the application of Quantum Mechanics. This principle is applied in our project as we are trying to use different fluorescence spectra to detect biological molecules commonly found in cancerous colorectal tissue and thereby differentiate the cancerous and non-cancerous colorectal polyps more accurately and specifically. In this paper, we use Fluorescence Lifetime Spectrometer (Edinburgh Instruments FL920) to measure decay time of autofluorescence of colorectal cancerous and normal tissue sample. All specimens are from Department of Colorectal Surgery, Singapore General Hospital. The tissues are placed in the time-resolved autofluorescence instrument, which records and calculates the decay time of the autofluorescence in the tissue sample at the excitation and emission wavelengths pre-determined from a conventional spectrometer. By studying the decay time,τ, etc. for cancerous and normal tissue, we aim to present time-resolved autofluorescence as a feasible technique for earlier detection of malignant colorectal tissues. By using this concept, we try to contribute an algorithm even an application tool for real time early diagnosis of colorectal cancer for clinical services.

Nineteenth International Cosmic Ray Conference. HE Sessions, Volume 8

NASA Technical Reports Server (NTRS)

Jones, F. C. (Compiler)

1985-01-01

Papers submitted for presentation at the 19th International Cosmic Ray Conference are compiled. The present volume contains papers addressing high energy interactions and related phenomena. Specific topic areas include muons, neutrinos, magnetic monopoles, nucleon decay, searches for new particles, and acoustic and thermoluminescence detection techniques.

Use of a SQUID array to detect T-cells with magnetic nanoparticles in determining transplant rejection

NASA Astrophysics Data System (ADS)

Flynn, Edward R.; Bryant, H. C.; Bergemann, Christian; Larson, Richard S.; Lovato, Debbie; Sergatskov, Dmitri A.

2007-04-01

Acute rejection in organ transplant is signaled by the proliferation of T-cells that target and kill the donor cells requiring painful biopsies to detect rejection onset. An alternative non-invasive technique is proposed using a multi-channel superconducting quantum interference device (SQUID) magnetometer to detect T-cell lymphocytes in the transplanted organ labeled with magnetic nanoparticles conjugated to antibodies specifically attached to lymphocytic ligand receptors. After a magnetic field pulse, the T-cells produce a decaying magnetic signal with a characteristic time of the order of a second. The extreme sensitivity of this technique, 10 5 cells, can provide early warning of impending transplant rejection and monitor immune-suppressive chemotherapy.

Simultaneous determination of radionuclides separable into natural decay series by use of time-interval analysis.

PubMed

Hashimoto, Tetsuo; Sanada, Yukihisa; Uezu, Yasuhiro

2004-05-01

A delayed coincidence method, time-interval analysis (TIA), has been applied to successive alpha- alpha decay events on the millisecond time-scale. Such decay events are part of the (220)Rn-->(216)Po ( T(1/2) 145 ms) (Th-series) and (219)Rn-->(215)Po ( T(1/2) 1.78 ms) (Ac-series). By using TIA in addition to measurement of (226)Ra (U-series) from alpha-spectrometry by liquid scintillation counting (LSC), two natural decay series could be identified and separated. The TIA detection efficiency was improved by using the pulse-shape discrimination technique (PSD) to reject beta-pulses, by solvent extraction of Ra combined with simple chemical separation, and by purging the scintillation solution with dry N(2) gas. The U- and Th-series together with the Ac-series were determined, respectively, from alpha spectra and TIA carried out immediately after Ra-extraction. Using the (221)Fr-->(217)At ( T(1/2) 32.3 ms) decay process as a tracer, overall yields were estimated from application of TIA to the (225)Ra (Np-decay series) at the time of maximum growth. The present method has proven useful for simultaneous determination of three radioactive decay series in environmental samples.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDonald, A. D.; Jones, B. J. P.; Nygren, D. R.

A new method to tag the barium daughter in the double beta decay ofmore » $$^{136}$$Xe is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba$$^{++}$$) resolution at a transparent scanning surface has been demonstrated. A single-step photo-bleach confirms the single ion interpretation. Individual ions are localized with super-resolution ($$\\sim$$2~nm), and detected with a statistical significance of 12.9~$$\\sigma$$ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.« less

Accelerated detection of brown-rot decay : comparison of soil block test, chemical analysis, mechanical properties, and immunodetection

Treesearch

C. A. Clausen; S. N. Kartal

2003-01-01

Early detection of wood decay is critical because decay fungi can cause rapid structural failure. The objective of this study was to compare the sensitivity of different methods purported to detect brown-rot decay in the early stages of development. The immunodiagnostic wood decay (IWD)test, soil block test/cake pan test, mechanical property tests, and chemical...

Fast, reagentless and reliable screening of "white powders" during the bioterrorism hoaxes.

PubMed

Włodarski, Maksymilian; Kaliszewski, Miron; Trafny, Elżbieta Anna; Szpakowska, Małgorzata; Lewandowski, Rafał; Bombalska, Aneta; Kwaśny, Mirosław; Kopczyński, Krzysztof; Mularczyk-Oliwa, Monika

2015-03-01

The classification of dry powder samples is an important step in managing the consequences of terrorist incidents. Fluorescence decays of these samples (vegetative bacteria, bacterial endospores, fungi, albumins and several flours) were measured with stroboscopic technique using an EasyLife LS system PTI. Three pulsed nanosecond LED sources, generating 280, 340 and 460nm were employed for samples excitation. The usefulness of a new 460nm light source for fluorescence measurements of dry microbial cells has been demonstrated. The principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been used for classification of dry biological samples. It showed that the single excitation wavelength was not sufficient for differentiation of biological samples of diverse origin. However, merging fluorescence decays from two or three excitation wavelengths allowed classification of these samples. An experimental setup allowing the practical implementation of this method for the real time fluorescence decay measurement was designed. It consisted of the LED emitting nanosecond pulses at 280nm and two fast photomultiplier tubes (PMTs) for signal detection in two fluorescence bands simultaneously. The positive results of the dry powder samples measurements confirmed that the fluorescence decay-based technique could be a useful tool for fast classification of the suspected "white powders" performed by the first responders. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Measurement of surface stay times for physical adsorption of gases. Ph.D. Thesis - Va. Univ.; [using molecular beam time of flight technique

NASA Technical Reports Server (NTRS)

Wilmoth, R. G.

1973-01-01

A molecular beam time-of-flight technique is studied as a means of determining surface stay times for physical adsorption. The experimental approach consists of pulsing a molecular beam, allowing the pulse to strike an adsorbing surface and detecting the molecular pulse after it has subsequently desorbed. The technique is also found to be useful for general studies of adsorption under nonequilibrium conditions including the study of adsorbate-adsorbate interactions. The shape of the detected pulse is analyzed in detail for a first-order desorption process. For mean stay times, tau, less than the mean molecular transit times involved, the peak of the detected pulse is delayed by an amount approximately equal to tau. For tau much greater than these transit times, the detected pulse should decay as exp(-t/tau). However, for stay times of the order of the transit times, both the molecular speed distributions and the incident pulse duration time must be taken into account.

Wood Performance in Doorways of Single-Family Houses

Treesearch

Thomas W. Popham; Rodney C. DeGroot; Ronald W. Howe

1978-01-01

Front doors and door frames in 175 new houses with slab-on-ground foundations were examined for moisture and decay problems in three Mississippi counties that border the Gulf of Mexico during summer 1973. Defects were often the result of building techniques of particular developers. No special problem was detected that would cause frames or doors to have excessively...

Magneto-optical detection of the relaxation dynamics of alloy nanoparticles with a high-stability magnetic circular dichroism setup

NASA Astrophysics Data System (ADS)

Cavigli, L.; de Julián Fernández, C.; Gatteschi, D.; Gurioli, M.; Sangregorio, C.; Mattei, G.; Mazzoldi, P.; Bogani, L.

2007-09-01

We present a versatile high-stability and high-sensitivity magneto-optical setup that allows transmission and reflection measurements at high fields and low temperatures. We apply the technique to measure the decay in time of the magnetization of highly monodisperse 3.3 nm Co33Ni67 alloy nanoparticles embedded in a silica host. We demonstrate the possibility of observing the dynamics of the magnetization over a macroscopic timescale in dilute samples, where other techniques are unavailable.

Radon assay for SNO+

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rumleskie, Janet

The SNO+ experiment will study neutrinos while located 6,800 feet below the surface of the earth at SNOLAB. Though shielded from surface backgrounds, emanation of radon radioisotopes from the surrounding rock leads to back-grounds. The characteristic decay of radon and its daughters allows for an alpha detection technique to count the amount of Rn-222 atoms collected. Traps can collect Rn-222 from various positions and materials, including an assay skid that will collect Rn-222 from the organic liquid scintillator used to detect interactions within SNO+.

Radon assay for SNO+

NASA Astrophysics Data System (ADS)

Rumleskie, Janet

2015-12-01

The SNO+ experiment will study neutrinos while located 6,800 feet below the surface of the earth at SNOLAB. Though shielded from surface backgrounds, emanation of radon radioisotopes from the surrounding rock leads to back-grounds. The characteristic decay of radon and its daughters allows for an alpha detection technique to count the amount of Rn-222 atoms collected. Traps can collect Rn-222 from various positions and materials, including an assay skid that will collect Rn-222 from the organic liquid scintillator used to detect interactions within SNO+.

The Decay of Motor Memories Is Independent of Context Change Detection

PubMed Central

Brennan, Andrew E.; Smith, Maurice A.

2015-01-01

When the error signals that guide human motor learning are withheld following training, recently-learned motor memories systematically regress toward untrained performance. It has previously been hypothesized that this regression results from an intrinsic volatility in these memories, resulting in an inevitable decay in the absence of ongoing error signals. However, a recently-proposed alternative posits that even recently-acquired motor memories are intrinsically stable, decaying only if a change in context is detected. This new theory, the context-dependent decay hypothesis, makes two key predictions: (1) after error signals are withheld, decay onset should be systematically delayed until the context change is detected; and (2) manipulations that impair detection by masking context changes should result in prolonged delays in decay onset and reduced decay amplitude at any given time. Here we examine the decay of motor adaptation following the learning of novel environmental dynamics in order to carefully evaluate this hypothesis. To account for potential issues in previous work that supported the context-dependent decay hypothesis, we measured decay using a balanced and baseline-referenced experimental design that allowed for direct comparisons between analogous masked and unmasked context changes. Using both an unbiased variant of the previous decay onset analysis and a novel highly-powered group-level version of this analysis, we found no evidence for systematically delayed decay onset nor for the masked context change affecting decay amplitude or its onset time. We further show how previous estimates of decay onset latency can be substantially biased in the presence of noise, and even more so with correlated noise, explaining the discrepancy between the previous results and our findings. Our results suggest that the decay of motor memories is an intrinsic feature of error-based learning that does not depend on context change detection. PMID:26111244

The LUCIFER/CUPID-0 demonstrator: searching for the neutrinoless double-beta decay with Zn82Se scintillating bolometers

NASA Astrophysics Data System (ADS)

Artusa, D. R.; Balzoni, A.; Beeman, J. W.; Bellini, F.; Biassoni, M.; Brofferio, C.; Camacho, A.; Capelli, S.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Clemenza, M.; Cremonesi, O.; Cruciani, A.; D'Addabbo, A.; Dafinei, I.; Di Domizio, S.; di Vacri, M. L.; Ferroni, F.; Gironi, L.; Giuliani, A.; Gotti, C.; Keppel, G.; Maino, M.; Mancuso, M.; Martinez, M.; Morganti, S.; Nagorny, S. S.; Nastasi, M.; Nisi, S.; Nones, C.; Orlandi, D.; Pagnanini, L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Pirro, S.; Pozzi, S.; Previtali, E.; Puiu, A.; Rusconi, C.; Schäffner, K.; Tomei, C.; Vignati, M.; Zolotarova, A.

2017-09-01

Future experiments on neutrinoless double beta-decay with the aim of exploring the inverted hierarchy region have to employ detectors with excellent energy resolution and zero background in the energy region of interest. Cryogenic scintillating bolometers turn out to be a suitable candidate since they offer particle discrimination: the dual channel detection of the heat and the scintillation light signal allows for particle identification. In particular such detectors permit for a suppression of α-induced backgrounds, a key-issue for next-generation tonne-scale bolometric experiments. We report on the progress and current status of the LUCIFER/CUPID-0 demonstrator, the first array of scintillating bolometers based on enriched Zn82Se crystals which is expected to start data taking in 2016 and the potential of this detection technique for a future tonne-scale bolometric experiment after CUORE.

Development of CANDLES low background HPGe detector and half-life measurement of 180Tam

NASA Astrophysics Data System (ADS)

Chan, W. M.; Kishimoto, T.; Umehara, S.; Matsuoka, K.; Suzuki, K.; Yoshida, S.; Nakajima, K.; Iida, T.; Fushimi, K.; Nomachi, M.; Ogawa, I.; Tamagawa, Y.; Hazama, R.; Takemoto, Y.; Nakatani, N.; Takihira, Y.; Tozawa, M.; Kakubata, H.; Trang, V. T. T.; Ohata, T.; Tetsuno, K.; Maeda, T.; Khai, B. T.; Li, X. L.; Batpurev, T.

2018-01-01

A low background HPGe detector system was developed at CANDLES Experimental Hall for multipurpose use. Various low background techniques were employed, including hermatic shield design, radon gas suppression, and background reduction analysis. A new pulse shape discrimination (PSD) method was specially created for coaxial Ge detector. Using this PSD method, microphonics noise and background event at low energy region less than 200 keV can be rejected effectively. Monte Carlo simulation by GEANT4 was performed to acquire the detection efficiency and study the interaction of gamma-rays with detector system. For rare decay measurement, the detector was utilized to detect the nature's most stable isomer tantalum-180m (180Tam) decay. Two phases of tantalum physics run were completed with total livetime of 358.2 days, which Phase II has upgraded shield configuration. The world most stringent half-life limit of 180Tam has been successfully achieved.

Method and apparatus for the detection of neutrons and gamma rays

DOEpatents

Reber, Edward L.; Aryaeinejad, Rahmat; Spencer, David F.

2005-10-11

A pulse discrimination method for discriminating between pulses having a short decay period and a long decay period, may comprise: Detecting the pulse; integrating a rise portion of the pulse; integrating a decay portion of the pulse; and comparing the integrated rise portion of the pulse with the integrated decay portion of the pulse to distinguish between a pulse having a long decay period and a pulse having a short decay period.

Decay diseases of stemwood: Detection, diagnosis, and management

Treesearch

Walter C. Shortle; Kevin T. Smith; Kenneth R. Dudzik

1996-01-01

Three major needs exist to better relate tree biology research to practical agroforesty (Larsen 1984). The first need is to identify the specific, desired product to be yielded from the forest. Valid and appropriate management techniques to yield one product may not be appropriate to yield a different product, even from the same species of trees. The second need is to...

Radon backgrounds in the DEAP-1 liquid-argon-based Dark Matter detector

NASA Astrophysics Data System (ADS)

Amaudruz, P.-A.; Batygov, M.; Beltran, B.; Boudjemline, K.; Boulay, M. G.; Cai, B.; Caldwell, T.; Chen, M.; Chouinard, R.; Cleveland, B. T.; Contreras, D.; Dering, K.; Duncan, F.; Ford, R.; Gagnon, R.; Giuliani, F.; Gold, M.; Golovko, V. V.; Gorel, P.; Graham, K.; Grant, D. R.; Hakobyan, R.; Hallin, A. L.; Harvey, P.; Hearns, C.; Jillings, C. J.; Kuźniak, M.; Lawson, I.; Li, O.; Lidgard, J.; Liimatainen, P.; Lippincott, W. H.; Mathew, R.; McDonald, A. B.; McElroy, T.; McFarlane, K.; McKinsey, D.; Muir, A.; Nantais, C.; Nicolics, K.; Nikkel, J.; Noble, T.; O'Dwyer, E.; Olsen, K. S.; Ouellet, C.; Pasuthip, P.; Pollmann, T.; Rau, W.; Retiere, F.; Ronquest, M.; Skensved, P.; Sonley, T.; Tang, J.; Vázquez-Jáuregui, E.; Veloce, L.; Ward, M.

2015-03-01

The DEAP-1 7 kg single phase liquid argon scintillation detector was operated underground at SNOLAB in order to test the techniques and measure the backgrounds inherent to single phase detection, in support of the DEAP-3600 Dark Matter detector. Backgrounds in DEAP are controlled through material selection, construction techniques, pulse shape discrimination, and event reconstruction. This report details the analysis of background events observed in three iterations of the DEAP-1 detector, and the measures taken to reduce them. The 222 Rn decay rate in the liquid argon was measured to be between 16 and 26 μBq kg-1. We found that the background spectrum near the region of interest for Dark Matter detection in the DEAP-1 detector can be described considering events from three sources: radon daughters decaying on the surface of the active volume, the expected rate of electromagnetic events misidentified as nuclear recoils due to inefficiencies in the pulse shape discrimination, and leakage of events from outside the fiducial volume due to imperfect position reconstruction. These backgrounds statistically account for all observed events, and they will be strongly reduced in the DEAP-3600 detector due to its higher light yield and simpler geometry.

Intraoperative β{sup -} detecting probe for radio-guided surgery in tumour resection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solfaroli Camillocci, Elena; Bellini, Fabio; Bocciy, Valerio

The development of the β{sup -} based radio-guided surgery aims to extend the technique to those tumours where surgery is the only possible treatment and the assessment of the resection would most profit from the low background around the lesion, as for brain tumours. Feasibility studies on meningioma and gliomas already estimated the potentiality of this new treatment. To validate the technique, a prototype of the intraoperative probe detecting β{sup -} decays and specific phantoms simulating tumour remnant patterns embedded in healthy tissue have been realized. The response of the probe in this simulated environment is tested with dedicated procedures.more » This document discusses the innovative aspects of the method, the status of the developed intraoperative β{sup -} detecting probe and the results of the preclinical tests. (authors)« less

Search for dark matter decay of the free neutron from the UCNA experiment: n →χ +e+e-

NASA Astrophysics Data System (ADS)

Sun, X.; Adamek, E.; Allgeier, B.; Blatnik, M.; Bowles, T. J.; Broussard, L. J.; Brown, M. A.-P.; Carr, R.; Clayton, S.; Cude-Woods, C.; Currie, S.; Dees, E. B.; Ding, X.; Filippone, B. W.; García, A.; Geltenbort, P.; Hasan, S.; Hickerson, K. P.; Hoagland, J.; Hong, R.; Hogan, G. E.; Holley, A. T.; Ito, T. M.; Knecht, A.; Liu, C.-Y.; Liu, J.; Makela, M.; Mammei, R.; Martin, J. W.; Melconian, D.; Mendenhall, M. P.; Moore, S. D.; Morris, C. L.; Nepal, S.; Nouri, N.; Pattie, R. W.; Pérez Galván, A.; Phillips, D. G.; Picker, R.; Pitt, M. L.; Plaster, B.; Ramsey, J. C.; Rios, R.; Salvat, D. J.; Saunders, A.; Sondheim, W.; Sjue, S.; Slutsky, S.; Swank, C.; Swift, G.; Tatar, E.; Vogelaar, R. B.; VornDick, B.; Wang, Z.; Wei, W.; Wexler, J.; Womack, T.; Wrede, C.; Young, A. R.; Zeck, B. A.; UCNA Collaboration

2018-05-01

It has been proposed recently that a previously unobserved neutron decay branch to a dark matter particle (χ ) could account for the discrepancy in the neutron lifetime observed in experiments that use two different measurement techniques. One of the possible final states discussed includes a single χ along with an e+e- pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ˜4 π acceptance using a pair of detectors that observe a volume of stored ultracold neutrons. The summed kinetic energy (Ee+e-) from such events is used to set limits, as a function of the χ mass, on the branching fraction for this decay channel. For χ masses consistent with resolving the neutron lifetime discrepancy, we exclude this as the dominant dark matter decay channel at ≫5 σ level for 100 90 % confidence level.

Intraoperative probe detecting β- decays in brain tumour radio-guided surgery

NASA Astrophysics Data System (ADS)

Solfaroli Camillocci, E.; Bocci, V.; Chiodi, G.; Collamati, F.; Donnarumma, R.; Faccini, R.; Mancini Terracciano, C.; Marafini, M.; Mattei, I.; Muraro, S.; Recchia, L.; Rucinski, A.; Russomando, A.; Toppi, M.; Traini, G.; Morganti, S.

2017-02-01

Radio-guided surgery (RGS) is a technique to intraoperatively detect tumour remnants, favouring a radical resection. Exploiting β- emitting tracers provides a higher signal to background ratio compared to the established technique with γ radiation, allowing the extension of the RGS applicability range. We developed and tested a detector based on para-terphenyl scintillator with high sensitivity to low energy electrons and almost transparent to γs to be used as intraoperative probe for RGS with β- emitting tracer. Portable read out electronics was customised to match the surgeon needs. This probe was used for preclinical test on specific phantoms and a test on "ex vivo" specimens from patients affected by meningioma showing very promising results for the application of this new technique on brain tumours. In this paper, the prototype of the intraoperative probe and the tests are discussed; then, the results on meningioma are used to make predictions on the performance of the probe detecting residuals of a more challenging and more interesting brain tumour: the glioma.

Detection of decay in fresh-cut lettuce using hyperspectral imaging and chlorophyll fluorescence imaging

USDA-ARS?s Scientific Manuscript database

Fresh-cut lettuce sold in modified atmosphere packaging (MAP) is a desirable, but highly perishable product. Decay of tissue can start a few days after processing and may be difficult to detect by quick visual observation. A system for early detection of decay and gradual evaluation of its progress ...

Photographic monitoring of soiling and decay of roadside walls in central Oxford, England

NASA Astrophysics Data System (ADS)

Thornbush, Mary J.; Viles, Heather A.

2008-12-01

As part of the Environmental Monitoring of Integrated Transport Strategies (EMITS) project, which examined the impact of the Oxford Transport Strategy (OTS) on the soiling and decay of buildings and structures in central Oxford, England, a simple photographic survey of a sample of roadside walls was carried out in 1997, with re-surveys in 1999 and 2003. Thirty photographs were taken each time, covering an area of stonework approximately 30 × 30 cm in dimensions at 1-1.3 m above pavement level. The resulting images have been used to investigate, both qualitatively as well as quantitatively, the progression of soiling and decay. Comparison of images by eye reveals a number of minor changes in soiling and decay patterns, but generally indicates stability except at one site where dramatic, superficial damage occurred over 2 years. Quantitative analysis of decay features (concavities resulting from surface blistering, flaking, and scaling), using simple techniques in Adobe Photoshop, shows variable pixel-based size proportions of concavities across 6 years of survey. Colour images (in Lab Color) generally have a reduced proportion of pixels, representing decay features in comparison to black and white (Grayscale) images. The study conveys that colour images provide more information both for general observations of soiling and decay patterns and for segmentation of decay-produced concavities. The study indicates that simple repeat photography can reveal useful information about changing patterns of both soiling and decay, although unavoidable variation in external lighting conditions between re-surveys is a factor limiting the accuracy of change detection.

Development and evaluation of a technique for in vivo monitoring of 60Co in human liver

NASA Astrophysics Data System (ADS)

Gomes, GH; Silva, MC; Mello, JQ; Dantas, ALA; Dantas, BM

2018-03-01

60Co is an artificial radioactive metal produced by activation of iron with neutrons. It decays by beta particles and gamma radiation and represents a risk of internal exposure of workers involved in the maintenance of nuclear power reactors. Intakes can be quantified through in vivo monitoring. This work describes the development of a technique for the quantification of 60Co in human liver. The sensitivity of the method is evaluated based on the minimum detectable effective doses. The results allow to state that the technique is suitable either for monitoring of occupational exposures or evaluation of accidental intakes.

Visual cues for woodpeckers: light reflectance of decayed wood varies by decay fungus

USGS Publications Warehouse

O'Daniels, Sean T.; Kesler, Dylan C.; Mihail, Jeanne D.; Webb, Elisabeth B.; Werner, Scott J.

2018-01-01

The appearance of wood substrates is likely relevant to bird species with life histories that require regular interactions with wood for food and shelter. Woodpeckers detect decayed wood for cavity placement or foraging, and some species may be capable of detecting trees decayed by specific fungi; however, a mechanism allowing for such specificity remains unidentified. We hypothesized that decay fungi associated with woodpecker cavity sites alter the substrate reflectance in a species-specific manner that is visually discriminable by woodpeckers. We grew 10 species of wood decay fungi from pure cultures on sterile wood substrates of 3 tree species. We then measured the relative reflectance spectra of decayed and control wood wafers and compared them using the receptor noise-limited (RNL) color discrimination model. The RNL model has been used in studies of feather coloration, egg shells, flowers, and fruit to model how the colors of objects appear to birds. Our analyses indicated 6 of 10 decayed substrate/control comparisons were above the threshold of discrimination (i.e., indicating differences discriminable by avian viewers), and 12 of 13 decayed substrate comparisons were also above threshold for a hypothetical woodpecker. We conclude that woodpeckers should be capable of visually detecting decayed wood on trees where bark is absent, and they should also be able to detect visually species-specific differences in wood substrates decayed by fungi used in this study. Our results provide evidence for a visual mechanism by which woodpeckers could identify and select substrates decayed by specific fungi, which has implications for understanding ecologically important woodpecker–fungus interactions.

Coincidence measurements in α/β/γ spectrometry with phoswich detectors using digital pulse shape discrimination analysis

NASA Astrophysics Data System (ADS)

de Celis, B.; de la Fuente, R.; Williart, A.; de Celis Alonso, B.

2007-09-01

A novel system has been developed for the detection of low radioactivity levels using coincidence techniques. The device combines a phoswich detector for α/β/γ ray recognition with a fast digital card for electronic pulse analysis. The detector is able to discriminate different types of radiation in a mixed α/β/γ field and can be used in a coincidence mode by identifying the composite signal produced by the simultaneous detection of β particles in a plastic scintillator and γ rays in an NaI(Tl) scintillator. Use of a coincidence technique with phoswich detectors was proposed recently to verify the Nuclear Test Ban Treaty, which made it necessary to monitor the low levels of xenon radioisotopes produced by underground nuclear explosions. Previous studies have shown that combining CaF 2(Eu) for β ray detection and NaI(Tl) for γ ray detection makes it difficult to identify the coincidence signals because of the similar fluorescence decay times of the two scintillators. With the device proposed here, it is possible to identify the coincidence events owing to the short fluorescence decay time of the plastic scintillator. The sensitivity of the detector may be improved by employing liquid scintillators, which allow low radioactivity levels from actinides to be measured when present in environmental samples. The device developed is simpler to use than conventional coincidence equipment because it uses a single detector and electronic circuit, and it offers fast and precise analysis of the coincidence signals by employing digital pulse shape analysis.

Identify source location and release time for pollutants undergoing super-diffusion and decay: Parameter analysis and model evaluation

NASA Astrophysics Data System (ADS)

Zhang, Yong; Sun, HongGuang; Lu, Bingqing; Garrard, Rhiannon; Neupauer, Roseanna M.

2017-09-01

Backward models have been applied for four decades by hydrologists to identify the source of pollutants undergoing Fickian diffusion, while analytical tools are not available for source identification of super-diffusive pollutants undergoing decay. This technical note evaluates analytical solutions for the source location and release time of a decaying contaminant undergoing super-diffusion using backward probability density functions (PDFs), where the forward model is the space fractional advection-dispersion equation with decay. Revisit of the well-known MADE-2 tracer test using parameter analysis shows that the peak backward location PDF can predict the tritium source location, while the peak backward travel time PDF underestimates the tracer release time due to the early arrival of tracer particles at the detection well in the maximally skewed, super-diffusive transport. In addition, the first-order decay adds additional skewness toward earlier arrival times in backward travel time PDFs, resulting in a younger release time, although this impact is minimized at the MADE-2 site due to tritium's half-life being relatively longer than the monitoring period. The main conclusion is that, while non-trivial backward techniques are required to identify pollutant source location, the pollutant release time can and should be directly estimated given the speed of the peak resident concentration for super-diffusive pollutants with or without decay.

REVIEWS OF TOPICAL PROBLEMS: Ultrahigh-energy neutrinos from astrophysical sources and superheavy particle decays

NASA Astrophysics Data System (ADS)

Ryabov, Vladimir A.

2006-09-01

Problems in the fields of neutrino astronomy and ultrahigh-energy astrophysics are reviewed. Neutrino fluxes produced in various astrophysical sources (bottom-up acceleration scenarios) and resulting from the decay of superheavy particles (top-down scenarios) are considered. Neutrino oscillation processes and the absorption and regeneration of neutrinos inside the earth are analyzed and some other factors affecting the intensity and flavor composition of astrophysical neutrino fluxes are discussed. Details of ultrahigh-energy neutrino interactions are discussed within the Standard Model, as well as using nonstandard scenarios predicting an anomalous increase in the inelastic neutrino-nucleon cross section. Ultrahigh-energy neutrino detection techniques currently in use in new-generation neutrino telescopes and cosmic ray detectors are also discussed.

Resolving environmental microheterogeneity and dielectric relaxation in fluorescence kinetics of protein

NASA Astrophysics Data System (ADS)

Rolinski, Olaf J.; McLaughlin, Damien; Birch, David J. S.; Vyshemirsky, Vladislav

2016-09-01

The fluorescence intensity decay of protein is easily measurable and reports on the intrinsic fluorophore-local environment interactions on the sub-nm spatial and sub-ns temporal scales, which are consistent with protein activity in numerous biomedical and industrial processes. This makes time-resolved fluorescence a perfect tool for understanding, monitoring and controlling these processes at the molecular level, but the complexity of the decay, which has been traditionally fitted to multi-exponential functions, has hampered the development of this technique over the last few decades. Using the example of tryptophan in HSA we present the alternative to the conventional approach to modelling intrinsic florescence intensity decay in protein where the key factors determining fluorescence decay, i.e. the excited-state depopulation and the dielectric relaxation (Toptygin and Brand 2000 Chem. Phys. Lett. 322 496-502), are represented by the individual relaxation functions. This allows quantification of both effects separately by determining their parameters from the global analysis of a series of fluorescence intensity decays measured at different detection wavelengths. Moreover, certain pairs of the recovered parameters of tryptophan were found to be correlated, indicating the influence of the dielectric relaxation on the transient rate of the electronic transitions. In this context the potential for the dual excited state depopulation /dielectric relaxation fluorescence lifetime sensing is discussed.

Search for dark matter decay of the free neutron from the UCNA experiment: n → χ + e + e –

DOE PAGES

Sun, X.; Adamek, E.; Allgeier, B.; ...

2018-05-21

It has been proposed recently that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in experiments that use two different measurement techniques. One of the possible final states discussed includes a single χ along with an e +e – pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ~4π acceptance using a pair of detectors that observe a volume of stored ultracold neutrons. The summed kinetic energy (E e+e–) from suchmore » events is used to set limits, as a function of the χ mass, on the branching fraction for this decay channel. For χ masses consistent with resolving the neutron lifetime discrepancy, we exclude this as the dominant dark matter decay channel at >>5σ level for 100 < E e+e– < 644keV. In conclusion, if the χ+e +e – final state is not the only one, we set limits on its branching fraction of <10 –4 for the above E e+e– range at >90% confidence level.« less

Search for dark matter decay of the free neutron from the UCNA experiment: n → χ + e + e –

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, X.; Adamek, E.; Allgeier, B.

It has been proposed recently that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in experiments that use two different measurement techniques. One of the possible final states discussed includes a single χ along with an e +e – pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ~4π acceptance using a pair of detectors that observe a volume of stored ultracold neutrons. The summed kinetic energy (E e+e–) from suchmore » events is used to set limits, as a function of the χ mass, on the branching fraction for this decay channel. For χ masses consistent with resolving the neutron lifetime discrepancy, we exclude this as the dominant dark matter decay channel at >>5σ level for 100 < E e+e– < 644keV. In conclusion, if the χ+e +e – final state is not the only one, we set limits on its branching fraction of <10 –4 for the above E e+e– range at >90% confidence level.« less

Environmental DNA (eDNA): A tool for quantifying the abundant but elusive round goby (Neogobius melanostomus)

USGS Publications Warehouse

Nevers, Meredith; Byappanahalli, Muruleedhara; Morris, Charles C.; Shively, Dawn; Przybyla-Kelly, Katarzyna; Spoljaric, Ashley M.; Dickey, Joshua; Roseman, Edward

2018-01-01

Environmental DNA (eDNA) is revolutionizing biodiversity monitoring, occupancy estimates, and real-time detections of invasive species. In the Great Lakes, the round goby (Neogobius melanostomus), an invasive benthic fish from the Black Sea, has spread to encompass all five lakes and many tributaries, outcompeting or consuming native species; however, estimates of round goby abundance are confounded by behavior and habitat preference, which impact reliable methods for estimating their population. By integrating eDNA into round goby monitoring, improved estimates of biomass may be obtainable. We conducted mesocosm experiments to estimate rates of goby DNA shedding and decay. Further, we compared eDNA with several methods of traditional field sampling to compare its use as an alternative/complementary monitoring method. Environmental DNA decay was comparable to other fish species, and first-order decay was lower at 12°C (k = 0.043) than at 19°C (k = 0.058). Round goby eDNA was routinely detected in known invaded sites of Lake Michigan and its tributaries (range log10 4.8–6.2 CN/L), but not upstream of an artificial fish barrier. Traditional techniques (mark-recapture, seining, trapping) in Lakes Michigan and Huron resulted in fewer, more variable detections than eDNA, but trapping and eDNA were correlated (Pearson R = 0.87). Additional field testing will help correlate round goby abundance with eDNA, providing insight on its role as a prey fish and its impact on food webs.

Environmental DNA (eDNA): A tool for quantifying the abundant but elusive round goby (Neogobius melanostomus)

PubMed Central

Byappanahalli, Murulee N.; Morris, Charles C.; Shively, Dawn; Przybyla-Kelly, Kasia; Spoljaric, Ashley M.; Dickey, Joshua; Roseman, Edward F.

2018-01-01

Environmental DNA (eDNA) is revolutionizing biodiversity monitoring, occupancy estimates, and real-time detections of invasive species. In the Great Lakes, the round goby (Neogobius melanostomus), an invasive benthic fish from the Black Sea, has spread to encompass all five lakes and many tributaries, outcompeting or consuming native species; however, estimates of round goby abundance are confounded by behavior and habitat preference, which impact reliable methods for estimating their population. By integrating eDNA into round goby monitoring, improved estimates of biomass may be obtainable. We conducted mesocosm experiments to estimate rates of goby DNA shedding and decay. Further, we compared eDNA with several methods of traditional field sampling to compare its use as an alternative/complementary monitoring method. Environmental DNA decay was comparable to other fish species, and first-order decay was lower at 12°C (k = 0.043) than at 19°C (k = 0.058). Round goby eDNA was routinely detected in known invaded sites of Lake Michigan and its tributaries (range log10 4.8–6.2 CN/L), but not upstream of an artificial fish barrier. Traditional techniques (mark-recapture, seining, trapping) in Lakes Michigan and Huron resulted in fewer, more variable detections than eDNA, but trapping and eDNA were correlated (Pearson R = 0.87). Additional field testing will help correlate round goby abundance with eDNA, providing insight on its role as a prey fish and its impact on food webs. PMID:29357382

Environmental DNA (eDNA): A tool for quantifying the abundant but elusive round goby (Neogobius melanostomus).

PubMed

Nevers, Meredith B; Byappanahalli, Murulee N; Morris, Charles C; Shively, Dawn; Przybyla-Kelly, Kasia; Spoljaric, Ashley M; Dickey, Joshua; Roseman, Edward F

2018-01-01

Environmental DNA (eDNA) is revolutionizing biodiversity monitoring, occupancy estimates, and real-time detections of invasive species. In the Great Lakes, the round goby (Neogobius melanostomus), an invasive benthic fish from the Black Sea, has spread to encompass all five lakes and many tributaries, outcompeting or consuming native species; however, estimates of round goby abundance are confounded by behavior and habitat preference, which impact reliable methods for estimating their population. By integrating eDNA into round goby monitoring, improved estimates of biomass may be obtainable. We conducted mesocosm experiments to estimate rates of goby DNA shedding and decay. Further, we compared eDNA with several methods of traditional field sampling to compare its use as an alternative/complementary monitoring method. Environmental DNA decay was comparable to other fish species, and first-order decay was lower at 12°C (k = 0.043) than at 19°C (k = 0.058). Round goby eDNA was routinely detected in known invaded sites of Lake Michigan and its tributaries (range log10 4.8-6.2 CN/L), but not upstream of an artificial fish barrier. Traditional techniques (mark-recapture, seining, trapping) in Lakes Michigan and Huron resulted in fewer, more variable detections than eDNA, but trapping and eDNA were correlated (Pearson R = 0.87). Additional field testing will help correlate round goby abundance with eDNA, providing insight on its role as a prey fish and its impact on food webs.

Single-Electron Detection and Spectroscopy via Relativistic Cyclotron Radiation.

PubMed

Asner, D M; Bradley, R F; de Viveiros, L; Doe, P J; Fernandes, J L; Fertl, M; Finn, E C; Formaggio, J A; Furse, D; Jones, A M; Kofron, J N; LaRoque, B H; Leber, M; McBride, E L; Miller, M L; Mohanmurthy, P; Monreal, B; Oblath, N S; Robertson, R G H; Rosenberg, L J; Rybka, G; Rysewyk, D; Sternberg, M G; Tedeschi, J R; Thümmler, T; VanDevender, B A; Woods, N L

2015-04-24

It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Although first derived in 1904, cyclotron radiation from a single electron orbiting in a magnetic field has never been observed directly. We demonstrate single-electron detection in a novel radio-frequency spectrometer. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay end point, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.

Use of ruthenium dyes for subnanosecond detector fidelity testing in real time transient absorption

NASA Astrophysics Data System (ADS)

Byrdin, Martin; Thiagarajan, Viruthachalam; Villette, Sandrine; Espagne, Agathe; Brettel, Klaus

2009-04-01

Transient absorption spectroscopy is a powerful tool for the study of photoreactions on time scales from femtoseconds to seconds. Typically, reactions slower than ˜1 ns are recorded by the "classical" technique; the reaction is triggered by an excitation flash, and absorption changes accompanying the reaction are recorded in real time using a continuous monitoring light beam and a detection system with sufficiently fast response. The pico- and femtosecond region can be accessed by the more recent "pump-probe" technique, which circumvents the difficulties of real time detection on a subnanosecond time scale. This is paid for by accumulation of an excessively large number of shots to sample the reaction kinetics. Hence, it is of interest to extend the classical real time technique as far as possible to the subnanosecond range. In order to identify and minimize detection artifacts common on a subnanosecond scale, like overshoot, ringing, and signal reflections, rigorous testing is required of how the detection system responds to fast changes of the monitoring light intensity. Here, we introduce a novel method to create standard signals for detector fidelity testing on a time scale from a few picoseconds to tens of nanoseconds. The signals result from polarized measurements of absorption changes upon excitation of ruthenium complexes {[Ru(bpy)3]2+ and a less symmetric derivative} by a short laser flash. Two types of signals can be created depending on the polarization of the monitoring light with respect to that of the excitation flash: a fast steplike bleaching at magic angle and a monoexponentially decaying bleaching for parallel polarizations. The lifetime of the decay can be easily varied via temperature and viscosity of the solvent. The method is applied to test the performance of a newly developed real time transient absorption setup with 300 ps time resolution and high sensitivity.

Results on Neutrinoless Double-Beta Decay from Gerda Phase I

NASA Astrophysics Data System (ADS)

Macolino, Carla

2014-12-01

The GERmanium Detector Array, GERDA, is designed to search for neutrinoless double-beta (0νββ) decay of 76Ge and it is installed in the Laboratori Nazionali del Gran Sasso (LNGS) of INFN, Italy. In this review, the detection principle and detector setup of GERDA are described. Also, the main physics results by GERDA Phase I, are discussed. They include the measurement of the half-life of 2νββ decay, the background decomposition of the energy spectrum and the techniques for the discrimination of the background, based on the pulse shape of the signal. In the last part of this review, the estimation of a limit on the half-life of 0νββ (T0ν 1/2>2.1ḑot 1025 yr at 90% C.L.) and the comparison with previous results are discussed. GERDA data from Phase I strongly disfavor the recent claim of 0νββ discovery, based on data from the Heidelberg-Moscow experiment.

Procedure for short-lived particle detection in the OPERA experiment and its application to charm decays

NASA Astrophysics Data System (ADS)

Agafonova, N.; Aleksandrov, A.; Anokhina, A.; Aoki, S.; Ariga, A.; Ariga, T.; Bender, D.; Bertolin, A.; Bozza, C.; Brugnera, R.; Buonaura, A.; Buontempo, S.; Büttner, B.; Chernyavsky, M.; Chukanov, A.; Consiglio, L.; D'Ambrosio, N.; De Lellis, G.; De Serio, M.; Del Amo Sanchez, P.; Di Crescenzo, A.; Di Ferdinando, D.; Di Marco, N.; Dmitrievski, S.; Dracos, M.; Duchesneau, D.; Dusini, S.; Dzhatdoev, T.; Ebert, J.; Ereditato, A.; Fini, R. A.; Fukuda, T.; Galati, G.; Garfagnini, A.; Giacomelli, G.; Göllnitz, C.; Goldberg, J.; Gornushkin, Y.; Grella, G.; Guler, M.; Gustavino, C.; Hagner, C.; Hara, T.; Hollnagel, A.; Hosseini, B.; Ishida, H.; Ishiguro, K.; Jakovcic, K.; Jollet, C.; Kamiscioglu, C.; Kamiscioglu, M.; Kawada, J.; Kim, J. H.; Kim, S. H.; Kitagawa, N.; Klicek, B.; Kodama, K.; Komatsu, M.; Kose, U.; Kreslo, I.; Lauria, A.; Lenkeit, J.; Ljubicic, A.; Longhin, A.; Loverre, P.; Malgin, A.; Malenica, M.; Mandrioli, G.; Matsuo, T.; Matveev, V.; Mauri, N.; Medinaceli, E.; Meregaglia, A.; Mikado, S.; Monacelli, P.; Montesi, M. C.; Morishima, K.; Muciaccia, M. T.; Naganawa, N.; Naka, T.; Nakamura, M.; Nakano, T.; Nakatsuka, Y.; Niwa, K.; Ogawa, S.; Okateva, N.; Olshevsky, A.; Omura, T.; Ozaki, K.; Paoloni, A.; Park, B. D.; Park, I. G.; Pasqualini, L.; Pastore, A.; Patrizii, L.; Pessard, H.; Pistillo, C.; Podgrudkov, D.; Polukhina, N.; Pozzato, M.; Pupilli, F.; Roda, M.; Rokujo, H.; Roganova, T.; Rosa, G.; Ryazhskaya, O.; Sato, O.; Schembri, A.; Shakiryanova, I.; Shchedrina, T.; Sheshukov, A.; Shibuya, H.; Shiraishi, T.; Shoziyoev, G.; Simone, S.; Sioli, M.; Sirignano, C.; Sirri, G.; Spinetti, M.; Stanco, L.; Starkov, N.; Stellacci, S. M.; Stipcevic, M.; Strauss, T.; Strolin, P.; Takahashi, S.; Tenti, M.; Terranova, F.; Tioukov, V.; Tufanli, S.; Vilain, P.; Vladimirov, M.; Votano, L.; Vuilleumier, J. L.; Wilquet, G.; Wonsak, B.; Yoon, C. S.; Zemskova, S.; Zghiche, A.

2014-08-01

The OPERA experiment, designed to perform the first observation of oscillations in appearance mode through the detection of the leptons produced in charged current interactions, has collected data from 2008 to 2012. In the present paper, the procedure developed to detect particle decays, occurring over distances of the order of from the neutrino interaction point, is described in detail and applied to the search for charmed hadrons, showing similar decay topologies as the lepton. In the analysed sample, 50 charm decay candidate events are observed while are expected, proving that the detector performance and the analysis chain applied to neutrino events are well reproduced by the OPERA simulation and thus validating the methods for appearance detection.

The Enriched Xenon Observatory: EXO-200 and Ba+ tagging

NASA Astrophysics Data System (ADS)

Dolinski, M. J.; EXO Collaboration

2012-08-01

The Enriched Xenon Observatory (EXO) is a proposed ton-scale double beta decay experiment with a tentative design sensitivity to the Majorana mass of ˜10 meV. The first phase of EXO is EXO-200, which uses 200 kg of Xe enriched to 80% in 136Xe to search for neutrinoless double beta decay. EXO-200 is a liquid Xe time projection chamber with the ability to detect both scintillation and ionization signals. The detector is constructed from ultra-low background materials and is currently installed at the Waste Isolation Pilot Plant, a salt mine with a 1600 meter water equivalent overburden. The projected 2 year sensitivity for EXO-200 is T1/20ν>6.4×1025 y at 90% confidence level. Looking toward a ton-scale EXO, one unique feature of the experiment is the proposal to identify the barium daughter produced by 136Xe double beta decay on an event-by-event basis. This technique will allow for the elimination of all backgrounds other than the background from the two-neutrino double beta decay spectrum. The EXO Collaboration is exploring a number of options to implement Ba-daughter tagging in the next generation EXO experiment.

Progress towards barium daughter tagging in Xe136 decay using single molecule fluorescence imaging

NASA Astrophysics Data System (ADS)

McDonald, Austin; NEXT Collaboration

2017-09-01

The existence of Majorana fermions is of great interest as it may be related to the asymmetry between matter and anti-matter particles in the universe. However, the search for them has proven to be a difficult one. Neutrino-less Double Beta decay (NLDB) offers a possible opportunity for direct observation of a Majorana Fermion. The rate for NLDB decay may be as low as 1 count /ton /year if the mass ordering is inverted. Current detector technologies have background rates between 4 to 300 count /ton /year /ROI at the 100kg scale which is much larger than the universal goal of 0.1 count /ton /year /ROI desired for ton-scale detectors. The premise of my research is to develop new detector technologies that will allow for a background-free experiment. My current work is to develop a sensor that will tag the daughter ion Ba++ from the Xe136 decay. The development of a sensor that is sensitive to single barium ion detection based on the single molecule fluorescence imaging technique is the major focus of this work. If successful, this could provide a path to a background-free experiment.

Progress towards barium daughter tagging in Xe136 decay using single molecule fluorescence imaging

NASA Astrophysics Data System (ADS)

McDonald, Austin; Jones, Ben; Benson, Jordan; Nygren, David; NEXT Collaboration

2017-01-01

The existence of Majorana Fermions has been predicted, and is of great interest as it may be related to the asymmetry between matter and anti-matter particles in the universe. However, the search for them has proven to be a difficult one. Neutrino-less Double Beta decay (NLDB) offers a possible opportunity for direct observation of a Majorana Fermion. The rate for NLDB decay may be as low as 1 count / ton / year . Current detector technologies have background rates between 4 to 300 count / ton / year / ROI which is much larger than the universal goal of 0 . 1 count / ton / year / ROI desired for ton-scale detectors. The premise of my research is to develop new detector technologies that will allow for a background-free experiment. My current work is to develop a sensor that will tag the daughter ion Ba++ from the Xe136 decay. The development of a sensor that is sensitive to single barium ion detection based on the single molecule fluorescence imaging technique is the major focus of this work. If successful, this could provide a path to a background-free experiment.

Beta-Delayed Neutron Spectroscopy with Trapped Fission Products

NASA Astrophysics Data System (ADS)

Czeszumska, A.; Scielzo, N. D.; Norman, E. B.; Savard, G.; Aprahamian, A.; Burkey, M.; Caldwell, S. A.; Chiara, C. J.; Clark, J. A.; Harker, J.; Marley, S. T.; Morgan, G.; Orford, R.; Padgett, S.; Perez Galvan, A.; Segel, R. E.; Sharma, K. S.; Siegl, K.; Strauss, S.; Yee, R. M.

2014-09-01

Characterizing β-delayed neutron emission (βn) is of importance in reactor safety modeling, understanding of r-process nucleosynthesis, and nuclear structure studies. A newly developed technique enables a reliable measurement of βn branching ratios and neutron energy spectra without directly detecting neutrons. Ions of interest are loaded into a Paul trap surrounded by an array of radiation detectors. Upon decay, recoiling daughter nuclei and emitted particles emerge from the center of the trap with minimal scattering. The neutron energy is then determined from the time-of-flight, and hence momentum, of the recoiling ions. I will explain the details of the technique, and present the results from the most recent experimental campaign at the CARIBU facility at Argonne National Laboratory. Characterizing β-delayed neutron emission (βn) is of importance in reactor safety modeling, understanding of r-process nucleosynthesis, and nuclear structure studies. A newly developed technique enables a reliable measurement of βn branching ratios and neutron energy spectra without directly detecting neutrons. Ions of interest are loaded into a Paul trap surrounded by an array of radiation detectors. Upon decay, recoiling daughter nuclei and emitted particles emerge from the center of the trap with minimal scattering. The neutron energy is then determined from the time-of-flight, and hence momentum, of the recoiling ions. I will explain the details of the technique, and present the results from the most recent experimental campaign at the CARIBU facility at Argonne National Laboratory. This work was supported under contracts DE-NA0000979 (NSSC), DE-AC52-07NA27344 (LLNL), DE-AC02-06CH11357 (ANL), DE-FG02-94ER40834 (U. Maryland), DE-FG02-98ER41086 (Northwestern U.), NSERC, Canada, under Application No. 216974, and DHS.

The role of singlet oxygen and oxygen concentration in photodynamic inactivation of bacteria

PubMed Central

Maisch, Tim; Baier, Jürgen; Franz, Barbara; Maier, Max; Landthaler, Michael; Szeimies, Rolf-Markus; Bäumler, Wolfgang

2007-01-01

New antibacterial strategies are required in view of the increasing resistance of bacteria to antibiotics. One promising technique involves the photodynamic inactivation of bacteria. Upon exposure to light, a photosensitizer in bacteria can generate singlet oxygen, which oxidizes proteins or lipids, leading to bacteria death. To elucidate the oxidative processes that occur during killing of bacteria, Staphylococcus aureus was incubated with a standard photosensitizer, and the generation and decay of singlet oxygen was detected directly by its luminescence at 1,270 nm. At low bacterial concentrations, the time-resolved luminescence of singlet oxygen showed a decay time of 6 ± 2 μs, which is an intermediate time for singlet oxygen decay in phospholipids of membranes (14 ± 2 μs) and in the surrounding water (3.5 ± 0.5 μs). Obviously, at low bacterial concentrations, singlet oxygen had sufficient access to water outside of S. aureus by diffusion. Thus, singlet oxygen seems to be generated in the outer cell wall areas or in adjacent cytoplasmic membranes of S. aureus. In addition, the detection of singlet oxygen luminescence can be used as a sensor of intracellular oxygen concentration. When singlet oxygen luminescence was measured at higher bacterial concentrations, the decay time increased significantly, up to ≈40 μs, because of oxygen depletion at these concentrations. This observation is an important indicator that oxygen supply is a crucial factor in the efficacy of photodynamic inactivation of bacteria, and will be of particular significance should this approach be used against multiresistant bacteria. PMID:17431036

Detection system for neutron β decay correlations in the UCNB and Nab experiments

DOE PAGES

Broussard, L. J.; Oak Ridge National Lab.; Zeck, B. A.; ...

2016-12-19

Here, we describe a detection system designed to precisely measure multiple correlations in neutron β decay. Furthermore, the system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications of energy thresholds below 10 keV, energy resolution of ~3 keV FWHM, and rise time of ~50 ns with 19 of the 127 detector pixels instrumented. We have demonstrated the coincident detection of β particles and recoil protons from neutron β decay, using ultracold neutrons at the Los Alamos Neutron Science Center, . The fully instrumented detection system willmore » be implemented in the UCNB and Nab experiments, to determine the neutron β decay parameters B, a, and b.« less

Detection of solar events

DOEpatents

Fischbach, Ephraim; Jenkins, Jere

2013-08-27

A flux detection apparatus can include a radioactive sample having a decay rate capable of changing in response to interaction with a first particle or a field, and a detector associated with the radioactive sample. The detector is responsive to a second particle or radiation formed by decay of the radioactive sample. The rate of decay of the radioactive sample can be correlated to flux of the first particle or the field. Detection of the first particle or the field can provide an early warning for an impending solar event.

Detection of neutrinos

DOEpatents

Fischbach, Ephraim; Jenkins, Jere

2016-05-10

A flux detection apparatus can include a radioactive sample having a decay rate capable of changing in response to interaction with a first particle or a field, and a detector associated with the radioactive sample. The detector is responsive to a second particle or radiation formed by decay of the radioactive sample. The rate of decay of the radioactive sample can be correlated to flux of the first particle or the field. Detection of the first particle or the field can provide an early warning for an impending solar event.

Detection of neutrinos

DOEpatents

Fischbach, Ephraim; Jenkins, Jere

2014-02-04

A flux detection apparatus can include a radioactive sample having a decay rate capable of changing in response to interaction with a first particle or a field, and a detector associated with the radioactive sample. The detector is responsive to a second particle or radiation formed by decay of the radioactive sample. The rate of decay of the radioactive sample can be correlated to flux of the first particle or the field. Detection of the first particle or the field can provide an early warning for an impending solar event.

Detection of neutrinos, antineutrinos, and neutrino-like particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischbach, Ephraim

An apparatus for detecting the presence of a nuclear reactor by the detection of antineutrinos from the reactor can include a radioactive sample having a measurable nuclear activity level and a decay rate capable of changing in response to the presence of antineutrinos, and a detector associated with the radioactive sample. The detector is responsive to at least one of a particle or radiation formed by decay of the radioactive sample. A processor associated with the detector can correlate rate of decay of the radioactive sample to a flux of the antineutrinos to detect the reactor.

Whole-cell biosensor of cellobiose and application to wood decay detection.

PubMed

Toussaint, Maxime; Bontemps, Cyril; Besserer, Arnaud; Hotel, Laurence; Gérardin, Philippe; Leblond, Pierre

2016-12-10

Fungal biodegradation of wood is one of the main threats regarding its use as a material. So far, the detection of this decaying process is empirically assessed by loss of mass, when the fungal attack is advanced and woody structure already damaged. Being able to detect fungal attack on wood in earlier steps is thus of special interest for the wood economy. In this aim, we designed here a new diagnostic tool for wood degradation detection based on the bacterial whole-cell biosensor technology. It was designed in diverting the soil bacteria Streptomyces CebR sensor system devoted to cellobiose detection, a cellulolytic degradation by-product emitted by lignolytic fungi since the onset of wood decaying process. The conserved regulation scheme of the CebR system among Streptomyces allowed constructing a molecular tool easily transferable in different strains or species and enabling the screen for optimal host strains for cellobiose detection. Assays are performed in microplates using one-day culture lysates. Diagnostic is performed within one hour by a spectrophotometric measuring of the cathecol deshydrogenase activity. The selected biosensor was able to detect specifically cellobiose at concentrations similar to those measured in decaying wood and in a spruce leachate attacked by a lignolytic fungus, indicating a high potential of applicability to detect ongoing wood decay process. Copyright © 2016 Elsevier B.V. All rights reserved.

Infrared light sensor applied to early detection of tooth decay

NASA Astrophysics Data System (ADS)

Benjumea, Eberto; Espitia, José; Díaz, Leonardo; Torres, Cesar

2017-08-01

The approach dentistry to dental care is gradually shifting to a model focused on early detection and oral-disease prevention; one of the most important methods of prevention of tooth decay is opportune diagnosis of decay and reconstruction. The present study aimed to introduce a procedure for early diagnosis of tooth decay and to compare result of experiment of this method with other common treatments. In this setup, a laser emitting infrared light is injected in core of one bifurcated fiber-optic and conduced to tooth surface and with the same bifurcated fiber the radiation reflected for the same tooth is collected and them conduced to surface of sensor that measures thermal and light frequencies to detect early signs of decay below a tooth surface, where demineralization is difficult to spot with x-ray technology. This device will can be used to diagnose tooth decay without any chemicals and rays such as high power lasers or X-rays.

A modular positron camera for the study of industrial processes

NASA Astrophysics Data System (ADS)

Leadbeater, T. W.; Parker, D. J.

2011-10-01

Positron imaging techniques rely on the detection of the back-to-back annihilation photons arising from positron decay within the system under study. A standard technique, called positron emitting particle tracking (PEPT) [1], uses a number of these detected events to rapidly determine the position of a positron emitting tracer particle introduced into the system under study. Typical applications of PEPT are in the study of granular and multi-phase materials in the disciplines of engineering and the physical sciences. Using components from redundant medical PET scanners a modular positron camera has been developed. This camera consists of a number of small independent detector modules, which can be arranged in custom geometries tailored towards the application in question. The flexibility of the modular camera geometry allows for high photon detection efficiency within specific regions of interest, the ability to study large and bulky systems and the application of PEPT to difficult or remote processes as the camera is inherently transportable.

X-ray detection capability of a BaCl{sub 2} single crystal scintillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koshimizu, Masanori; CREST, Japan Science and Technology Agency, Sanbancho, Chiyoda-ku, Tokyo 102-0075; Onodera, Kazuya

2012-01-15

The x-ray detection capability of a scintillation detector equipped with a BaCl{sub 2} single crystal was evaluated. The scintillation decay kinetics can be expressed by a sum of two exponential decay components. The fast and slow components have lifetimes of 1.5 and 85 ns, respectively. The total light output is 5% that of YAP:Ce. A subnanosecond timing resolution was obtained. The detection efficiency of a 67.41 keV x-ray is 87% for a detector equipped with a BaCl{sub 2} crystal 6-mm thick. Thus, excellent timing resolution and high detection efficiency can be simultaneously achieved. Additionally, luminescence decay characteristics under vacuum ultravioletmore » excitation have been investigated. Radiative decay of self-trapped excitons is thought to be responsible for the fast scintillation component.« less

Detection and Identification of Decay Fungi in Spruce Wood by Restriction Fragment Length Polymorphism Analysis of Amplified Genes Encoding rRNA†

PubMed Central

Jasalavich, Claudia A.; Ostrofsky, Andrea; Jellison, Jody

2000-01-01

We have developed a DNA-based assay to reliably detect brown rot and white rot fungi in wood at different stages of decay. DNA, isolated by a series of CTAB (cetyltrimethylammonium bromide) and organic extractions, was amplified by the PCR using published universal primers and basidiomycete-specific primers derived from ribosomal DNA sequences. We surveyed 14 species of wood-decaying basidiomycetes (brown-rot and white-rot fungi), as well as 25 species of wood-inhabiting ascomycetes (pathogens, endophytes, and saprophytes). DNA was isolated from pure cultures of these fungi and also from spruce wood blocks colonized by individual isolates of wood decay basidiomycetes or wood-inhabiting ascomycetes. The primer pair ITS1-F (specific for higher fungi) and ITS4 (universal primer) amplified the internal transcribed spacer region from both ascomycetes and basidiomycetes from both pure culture and wood, as expected. The primer pair ITS1-F (specific for higher fungi) and ITS4-B (specific for basidiomycetes) was shown to reliably detect the presence of wood decay basidiomycetes in both pure culture and wood; ascomycetes were not detected by this primer pair. We detected the presence of decay fungi in wood by PCR before measurable weight loss had occurred to the wood. Basidiomycetes were identified to the species level by restriction fragment length polymorphisms of the internal transcribed spacer region. PMID:11055916

Tumor detection in mice by measurement of fluorescence decay time matrices

NASA Astrophysics Data System (ADS)

Cubeddu, R.; Pifferi, A.; Taroni, P.; Valentini, G.; Canti, G.

1995-12-01

An intensified CCD video camera has been used to measure the spatial distribution of the fluorescence decay time in tumor-bearing mice sensitized with hematoporphyrin derivative. Mice were injected with five doses of sensitizer, ranging from 0.1 to 10 mg / kg body weight. For any drug dose the decay time of the exogenous fluorescence in the tumor is always significantly longer than in normal tissues. The image created by associating a gray-shade scale to the decay time matrix of each mouse permits a reliable and precise detection of the neoplasia.

Measurement of ortho-positronium properties in liquid scintillators

NASA Astrophysics Data System (ADS)

Perasso, S.; Consolati, G.; Franco, D.; Jollet, C.; Meregaglia, A.; Tonazzo, A.; Yeh, M.

2014-03-01

Pulse shape discrimination is a well-established technique for background rejection in liquid scintillator detectors. It is particularly effective in separating heavy particles from light particles, but not in distinguishing electrons from positrons. This inefficiency can be overtaken by exploiting the formation of ortho-positronium (o-Ps), which alters the time profile of light pulses induced by positrons. We characterized the o-Ps properties in the most commonly used liquid scintillators, i.e. PC, PXE, LAB, OIL and PC + PPO. In addition, we studied the effects of scintillator doping on the o-Ps properties for dopants used in neutrino-less double beta decay experiments (Nd and Te) and in anti-neutrino and neutron detection (Gd and Li respectively). We found that the o-Ps properties are similar in all the tested scintillators, with a lifetime around 3 ns and a formation probability of about 50%. This result indicates that an o-Ps-enhanced pulse shape discrimination can be applied in liquid scintillator detectors for neutrino and anti-neutrino detection and for neutrino-less double beta decay search.

[Rapid measurement of trace mercury in aqueous solutions with optical-electrical dual pulse LIBS technique].

PubMed

Zhang, Qian; Xiong, Wei; Chen, Yu-Qi; Li, Run-Hua

2011-02-01

A wood slice was used as absorber to transfer liquid sample to solid sample in order to solve the problems existing in directly analyzing aqueous solutions with laser-induced breakdown spectroscopy (LIBS). An optical-electrical dual pulse LIBS (OEDP-LIBS) technique was first used to enhance atomic emission of mercury in laser-induced plasma. The calibration curves of mercury were obtained by typical single pulse LIBS and OEDP-LIBS techniques. The limit of detection (LOD) of mercury in these two techniques reaches 2.4 and 0.3 mg x L(-1), respectively. Under current experimental conditions, the time-integrated a tomic emission of mercury at 253.65 nm was enhanced 50 times and the LOD of mercury was improved by one order, if comparing OEDP-LIBS to single pulse LIBS. The required time for a whole analysis process is less than 5 minutes. As the atomic emission of mercury decays slowly while increasing the delay time between electrical pulse and laser pulse, increasing the electrical pulse width can further enhance the time integrated intensity of mercury emission and improve the detection sensitivity of mercury by OEDP-LIBS technique.

Fractionating power and outlet stream polydispersity in asymmetrical flow field-flow fractionation. Part II: programmed operation.

PubMed

Williams, P Stephen

2017-01-01

Asymmetrical flow field-flow fractionation (As-FlFFF) is a widely used technique for analyzing polydisperse nanoparticle and macromolecular samples. The programmed decay of cross flow rate is often employed. The interdependence of the cross flow rate through the membrane and the fluid flow along the channel length complicates the prediction of elution time and fractionating power. The theory for their calculation is presented. It is also confirmed for examples of exponential decay of cross flow rate with constant channel outlet flow rate that the residual sample polydispersity at the channel outlet is quite well approximated by the reciprocal of four times the fractionating power. Residual polydispersity is of importance when online MALS or DLS detection are used to extract quantitative information on particle size or molecular weight. The theory presented here provides a firm basis for the optimization of programmed flow conditions in As-FlFFF. Graphical abstract Channel outlet polydispersity remains significant following fractionation by As-FlFFF under conditions of programmed decay of cross flow rate.

pH and chloride recordings in living cells using two-photon fluorescence lifetime imaging microscopy

NASA Astrophysics Data System (ADS)

Lahn, Mattes; Hille, Carsten; Koberling, Felix; Kapusta, Peter; Dosche, Carsten

2010-02-01

Today fluorescence lifetime imaging microscopy (FLIM) has become an extremely powerful technique in life sciences. The independency of the fluorescence decay time on fluorescence dye concentration and emission intensity circumvents many artefacts arising from intensity based measurements. To minimize cell damage and improve scan depth, a combination with two-photon (2P) excitation is quite promising. Here, we describe the implementation of a 2P-FLIM setup for biological applications. For that we used a commercial fluorescence lifetime microscope system. 2P-excitation at 780nm was achieved by a non-tuneable, but inexpensive and easily manageable mode-locked fs-fiber laser. Time-resolved fluorescence image acquisition was performed by objective-scanning with the reversed time-correlated single photon counting (TCSPC) technique. We analyzed the suitability of the pH-sensitive dye BCECF and the chloride-sensitive dye MQAE for recordings in an insect tissue. Both parameters are quite important, since they affect a plethora of physiological processes in living tissues. We performed a straight forward in situ calibration method to link the fluorescence decay time with the respective ion concentration and carried out spatially resolved measurements under resting conditions. BCECF still offered only a limited dynamic range regarding fluorescence decay time changes under physiologically pH values. However, MQAE proofed to be well suited to record chloride concentrations in the physiologically relevant range. Subsequently, several chloride transport pathways underlying the intracellular chloride homeostasis were investigated pharmacologically. In conclusion, 2P-FLIM is well suited for ion detection in living tissues due to precise and reproducible decay time measurements in combination with reduced cell and dye damages.

Neutron activation analyses and half-life measurements at the usgs triga reactor

NASA Astrophysics Data System (ADS)

Larson, Robert E.

Neutron activation of materials followed by gamma spectroscopy using high-purity germanium detectors is an effective method for making measurements of nuclear beta decay half-lives and for detecting trace amounts of elements present in materials. This research explores applications of neutron activation analysis (NAA) in two parts. Part 1. High Precision Methods for Measuring Decay Half-Lives, Chapters 1 through 8 Part one develops research methods and data analysis techniques for making high precision measurements of nuclear beta decay half-lives. The change in the electron capture half-life of 51Cr in pure chromium versus chromium mixed in a gold lattice structure is explored, and the 97Ru electron capture decay half-life are compared for ruthenium in a pure crystal versus ruthenium in a rutile oxide state, RuO2. In addition, the beta-minus decay half-life of 71mZn is measured and compared with new high precision findings. Density Functional Theory is used to explain the measured magnitude of changes in electron capture half-life from changes in the surrounding lattice electron configuration. Part 2. Debris Collection Nuclear Diagnostic at the National Ignition Facility, Chapters 9 through 11 Part two explores the design and development of a solid debris collector for use as a diagnostic tool at the National Ignition Facility (NIF). NAA measurements are performed on NIF post-shot debris collected on witness plates in the NIF chamber. In this application NAA is used to detect and quantify the amount of trace amounts of gold from the hohlraum and germanium from the pellet present in the debris collected after a NIF shot. The design of a solid debris collector based on material x-ray ablation properties is given, and calculations are done to predict performance and results for the collection and measurements of trace amounts of gold and germanium from dissociated hohlraum debris.

Above-ground Antineutrino Detection for Nuclear Reactor Monitoring

DOE PAGES

Sweany, Melinda; Brennan, James S.; Cabrera-Palmer, Belkis; ...

2014-08-01

Antineutrino monitoring of nuclear reactors has been demonstrated many times, however the technique has not as of yet been developed into a useful capability for treaty verification purposes. The most notable drawback is the current requirement that detectors be deployed underground, with at least several meters-water-equivalent of shielding from cosmic radiation. In addition, the deployment of liquid-based detector media presents a challenge in reactor facilities. We are currently developing a detector system that has the potential to operate above ground and circumvent deployment problems associated with a liquid detection media: the system is composed of segments of plastic scintillator surroundedmore » by 6LiF/ZnS:Ag. ZnS:Ag is a radio-luminescent phosphor used to detect the neutron capture products of lithium-6. Because of its long decay time compared to standard plastic scintillators, pulse-shape discrimination can be used to distinguish positron and neutron interactions resulting from the inverse beta decay (IBD) of antineutrinos within the detector volume, reducing both accidental and correlated backgrounds. Segmentation further reduces backgrounds by identifying the positron’s annihilation gammas, which are absent for most correlated and uncorrelated backgrounds. This work explores different configurations in order to maximize the size of the detector segments without reducing the intrinsic neutron detection efficiency. We believe this technology will ultimately be applicable to potential safeguards scenarios such as those recently described.« less

Detecting decay fungi with antibody-based tests and immunoassays

Treesearch

Carol A. Clausen

2003-01-01

Early detection of wood decay can prolong the service life of wood. Antibodies are the ideal probe for detecting fungi that cause biodeterioration because they are highly specific and can quantitatively determine the fungal antigen concentration from highly complex structures, such as wood. Polyclonal antibodies recognize multiple chemical sites of the targeted...

Side-detecting optical fiber coated with Zn(OH)2 nanorods for ultraviolet sensing applications

NASA Astrophysics Data System (ADS)

Azad, S.; Parvizi, R.; Sadeghi, E.

2017-09-01

This paper presents an improved coupling efficiency and side detecting of UV radiation induced by light scattering and luminescent features of Zn(OH)2 nanorods coated multimode optical fibers. Uniform and high density Zn(OH)2 nanorods were grown hydrothermally on the core of chemically etched multimode optical fibers. The prepared samples were characterized through x-ray diffraction patterns, scanning electron microscopy and photoluminescence spectroscopy. The detecting technique was based on the intensity modulation of the side coupled light through the Zn(OH)2 nanorods. A simple and cost-effective UV radiation detecting setup has been designed. Experimentally estimated coupling efficiency of the proposed setup was obtained near 11%. The proposed device exhibited stable and reversible responses with a fast rising and decaying time of about 1.4 s and 0.85 s, respectively.

Above-ground antineutrino detection for nuclear reactor monitoring

NASA Astrophysics Data System (ADS)

Sweany, M.; Brennan, J.; Cabrera-Palmer, B.; Kiff, S.; Reyna, D.; Throckmorton, D.

2015-01-01

Antineutrino monitoring of nuclear reactors has been demonstrated many times (Klimov et al., 1994 [1]; Bowden et al., 2009 [2]; Oguri et al., 2014 [3]), however the technique has not as of yet been developed into a useful capability for treaty verification purposes. The most notable drawback is the current requirement that detectors be deployed underground, with at least several meters-water-equivalent of shielding from cosmic radiation. In addition, the deployment of liquid-based detection media presents a challenge in reactor facilities. We are currently developing a detector system that has the potential to operate above ground and circumvent deployment problems associated with a liquid detection media: the system is composed of segments of plastic scintillator surrounded by 6LiF/ZnS:Ag. ZnS:Ag is a radio-luminescent phosphor used to detect the neutron capture products of 6Li. Because of its long decay time compared to standard plastic scintillators, pulse-shape discrimination can be used to distinguish positron and neutron interactions resulting from the inverse beta decay (IBD) of antineutrinos within the detector volume, reducing both accidental and correlated backgrounds. Segmentation further reduces backgrounds by identifying the positron's annihilation gammas, a signature that is absent for most correlated and uncorrelated backgrounds. This work explores different configurations in order to maximize the size of the detector segments without reducing the intrinsic neutron detection efficiency. We believe that this technology will ultimately be applicable to potential safeguards scenarios such as those recently described by Huber et al. (2014) [4,5].

Detection of fissionable material in cargo containers using active neutron interrogation

NASA Astrophysics Data System (ADS)

Church, Jennifer

2006-10-01

Roughly 6 million cargo containers will be shipped to U.S. seaports in a single year, each container carrying up to 30 tons of freight in varied configurations. Highly enriched uranium and other fissionable material concealed inside these containers is a challenge for existing portal monitors, due in part to the attenuation of signals in the cargo. A system is currently being developed to overcome these challenges without slowing the flow of commerce through the port, keeping the likelihood of false-negative and false- positive detections to a minimum. The technique utilizes a neutron beam to induce fission, and a wall of plastic scintillators to detect subsequent delayed high-energy γ- rays after β-decay of the fission products Decay curves utilizing these delayed γ-rays with energies above 3 MeV are an efficient diagnostic. New experimental work using a 3-7 MeV broad spectrum neutron source will be presented and compared to simulations and past experimental results. This work is performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory contract No. W-7405-Eng-4, UCRL-ABS-219231. E.B.,orman et al., Nucl. Instr. Methods Phys. Res. A, 521, 608 (2004).

The NUMEN project: NUclear Matrix Elements for Neutrinoless double beta decay

NASA Astrophysics Data System (ADS)

Cappuzzello, F.; Agodi, C.; Cavallaro, M.; Carbone, D.; Tudisco, S.; Lo Presti, D.; Oliveira, J. R. B.; Finocchiaro, P.; Colonna, M.; Rifuggiato, D.; Calabretta, L.; Calvo, D.; Pandola, L.; Acosta, L.; Auerbach, N.; Bellone, J.; Bijker, R.; Bonanno, D.; Bongiovanni, D.; Borello-Lewin, T.; Boztosun, I.; Brunasso, O.; Burrello, S.; Calabrese, S.; Calanna, A.; Chávez Lomelí, E. R.; D'Agostino, G.; De Faria, P. N.; De Geronimo, G.; Delaunay, F.; Deshmukh, N.; Ferreira, J. L.; Fisichella, M.; Foti, A.; Gallo, G.; Garcia-Tecocoatzi, H.; Greco, V.; Hacisalihoglu, A.; Iazzi, F.; Introzzi, R.; Lanzalone, G.; Lay, J. A.; La Via, F.; Lenske, H.; Linares, R.; Litrico, G.; Longhitano, F.; Lubian, J.; Medina, N. H.; Mendes, D. R.; Moralles, M.; Muoio, A.; Pakou, A.; Petrascu, H.; Pinna, F.; Reito, S.; Russo, A. D.; Russo, G.; Santagati, G.; Santopinto, E.; Santos, R. B. B.; Sgouros, O.; da Silveira, M. A. G.; Solakci, S. O.; Souliotis, G.; Soukeras, V.; Spatafora, A.; Torresi, D.; Magana Vsevolodovna, R.; Yildirim, A.; Zagatto, V. A. B.

2018-05-01

The article describes the main achievements of the NUMEN project together with an updated and detailed overview of the related R&D activities and theoretical developments. NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of heavy-ion induced Double Charge Exchange (DCE) reactions. Despite the fact that the two processes, namely neutrinoless double beta decay and DCE reactions, are triggered by the weak and strong interaction respectively, important analogies are suggested. The basic point is the coincidence of the initial and final state many-body wave functions in the two types of processes and the formal similarity of the transition operators. First experimental results obtained at the INFN-LNS laboratory for the 40Ca(18O,18Ne)40Ar reaction at 270MeV give an encouraging indication on the capability of the proposed technique to access relevant quantitative information. The main experimental tools for this project are the K800 Superconducting Cyclotron and MAGNEX spectrometer. The former is used for the acceleration of the required high resolution and low emittance heavy-ion beams and the latter is the large acceptance magnetic spectrometer for the detection of the ejectiles. The use of the high-order trajectory reconstruction technique, implemented in MAGNEX, allows to reach the experimental resolution and sensitivity required for the accurate measurement of the DCE cross sections at forward angles. However, the tiny values of such cross sections and the resolution requirements demand beam intensities much larger than those manageable with the present facility. The on-going upgrade of the INFN-LNS facilities in this perspective is part of the NUMEN project and will be discussed in the article.

New Technique for Barium Daughter Ion Identification in a Liquid Xe-136 Double Beta Decay Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fairbank, William

2016-06-08

This work addresses long-standing issues of fundamental interest in elementary particle physics. The most important outcome of this work is a new limit on neutrinoless double beta decay. This is an extremely rare and long-sought-after type of radioactive decay. If discovered, it would require changes in the standard model of the elementary constituents of matter, and would prove that neutrinos and antineutrinos are the same, a revolutionary concept in particle physics. Neutrinos are major components of the matter in the universe that are so small and so weakly interacting with other matter that their masses have not yet been discovered.more » A discovery of neutrinoless double beta decay could help determine the neutrino masses. An important outcome of the work on this project was the Colorado State University role in operating the EXO-200 neutrinoless double beta decay experiment and in analysis of the data from this experiment. One type of double beta decay of the isotope 136Xe, the two-neutrino variety, was discovered in this work. Although the other type of double beta decay, the neutrinoless variety, was not yet discovered in this work, a world’s best sensitivity of 1.9x10 25 year half-life was obtained. This result rules out a previous claim of a positive result in a different isotope. This work also establishes that the masses of the neutrinos are less than one millionth of that of electrons. A unique EXO-200 analysis, in which the CSU group had a leading role, has established for the first time ever in a liquid noble gas the fraction of daughter atoms from alpha and beta decay that are ionized. This result has important impact on other pending studies, including nucleon decay and barium tagging. Novel additional discoveries include multiphoton ionization of liquid xenon with UV pulsed lasers, which may find application in calibration of future noble liquid detectors, and studies of association and dissociation reactions of Ba + ions in gaseous xenon. Through this project, we are substantially closer to demonstrating “barium tagging”, i.e., detection of single daughter 136Ba atoms from 136Xe double beta decay. Milestones achieved include obtaining spectra of small numbers of Ba atoms and cryoprobe advances toward trapping single 136Ba atoms in solid xenon and probe extraction for detection. One of the other benefits to society is the training of six Ph.D. students in a variety of state-of-the-art technologies, half under primary support of this grant and half with partial support, with four finishing their Ph.D. degrees and two well on their way.« less

Coherent Anti-Stokes Raman Scattering Spectroscopy of Single Molecules in Solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sunney Xie, Wei Min, Chris Freudiger, Sijia Lu

2012-01-18

During this funding period, we have developed two breakthrough techniques. The first is stimulated Raman scattering microscopy, providing label-free chemical contrast for chemical and biomedical imaging based on vibrational spectroscopy. Spontaneous Raman microscopy provides specific vibrational signatures of chemical bonds, but is often hindered by low sensitivity. We developed a three-dimensional multiphoton vibrational imaging technique based on stimulated Raman scattering (SRS). The sensitivity of SRS imaging is significantly greater than that of spontaneous Raman microscopy, which is achieved by implementing high-frequency (megahertz) phase-sensitive detection. SRS microscopy has a major advantage over previous coherent Raman techniques in that it offers background-freemore » and readily interpretable chemical contrast. We demonstrated a variety of biomedical applications, such as differentiating distributions of omega-3 fatty acids and saturated lipids in living cells, imaging of brain and skin tissues based on intrinsic lipid contrast, and monitoring drug delivery through the epidermis. This technology offers exciting prospect for medical imaging. The second technology we developed is stimulated emission microscopy. Many chromophores, such as haemoglobin and cytochromes, absorb but have undetectable fluorescence because the spontaneous emission is dominated by their fast non-radiative decay. Yet the detection of their absorption is difficult under a microscope. We use stimulated emission, which competes effectively with the nonradiative decay, to make the chromophores detectable, as a new contrast mechanism for optical microscopy. We demonstrate a variety of applications of stimulated emission microscopy, such as visualizing chromoproteins, non-fluorescent variants of the green fluorescent protein, monitoring lacZ gene expression with a chromogenic reporter, mapping transdermal drug distribu- tions without histological sectioning, and label-free microvascular imaging based on endogenous contrast of haemoglobin. For all these applications, sensitivity is orders of magnitude higher than for spontaneous emission or absorption contrast, permitting nonfluorescent reporters for molecular imaging. Although we did not accomplish the original goal of detecting single-molecule by CARS, our quest for high sensitivity of nonlinear optical microscopy paid off in providing the two brand new enabling technologies. Both techniques were greatly benefited from the use of high frequency modulation for microscopy, which led to orders of magnitude increase in sensitivity. Extensive efforts have been made on optics and electronics to accomplish these breakthroughs.« less

Protecting log cabins from decay

Treesearch

R. M. Rowell; J. M. Black; L. R. Gjovik; W. C. Feist

1977-01-01

This report answers the questions most often asked of the Forest Service on the protection of log cabins from decay, and on practices for the exterior finishing and maintenance of existing cabins. Causes of stain and decay are discussed, as are some basic techniques for building a cabin that will minimize decay. Selection and handling of logs, their preservative...

Flash lamp-excited time-resolved fluorescence microscope suppresses autofluorescence in water concentrates to deliver an 11-fold increase in signal-to-noise ratio.

PubMed

Connally, Russell; Veal, Duncan; Piper, James

2004-01-01

The ubiquity of naturally fluorescing components (autofluorophores) encountered in most biological samples hinders the detection and identification of labeled targets through fluorescence-based techniques. Time-resolved fluorescence (TRF) is a technique by which the effects of autofluorescence are reduced by using specific fluorescent labels with long fluorescence lifetimes (compared with autofluorophores) in conjunction with time-gated detection. A time-resolved fluorescence microscope (TRFM) is described that is based on a standard epifluorescence microscope modified by the addition of a pulsed excitation source and an image-intensified time-gateable CCD camera. The choice of pulsed excitation source for TRFM has a large impact on the price and performance of the instrument. A flash lamp with rapid discharge characteristics was selected for our instrument because of the high spectral energy in the UV region and short pulse length. However, the flash output decayed with an approximate lifetime of 18 micros and the TRFM required a long-lived lanthanide chelate label to ensure that probe fluorescence was visible after decay of the flash plasma. We synthesized a recently reported fluorescent chelate (BHHCT) and conjugated it to a monoclonal antibody directed against the waterborne parasite Giardia lamblia. For a 600-nm bandpass filter set and a gate delay of 60 micros, the TRFM provided an 11.3-fold improvement in the signal-to-noise ratio (S/N) of labeled Giardia over background. A smaller gain in an SNR of 9.69-fold was achieved with a 420-nm longpass filter set; however, the final contrast ratio between labeled cyst and background was higher (11.3 versus 8.5). Despite the decay characteristics of the light pulse, flash lamps have many practical advantages compared with optical chopper wheels and modulated lasers for applications in TRFM.

Decay assessment through thermographic analysis in architectural and archaeological heritage

NASA Astrophysics Data System (ADS)

Gomez-Heras, Miguel; Martinez-Perez, Laura; Fort, Rafael; Alvarez de Buergo, Monica

2010-05-01

Any exposed stone-built structure is subject to thermal variations due to daily, seasonal and secular environmental temperature changes. Surface temperature is a function of air temperature (due to convective heat transfer) and of infrared radiation received through insolation. While convective heat transfer homogenizes surface temperature, stone response to insolation is much more complex and the temporal and spatial temperature differences across structures are enhanced. Surface temperature in stone-built structures will be affected by orientation, sunlight inclination and the complex patterns of light and shadows generated by the often intricate morphology of historical artefacts and structures. Surface temperature will also be affected by different material properties, such as albedo, thermal conductivity, transparency and absorbance to infrared radiation of minerals and rocks. Moisture and the occurrence of salts will also be a factor affecting surface temperatures. Surface temperatures may as well be affected by physical disruptions of rocks due to differences in thermal inertia generated by cracks and other discontinuities. Thermography is a non-invasive, non-destructive technique that measures temperature variations on the surface of a material. With this technique, surface temperature rates of change and their spatial variations can be analysed. This analysis may be used not only to evaluate the incidence of thermal decay as a factor that generates or enhances stone decay, but also to detect and evaluate other factors that affect the state of conservation of architectural and archaeological heritage, as for example moisture, salts or mechanical disruptions.

Vacuum decay container/closure integrity testing technology. Part 2. Comparison to dye ingress tests.

PubMed

Wolf, Heinz; Stauffer, Tony; Chen, Shu-Chen Y; Lee, Yoojin; Forster, Ronald; Ludzinski, Miron; Kamat, Madhav; Mulhall, Brian; Guazzo, Dana Morton

2009-01-01

Part 1 of this series demonstrated that a container closure integrity test performed according to ASTM F2338-09 Standard Test Method for Nondestructive Detection of Leaks in Packages by Vacuum Decay Method using a VeriPac 325/LV vacuum decay leak tester by Packaging Technologies & Inspection, LLC (PTI) is capable of detecting leaks > or = 5.0 microm (nominal diameter) in rigid, nonporous package systems, such as prefilled glass syringes. The current study compared USP, Ph.Eur. and ISO dye ingress integrity test methods to PTI's vacuum decay technology for the detection of these same 5-, 10-, and 15-microm laser-drilled hole defects in 1-mL glass prefilled syringes. The study was performed at three test sites using several inspectors and a variety of inspection conditions. No standard dye ingress method was found to reliably identify all holed syringes. Modifications to these standard dye tests' challenge conditions increased the potential for dye ingress, and adjustments to the visual inspection environment improved dye ingress detection. However, the risk of false positive test results with dye ingress tests remained. In contrast, the nondestructive vacuum decay leak test method reliably identified syringes with holes > or = 5.0 microm.

Radiative decay of neutron-unbound intruder states in 19O

NASA Astrophysics Data System (ADS)

Dungan, R.; Tabor, S. L.; Tripathi, Vandana; Volya, A.; Kravvaris, K.; Abromeit, B.; Caussyn, D. D.; Morrow, S.; Parker, J. J.; Tai, P.-L.; VonMoss, J. M.

2016-02-01

The 9Be(14C, α γ ) reaction at EL a b=30 and 35 MeV was used to study excited states of 19O. The Florida State University (FSU) γ detector array was used to detect γ radiation in coincidence with charged particles detected and identified with a silicon Δ E -E particle telescope. γ decays have been observed for the first time from six states ranging from 368 to 2147 keV above the neutron separation energy (Sn=3962 keV) in 19O. The γ -decaying states are interspersed among states previously observed to decay by neutron emission. The ability of electromagnetic decay to compete successfully with neutron decay is explained in terms of neutron angular momentum barriers and small spectroscopic factors implying higher spin and complex structure for these intruder states. These results illustrate the need for complementary experimental approaches to best illuminate the complete nuclear structure.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adrián-Martínez, S.; Albert, A.; André, M.

A search for Secluded Dark Matter annihilation in the Sun using 2007–2012 data of the ANTARES neutrino telescope is presented. Three different cases are considered: a) detection of dimuons that result from the decay of the mediator, or neutrino detection from: b) mediator that decays into a dimuon and, in turn, into neutrinos, and c) mediator that decays directly into neutrinos. As no significant excess over background is observed, constraints are derived on the dark matter mass and the lifetime of the mediator.

Pulse-shape discrimination techniques for the COBRA double beta-decay experiment at LNGS

NASA Astrophysics Data System (ADS)

Zatschler, S.; COBRA Collaboration

2017-09-01

In modern elementary particle physics several questions arise from the fact that neutrino oscillation experiments have found neutrinos to be massive. Among them is the so far unknown nature of neutrinos: either they act as so-called Majorana particles, where one cannot distinguish between particle and antiparticle, or they are Dirac particles like all the other fermions in the Standard Model. The study of neutrinoless double beta-decay (0νββ-decay), where the lepton number conservation is violated by two units, could answer the question regarding the underlying nature of neutrinos and might also shed light on the mechanism responsible for the mass generation. So far there is no experimental evidence for the existence of 0νββ-decay, hence, existing experiments have to be improved and novel techniques should be explored. One of the next-generation experiments dedicated to the search for this ultra-rare decay is the COBRA experiment. This article gives an overview of techniques to identify and reject background based on pulse-shape discrimination.

Current Status and Future Perspectives of the LUCIFER Experiment

DOE PAGES

Beeman, J. W.; Bellini, F.; Benetti, P.; ...

2013-09-30

In the field of fundamental particle physics, the neutrino has become more and more important in the last few years, since the discovery of its mass. In particular, the ultimate nature of the neutrino (if it is a Dirac or a Majorana particle) plays a crucial role not only in neutrino physics, but also in the overall framework of fundamental particle interactions and in cosmology. The only way to disentangle its ultimate nature is to search for the neutrinoless double beta decay. The idea of LUCIFER is to combine the bolometric technique proposed for the CUORE experiment with the bolometricmore » light detection technique used in cryogenic dark matter experiments. The bolometric technique allows an extremely good energy resolution while its combination with the scintillation detection offers an ultimate tool for background rejection. The goal of LUCIFER is not only to build a background-free small-scale experiment but also to directly prove the potentiality of this technique. Preliminary tests on several detectors containing different interesting DBD emitters have clearly demonstrated the excellent background rejection capabilities that arise from the simultaneous, independent, double readout of heat and scintillation light.« less

a High-Precision Branching-Ratio Measurement for the Superallowed β+ Emitter 74Rb

NASA Astrophysics Data System (ADS)

Dunlop, R.; Chagnon-Lessard, S.; Finlay, P.; Garrett, P. E.; Hadinia, B.; Leach, K. G.; Svensson, C. E.; Wong, J.; Ball, G.; Garnsworthy, A. B.; Glister, J.; Hackman, G.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Leslie, J. R.; Andreoiu, C.; Chester, A.; Cross, D.; Starosta, K.; Yates, S. W.; Zganjar, E. F.

2013-03-01

Precision measurements of superallowed Fermi beta decay allow for tests of the Cabibbo-Kobayashi-Maskawa matrix (CKM) unitarity, the conserved vector current hypothesis, and the magnitude of isospin-symmetry-breaking effects in nuclei. A high-precision measurement of the branching ratio for the β+ decay of 74Rb has been performed at the Isotope Separator and ACcelerator (ISAC) facility at TRIUMF. The 8π spectrometer, an array of 20 close-packed HPGe detectors, was used to detect gamma rays emitted following the decay of 74Rb. PACES, an array of 5 Si(Li) detectors, was used to detect emitted conversion electrons, while SCEPTAR, an array of plastic scintillators, was used to detect emitted beta particles. A total of 51γ rays have been identified following the decay of 21 excited states in the daughter nucleus 74Kr.

Ambiguities in model-independent partial-wave analysis

NASA Astrophysics Data System (ADS)

Krinner, F.; Greenwald, D.; Ryabchikov, D.; Grube, B.; Paul, S.

2018-06-01

Partial-wave analysis is an important tool for analyzing large data sets in hadronic decays of light and heavy mesons. It commonly relies on the isobar model, which assumes multihadron final states originate from successive two-body decays of well-known undisturbed intermediate states. Recently, analyses of heavy-meson decays and diffractively produced states have attempted to overcome the strong model dependences of the isobar model. These analyses have overlooked that model-independent, or freed-isobar, partial-wave analysis can introduce mathematical ambiguities in results. We show how these ambiguities arise and present general techniques for identifying their presence and for correcting for them. We demonstrate these techniques with specific examples in both heavy-meson decay and pion-proton scattering.

CsI-Silicon Particle detector for Heavy ions Orbiting in Storage rings (CsISiPHOS)

NASA Astrophysics Data System (ADS)

Najafi, M. A.; Dillmann, I.; Bosch, F.; Faestermann, T.; Gao, B.; Gernhäuser, R.; Kozhuharov, C.; Litvinov, S. A.; Litvinov, Yu. A.; Maier, L.; Nolden, F.; Popp, U.; Sanjari, M. S.; Spillmann, U.; Steck, M.; Stöhlker, T.; Weick, H.

2016-11-01

A heavy-ion detector was developed for decay studies in the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. This detector serves as a prototype for the in-pocket particle detectors for future experiments with the Collector Ring (CR) at FAIR (Facility for Antiproton and Ion Research). The detector includes a stack of six silicon pad sensors, a double-sided silicon strip detector (DSSD), and a CsI(Tl) scintillation detector. It was used successfully in a recent experiment for the detection of the β+-decay of highly charged 142Pm60+ ions. Based on the ΔE / E technique for particle identification and an energy resolution of 0.9% for ΔE and 0.5% for E (Full Width at Half Maximum (FWHM)), the detector is well-suited to distinguish neighbouring isobars in the region of interest.

Fast quantitative optical detection of heat dissipation by surface plasmon polaritons.

PubMed

Möller, Thomas B; Ganser, Andreas; Kratt, Martina; Dickreuter, Simon; Waitz, Reimar; Scheer, Elke; Boneberg, Johannes; Leiderer, Paul

2018-06-13

Heat management at the nanoscale is an issue of increasing importance. In optoelectronic devices the transport and decay of plasmons contribute to the dissipation of heat. By comparison of experimental data and simulations we demonstrate that it is possible to gain quantitative information about excitation, propagation and decay of surface plasmon polaritons (SPPs) in a thin gold stripe supported by a silicon membrane. The temperature-dependent optical transmissivity of the membrane is used to determine the temperature distribution around the metal stripe with high spatial and temporal resolution. This method is complementary to techniques where the propagation of SPPs is monitored optically, and provides additional information which is not readily accessible by other means. In particular, we demonstrate that the thermal conductivity of the membrane can also be derived from our analysis. The results presented here show the high potential of this tool for heat management studies in nanoscale devices.

Detection of Planets Orbiting Sun-Like Stars

NASA Astrophysics Data System (ADS)

Marcy, Geoffrey W.; Butler, R. Paul

1996-12-01

During the past 11 months, astronomers have finally discovered planets orbiting Sun-like stars. A total of eight planets has been detected by the Doppler technique, and there are possible planets detected by astrometry around one other star. Some of the new planets exhibit properties similar to those in our Solar System. But many of them have properties that were unexpected. Several planets are more massive than Jupiter, and some orbit their host star in orbits smaller than Mercury's orbit. Equally unexpected is that three of these planets have noncircular orbits. Current theory of the formation of planetary systems is challenged to account for these new planetary properties, but several models are emerging, involving gravitational scattering of planetesimals and viscous or tidal decay of orbits. The occurrence rate of true analogs of our Solar System will soon be determined with the detection of long-period gas giants analogous to Jupiter.

Bridgman Growth of Large SrI2:Eu2+ Single Crystals: A High-performance Scintillator for Radiation Detection Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boatner, Lynn A; Ramey, Joanne Oxendine; Kolopus, James A

2013-01-01

Single-crystal strontium iodide (SrI2) doped with relatively high levels (e.g., 3 - 6 %) of Eu2+ exhibits characteristics that make this material superior, in a number of respects, to other scintillators that are currently used for radiation detection. Specifically, SrI2:Eu2+ has a light yield that is significantly higher than LaBr3:Ce3+ -a currently employed commercial high-performance scintillator. Additionally, SrI2:Eu2+ is characterized by an energy resolution as high as 2.6% at the 137Cs gamma-ray energy of 662 keV, and there is no radioactive component in SrI2:Eu2+ - unlike LaBr3:Ce3+ that contains 138La. The Ce3+-doped LaBr3 decay time is, however, faster (30 nsec)more » than the 1.2 sec decay time of SrI2:Eu2+. Due to the relatively low melting point of strontium iodide (~515 oC), crystal growth can be carried out in quartz crucibles by the vertical Bridgman technique. Materials-processing and crystal-growth techniques that are specific to the Bridgman growth of europium-doped strontium iodide scintillators are described here. These techniques include the use of a porous quartz frit to physically filter the molten salt from a quartz antechamber into the Bridgman growth crucible and the use of a bent or bulb grain selector design to suppress multiple grain growth. Single crystals of SrI2:Eu2+ scintillators with good optical quality and scintillation characteristics have been grown in sizes up to 5.0 cm in diameter by applying these techniques. Other aspects of the SrI2:Eu2+ crystal-growth methods and of the still unresolved crystal-growth issues are described here.« less

TCSPC based approaches for multiparameter detection in living cells

NASA Astrophysics Data System (ADS)

Jahn, Karolina; Buschmann, Volker; Koberling, Felix; Hille, Carsten

2014-03-01

In living cells a manifold of processes take place simultaneously. This implies a precise regulation of intracellular ion homeostasis. In order to understand their spatio-temporal pattern comprehensively, the development of multiplexing concepts is essential. Due to the multidimensional characteristics of fluorescence dyes (absorption and emission spectra, decay time, anisotropy), the highly sensitive and non-invasive fluorescence microscopy is a versatile tool for realising multiplexing concepts. A prerequisite are analyte-specific fluorescence dyes with low cross-sensitivity to other dyes and analytes, respectively. Here, two approaches for multiparameter detection in living cells are presented. Insect salivary glands are well characterised secretory active tissues which were used as model systems to evaluate multiplexing concepts. Salivary glands secrete a KCl-rich or NaCl-rich fluid upon stimulation which is mainly regulated by intracellular Ca2+ as second messenger. Thus, pairwise detection of intracellular Na+, Cl- and Ca2+ with the fluorescent dyes ANG2, MQAE and ACR were tested. Therefore, the dyes were excited simultaneously (2-photon excitation) and their corresponding fluorescence decay times were recorded within two spectral ranges using time-correlated singlephoton counting (TCSPC). A second approach presented here is based on a new TCSPC-platform covering decay time detection from picoseconds to milliseconds. Thereby, nanosecond decaying cellular fluorescence and microsecond decaying phosphorescence of Ruthenium-complexes, which is quenched by oxygen, were recorded simultaneously. In both cases changes in luminescence decay times can be linked to changes in analyte concentrations. In consequence of simultaneous excitation as well as detection, it is possible to get a deeper insight into spatio-temporal pattern in living tissues.

HyperCP: A high-rate spectrometer for the study of charged hyperon and kaon decays

NASA Astrophysics Data System (ADS)

Burnstein, R. A.; Chakravorty, A.; Chan, A.; Chen, Y. C.; Choong, W.-S.; Clark, K.; Dukes, E. C.; Durandet, C.; Felix, J.; Fuzesy, R.; Gidal, G.; Gu, P.; Gustafson, H. R.; Ho, C.; Holmstrom, T.; Huang, M.; James, C.; Jenkins, C. M.; Jones, T. D.; Kaplan, D. M.; Lederman, L. M.; Leros, N.; Longo, M. J.; Lopez, F.; Lu, L. C.; Luebke, W.; Luk, K.-B.; Nelson, K. S.; Park, H. K.; Perroud, J.-P.; Rajaram, D.; Rubin, H. A.; Teng, P. K.; Turko, B.; Volk, J.; White, C. G.; White, S. L.; Zyla, P.

2005-04-01

The HyperCP experiment (Fermilab E871) was designed to search for rare phenomena in the decays of charged strange particles, in particular CP violation in Ξ and Λ hyperon decays with a sensitivity of 10-4. Intense charged secondary beams were produced by 800 GeV/ c protons and momentum selected by a magnetic channel. Decay products were detected in a large-acceptance, high-rate magnetic spectrometer using multiwire proportional chambers, trigger hodoscopes, a hadronic calorimeter, and a muon-detection system. Nearly identical acceptances and efficiencies for hyperons and antihyperons decaying within an evacuated volume were achieved by reversing the polarities of the channel and spectrometer magnets. A high-rate data-acquisition system enabled 231 billion events to be recorded in 12 months of data-taking.

Techniques for the treatment of IR divergences in decay processes at NLO and application to the top-quark decay.

PubMed

Basso, Lorenzo; Dittmaier, Stefan; Huss, Alexander; Oggero, Luisa

We present the extension of two general algorithms for the treatment of infrared singularities arising in electroweak corrections to decay processes at next-to-leading order: the dipole subtraction formalism and the one-cutoff slicing method. The former is extended to the case of decay kinematics which has not been considered in the literature so far. The latter is generalised to production and decay processes with more than two charged particles, where new "surface" terms arise. Arbitrary patterns of massive and massless external particles are considered, including the treatment of infrared singularities in dimensional or mass regularisation. As an application of the two techniques we present the calculation of the next-to-leading order QCD and electroweak corrections to the top-quark decay width including all off-shell and decay effects of intermediate [Formula: see text] bosons. The result, e.g., represents a building block of a future calculation of NLO electroweak effects to off-shell top-quark pair ([Formula: see text]) production. Moreover, this calculation can serve as the first step towards an event generator for top-quark decays at next-to-leading order accuracy, which can be used to attach top-quark decays to complicated many-particle top-quark processes, such as for [Formula: see text] or [Formula: see text].

Correlation of gravestone decay and air quality 1960-2010

NASA Astrophysics Data System (ADS)

Mooers, H. D.; Carlson, M. J.; Harrison, R. M.; Inkpen, R. J.; Loeffler, S.

2017-03-01

Evaluation of spatial and temporal variability in surface recession of lead-lettered Carrara marble gravestones provides a quantitative measure of acid flux to the stone surfaces and is closely related to local land use and air quality. Correlation of stone decay, land use, and air quality for the period after 1960 when reliable estimates of atmospheric pollution are available is evaluated. Gravestone decay and SO2 measurements are interpolated spatially using deterministic and geostatistical techniques. A general lack of spatial correlation was identified and therefore a land-use-based technique for correlation of stone decay and air quality is employed. Decadally averaged stone decay is highly correlated with land use averaged spatially over an optimum radius of ≈7 km even though air quality, determined by records from the UK monitoring network, is not highly correlated with gravestone decay. The relationships among stone decay, air-quality, and land use is complicated by the relatively low spatial density of both gravestone decay and air quality data and the fact that air quality data is available only as annual averages and therefore seasonal dependence cannot be evaluated. However, acid deposition calculated from gravestone decay suggests that the deposition efficiency of SO2 has increased appreciably since 1980 indicating an increase in the SO2 oxidation process possibly related to reactions with ammonia.

Pile-up corrections for high-precision superallowed β decay half-life measurements via γ-ray photopeak counting

NASA Astrophysics Data System (ADS)

Grinyer, G. F.; Svensson, C. E.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Hackman, G.; Hyland, B.; Kulp, W. D.; Leach, K. G.; Leslie, J. R.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Williams, S. J.; Wong, J.; Wood, J. L.; Zganjar, E. F.

2007-09-01

A general technique that corrects γ-ray gated β decay-curve data for detector pulse pile-up is presented. The method includes corrections for non-zero time-resolution and energy-threshold effects in addition to a special treatment of saturating events due to cosmic rays. This technique is verified through a Monte Carlo simulation and experimental data using radioactive beams of Na26 implanted at the center of the 8π γ-ray spectrometer at the ISAC facility at TRIUMF in Vancouver, Canada. The β-decay half-life of Na26 obtained from counting 1809-keV γ-ray photopeaks emitted by the daughter Mg26 was determined to be T=1.07167±0.00055 s following a 27σ correction for detector pulse pile-up. This result is in excellent agreement with the result of a previous measurement that employed direct β counting and demonstrates the feasibility of high-precision β-decay half-life measurements through the use of high-purity germanium γ-ray detectors. The technique presented here, while motivated by superallowed-Fermi β decay studies, is general and can be used for all half-life determinations (e.g. α-, β-, X-ray, fission) in which a γ-ray photopeak is used to select the decays of a particular isotope.

Need for Nondestructive Evaluation (NDE) in the Detection of Decay in Structures

Treesearch

W. Wayne Wilcox

1991-01-01

Examples of the need for nondestructive and remote sensing technologies for evaluating early stages of decay are presented. The need is critical to develop methods of analyzing internal decay, at the center of large wood members, and decay behind concealing coverings. Current technologies are reviewed and their inadequacies discussed. Acoustic emission and...

Using ultrasound to detect defects in trees: current knowledge and future needs

Treesearch

Theodor D. Leininger; Daniel L. Schmoldt; F.H. Tainter

2001-01-01

Ultrasonic decay detectors (UDDs) have been available commercially for several years and can be used successfully to detect decay in live hardwood and conifer trees. Recently, a UDD has shown promise in detecting bacterial wetwood in red oaks in the southern United States and in a Chilean hardwood species. Two improvements to the UDD tested would make it more useful...

Ruthenium trisbipyridine as a candidate for gas-phase spectroscopic studies in a Fourier transform mass spectrometer

DOE PAGES

Scott, Jill R.; Ham, Jason E.; Durham, Bill; ...

2004-01-01

Metal polypyridines are excellent candidates for gas-phase optical experiments where their intrinsic properties can be studied without complications due to the presence of solvent. The fluorescence lifetimes of [Ru(bpy) 3 ] 1+ trapped in an optical detection cell within a Fourier transform mass spectrometer were obtained using matrix-assisted laser desorption/ionization to generate the ions with either 2,5-dihydroxybenzoic acid (DHB) or sinapinic acid (SA) as matrix. All transients acquired, whether using DHB or SA for ion generation, were best described as approximately exponential decays. The rate constant for transients derived using DHB as matrix was 4×10 7 s −1 , whilemore » the rate constant using SA was 1×10 7 s −1 . Some suggestions of multiple exponential decay were evident although limited by the quality of the signals. Photodissociation experiments revealed that [Ru(bpy) 3 ] 1+ generated using DHB can decompose to [Ru(bpy) 2 ] 1+ , whereas ions generated using SA showed no decomposition. Comparison of the mass spectra with the fluorescence lifetimes illustrates the promise of incorporating optical detection with trapped ion mass spectrometry techniques.« less

Probing high scale physics with top quarks at the Large Hadron Collider

NASA Astrophysics Data System (ADS)

Dong, Zhe

With the Large Hadron Collider (LHC) running at TeV scale, we are expecting to find the deviations from the Standard Model in the experiments, and understanding what is the origin of these deviations. Being the heaviest elementary particle observed so far in the experiments with the mass at the electroweak scale, top quark is a powerful probe for new phenomena of high scale physics at the LHC. Therefore, we concentrate on studying the high scale physics phenomena with top quark pair production or decay at the LHC. In this thesis, we study the discovery potential of string resonances decaying to t/tbar final state, and examine the possibility of observing baryon-number-violating top-quark production or decay, at the LHC. We point out that string resonances for a string scale below 4 TeV can be detected via the t/tbar channel, by reconstructing center-of-mass frame kinematics of the resonances from either the t/tbar semi-leptonic decay or recent techniques of identifying highly boosted tops. For the study of baryon-number-violating processes, by a model independent effective approach and focusing on operators with minimal mass-dimension, we find that corresponding effective coefficients could be directly probed at the LHC already with an integrated luminosity of 1 inverse femtobarns at 7 TeV, and further constrained with 30 (100) inverse femtobarns at 7 (14) TeV.

Proposal and verification numerical simulation for a microwave forward scattering technique at upper hybrid resonance for the measurement of electron gyroscale density fluctuations in the electron cyclotron frequency range in magnetized plasmas

NASA Astrophysics Data System (ADS)

Kawamori, E.; Igami, H.

2017-11-01

A diagnostic technique for detecting the wave numbers of electron density fluctuations at electron gyro-scales in an electron cyclotron frequency range is proposed, and the validity of the idea is checked by means of a particle-in-cell (PIC) numerical simulation. The technique is a modified version of the scattering technique invented by Novik et al. [Plasma Phys. Controlled Fusion 36, 357-381 (1994)] and Gusakov et al., [Plasma Phys. Controlled Fusion 41, 899-912 (1999)]. The novel method adopts forward scattering of injected extraordinary probe waves at the upper hybrid resonance layer instead of the backward-scattering adopted by the original method, enabling the measurement of the wave-numbers of the fine scale density fluctuations in the electron-cyclotron frequency band by means of phase measurement of the scattered waves. The verification numerical simulation with the PIC method shows that the technique has a potential to be applicable to the detection of electron gyro-scale fluctuations in laboratory plasmas if the upper-hybrid resonance layer is accessible to the probe wave. The technique is a suitable means to detect electron Bernstein waves excited via linear mode conversion from electromagnetic waves in torus plasma experiments. Through the numerical simulations, some problems that remain to be resolved are revealed, which include the influence of nonlinear processes such as the parametric decay instability of the probe wave in the scattering process, and so on.

Emergency Dose Estimation Using Optically Stimulated Luminescence from Human Tooth Enamel.

PubMed

Sholom, S; Dewitt, R; Simon, S L; Bouville, A; McKeever, S W S

2011-09-01

Human teeth were studied for potential use as emergency Optically Stimulated Luminescence (OSL) dosimeters. By using multiple-teeth samples in combination with a custom-built sensitive OSL reader, (60)Co-equivalent doses below 0.64 Gy were measured immediately after exposure with the lowest value being 27 mGy for the most sensitive sample. The variability of OSL sensitivity, from individual to individual using multiple-teeth samples, was determined to be 53%. X-ray and beta exposure were found to produce OSL curves with the same shape that differed from those due to ultraviolet (UV) exposure; as a result, correlation was observed between OSL signals after X-ray and beta exposure and was absent if compared to OSL signals after UV exposure. Fading of the OSL signal was "typical" for most teeth with just a few of incisors showing atypical behavior. Typical fading dependences were described by a bi-exponential decay function with "fast" (decay time around of 12 min) and "slow" (decay time about 14 h) components. OSL detection limits, based on the techniques developed to-date, were found to be satisfactory from the point-of-view of medical triage requirements if conducted within 24 hours of the exposure.

Elastic and Inelastic Scattering of Neutrons from Neon and Argon: Impact on Neutrinoless Double-Beta Decay and Dark Matter Experimental Programs

NASA Astrophysics Data System (ADS)

MacMullin, Sean Patrick

In underground physics experiments, such as neutrinoless double-beta decay and dark matter searches, fast neutrons may be the dominant and potentially irreducible source of background. Experimental data for the elastic and inelastic scattering cross sections of neutrons from argon and neon, which are target and shielding materials of interest to the dark matter and neutrinoless double-beta decay communities, were previously unavailable. Unmeasured neutron scattering cross sections are often accounted for incorrectly in Monte-Carlo simulations. Elastic scattering cross sections were measured at the Triangle Universities Nuclear Laboratory (TUNL) using the neutron time-of-flight technique. Angular distributions for neon were measured at 5.0 and 8.0 MeV. One full angular distribution was measured for argon at 6.0 MeV. The cross-section data were compared to calculations using a global optical model. Data were also fit using the spherical optical model. These model fits were used to predict the elastic scattering cross section at unmeasured energies and also provide a benchmark where the global optical models are not well constrained. Partial gamma-ray production cross sections for (n,xngamma ) reactions in natural argon and neon were measured using the broad spectrum neutron beam at the Los Alamos Neutron Science Center (LANSCE). Neutron energies were determined using time of flight and resulting gamma rays from neutron-induced reactions were detected using the GErmanium Array for Neutron Induced Excitations (GEANIE). Partial gamma-ray production cross sections for six transitions in 40Ar, two transitions in 39Ar and the first excited state transitions is 20Ne and 22Ne were measured from threshold to a neutron energy where the gamma-ray yield dropped below the detection sensitivity. Measured (n,xngamma) cross sections were compared with calculations using the TALYS and CoH3 nuclear reaction codes. These new measurements will help to identify potential backgrounds in neutrinoless double-beta decay and dark matter experiments that use argon or neon. The measurements will also aid in the identification of neutron interactions in these experiments through the detection of gamma rays produced by ( n,xngamma) reactions.

Pyranose Oxidase, a Major Source of H(2)O(2) during Wood Degradation by Phanerochaete chrysosporium, Trametes versicolor, and Oudemansiella mucida.

PubMed

Daniel, G; Volc, J; Kubatova, E

1994-07-01

The production of the H(2)O(2)-generating enzyme pyranose oxidase (POD) (EC 1.1.3.10) (synonym, glucose 2-oxidase), two ligninolytic peroxidases, and laccase in wood decayed by three white rot fungi was investigated by correlated biochemical, immunological, and transmission electron microscopic techniques. Enzyme activities were assayed in extracts from decayed birch wood blocks obtained by a novel extraction procedure. With the coupled peroxidase-chromogen (3-dimethylaminobenzoic acid plus 3-methyl-2-benzothiazolinone hydrazone hydrochloride) spectrophotometric assay, the highest POD activities were detected in wood blocks degraded for 4 months and were for Phanerochaete chrysosporium (149 mU g [dry weight] of decayed wood), Trametes versicolor (45 mU g), and Oudemansiella mucida (1.2 mU g), corresponding to wood dry weight losses of 74, 58, and 13%, respectively. Mn-dependent peroxidase activities in the same extracts were comparable to those of POD, while lignin peroxidase activity was below the detection limit for all fungi with the veratryl alcohol assay. Laccase activity was high with T. versicolor (422 mU g after 4 months), in trace levels with O. mucida, and undetectable in P. chrysosporium extracts. Evidence for C-2 specificity of POD was shown by thin-layer chromatography detection of 2-keto-d-glucose as the reaction product. By transmission electron microscopy-immunocytochemistry, POD was found to be preferentially localized in the hyphal periplasmic space of P. chrysosporium and O. mucida and associated with membranous materials in hyphae growing within the cell lumina or cell walls of partially and highly degraded birch fibers. An extracellular distribution of POD associated with slime coating wood cell walls was also noted. The periplasmic distribution in hyphae and extracellular location of POD are consistent with the reported ultrastructural distribution of H(2)O(2)-dependent Mn-dependent peroxidases. This fact and the dominant presence of POD and Mn-dependent peroxidase in extracts from degraded wood suggest a cooperative role of the two enzymes during white rot decay by the test fungi.

Determination of bacterial activity by use of an evanescent-wave fiber-optic sensor

NASA Astrophysics Data System (ADS)

John, M. Shelly; Kishen, Anil; Sing, Lim Chu; Asundi, Anand

2002-12-01

A novel technique based on fiber-optic evanescent-wave spectroscopy is proposed for the detection of bacterial activity in human saliva. The sensor determines the specific concentration of Streptococcus mutans in saliva, which is a major causative factor in dental caries. In this design, one prepares the fiber-optic bacterial sensor by replacing a portion of the cladding region of a multimode fiber with a dye-encapsulated xerogel, using the solgel technique. The exponential decay of the evanescent wave at the core-cladding interface of a multimode fiber is utilized for the determination of bacterial activity in saliva. The acidogenic profile of Streptococcus mutans is estimated by use of evanescent-wave absorption spectra at various levels of bacterial activity.

Examination of the Arborsonic Decay Detector for Detecting Bacterial Wetwood in Red Oaks

Treesearch

Zicai Xu; Theodor D. Leininger; James G. Williams; Frank H. Tainter

2000-01-01

The Arborsonic Decay Detector (ADD; Fujikura Europe Limited, Wiltshire, England) was used to measure the time it took an ultrasound wave to cross 280 diameters in red oak trees with varying degrees of bacterial wetwood or heartwood decay. Linear regressions derived from the ADD readings of trees in Mississippi and South Carolina with wetwood and heartwood decay...

Search for decays of stopped exotic long-lived particles produced in proton-proton collisions at √{s}=13 TeV

NASA Astrophysics Data System (ADS)

Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Escalante Del Valle, A.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Grossmann, J.; Hrubec, J.; Jeitler, M.; König, A.; Krammer, N.; Krätschmer, I.; Liko, D.; Madlener, T.; Mikulec, I.; Pree, E.; Rad, N.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Spanring, M.; Spitzbart, D.; Taurok, A.; Waltenberger, W.; Wittmann, J.; Wulz, C.-E.; Zarucki, M.; Chekhovsky, V.; Mossolov, V.; Suarez Gonzalez, J.; De Wolf, E. A.; Di Croce, D.; Janssen, X.; Lauwers, J.; Pieters, M.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; De Bruyn, I.; De Clercq, J.; Deroover, K.; Flouris, G.; Lontkovskyi, D.; Lowette, S.; Marchesini, I.; Moortgat, S.; Moreels, L.; Python, Q.; Skovpen, K.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Parijs, I.; Beghin, D.; Bilin, B.; Brun, H.; Clerbaux, B.; De Lentdecker, G.; Delannoy, H.; Dorney, B.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Kalsi, A. K.; Lenzi, T.; Luetic, J.; Maerschalk, T.; Seva, T.; Starling, E.; Vander Velde, C.; Vanlaer, P.; Vannerom, D.; Yonamine, R.; Zenoni, F.; Cornelis, T.; Dobur, D.; Fagot, A.; Gul, M.; Khvastunov, I.; Poyraz, D.; Roskas, C.; Trocino, D.; Tytgat, M.; Verbeke, W.; Vit, M.; Zaganidis, N.; Bakhshiansohi, H.; Bondu, O.; Brochet, S.; Bruno, G.; Caputo, C.; Caudron, A.; David, P.; De Visscher, S.; Delaere, C.; Delcourt, M.; Francois, B.; Giammanco, A.; Krintiras, G.; Lemaitre, V.; Magitteri, A.; Mertens, A.; Musich, M.; Piotrzkowski, K.; Quertenmont, L.; Saggio, A.; Vidal Marono, M.; Wertz, S.; Zobec, J.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Correia Silva, G.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Coelho, E.; Da Costa, E. M.; Da Silveira, G. G.; De Jesus Damiao, D.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Melo De Almeida, M.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Sanchez Rosas, L. J.; Santoro, A.; Sznajder, A.; Thiel, M.; Tonelli Manganote, E. J.; Torres Da Silva De Araujo, F.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Marinov, A.; Misheva, M.; Rodozov, M.; Shopova, M.; Sultanov, G.; Dimitrov, A.; Litov, L.; Pavlov, B.; Petkov, P.; Fang, W.; Gao, X.; Yuan, L.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Chen, Y.; Jiang, C. H.; Leggat, D.; Liao, H.; Liu, Z.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Yazgan, E.; Zhang, H.; Zhao, J.; Ban, Y.; Chen, G.; Li, J.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Wang, Y.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; González Hernández, C. F.; Ruiz Alvarez, J. 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I.; Bencze, G.; Hajdu, C.; Horvath, D.; Hunyadi, Á.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Beni, N.; Czellar, S.; Karancsi, J.; Makovec, A.; Molnar, J.; Szillasi, Z.; Bartók, M.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Choudhury, S.; Komaragiri, J. R.; Bahinipati, S.; Mal, P.; Mandal, K.; Nayak, A.; Sahoo, D. K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Dhingra, N.; Kaur, A.; Kaur, M.; Kaur, S.; Kumar, R.; Kumari, P.; Mehta, A.; Singh, J. B.; Walia, G.; Kumar, Ashok; Shah, Aashaq; Bhardwaj, A.; Chauhan, S.; Choudhary, B. C.; Garg, R. B.; Keshri, S.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, R.; Bhardwaj, R.; Bhattacharya, R.; Bhattacharya, S.; Bhawandeep, U.; Bhowmik, D.; Dey, S.; Dutt, S.; Dutta, S.; Ghosh, S.; Majumdar, N.; Modak, A.; Mondal, K.; Mukhopadhyay, S.; Nandan, S.; Purohit, A.; Rout, P. K.; Roy, A.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Singh, B.; Thakur, S.; Behera, P. 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M.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Colaleo, A.; Creanza, D.; Cristella, L.; De Filippis, N.; De Palma, M.; Di Florio, A.; Errico, F.; Fiore, L.; Iaselli, G.; Lezki, S.; Maggi, G.; Maggi, M.; Marangelli, B.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Sharma, A.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Zito, G.; Abbiendi, G.; Battilana, C.; Bonacorsi, D.; Borgonovi, L.; Braibant-Giacomelli, S.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Chhibra, S. S.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Iemmi, F.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. 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A.; Lista, L.; Meola, S.; Paolucci, P.; Sciacca, C.; Thyssen, F.; Azzi, P.; Bacchetta, N.; Benato, L.; Bisello, D.; Boletti, A.; Carlin, R.; Carvalho Antunes De Oliveira, A.; Checchia, P.; Dall'Osso, M.; De Castro Manzano, P.; Dorigo, T.; Dosselli, U.; Gasparini, U.; Gozzelino, A.; Lacaprara, S.; Lujan, P.; Margoni, M.; Meneguzzo, A. T.; Pozzobon, N.; Ronchese, P.; Rossin, R.; Simonetto, F.; Tiko, A.; Torassa, E.; Zanetti, M.; Zotto, P.; Zumerle, G.; Braghieri, A.; Magnani, A.; Montagna, P.; Ratti, S. P.; Re, V.; Ressegotti, M.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Solestizi, L. Alunni; Biasini, M.; Bilei, G. M.; Cecchi, C.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Leonardi, R.; Manoni, E.; Mantovani, G.; Mariani, V.; Menichelli, M.; Rossi, A.; Santocchia, A.; Spiga, D.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bianchini, L.; Boccali, T.; Borrello, L.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Fedi, G.; Giannini, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Manca, E.; Mandorli, G.; Messineo, A.; Palla, F.; Rizzi, A.; Spagnolo, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Barone, L.; Cavallari, F.; Cipriani, M.; Daci, N.; Del Re, D.; Di Marco, E.; Diemoz, M.; Gelli, S.; Longo, E.; Margaroli, F.; Marzocchi, B.; Meridiani, P.; Organtini, G.; Paramatti, R.; Preiato, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bartosik, N.; Bellan, R.; Biino, C.; Cartiglia, N.; Castello, R.; Cenna, F.; Costa, M.; Covarelli, R.; Degano, A.; Demaria, N.; Kiani, B.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Monteil, E.; Monteno, M.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Romero, A.; Ruspa, M.; Sacchi, R.; Shchelina, K.; Sola, V.; Solano, A.; Staiano, A.; Traczyk, P.; Belforte, S.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Zanetti, A.; Kim, D. H.; Kim, G. N.; Kim, M. S.; Lee, J.; Lee, S.; Lee, S. W.; Moon, C. S.; Oh, Y. D.; Sekmen, S.; Son, D. C.; Yang, Y. C.; Kim, H.; Moon, D. H.; Oh, G.; Brochero Cifuentes, J. A.; Goh, J.; Kim, T. J.; Cho, S.; Choi, S.; Go, Y.; Gyun, D.; Ha, S.; Hong, B.; Jo, Y.; Kim, Y.; Lee, K.; Lee, K. S.; Lee, S.; Lim, J.; Park, S. K.; Roh, Y.; Almond, J.; Kim, J.; Kim, J. S.; Lee, H.; Lee, K.; Nam, K.; Oh, S. B.; Radburn-Smith, B. C.; Seo, S. h.; Yang, U. K.; Yoo, H. D.; Yu, G. B.; Kim, H.; Kim, J. H.; Lee, J. S. H.; Park, I. C.; Choi, Y.; Hwang, C.; Lee, J.; Yu, I.; Dudenas, V.; Juodagalvis, A.; Vaitkus, J.; Ahmed, I.; Ibrahim, Z. A.; Md Ali, M. A. B.; Mohamad Idris, F.; Wan Abdullah, W. A. T.; Yusli, M. N.; Zolkapli, Z.; Reyes-Almanza, R.; Ramirez-Sanchez, G.; Duran-Osuna, M. C.; Castilla-Valdez, H.; De La Cruz-Burelo, E.; Heredia-De La Cruz, I.; Rabadan-Trejo, R. I.; Lopez-Fernandez, R.; Mejia Guisao, J.; Sanchez-Hernandez, A.; Carrillo Moreno, S.; Oropeza Barrera, C.; Vazquez Valencia, F.; Eysermans, J.; Pedraza, I.; Salazar Ibarguen, H. A.; Uribe Estrada, C.; Morelos Pineda, A.; Krofcheck, D.; Butler, P. H.; Ahmad, A.; Ahmad, M.; Hassan, Q.; Hoorani, H. R.; Saddique, A.; Shah, M. A.; Shoaib, M.; Waqas, M.; Bialkowska, H.; Bluj, M.; Boimska, B.; Frueboes, T.; Górski, M.; Kazana, M.; Nawrocki, K.; Szleper, M.; Zalewski, P.; Bunkowski, K.; Byszuk, A.; Doroba, K.; Kalinowski, A.; Konecki, M.; Krolikowski, J.; Misiura, M.; Olszewski, M.; Pyskir, A.; Walczak, M.; Bargassa, P.; Beirão Da Cruz E Silva, C.; Di Francesco, A.; Faccioli, P.; Galinhas, B.; Gallinaro, M.; Hollar, J.; Leonardo, N.; Lloret Iglesias, L.; Nemallapudi, M. V.; Seixas, J.; Strong, G.; Toldaiev, O.; Vadruccio, D.; Varela, J.; Afanasiev, S.; Bunin, P.; Gavrilenko, M.; Golutvin, I.; Gorbunov, I.; Kamenev, A.; Karjavin, V.; Lanev, A.; Malakhov, A.; Matveev, V.; Moisenz, P.; Palichik, V.; Perelygin, V.; Shmatov, S.; Shulha, S.; Skatchkov, N.; Smirnov, V.; Voytishin, N.; Zarubin, A.; Ivanov, Y.; Kim, V.; Kuznetsova, E.; Levchenko, P.; Murzin, V.; Oreshkin, V.; Smirnov, I.; Sosnov, D.; Sulimov, V.; Uvarov, L.; Vavilov, S.; Vorobyev, A.; Andreev, Yu.; Dermenev, A.; Gninenko, S.; Golubev, N.; Karneyeu, A.; Kirsanov, M.; Krasnikov, N.; Pashenkov, A.; Tlisov, D.; Toropin, A.; Epshteyn, V.; Gavrilov, V.; Lychkovskaya, N.; Popov, V.; Pozdnyakov, I.; Safronov, G.; Spiridonov, A.; Stepennov, A.; Stolin, V.; Toms, M.; Vlasov, E.; Zhokin, A.; Aushev, T.; Bylinkin, A.; Chistov, R.; Danilov, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Tarkovskii, E.; Andreev, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Rusakov, S. V.; Terkulov, A.; Baskakov, A.; Belyaev, A.; Boos, E.; Dubinin, M.; Dudko, L.; Ershov, A.; Gribushin, A.; Klyukhin, V.; Kodolova, O.; Lokhtin, I.; Miagkov, I.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Snigirev, A.; Blinov, V.; Shtol, D.; Skovpen, Y.; Azhgirey, I.; Bayshev, I.; Bitioukov, S.; Elumakhov, D.; Godizov, A.; Kachanov, V.; Kalinin, A.; Konstantinov, D.; Mandrik, P.; Petrov, V.; Ryutin, R.; Sobol, A.; Troshin, S.; Tyurin, N.; Uzunian, A.; Volkov, A.; Babaev, A.; Adzic, P.; Cirkovic, P.; Devetak, D.; Dordevic, M.; Milosevic, J.; Alcaraz Maestre, J.; Bachiller, I.; Barrio Luna, M.; Cerrada, M.; Colino, N.; De La Cruz, B.; Delgado Peris, A.; Fernandez Bedoya, C.; Fernández Ramos, J. P.; Flix, J.; Fouz, M. C.; Gonzalez Lopez, O.; Goy Lopez, S.; Hernandez, J. M.; Josa, M. I.; Moran, D.; Pérez-Calero Yzquierdo, A.; Puerta Pelayo, J.; Redondo, I.; Romero, L.; Soares, M. S.; Triossi, A.; Álvarez Fernández, A.; Albajar, C.; de Trocóniz, J. F.; Cuevas, J.; Erice, C.; Fernandez Menendez, J.; Folgueras, S.; Gonzalez Caballero, I.; González Fernández, J. R.; Palencia Cortezon, E.; Sanchez Cruz, S.; Vischia, P.; Vizan Garcia, J. M.; Cabrillo, I. J.; Calderon, A.; Chazin Quero, B.; Duarte Campderros, J.; Fernandez, M.; Fernández Manteca, P. J.; Garcia-Ferrero, J.; García Alonso, A.; Gomez, G.; Lopez Virto, A.; Marco, J.; Martinez Rivero, C.; Martinez Ruiz del Arbol, P.; Matorras, F.; Piedra Gomez, J.; Prieels, C.; Rodrigo, T.; Ruiz-Jimeno, A.; Scodellaro, L.; Trevisani, N.; Vila, I.; Vilar Cortabitarte, R.; Abbaneo, D.; Akgun, B.; Auffray, E.; Baillon, P.; Ball, A. H.; Barney, D.; Bendavid, J.; Bianco, M.; Bocci, A.; Botta, C.; Camporesi, T.; Cepeda, M.; Cerminara, G.; Chapon, E.; Chen, Y.; d'Enterria, D.; Dabrowski, A.; Daponte, V.; David, A.; De Gruttola, M.; De Roeck, A.; Deelen, N.; Dobson, M.; du Pree, T.; Dünser, M.; Dupont, N.; Elliott-Peisert, A.; Everaerts, P.; Fallavollita, F.; Franzoni, G.; Fulcher, J.; Funk, W.; Gigi, D.; Gilbert, A.; Gill, K.; Glege, F.; Gulhan, D.; Hegeman, J.; Innocente, V.; Jafari, A.; Janot, P.; Karacheban, O.; Kieseler, J.; Knünz, V.; Kornmayer, A.; Kortelainen, M. J.; Krammer, M.; Lange, C.; Lecoq, P.; Lourenço, C.; Lucchini, M. T.; Malgeri, L.; Mannelli, M.; Martelli, A.; Meijers, F.; Merlin, J. A.; Mersi, S.; Meschi, E.; Milenovic, P.; Moortgat, F.; Mulders, M.; Neugebauer, H.; Ngadiuba, J.; Orfanelli, S.; Orsini, L.; Pantaleo, F.; Pape, L.; Perez, E.; Peruzzi, M.; Petrilli, A.; Petrucciani, G.; Pfeiffer, A.; Pierini, M.; Pitters, F. M.; Rabady, D.; Racz, A.; Reis, T.; Rolandi, G.; Rovere, M.; Sakulin, H.; Schäfer, C.; Schwick, C.; Seidel, M.; Selvaggi, M.; Sharma, A.; Silva, P.; Sphicas, P.; Stakia, A.; Steggemann, J.; Stoye, M.; Tosi, M.; Treille, D.; Tsirou, A.; Veckalns, V.; Verweij, M.; Zeuner, W. D.; Bertl, W.; Caminada, L.; Deiters, K.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H. C.; Kotlinski, D.; Langenegger, U.; Rohe, T.; Wiederkehr, S. A.; Backhaus, M.; Bäni, L.; Berger, P.; Casal, B.; Dissertori, G.; Dittmar, M.; Donegà, M.; Dorfer, C.; Grab, C.; Heidegger, C.; Hits, D.; Hoss, J.; Klijnsma, T.; Lustermann, W.; Mangano, B.; Marionneau, M.; Meinhard, M. T.; Meister, D.; Micheli, F.; Musella, P.; Nessi-Tedaldi, F.; Pandolfi, F.; Pata, J.; Pauss, F.; Perrin, G.; Perrozzi, L.; Quittnat, M.; Reichmann, M.; Sanz Becerra, D. A.; Schönenberger, M.; Shchutska, L.; Tavolaro, V. R.; Theofilatos, K.; Vesterbacka Olsson, M. L.; Wallny, R.; Zhu, D. H.; Aarrestad, T. K.; Amsler, C.; Brzhechko, D.; Canelli, M. F.; De Cosa, A.; Del Burgo, R.; Donato, S.; Galloni, C.; Hreus, T.; Kilminster, B.; Neutelings, I.; Pinna, D.; Rauco, G.; Robmann, P.; Salerno, D.; Schweiger, K.; Seitz, C.; Takahashi, Y.; Zucchetta, A.; Candelise, V.; Chang, Y. H.; Cheng, K. y.; Doan, T. H.; Jain, Sh.; Khurana, R.; Kuo, C. M.; Lin, W.; Pozdnyakov, A.; Yu, S. S.; Kumar, Arun; Chang, P.; Chao, Y.; Chen, K. F.; Chen, P. H.; Fiori, F.; Hou, W.-S.; Hsiung, Y.; Liu, Y. F.; Lu, R.-S.; Paganis, E.; Psallidas, A.; Steen, A.; Tsai, J. f.; Asavapibhop, B.; Kovitanggoon, K.; Singh, G.; Srimanobhas, N.; Bat, A.; Boran, F.; Cerci, S.; Damarseckin, S.; Demiroglu, Z. S.; Dozen, C.; Dumanoglu, I.; Girgis, S.; Gokbulut, G.; Guler, Y.; Hos, I.; Kangal, E. E.; Kara, O.; Kayis Topaksu, A.; Kiminsu, U.; Oglakci, M.; Onengut, G.; Ozdemir, K.; Sunar Cerci, D.; Tali, B.; Tok, U. G.; Turkcapar, S.; Zorbakir, I. S.; Zorbilmez, C.; Karapinar, G.; Ocalan, K.; Yalvac, M.; Zeyrek, M.; Gülmez, E.; Kaya, M.; Kaya, O.; Tekten, S.; Yetkin, E. A.; Agaras, M. N.; Atay, S.; Cakir, A.; Cankocak, K.; Komurcu, Y.; Grynyov, B.; Levchuk, L.; Ball, F.; Beck, L.; Brooke, J. J.; Burns, D.; Clement, E.; Cussans, D.; Davignon, O.; Flacher, H.; Goldstein, J.; Heath, G. P.; Heath, H. F.; Kreczko, L.; Newbold, D. M.; Paramesvaran, S.; Sakuma, T.; Seif El Nasr-storey, S.; Smith, D.; Smith, V. J.; Bell, K. W.; Belyaev, A.; Brew, C.; Brown, R. M.; Calligaris, L.; Cieri, D.; Cockerill, D. J. A.; Coughlan, J. A.; Harder, K.; Harper, S.; Linacre, J.; Olaiya, E.; Petyt, D.; Shepherd-Themistocleous, C. H.; Thea, A.; Tomalin, I. R.; Williams, T.; Womersley, W. J.; Auzinger, G.; Bainbridge, R.; Bloch, P.; Borg, J.; Breeze, S.; Buchmuller, O.; Bundock, A.; Casasso, S.; Colling, D.; Corpe, L.; Dauncey, P.; Davies, G.; Della Negra, M.; Di Maria, R.; Haddad, Y.; Hall, G.; Iles, G.; James, T.; Komm, M.; Lane, R.; Laner, C.; Lyons, L.; Magnan, A.-M.; Malik, S.; Mastrolorenzo, L.; Matsushita, T.; Nash, J.; Nikitenko, A.; Palladino, V.; Pesaresi, M.; Richards, A.; Rose, A.; Scott, E.; Seez, C.; Shtipliyski, A.; Strebler, T.; Summers, S.; Tapper, A.; Uchida, K.; Vazquez Acosta, M.; Virdee, T.; Wardle, N.; Winterbottom, D.; Wright, J.; Zenz, S. C.; Cole, J. E.; Hobson, P. R.; Khan, A.; Kyberd, P.; Morton, A.; Reid, I. D.; Teodorescu, L.; Zahid, S.; Borzou, A.; Call, K.; Dittmann, J.; Hatakeyama, K.; Liu, H.; Pastika, N.; Smith, C.; Bartek, R.; Dominguez, A.; Buccilli, A.; Cooper, S. I.; Henderson, C.; Rumerio, P.; West, C.; Arcaro, D.; Avetisyan, A.; Bose, T.; Gastler, D.; Rankin, D.; Richardson, C.; Rohlf, J.; Sulak, L.; Zou, D.; Benelli, G.; Cutts, D.; Hadley, M.; Hakala, J.; Heintz, U.; Hogan, J. M.; Kwok, K. H. M.; Laird, E.; Landsberg, G.; Lee, J.; Mao, Z.; Narain, M.; Pazzini, J.; Piperov, S.; Sagir, S.; Syarif, R.; Yu, D.; Band, R.; Brainerd, C.; Breedon, R.; Burns, D.; Calderon De La Barca Sanchez, M.; Chertok, M.; Conway, J.; Conway, R.; Cox, P. T.; Erbacher, R.; Flores, C.; Funk, G.; Ko, W.; Lander, R.; Mclean, C.; Mulhearn, M.; Pellett, D.; Pilot, J.; Shalhout, S.; Shi, M.; Smith, J.; Stolp, D.; Taylor, D.; Tos, K.; Tripathi, M.; Wang, Z.; Zhang, F.; Bachtis, M.; Bravo, C.; Cousins, R.; Dasgupta, A.; Florent, A.; Hauser, J.; Ignatenko, M.; Mccoll, N.; Regnard, S.; Saltzberg, D.; Schnaible, C.; Valuev, V.; Bouvier, E.; Burt, K.; Clare, R.; Ellison, J.; Gary, J. W.; Ghiasi Shirazi, S. M. A.; Hanson, G.; Karapostoli, G.; Kennedy, E.; Lacroix, F.; Long, O. R.; Olmedo Negrete, M.; Paneva, M. I.; Si, W.; Wang, L.; Wei, H.; Wimpenny, S.; Yates, B. R.; Branson, J. G.; Cittolin, S.; Derdzinski, M.; Gerosa, R.; Gilbert, D.; Hashemi, B.; Holzner, A.; Klein, D.; Kole, G.; Krutelyov, V.; Letts, J.; Masciovecchio, M.; Olivito, D.; Padhi, S.; Pieri, M.; Sani, M.; Sharma, V.; Simon, S.; Tadel, M.; Vartak, A.; Wasserbaech, S.; Wood, J.; Würthwein, F.; Yagil, A.; Zevi Della Porta, G.; Amin, N.; Bhandari, R.; Bradmiller-Feld, J.; Campagnari, C.; Citron, M.; Dishaw, A.; Dutta, V.; Franco Sevilla, M.; Gouskos, L.; Heller, R.; Incandela, J.; Ovcharova, A.; Qu, H.; Richman, J.; Stuart, D.; Suarez, I.; Yoo, J.; Anderson, D.; Bornheim, A.; Bunn, J.; Lawhorn, J. M.; Newman, H. B.; Nguyen, T. Q.; Pena, C.; Spiropulu, M.; Vlimant, J. R.; Wilkinson, R.; Xie, S.; Zhang, Z.; Zhu, R. Y.; Andrews, M. B.; Ferguson, T.; Mudholkar, T.; Paulini, M.; Russ, J.; Sun, M.; Vogel, H.; Vorobiev, I.; Weinberg, M.; Cumalat, J. P.; Ford, W. T.; Jensen, F.; Johnson, A.; Krohn, M.; Leontsinis, S.; Macdonald, E.; Mulholland, T.; Stenson, K.; Ulmer, K. A.; Wagner, S. R.; Alexander, J.; Chaves, J.; Cheng, Y.; Chu, J.; Datta, A.; Dittmer, S.; Mcdermott, K.; Mirman, N.; Patterson, J. R.; Quach, D.; Rinkevicius, A.; Ryd, A.; Skinnari, L.; Soffi, L.; Tan, S. M.; Tao, Z.; Thom, J.; Tucker, J.; Wittich, P.; Zientek, M.; Abdullin, S.; Albrow, M.; Alyari, M.; Apollinari, G.; Apresyan, A.; Apyan, A.; Banerjee, S.; Bauerdick, L. A. T.; Beretvas, A.; Berryhill, J.; Bhat, P. C.; Bolla, G.; Burkett, K.; Butler, J. N.; Canepa, A.; Cerati, G. B.; Cheung, H. W. K.; Chlebana, F.; Cremonesi, M.; Duarte, J.; Elvira, V. D.; Freeman, J.; Gecse, Z.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl, S.; Gutsche, O.; Hanlon, J.; Harris, R. M.; Hasegawa, S.; Hirschauer, J.; Hu, Z.; Jayatilaka, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Klima, B.; Kreis, B.; Lammel, S.; Lincoln, D.; Lipton, R.; Liu, M.; Liu, T.; Lopes De Sá, R.; Lykken, J.; Maeshima, K.; Magini, N.; Marraffino, J. M.; Mason, D.; McBride, P.; Merkel, P.; Mrenna, S.; Nahn, S.; O'Dell, V.; Pedro, K.; Prokofyev, O.; Rakness, G.; Ristori, L.; Savoy-Navarro, A.; Schneider, B.; Sexton-Kennedy, E.; Soha, A.; Spalding, W. J.; Spiegel, L.; Stoynev, S.; Strait, J.; Strobbe, N.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vernieri, C.; Verzocchi, M.; Vidal, R.; Wang, M.; Weber, H. A.; Whitbeck, A.; Wu, W.; Acosta, D.; Avery, P.; Bortignon, P.; Bourilkov, D.; Brinkerhoff, A.; Carnes, A.; Carver, M.; Curry, D.; Field, R. D.; Furic, I. K.; Gleyzer, S. V.; Joshi, B. M.; Konigsberg, J.; Korytov, A.; Kotov, K.; Ma, P.; Matchev, K.; Mei, H.; Mitselmakher, G.; Shi, K.; Sperka, D.; Terentyev, N.; Thomas, L.; Wang, J.; Wang, S.; Yelton, J.; Joshi, Y. R.; Linn, S.; Markowitz, P.; Rodriguez, J. L.; Ackert, A.; Adams, T.; Askew, A.; Hagopian, S.; Hagopian, V.; Johnson, K. F.; Kolberg, T.; Martinez, G.; Perry, T.; Prosper, H.; Saha, A.; Santra, A.; Sharma, V.; Yohay, R.; Baarmand, M. M.; Bhopatkar, V.; Colafranceschi, S.; Hohlmann, M.; Noonan, D.; Roy, T.; Yumiceva, F.; Adams, M. R.; Apanasevich, L.; Berry, D.; Betts, R. R.; Cavanaugh, R.; Chen, X.; Evdokimov, O.; Gerber, C. E.; Hangal, D. A.; Hofman, D. J.; Jung, K.; Kamin, J.; Sandoval Gonzalez, I. D.; Tonjes, M. B.; Varelas, N.; Wang, H.; Wu, Z.; Zhang, J.; Bilki, B.; Clarida, W.; Dilsiz, K.; Durgut, S.; Gandrajula, R. P.; Haytmyradov, M.; Khristenko, V.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Snyder, C.; Tiras, E.; Wetzel, J.; Yi, K.; Blumenfeld, B.; Cocoros, A.; Eminizer, N.; Fehling, D.; Feng, L.; Gritsan, A. V.; Maksimovic, P.; Roskes, J.; Sarica, U.; Swartz, M.; Xiao, M.; You, C.; Al-bataineh, A.; Baringer, P.; Bean, A.; Boren, S.; Bowen, J.; Castle, J.; Khalil, S.; Kropivnitskaya, A.; Majumder, D.; Mcbrayer, W.; Murray, M.; Rogan, C.; Royon, C.; Sanders, S.; Schmitz, E.; Tapia Takaki, J. D.; Wang, Q.; Ivanov, A.; Kaadze, K.; Maravin, Y.; Mohammadi, A.; Saini, L. K.; Skhirtladze, N.; Rebassoo, F.; Wright, D.; Baden, A.; Baron, O.; Belloni, A.; Eno, S. C.; Feng, Y.; Ferraioli, C.; Hadley, N. J.; Jabeen, S.; Jeng, G. Y.; Kellogg, R. G.; Kunkle, J.; Mignerey, A. C.; Ricci-Tam, F.; Shin, Y. H.; Skuja, A.; Tonwar, S. C.; Abercrombie, D.; Allen, B.; Azzolini, V.; Barbieri, R.; Baty, A.; Bauer, G.; Bi, R.; Brandt, S.; Busza, W.; Cali, I. A.; D'Alfonso, M.; Demiragli, Z.; Gomez Ceballos, G.; Goncharov, M.; Harris, P.; Hsu, D.; Hu, M.; Iiyama, Y.; Innocenti, G. M.; Klute, M.; Kovalskyi, D.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Maier, B.; Marini, A. C.; Mcginn, C.; Mironov, C.; Narayanan, S.; Niu, X.; Paus, C.; Roland, C.; Roland, G.; Salfeld-Nebgen, J.; Stephans, G. S. F.; Sumorok, K.; Tatar, K.; Velicanu, D.; Wang, J.; Wang, T. W.; Wyslouch, B.; Benvenuti, A. C.; Chatterjee, R. M.; Evans, A.; Hansen, P.; Kalafut, S.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Turkewitz, J.; Wadud, M. A.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Claes, D. R.; Fangmeier, C.; Golf, F.; Gonzalez Suarez, R.; Kamalieddin, R.; Kravchenko, I.; Monroy, J.; Siado, J. E.; Snow, G. R.; Stieger, B.; Dolen, J.; Godshalk, A.; Harrington, C.; Iashvili, I.; Nguyen, D.; Parker, A.; Rappoccio, S.; Roozbahani, B.; Alverson, G.; Barberis, E.; Freer, C.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Orimoto, T.; Teixeira De Lima, R.; Wamorkar, T.; Wang, B.; Wisecarver, A.; Wood, D.; Bhattacharya, S.; Charaf, O.; Hahn, K. A.; Mucia, N.; Odell, N.; Schmitt, M. H.; Sung, K.; Trovato, M.; Velasco, M.; Bucci, R.; Dev, N.; Hildreth, M.; Hurtado Anampa, K.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Li, W.; Loukas, N.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Planer, M.; Reinsvold, A.; Ruchti, R.; Siddireddy, P.; Smith, G.; Taroni, S.; Wayne, M.; Wightman, A.; Wolf, M.; Woodard, A.; Alimena, J.; Antonelli, L.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Francis, B.; Hart, A.; Hill, C.; Ji, W.; Ling, T. Y.; Luo, W.; Winer, B. L.; Wulsin, H. W.; Cooperstein, S.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Higginbotham, S.; Kalogeropoulos, A.; Lange, D.; Luo, J.; Marlow, D.; Mei, K.; Ojalvo, I.; Olsen, J.; Palmer, C.; Piroué, P.; Stickland, D.; Tully, C.; Malik, S.; Norberg, S.; Barker, A.; Barnes, V. E.; Das, S.; Gutay, L.; Jones, M.; Jung, A. W.; Khatiwada, A.; Miller, D. H.; Neumeister, N.; Peng, C. C.; Qiu, H.; Schulte, J. F.; Sun, J.; Wang, F.; Xiao, R.; Xie, W.; Cheng, T.; Parashar, N.; Chen, Z.; Ecklund, K. M.; Freed, S.; Geurts, F. J. M.; Guilbaud, M.; Kilpatrick, M.; Li, W.; Michlin, B.; Padley, B. P.; Roberts, J.; Rorie, J.; Shi, W.; Tu, Z.; Zabel, J.; Zhang, A.; Bodek, A.; de Barbaro, P.; Demina, R.; Duh, Y. t.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Hindrichs, O.; Khukhunaishvili, A.; Lo, K. H.; Tan, P.; Verzetti, M.; Ciesielski, R.; Goulianos, K.; Mesropian, C.; Agapitos, A.; Chou, J. P.; Gershtein, Y.; Gómez Espinosa, T. A.; Halkiadakis, E.; Heindl, M.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Kyriacou, S.; Lath, A.; Montalvo, R.; Nash, K.; Osherson, M.; Saka, H.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Delannoy, A. G.; Heideman, J.; Riley, G.; Rose, K.; Spanier, S.; Thapa, K.; Bouhali, O.; Castaneda Hernandez, A.; Celik, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Gilmore, J.; Huang, T.; Kamon, T.; Mueller, R.; Pakhotin, Y.; Patel, R.; Perloff, A.; Perniè, L.; Rathjens, D.; Safonov, A.; Tatarinov, A.; Akchurin, N.; Damgov, J.; De Guio, F.; Dudero, P. R.; Faulkner, J.; Gurpinar, E.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Mengke, T.; Muthumuni, S.; Peltola, T.; Undleeb, S.; Volobouev, I.; Wang, Z.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Melo, A.; Ni, H.; Padeken, K.; Sheldon, P.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Barria, P.; Cox, B.; Hirosky, R.; Joyce, M.; Ledovskoy, A.; Li, H.; Neu, C.; Sinthuprasith, T.; Wang, Y.; Wolfe, E.; Xia, F.; Harr, R.; Karchin, P. E.; Poudyal, N.; Sturdy, J.; Thapa, P.; Zaleski, S.; Brodski, M.; Buchanan, J.; Caillol, C.; Carlsmith, D.; Dasu, S.; Dodd, L.; Duric, S.; Gomber, B.; Grothe, M.; Herndon, M.; Hervé, A.; Hussain, U.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Rekovic, V.; Ruggles, T.; Savin, A.; Smith, N.; Smith, W. H.; Woods, N.

2018-05-01

A search is presented for the decays of heavy exotic long-lived particles (LLPs) that are produced in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC and come to rest in the CMS detector. Their decays would be visible during periods of time well separated from proton-proton collisions. Two decay scenarios of stopped LLPs are explored: a hadronic decay detected in the calorimeter and a decay into muons detected in the muon system. The calorimeter (muon) search covers a period of sensitivity totaling 721 (744) hours in 38.6 (39.0) fb-1 of data collected by the CMS detector in 2015 and 2016. The results are interpreted in several scenarios that predict LLPs. Production cross section limits are set as a function of the mean proper lifetime and the mass of the LLPs, for lifetimes between 100 ns and 10 days. These are the most stringent limits to date on the mass of hadronically decaying stopped LLPs, and this is the first search at the LHC for stopped LLPs that decay to muons. [Figure not available: see fulltext.

Search for decays of stopped exotic long-lived particles produced in proton-proton collisions at $$ \\sqrt{s}=13 $$ TeV

DOE PAGES

Sirunyan, A. M.; Tumasyan, A.; Adam, W.; ...

2018-05-21

Here, a search is presented for the decays of heavy exotic long-lived particles (LLPs) that are produced in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC and come to rest in the CMS detector. Their decays would be visible during periods of time well separated from proton-proton collisions. Two decay scenarios of stopped LLPs are explored: a hadronic decay detected in the calorimeter and a decay into muons detected in the muon system. The calorimeter (muon) search covers a period of sensitivity totaling 721 (744) hours in 38.6 (39.0) fbmore » $$^{-1}$$ of data collected by the CMS detector in 2015 and 2016. The results are interpreted in several scenarios that predict LLPs. Production cross section limits are set as a function of the mean proper lifetime and the mass of the LLPs, for lifetimes between 100 ns and 10 days. These are the most stringent limits to date on the mass of hadronically decaying stopped LLPs, and this is the first search at the LHC for stopped LLPs that decay to muons.« less

Search for decays of stopped exotic long-lived particles produced in proton-proton collisions at $$\\sqrt{s}=$$ 13 TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sirunyan, Albert M; et al.

2018-05-21

A search is presented for the decays of heavy exotic long-lived particles (LLPs) that are produced in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC and come to rest in the CMS detector. Their decays would be visible during periods of time well separated from proton-proton collisions. Two decay scenarios of stopped LLPs are explored: a hadronic decay detected in the calorimeter and a decay into muons detected in the muon system. The calorimeter (muon) search covers a period of sensitivity totaling 721 (744) hours in 38.6 (39.0) fbmore » $$^{-1}$$ of data collected by the CMS detector in 2015 and 2016. The results are interpreted in several scenarios that predict LLPs. Production cross section limits are set as a function of the mean proper lifetime and the mass of the LLPs, for lifetimes between 100 ns and 10 days. These are the most stringent limits to date on the mass of hadronically decaying stopped LLPs, and this is the first search at the LHC for stopped LLPs that decay to muons.« less

Search for decays of stopped exotic long-lived particles produced in proton-proton collisions at $$ \\sqrt{s}=13 $$ TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sirunyan, A. M.; Tumasyan, A.; Adam, W.

Here, a search is presented for the decays of heavy exotic long-lived particles (LLPs) that are produced in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC and come to rest in the CMS detector. Their decays would be visible during periods of time well separated from proton-proton collisions. Two decay scenarios of stopped LLPs are explored: a hadronic decay detected in the calorimeter and a decay into muons detected in the muon system. The calorimeter (muon) search covers a period of sensitivity totaling 721 (744) hours in 38.6 (39.0) fbmore » $$^{-1}$$ of data collected by the CMS detector in 2015 and 2016. The results are interpreted in several scenarios that predict LLPs. Production cross section limits are set as a function of the mean proper lifetime and the mass of the LLPs, for lifetimes between 100 ns and 10 days. These are the most stringent limits to date on the mass of hadronically decaying stopped LLPs, and this is the first search at the LHC for stopped LLPs that decay to muons.« less

Photonic band edge assisted spontaneous emission enhancement from all Er3+ 1-D photonic band gap structure

NASA Astrophysics Data System (ADS)

Chiasera, A.; Meroni, C.; Varas, S.; Valligatla, S.; Scotognella, F.; Boucher, Y. G.; Lukowiak, A.; Zur, L.; Righini, G. C.; Ferrari, M.

2018-06-01

All Er3+ doped dielectric 1-D Photonic Band Gap Structure was fabricated by rf-sputtering technique. The structure was constituted by of twenty pairs of SiO2/TiO2 alternated layers doped with Er3+ ions. The scanning electron microscopy was used to check the morphology of the structure. Transmission measurements put in evidence the stop band in the range 1500 nm-1950 nm. The photoluminescence measurements were obtained by optically exciting the sample and detecting the emitted light in the 1.5 μm region at different detection angles. Luminescence spectra and luminescence decay curves put in evidence that the presence of the stop band modify the emission features of the Er3+ ions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sweany, Melinda; Brennan, James S.; Cabrera-Palmer, Belkis

Antineutrino monitoring of nuclear reactors has been demonstrated many times, however the technique has not as of yet been developed into a useful capability for treaty verification purposes. The most notable drawback is the current requirement that detectors be deployed underground, with at least several meters-water-equivalent of shielding from cosmic radiation. In addition, the deployment of liquid-based detector media presents a challenge in reactor facilities. We are currently developing a detector system that has the potential to operate above ground and circumvent deployment problems associated with a liquid detection media: the system is composed of segments of plastic scintillator surroundedmore » by 6LiF/ZnS:Ag. ZnS:Ag is a radio-luminescent phosphor used to detect the neutron capture products of lithium-6. Because of its long decay time compared to standard plastic scintillators, pulse-shape discrimination can be used to distinguish positron and neutron interactions resulting from the inverse beta decay (IBD) of antineutrinos within the detector volume, reducing both accidental and correlated backgrounds. Segmentation further reduces backgrounds by identifying the positron’s annihilation gammas, which are absent for most correlated and uncorrelated backgrounds. This work explores different configurations in order to maximize the size of the detector segments without reducing the intrinsic neutron detection efficiency. We believe this technology will ultimately be applicable to potential safeguards scenarios such as those recently described.« less

Proton-decaying, light nuclei accessed via the invariant-mass method

NASA Astrophysics Data System (ADS)

Brown, Kyle

2017-01-01

Two-nucleon decay is the most recently discovered nuclear decay mode. For proton-rich nuclei, the majority of multi-proton decays occur via sequential steps of one-proton emission. Direct two-proton (2p) decay was believed to occur only in even-Z nuclei beyond the proton drip line where one-proton decay is energy forbidden. This has been observed for the ground states of around a dozen nuclei including 6Be, the lightest case, and 54Zn, the heaviest case. Direct 2p decay has also recently been observed for isobaric analog states where all possible 1p intermediates are either isospin allowed and energy forbidden, or energy-allowed and isospin forbidden. For light proton emitters, the lifetimes are short enough that the invariant-mass technique is ideal for measuring the decay energy, intrinsic width and, for multi-proton decays, the momentum correlations between the fragments. I will describe recent measurements of proton emitters using the invariant-mass technique with the High Resolution Array (HiRA). I will present a new, high-statistics measurement on the sequential 2p decay of excited states in 17Ne. Measuring the momentum correlations between the decay fragments allow us to determine the 1p intermediate state through which the decay proceeds. I will present data on the isobaric-analog pair 8C and 8BIAS, which highlight the two known types of direct 2p decay. I will also present the first observation of 17Na, which is unbound with respect to three-proton emission. Finally I will present a new measurement on the width of the first-excited state of 9C and compare to recent theoretical calculations.

AMS-02 positron excess and indirect detection of three-body decaying dark matter

NASA Astrophysics Data System (ADS)

Cheng, Hsin-Chia; Huang, Wei-Chih; Huang, Xiaoyuan; Low, Ian; Sming Tsai, Yue-Lin; Yuan, Qiang

2017-03-01

We consider indirect detection of meta-stable dark matter particles decaying into a stable neutral particle and a pair of standard model fermions. Due to the softer energy spectra from the three-body decay, such models could potentially explain the AMS-02 positron excess without being constrained by the Fermi-LAT gamma-ray data and the cosmic ray anti-proton measurements. We scrutinize over different final state fermions, paying special attention to handling of the cosmic ray background and including various contributions from cosmic ray propagation with the help of the LIKEDM package. It is found that primary decays into an electron-positron pair and a stable neutral particle could give rise to the AMS-02 positron excess and, at the same time, stay unscathed against the gamma-ray and anti-proton constraints. Decays to a muon pair or a mixed flavor electron-muon pair may also be viable depending on the propagation models. Decays to all other standard model fermions are severely disfavored.

Post flooding damage assessment of earth dams and historical reservoirs using non-invasive geophysical techniques

NASA Astrophysics Data System (ADS)

Sentenac, Philippe; Benes, Vojtech; Budinsky, Vladimir; Keenan, Helen; Baron, Ron

2017-11-01

This paper describes the use of four geophysical techniques to map the structural integrity of historical earth reservoir embankments which are susceptible to natural decay with time. The four techniques that were used to assess the post flood damage were 1. A fast scanning technique using a dipole electromagnetic profile apparatus (GEM2), 2. Electrical Resistivity Tomography (ERT) in order to obtain a high resolution image of the shape of the damaged/seepage zone, 3. Self-Potential surveys were carried out to relate the detected seepage evolution and change of the water displacement inside the embankment, 4. The washed zone in the areas with piping was characterised with microgravimetry. The four geophysical techniques used were evaluated against the case studies of two reservoirs in South Bohemia, Czech Republic. A risk approach based on the Geophysical results was undertaken for the reservoir embankments. The four techniques together enabled a comprehensive non-invasive assessment whereby remedial action could be recommended where required. Conclusions were also drawn on the efficiency of the techniques to be applied for embankments with wood structures.

Development of a sensitive setup for laser spectroscopy studies of very exotic calcium isotopes

NASA Astrophysics Data System (ADS)

Garcia Ruiz, R. F.; Gorges, C.; Bissell, M.; Blaum, K.; Gins, W.; Heylen, H.; Koenig, K.; Kaufmann, S.; Kowalska, M.; Krämer, J.; Lievens, P.; Malbrunot-Ettenauer, S.; Neugart, R.; Neyens, G.; Nörtershäuser, W.; Yordanov, D. T.; Yang, X. F.

2017-04-01

An experimental setup for sensitive high-resolution measurements of hyperfine structure spectra of exotic calcium isotopes has been developed and commissioned at the COLLAPS beam line at ISOLDE, CERN. The technique is based on the radioactive detection of decaying isotopes after optical pumping and state selective neutralization (ROC) (Vermeeren et al 1992 Phys. Rev. Lett. 68 1679). The improvements and developments necessary to extend the applicability of the experimental technique to calcium isotopes produced at rates as low as few ions s-1 are discussed. Numerical calculations of laser-ion interaction and ion-beam simulations were explored to obtain the optimum performance of the experimental setup. Among the implemented features are a multi-step optical pumping region for sensitive measurements of isotopes with hyperfine splitting, a high-voltage platform for adequate control of low-energy ion beams and simultaneous β-detection of neutralized and remaining ions. The commissioning of the experimental setup, and the first online results on neutron-rich calcium isotopes are presented.

Dynamics of Functionalized Surface Molecular Monolayers Studied with Ultrafast Infrared Vibrational Spectroscopy

PubMed Central

Rosenfeld, Daniel E.; Nishida, Jun; Yan, Chang; Gengeliczki, Zsolt; Smith, Brian J.; Fayer, Michael D.

2012-01-01

The structural dynamics of thin films consisting of tricarbonyl (1,10-phenanthroline)rhenium chloride (RePhen(CO)3Cl) linked to an alkyl silane monolayer through a triazole linker synthesized on silica-on-calcium-fluoride substrates are investigated using ultrafast infrared (IR) techniques. Ultrafast 2D IR vibrational echo experiments and polarization selective heterodyne detected transient grating (HDTG) measurements, as well as polarization dependent FT-IR and AFM experiments are employed to study the samples. The vibrational echo experiments measure spectral diffusion, while the HDTG experiments measure the vibrational excited state population relaxation and investigate the vibrational transition dipole orientational anisotropy decay. To investigate the anticipated impact of vibrational excitation transfer, which can be caused by the high concentration of RePhen(CO)3Cl in the monolayer, a concentration dependence of the spectral diffusion is measured. To generate a range of concentrations, mixed monolayers consisting of both hydrogen terminated and triazole/RePhen(CO)3Cl terminated alkyl silanes are synthesized. It is found that the measured rate of spectral diffusion is independent of concentration, with all samples showing spectral diffusion of 37 ± 6 ps. To definitively test for vibrational excitation transfer, polarization selective HDTG experiments are conducted. Excitation transfer will cause anisotropy decay. Polarization resolved heterodyne detected transient grating spectroscopy is sensitive to anisotropy decay (depolarization) caused by excitation transfer and molecular reorientation. The HDTG experiments show no evidence of anisotropy decay on the appropriate time scale, demonstrating the absence of excitation transfer the RePhen(CO)3Cl. Therefore the influence of excitation transfer on spectral diffusion is inconsequential in these samples, and the vibrational echo measurements of spectral diffusion report solely on structural dynamics. A small amount of very fast (~2 ps time scale) anisotropy decay is observed. The decay is concentration independent, and is assigned to wobbling-in-a-cone orientational motions of the RePhen(CO)3Cl. Theoretical calculations reported previously for experiments on a single concentration of the same type of sample suggested the presence of some vibrational excitation transfer and excitation transfer induced spectral diffusion. Possible reasons for the experimentally observed lack of excitation transfer in these high concentration samples are discussed. PMID:23259027

Annual Continuation And Progress Report For Low-Energy Nuclear Physics Research At Lawrence Livermore National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scielzo, N. D.; Wu, C.

2015-10-27

(I)In this project, the Beta-­decay Paul Trap, an open-­geometry RFQ ion trap that can be instrumented with sophisticated radiation detection arrays, is used for precision β-­decay studies. Measurements of β-­decay angular correlations, which are sensitive to exotic particles and other phenomena beyond the Standard Model (SM) of particle physics that may occur at the TeV-­energy scale, are being performed by taking advantage of the favorable properties of the mirror 8Li and 8B β ± decays and the benefits afforded by using trapped ions. By detecting the β and two α particles emitted in these decays, the complete kinematics can bemore » reconstructed. This allows a simultaneous measurement of the β-­n, β-­n-­α, and β-α correlations and a determination of the neutrino energy and momentum event by event. In addition, the 8B neutrino spectrum, of great interest in solar neutrino oscillation studies, can be determined in a new way. Beta-­delayed neutron spectroscopy is also being performed on neutron-­rich isotopes by studying the β-­decay recoil ions that emerge from the trap with high efficiency, good energy resolution, and practically no backgrounds. This novel technique is being used to study isotopes of mass-­number A~130 in the vicinity of the N=82 neutron magic number to help understand the rapid neutron-­capture process (r-­process) that creates many of the heavy isotopes observed in the cosmos. (II)A year-long CHICO2 campaign at ANL/ATLAS together with GRETINA included a total of 10 experiments, seven with the radioactive beams from CARIBU and three with stable beams, with 82 researchers involved from 27 institutions worldwide. CHICO2 performed flawlessly during this long campaign with achieved position resolution matching to that of GRETINA, which greatly enhances the sensitivity in the study of nuclear γ-­ray spectroscopy. This can be demonstrated in our results on 144Ba and 146Ba where the octupole deformation is evident from the measured B(E3; 3 -→0 +) strengths that significantly greater than the theoretical predictions. We anticipate that CHICO2 will continue to be a viable charged-­particle detector for the research need of the low-­energy nuclear physics community.« less

Neutron detection by scintillation of noble-gas excimers

NASA Astrophysics Data System (ADS)

McComb, Jacob Collin

Neutron detection is a technique essential to homeland security, nuclear reactor instrumentation, neutron diffraction science, oil-well logging, particle physics and radiation safety. The current shortage of helium-3, the neutron absorber used in most gas-filled proportional counters, has created a strong incentive to develop alternate methods of neutron detection. Excimer-based neutron detection (END) provides an alternative with many attractive properties. Like proportional counters, END relies on the conversion of a neutron into energetic charged particles, through an exothermic capture reaction with a neutron absorbing nucleus (10B, 6Li, 3He). As charged particles from these reactions lose energy in a surrounding gas, they cause electron excitation and ionization. Whereas most gas-filled detectors collect ionized charge to form a signal, END depends on the formation of diatomic noble-gas excimers (Ar*2, Kr*2,Xe* 2) . Upon decaying, excimers emit far-ultraviolet (FUV) photons, which may be collected by a photomultiplier tube or other photon detector. This phenomenon provides a means of neutron detection with a number of advantages over traditional methods. This thesis investigates excimer scintillation yield from the heavy noble gases following the boron-neutron capture reaction in 10B thin-film targets. Additionally, the thesis examines noble-gas excimer lifetimes with relationship to gas type and gas pressure. Experimental data were collected both at the National Institute of Standards and Technology (NIST) Center for Neutron Research, and on a newly developed neutron beamline at the Maryland University Training Reactor. The components of the experiment were calibrated at NIST and the University of Maryland, using FUV synchrotron radiation, neutron imaging, and foil activation techniques, among others. Computer modeling was employed to simulate charged-particle transport and excimer photon emission within the experimental apparatus. The observed excimer scintillation yields from the 10B( n, alpha)7Li reaction are comparable to the yields of many liquid and solid neutron scintillators. Additionally, the observed slow triplet-state decay of neutron-capture-induced excimers may be used in a practical detector to discriminate neutron interactions from gamma-ray interactions. The results of these measurements and simulations will contribute to the development and optimization of a deployable neutron detector based on noble-gas excimer scintillation.

Early detection and progression of decay in L-joints and lap-joints in a moderate decay hazard zone

Treesearch

Carol A. Clausen; Terry L. Highley; Daniel L. Lindner

2006-01-01

Accelerated test methods are needed to evaluate the initiation and progression of decay in wood exposed aboveground. The relationship between test conditions and initiation of decay, however, is poorly understood. Southern pine and maple L-joints and lap-joints were exposed aboveground in a configuration that encouraged water entrapment at the Valley View Experimental...

Gaseous time projection chambers for rare event detection: results from the T-REX project. I. Double beta decay

NASA Astrophysics Data System (ADS)

Irastorza, I. G.; Aznar, F.; Castel, J.; Cebrián, S.; Dafni, T.; Galán, J.; Garcia, J. A.; Garza, J. G.; Gómez, H.; Herrera, D. C.; Iguaz, F. J.; Luzon, G.; Mirallas, H.; Ruiz, E.; Seguí, L.; Tomás, A.

2016-01-01

As part of the T-REX project, a number of R&D and prototyping activities have been carried out during the last years to explore the applicability of gaseous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) in rare event searches like double beta decay, axion research and low-mass WIMP searches. In both this and its companion paper, we compile the main results of the project and give an outlook of application prospects for this detection technique. While in the companion paper we focus on axions and WIMPs, in this paper we focus on the results regarding the measurement of the double beta decay (DBD) of 136Xe in a high pressure Xe (HPXe) TPC. Micromegas of the microbulk type have been extensively studied in high pressure Xe and Xe mixtures. Particularly relevant are the results obtained in Xe + trimethylamine (TMA) mixtures, showing very promising results in terms of gain, stability of operation, and energy resolution at high pressures up to 10 bar. The addition of TMA at levels of ~ 1% reduces electron diffusion by up to a factor of 10 with respect to pure Xe, improving the quality of the topological pattern, with a positive impact on the discrimination capability. Operation with a medium size prototype of 30 cm diameter and 38 cm of drift (holding about 1 kg of Xe at 10 bar in the fiducial volume, enough to contain high energy electron tracks in the detector volume) has allowed to test the detection concept in realistic experimental conditions. Microbulk Micromegas are able to image the DBD ionization signature with high quality while, at the same time, measuring its energy deposition with a resolution of at least a ~ 3% FWHM @ Qββ. This value was experimentally demonstrated for high-energy extended tracks at 10 bar, and is probably improvable down to the ~ 1% FWHM levels as extrapolated from low energy events. In addition, first results on the topological signature information (one straggling track ending in two blobs) show promising background discrimination capabilities out of reach of other experimental implementations. Moreover, microbulk Micromegas have very low levels of intrinsic radioactivity, and offer cost-effective scaling-up options. All these results demonstrate that Micromegas-read HPXe TPC remains a very competitive technique for the next generation DBD experiments.

Measurement of radon progenies using the Timepix detector.

PubMed

Bulanek, Boris; Jilek, Karel; Cermak, Pavel

2014-07-01

After an introduction of Timepix detector, results of these detectors with silicon and cadmium telluride detection layer in assessment of activity of short-lived radon decay products are presented. They were collected on an open-face filter by means of one-grab sampling method from the NRPI radon chamber. Activity of short-lived radon decay products was estimated from measured alpha decays of 218,214Po. The results indicate very good agreement between the use of both Timepix detectors and an NRPI reference instrument, continuous monitor Fritra 4. Low-level detection limit for EEC was estimated to be 41 Bq m(-3) for silicon detection layer and 184 Bq m(-3) for CdTe detection layer, respectively. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Quality Characterization of Silicon Bricks using Photoluminescence Imaging and Photoconductive Decay: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, S.; Yan, F.; Zaunbrecher, K.

2012-06-01

Imaging techniques can be applied to multicrystalline silicon solar cells throughout the production process, which includes as early as when the bricks are cut from the cast ingot. Photoluminescence (PL) imaging of the band-to-band radiative recombination is used to characterize silicon quality and defects regions within the brick. PL images of the brick surfaces are compared to minority-carrier lifetimes measured by resonant-coupled photoconductive decay (RCPCD). Photoluminescence images on silicon bricks can be correlated to lifetime measured by photoconductive decay and could be used for high-resolution characterization of material before wafers are cut. The RCPCD technique has shown the longest lifetimesmore » of any of the lifetime measurement techniques we have applied to the bricks. RCPCD benefits from the low-frequency and long-excitation wavelengths used. In addition, RCPCD is a transient technique that directly monitors the decay rate of photoconductivity and does not rely on models or calculations for lifetime. The measured lifetimes over brick surfaces have shown strong correlations to the PL image intensities; therefore, this correlation could then be used to transform the PL image into a high-resolution lifetime map.« less

Nondestructive evaluation of incipient decay in hardwood logs

Treesearch

Xiping Wang; Jan Wiedenbeck; Robert J. Ross; John W. Forsman; John R. Erickson; Crystal Pilon; Brian K. Brashaw

2005-01-01

Decay can cause significant damage to high-value hardwood timber. New nondestructive evaluation (NDE) technologies are urgently needed to effectively detect incipient decay in hardwood timber at the earliest possible stage. Currently, the primary means of inspecting timber relies on visual assessment criteria. When visual inspections are used exclusively, they provide...

Polarization spectroscopy of the sodium dimer utilizing a triple-resonance technique in the presence of argon

NASA Astrophysics Data System (ADS)

Arndt, Phillip; Horton, Timothy; McFarland, Jacob; Bayram, Burcin; Miami University Spectroscopy Team

2015-05-01

The collisional dynamics of molecular sodium in the 61Σg electronic state is under investigation using a triple resonance technique in the presence of argon. A continuous wave ring dye laser is used to populate specific rovibrational levels of the A1Σu electronic state. A pump-probe technique is then employed where the pump laser populates the 61Σg state, and the probe laser dumps the population to the B1Σu state. From this level, fluorescence is detected as the system decays to the X1Σg state. We measure the polarization of this signal in the presence of various argon pressures. We will present our current work as well as the processes involved in the experiment. Financial support from the National Science Foundation (Grant No. NSF-PHY-1309571) is gratefully acknowledged.

Assessing the Ability of Ground-Penetrating Radar to Detect Fungal Decay in Douglas-Fir Beams

Treesearch

Christopher Adam Senalik; James Wacker; Xiping Wang; F. Jalinoos

2016-01-01

This paper describes the testing plan and current progress for assessing the efficacy of using ground-penetrating radar (GPR) to detect fungal decay within Douglas-fir beams. Initially, the beams were assessed using a variety of physical, mechanical, and nondestructive evaluation (NDE) test methods including micro-resistance drilling, Janka hardness, ultrasonic...

Decay of motor memories in the absence of error

PubMed Central

Vaswani, Pavan A.; Shadmehr, Reza

2013-01-01

When motor commands are accompanied by an unexpected outcome, the resulting error induces changes in subsequent commands. However, when errors are artificially eliminated, changes in motor commands are not sustained, but show decay. Why does the adaptation-induced change in motor output decay in the absence of error? A prominent idea is that decay reflects the stability of the memory. We show results that challenge this idea and instead suggest that motor output decays because the brain actively disengages a component of the memory. Humans adapted their reaching movements to a perturbation and were then introduced to a long period of trials in which errors were absent (error-clamp). We found that, in some subjects, motor output did not decay at the onset of the error-clamp block, but a few trials later. We manipulated the kinematics of movements in the error-clamp block and found that as movements became more similar to subjects’ natural movements in the perturbation block, the lag to decay onset became longer and eventually reached hundreds of trials. Furthermore, when there was decay in the motor output, the endpoint of decay was not zero, but a fraction of the motor memory that was last acquired. Therefore, adaptation to a perturbation installed two distinct kinds of memories: one that was disengaged when the brain detected a change in the task, and one that persisted despite it. Motor memories showed little decay in the absence of error if the brain was prevented from detecting a change in task conditions. PMID:23637163

Near-Unity Internal Quantum Efficiency of Luminescent Silicon Nanocrystals with Ligand Passivation.

PubMed

Sangghaleh, Fatemeh; Sychugov, Ilya; Yang, Zhenyu; Veinot, Jonathan G C; Linnros, Jan

2015-07-28

Spectrally resolved photoluminescence (PL) decays were measured for samples of colloidal, ligand-passivated silicon nanocrystals. These samples have PL emission energies with peak positions in the range ∼1.4-1.8 eV and quantum yields of ∼30-70%. Their ensemble PL decays are characterized by a stretched-exponential decay with a dispersion factor of ∼0.8, which changes to an almost monoexponential character at fixed detection energies. The dispersion factors and decay rates for various detection energies were extracted from spectrally resolved curves using a mathematical approach that excluded the effect of homogeneous line width broadening. Since nonradiative recombination would introduce a random lifetime variation, leading to a stretched-exponential decay for an ensemble, we conclude that the observed monoexponential decay in size-selected ensembles signifies negligible nonradiative transitions of a similar strength to the radiative one. This conjecture is further supported as extracted decay rates agree with radiative rates reported in the literature, suggesting 100% internal quantum efficiency over a broad range of emission wavelengths. The apparent differences in the quantum yields can then be explained by a varying fraction of "dark" or blinking nanocrystals.

Impact of the quenching of gA on the sensitivity of 0 ν β β experiments

NASA Astrophysics Data System (ADS)

Suhonen, Jouni

2017-11-01

Detection of the neutrinoless β β (0 ν β β ) decay is of high priority in the particle- and neutrino-physics communities. The detectability of this decay mode is strongly influenced by the value of the weak axial-vector coupling constant gA. The recent nuclear-model analyses of β and β β decays suggest that the value of gA could be dramatically quenched, reaching ratios of gAfree/gA≈4 , where gAfree=1.27 is the free, neutron-decay, value of gA. The effects of this quenching appear devastating for the sensitivity of the present and future 0 ν β β experiments since the fourth power of this ratio scales the 0 ν β β half-lives. This, in turn, could lead to some two orders of magnitude less sensitivity for the 0 ν β β experiments. In the present article it is shown that by using a consistent approach to both the two-neutrino β β and 0 ν β β decays by the proton-neutron quasiparticle random-phase approximation, the feared two-orders-of-magnitude reduction in the sensitivity of the 0 ν β β experiments actually shrinks to a reduction by factors in the range 2 -6 . This certainly has dramatic consequences for the potential to detect the 0 ν β β decay.

Heterodyne-detected dispersed vibrational echo spectroscopy.

PubMed

Jones, Kevin C; Ganim, Ziad; Tokmakoff, Andrei

2009-12-24

We develop heterodyned dispersed vibrational echo spectroscopy (HDVE) and demonstrate the new capabilities in biophysical applications. HDVE is a robust ultrafast technique that provides a characterization of the real and imaginary components of third-order nonlinear signals with high sensitivity and single-laser-shot capability and can be used to extract dispersed pump-probe and dispersed vibrational echo spectra. Four methods for acquiring HDVE phase and amplitude spectra were compared: Fourier transform spectral interferometry, a new phase modulation spectral interferometry technique, and combination schemes. These extraction techniques were demonstrated in the context of protein amide I spectroscopy. Experimental HDVE and heterodyned free induction decay amide I spectra were explicitly compared to conventional dispersed pump-probe, dispersed vibrational echo, and absorption spectra. The new capabilities of HDVE were demonstrated by acquiring single-shot spectra and melting curves of ubiquitin and concentration-dependent spectra of insulin suitable for extracting the binding constant for dimerization. The introduced techniques will prove particularly useful in transient experiments, studying irreversible reactions, and micromolar concentration studies of small proteins.

Improving the limits of detection of low background alpha emission measurements

NASA Astrophysics Data System (ADS)

McNally, Brendan D.; Coleman, Stuart; Harris, Jack T.; Warburton, William K.

2018-01-01

Alpha particle emission - even at extremely low levels - is a significant issue in the search for rare events (e.g., double beta decay, dark matter detection). Traditional measurement techniques require long counting times to measure low sample rates in the presence of much larger instrumental backgrounds. To address this, a commercially available instrument developed by XIA uses pulse shape analysis to discriminate alpha emissions produced by the sample from those produced by other surfaces of the instrument itself. Experience with this system has uncovered two residual sources of background: cosmogenics and radon emanation from internal components. An R&D program is underway to enhance the system and extend the pulse shape analysis technique further, so that these residual sources can be identified and rejected as well. In this paper, we review the theory of operation and pulse shape analysis techniques used in XIA's alpha counter, and briefly explore data suggesting the origin of the residual background terms. We will then present our approach to enhance the system's ability to identify and reject these terms. Finally, we will describe a prototype system that incorporates our concepts and demonstrates their feasibility.

Total absorption studies of high priority decays for reactor applications: 86 Br and 91 Rb

DOE PAGES

Algora, A.; Rice, S.; Guadilla, V.; ...

2017-09-13

Preliminary results from beta decay studies of nuclei that are important for reactor applications are presented. The beta decays have been studied using the total absorption technique (TAS) and the pure beams provided by the JYFLTRAP system at the IGISOL facility of the University of Jyväskylä.

Complete ? -decay pattern for the high-priority decay-heat isotopes I 137 and Xe 137 determined using total absorption spectroscopy

DOE PAGES

Rasco, B. C.; Rykaczewski, K. P.; Fijalkowska, A.; ...

2017-05-31

We measured the complete -decay intensities of 137I and 137Xe with the Modular Total Absorption Spectrometer at Oak Ridge National Laboratory. We describe a novel technique for measuring the -delayed neutron energy spectrum, which also provides a measurement of the -neutron branching ratio, P n.

Analysis and Validation of Contactless Time-Gated Interrogation Technique for Quartz Resonator Sensors

PubMed Central

Baù, Marco; Ferrari, Marco; Ferrari, Vittorio

2017-01-01

A technique for contactless electromagnetic interrogation of AT-cut quartz piezoelectric resonator sensors is proposed based on a primary coil electromagnetically air-coupled to a secondary coil connected to the electrodes of the resonator. The interrogation technique periodically switches between interleaved excitation and detection phases. During the excitation phase, the resonator is set into vibration by a driving voltage applied to the primary coil, whereas in the detection phase, the excitation signal is turned off and the transient decaying response of the resonator is sensed without contact by measuring the voltage induced back across the primary coil. This approach ensures that the readout frequency of the sensor signal is to a first order approximation independent of the interrogation distance between the primary and secondary coils. A detailed theoretical analysis of the interrogation principle based on a lumped-element equivalent circuit is presented. The analysis has been experimentally validated on a 4.432 MHz AT-cut quartz crystal resonator, demonstrating the accurate readout of the series resonant frequency and quality factor over an interrogation distance of up to 2 cm. As an application, the technique has been applied to the measurement of liquid microdroplets deposited on a 4.8 MHz AT-cut quartz crystal. More generally, the proposed technique can be exploited for the measurement of any physical or chemical quantities affecting the resonant response of quartz resonator sensors. PMID:28574459

Analysis and Validation of Contactless Time-Gated Interrogation Technique for Quartz Resonator Sensors.

PubMed

Baù, Marco; Ferrari, Marco; Ferrari, Vittorio

2017-06-02

A technique for contactless electromagnetic interrogation of AT-cut quartz piezoelectric resonator sensors is proposed based on a primary coil electromagnetically air-coupled to a secondary coil connected to the electrodes of the resonator. The interrogation technique periodically switches between interleaved excitation and detection phases. During the excitation phase, the resonator is set into vibration by a driving voltage applied to the primary coil, whereas in the detection phase, the excitation signal is turned off and the transient decaying response of the resonator is sensed without contact by measuring the voltage induced back across the primary coil. This approach ensures that the readout frequency of the sensor signal is to a first order approximation independent of the interrogation distance between the primary and secondary coils. A detailed theoretical analysis of the interrogation principle based on a lumped-element equivalent circuit is presented. The analysis has been experimentally validated on a 4.432 MHz AT-cut quartz crystal resonator, demonstrating the accurate readout of the series resonant frequency and quality factor over an interrogation distance of up to 2 cm. As an application, the technique has been applied to the measurement of liquid microdroplets deposited on a 4.8 MHz AT-cut quartz crystal. More generally, the proposed technique can be exploited for the measurement of any physical or chemical quantities affecting the resonant response of quartz resonator sensors.

Thermographic Phosphors for High Temperature Measurements: Principles, Current State of the Art and Recent Applications

PubMed Central

Khalid, Ashiq Hussain; Kontis, Konstantinos

2008-01-01

This paper reviews the state of phosphor thermometry, focusing on developments in the past 15 years. The fundamental principles and theory are presented, and the various spectral and temporal modes, including the lifetime decay, rise time and intensity ratio, are discussed. The entire phosphor measurement system, including relative advantages to conventional methods, choice of phosphors, bonding techniques, excitation sources and emission detection, is reviewed. Special attention is given to issues that may arise at high temperatures. A number of recent developments and applications are surveyed, with examples including: measurements in engines, hypersonic wind tunnel experiments, pyrolysis studies and droplet/spray/gas temperature determination. They show the technique is flexible and successful in measuring temperatures where conventional methods may prove to be unsuitable. PMID:27873836

Histone mRNA degradation in vivo: the first detectable step occurs at or near the 3' terminus.

PubMed Central

Ross, J; Peltz, S W; Kobs, G; Brewer, G

1986-01-01

The first detectable step in the degradation of human H4 histone mRNA occurs at the 3' terminus in a cell-free mRNA decay system (J. Ross and G. Kobs, J. Mol. Biol. 188:579-593, 1986). Most or all of the remainder of the mRNA is then degraded in a 3'-to-5' direction. The experiments described here were designed to determine whether a similar degradation pathway is followed in whole cells. Two sets of short-lived histone mRNA decay products were detected in logarithmically growing erythroleukemia (K562) cells. These products, designated the -5 and -12 RNAs, were generated by the loss of approximately 4 to 6 and 11 to 13 nucleotides, respectively, from the 3' terminus of histone mRNA. The same decay products were observed after a brief incubation in vitro. They were in low abundance or absent from cells that were not degrading histone mRNA. In contrast, they were readily detectable in cells that degraded the mRNA at an accelerated rate, i.e., in cells cultured with a DNA synthesis inhibitor, either cytosine arabinoside or hydroxyurea. During the initial stages of the decay process, as the 3' terminus of the mRNA was being degraded, the 5'-terminal region remained intact. These results indicate that the first detectable step in human H4 histone mRNA decay occurs at the 3' terminus and that degradation proceeds 3' to 5', both in cells and in cell-free reactions. Images PMID:3467177

Histone mRNA degradation in vivo: the first detectable step occurs at or near the 3' terminus.

PubMed

Ross, J; Peltz, S W; Kobs, G; Brewer, G

1986-12-01

The first detectable step in the degradation of human H4 histone mRNA occurs at the 3' terminus in a cell-free mRNA decay system (J. Ross and G. Kobs, J. Mol. Biol. 188:579-593, 1986). Most or all of the remainder of the mRNA is then degraded in a 3'-to-5' direction. The experiments described here were designed to determine whether a similar degradation pathway is followed in whole cells. Two sets of short-lived histone mRNA decay products were detected in logarithmically growing erythroleukemia (K562) cells. These products, designated the -5 and -12 RNAs, were generated by the loss of approximately 4 to 6 and 11 to 13 nucleotides, respectively, from the 3' terminus of histone mRNA. The same decay products were observed after a brief incubation in vitro. They were in low abundance or absent from cells that were not degrading histone mRNA. In contrast, they were readily detectable in cells that degraded the mRNA at an accelerated rate, i.e., in cells cultured with a DNA synthesis inhibitor, either cytosine arabinoside or hydroxyurea. During the initial stages of the decay process, as the 3' terminus of the mRNA was being degraded, the 5'-terminal region remained intact. These results indicate that the first detectable step in human H4 histone mRNA decay occurs at the 3' terminus and that degradation proceeds 3' to 5', both in cells and in cell-free reactions.

The use of portable Non-Destructive Techniques for material decay characterisation of palaeontological Geosites

NASA Astrophysics Data System (ADS)

Gomez-Heras, Miguel; Ortega-Becerril, Jose A.; López-Martínez, Jerónimo; Oliva-Urcia, Belén; Maestro, Adolfo

2017-04-01

The conservation of both natural and cultural heritage is regarded as a priority for humankind and it is therefore recognised by the UNESCO since the Convention Concerning the Protection of the World Cultural and Natural Heritage in 1972. The International Union of Geological Sciences launched in 1995 in collaboration with UNESCO the Global Geosites programme to create an inventory of geological heritage sites. Although the conservation of Geosites may face different issues to those of stone-built cultural heritage, much could be learnt from techniques initially used to characterise weathering and material decay in stone-built cultural heritage. This is especially the case for portable Non-Destructive Techniques (NDT). Portable NDT allow characterising on-site the degree of material decay and are, therefore, a good way to assess the state of conservation of certain Geosites whose relevance lies on localised features. Geosites chosen for the outstanding occurrence of dinosaur ichnites, such as those in the Cameros Massif (north-western part of the Iberian Range, Spain), are a good example of this. This communication explores the potential of portable NDT to characterise the state of decay and susceptibility to further decay of dinosaur ichnites in the Cameros Massif. These techniques included: Ultrasound Pulse Velocity determination, Leeb hardness rebound test, colour determination by means of a spectrophotometer and thermal imaging obtained with an infrared camera. Results will show the potential of these techniques to characterise differential weathering patterns in both individual ichnites as well as on tracks in addition to assessing the possible effects of conservation strategies on the long-term preservation of the mentioned Geosites. Research funded by Madrid's Regional Government project Geomateriales 2 S2013/MIT-2914

Active background suppression with the liquid argon scintillation veto of GERDA Phase II

NASA Astrophysics Data System (ADS)

Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Selivanenko, O.; Shevzik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

2017-09-01

The observation of neutrinoless double beta decay would allow to shed light onto the particle nature of neutrinos. Gerda is aiming to perform a background-free search for this process using high purity germanium detectors enriched in 76Ge operated in liquid argon. This goal relies on the application of active background suppression techniques. A low background light instrumentation has been installed for Phase II to detect events with coincident energy deposition in the nearby liquid argon. The intended background index of ˜10-3 cts/(keV·ky·yr) has been confirmed.

How to make Raman-inactive helium visible in Raman spectra of tritium-helium gas mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schloesser, M.; Pakari, O.; Rupp, S.

2015-03-15

Raman spectroscopy, a powerful method for the quantitative compositional analysis of molecular gases, e.g. mixtures of hydrogen isotopologues, is not able to detect monoatomic species like helium. This deficit can be overcome by using radioluminescence emission from helium atoms induced by β-electrons from tritium decay. We present theoretical considerations and combined Raman/radioluminescence spectra. Furthermore, we discuss the linearity of the method together with validation measurements for determining the pressure dependence. Finally, we conclude how this technique can be used for samples of helium with traces of tritium, and vice versa. (authors)

Evaluation of a portable MOS electronic nose to detect root rots in shade tree species

Treesearch

Manuela Baietto; Letizia Pozzi; Alphus Dan Wilson; Daniele Bassi

2013-01-01

The early detection of wood decays in high-value standing trees is very important in urban areas because mitigating control measures must be implemented long before tree failures result in property damage or injuries to citizens. Adverse urban environments increase physiological stresses in trees, causing greater susceptibility to attacks by pathogenic decay fungi. The...

Acoustic tomography for decay detection in black cherry trees

Treesearch

Xiping Wang; Jan Wiedenbeck; Shanqing Liang

2009-01-01

This study investigated the potential of using acoustic tomography for detecting internal decay in high-value hardwood trees in the forest. Twelve black cherry (Prunus serotina) trees that had a wide range of physical characteristics were tested in a stand of second-growth hardwoods in Kane, PA, using a PiCUS Sonic Tomograph tool. The trees were felled after the field...

Nondestructive detection of decay in living trees

Treesearch

Bertil Larsson; Bengt Bengtsson; Mats Gustaffson

2004-01-01

We used a four-point resistivity method to detect wood decay in living trees. low-frequency alternating current was applied to the stem and the induced voltage measured between two points along the stem. The effective resistivity of the stem was estimated based on stem cross-sectional area. A comparison within a group of trees showed that trees with butt rot had an...

Need for new caries detection methods

NASA Astrophysics Data System (ADS)

Young, Douglas A.; Featherstone, John D. B.

1999-05-01

Dental caries (tooth decay) continues to be a major problems for adults as well as children, even though great advances have been made in preventive methods in the last 20 years. New methods for the management of caries will work best if lesions can be detected at an early stage and chemical rather than physical intervention can take place, thereby preserving the natural tooth structure and helping the saliva to heal, or remineralize, the areas of early decay. Clinical detection of caries in the US relies on visual examination, tactile with hand held explorer, and conventional radiographs, all of which are inadequate for the occlusal (biting) surfaces of the teeth where most of the decay now occurs. The dentist often has to explore by drilling with a dental bur to confirm early decay in these areas. New method that can determine the extent and degree of subsurface lesions in these surfaces non-destructively are essential for further advances in the clinical management of dental caries. Optical methods, which exploit the differences between sound and carious enamel and dentin, show great promise for the accurate detection of these lesions. Two or three- dimensional images, which include a measure of severity will be needed.

First measurement of the isoscalar excitation above the neutron emission threshold of the Pygmy Dipole Resonance in 68Ni

NASA Astrophysics Data System (ADS)

Martorana, N. S.; Cardella, G.; Lanza, E. G.; Acosta, L.; Andrés, M. V.; Auditore, L.; Catara, F.; De Filippo, E.; De Luca, S.; Dell'Aquila, D.; Gnoffo, B.; Lanzalone, G.; Lombardo, I.; Maiolino, C.; Norella, S.; Pagano, A.; Pagano, E. V.; Papa, M.; Pirrone, S.; Politi, G.; Quattrocchi, L.; Rizzo, F.; Russotto, P.; Santonocito, D.; Trifirò, A.; Trimarchi, M.; Vigilante, M.; Vitturi, A.

2018-07-01

The excitation of the Pygmy Dipole Resonance (PDR) in the 68Ni nucleus, above the neutron emission threshold, via an isoscalar probe has been observed for the first time. The excitation has been produced in reactions where a 68Ni beam, obtained by the fragmentation of a 70Zn primary beam at INFN-LNS, impinged on a 12C target. The γ-ray decay was detected using the CsI(Tl) detectors of the CHIMERA multidetector sphere. The 68Ni isotope as well as other heavy ion fragments were detected using the FARCOS array. The population of the PDR was evidenced by comparing the detected γ-ray energy spectra with statistical code calculations. The isotopic resolution of the detection system allows also to directly compare neutron decay channels with the 68Ni channel, better evidencing the PDR decay response function. This comparison allows also the extraction of the PDR cross section and the relative γ-ray angular distribution. The measured γ-ray angular distribution confirms the E1 character of the transition. The γ decay cross section for the excitation of the PDR was measured to be 0.32 mb with a 18% of statistical error.

Astroparticle Physics: Detectors for Cosmic Rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salazar, Humberto; Villasenor, Luis

2006-09-25

We describe the work that we have done over the last decade to design and construct instruments to measure properties of cosmic rays in Mexico. We describe the measurement of the muon lifetime and the ratio of positive to negative muons in the natural background of cosmic ray muons at 2000 m.a.s.l. Next we describe the detection of decaying and crossing muons in a water Cherenkov detector as well as a technique to separate isolated particles. We also describe the detection of isolated muons and electrons in a liquid scintillator detector and their separation. Next we describe the detection ofmore » extensive air showers (EAS) with a hybrid detector array consisting of water Cherenkov and liquid scintillator detectors, located at the campus of the University of Puebla. Finally we describe work in progress to detect EAS at 4600 m.a.s.l. with a water Cherenkov detector array and a fluorescence telescope at the Sierra Negra mountain.« less

Light vector mesons in the nuclear medium

NASA Astrophysics Data System (ADS)

Wood, M. H.; Nasseripour, R.; Weygand, D. P.; Djalali, C.; Tur, C.; Mosel, U.; Muehlich, P.; Adams, G.; Amaryan, M. J.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Battaglieri, M.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Blaszczyk, L.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Carnahan, B.; Casey, L.; Chen, S.; Cheng, L.; Cole, P. L.; Collins, P.; Coltharp, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Dashyan, N.; de Vita, R.; de Sanctis, E.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Dickson, R.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Feldman, G.; Feuerbach, R. J.; Fradi, A.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gordon, C. I. O.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hakobyan, R. S.; Hanretty, C.; Hardie, J.; Hassall, N.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Kellie, J. D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Kossov, M.; Krahn, Z.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, Ji; Livingston, K.; Lu, H. Y.; MacCormick, M.; Markov, N.; Mattione, P.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Munevar, E.; Mutchler, G. S.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Pereira, S. Anefalos; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Sabatié, F.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Sharov, D.; Shvedunov, N. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Sokhan, D.; Stavinsky, A.; Stepanyan, S.; Stepanyan, S. S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Williams, M.; Wolin, E.; Yegneswaran, A.; Zana, L.; Zhang, B.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2008-07-01

The light vector mesons (ρ,ω, and ϕ) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the ρ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to e+e-. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The ρ-meson mass spectrum was extracted after the ω and ϕ signals were removed in a nearly model-independent way. Comparisons were made between the ρ mass spectra from the heavy targets (A>2) with the mass spectrum extracted from the deuterium target. With respect to the ρ-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body effects such as collisional broadening and Fermi motion.

Predicting thunderstorm evolution using ground-based lightning detection networks

NASA Technical Reports Server (NTRS)

Goodman, Steven J.

1990-01-01

Lightning measurements acquired principally by a ground-based network of magnetic direction finders are used to diagnose and predict the existence, temporal evolution, and decay of thunderstorms over a wide range of space and time scales extending over four orders of magnitude. The non-linear growth and decay of thunderstorms and their accompanying cloud-to-ground lightning activity is described by the three parameter logistic growth model. The growth rate is shown to be a function of the storm size and duration, and the limiting value of the total lightning activity is related to the available energy in the environment. A new technique is described for removing systematic bearing errors from direction finder data where radar echoes are used to constrain site error correction and optimization (best point estimate) algorithms. A nearest neighbor pattern recognition algorithm is employed to cluster the discrete lightning discharges into storm cells and the advantages and limitations of different clustering strategies for storm identification and tracking are examined.

Measurement of the Spin Relaxation Lifetime (T 1) in a One-Electron Strained-Si Accumulation-Mode Quantum Dot

NASA Astrophysics Data System (ADS)

Croke, Edward; Borselli, Matthew; Kiselev, Andrey; Deelman, Peter; Milosavljevic, Ivan; Alvarado-Rodriguez, Ivan; Ross, Richard; Schmitz, Adele; Gyure, Mark; Hunter, Andrew

2011-03-01

We report measurements of the spin-relaxation lifetime (T1) as a function of magnetic field in a strained-Si, accumulation-mode quantum dot. An integrated quantum-point contact (QPC) charge sensor was used to detect changes in dot occupancy as a function of bias applied to a single gate electrode. The addition spectra we obtained are consistent with theoretical predictions starting at N=0. The conductance of the charge sensor was measured by applying an AC voltage across the QPC and a 3 k Ω resistor. Lifetime measurements were conducted using a three-pulse technique consisting of a load, read, and flush sequence. T1 was measured by observing the decay of the spin bump amplitude as a function of the load pulse length. We measured decay times ranging from approximately 75 msec at 2T to 12 msec at 3T, consistent with previous reports and theoretical predictions. Sponsored by United States Department of Defense. Approved for Public Release, Distribution Unlimited.

Mitigation of radon and thoron decay products by filtration.

PubMed

Wang, Jin; Meisenberg, Oliver; Chen, Yongheng; Karg, Erwin; Tschiersch, Jochen

2011-09-01

Inhalation of indoor radon ((222)Rn) and thoron ((220)Rn) decay products is the most important source of exposure to ionizing radiation for the human respiratory tract. Decreasing ventilation rates due to energy saving reasons in new buildings suggest additional active mitigation techniques to reduce the exposure in homes with high radon and thoron concentrations but poor ventilation. Filtration techniques with HEPA filters and simple surgical mask material have been tested for their potential to reduce the indoor exposure in terms of the total effective dose for mixed radon and thoron indoor atmospheres. The tests were performed inside an experimental room providing stable conditions. Filtration (at filtration rates of 0.2 h(-1) and larger) removes attached radon and thoron decay products effectively but indoor aerosol as well. Therefore the concentration of unattached decay products (which have a higher dose coefficient) may increase. The decrease of the attached decay product concentrations could be theoretically described by a slowly decreasing exponential process. For attached radon decay products, it exhibited a faster but weaker removal process compared to attached thoron decay products (-70% for attached radon decay products and -80% for attached thoron decay products at a filtration rate of 0.5 h(-1) with an HEPA filter). The concentration of unattached thoron decay products increased distinctly during the filtration process (+300%) while that of unattached radon decay products rose only slightly though at a much higher level (+17%). In the theoretical description these observed differences could be attributed to the different half-lives of the nuclides. Considering both effects, reduced attached and increased unattached decay product concentrations, filtration could significantly decrease the total effective dose from thoron whereas the overall effect on radon dose is small. A permanent filtration is recommended because of the slow decrease of the thoron decay product concentrations. Copyright © 2011 Elsevier B.V. All rights reserved.

Imaging free radicals in organelles, cells, tissue, and in vivo with immuno-spin trapping.

PubMed

Mason, Ronald Paul

2016-08-01

The accurate and sensitive detection of biological free radicals in a reliable manner is required to define the mechanistic roles of such species in biochemistry, medicine and toxicology. Most of the techniques currently available are either not appropriate to detect free radicals in cells and tissues due to sensitivity limitations (electron spin resonance, ESR) or subject to artifacts that make the validity of the results questionable (fluorescent probe-based analysis). The development of the immuno-spin trapping technique overcomes all these difficulties. This technique is based on the reaction of amino acid- and DNA base-derived radicals with the spin trap 5, 5-dimethyl-1-pyrroline N-oxide (DMPO) to form protein- and DNA-DMPO nitroxide radical adducts, respectively. These adducts have limited stability and decay to produce the very stable macromolecule-DMPO-nitrone product. This stable product can be detected by mass spectrometry, NMR or immunochemistry by the use of anti-DMPO nitrone antibodies. The formation of macromolecule-DMPO-nitrone adducts is based on the selective reaction of free radical addition to the spin trap and is thus not subject to artifacts frequently encountered with other methods for free radical detection. The selectivity of spin trapping for free radicals in biological systems has been proven by ESR. Immuno-spin trapping is proving to be a potent, sensitive (a million times higher sensitivity than ESR), and easy (not quantum mechanical) method to detect low levels of macromolecule-derived radicals produced in vitro and in vivo. Anti-DMPO antibodies have been used to determine the distribution of free radicals in cells and tissues and even in living animals. In summary, the invention of the immuno-spin trapping technique has had a major impact on the ability to accurately and sensitively detect biological free radicals and, subsequently, on our understanding of the role of free radicals in biochemistry, medicine and toxicology. Published by Elsevier B.V.

Radiative Penguin Decays at the B Factories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koneke, Karsten; /MIT, LNS

2007-11-16

In this article, I review the most recent results in radiative penguin decays from the B factories Belle and BABAR. Most notably, I will talk about the recent new observations in the decays B {yields} ({rho}/{omega}) {gamma}, a new analysis technique in b {yields} s{gamma}, and first measurements of radiative penguin decays in the B{sup 0}{sub s} meson system. Finally, I will summarize the current status and future prospects of radiative penguin B physics at the B factories.

Ability Of Optical Coherence Tomography To Detect Caries Beneath Commonly Used Dental Sealants

PubMed Central

Osann, Kathryn; Pharar, Jessica; Lee, Kenneth; Ahn, Yeh-chan; Tucker, Travis; Sabet, Sharareh; Chen, Zhongping; Gukasyan, Ripsik; Wilder-Smith, Petra

2010-01-01

Background and Objective The onset and progression of early tooth decay is often preventable with dental sealants. However, occasionally decay progresses underneath the sealant. Current technology does not permit monitoring of potential lesion progression or arrest. Dental sealants themselves mask the visual cues that identify early tooth decay, and radiographs are not sufficiently sensitive. Therefore clinicians can be reluctant to use dental sealant. The objective of this ex vivo study was to evaluate the ability of dentists to detect decay beneath commonly used dental sealants using Optical Coherence Tomography (OCT) imaging. Study Designs/Materials/Methods Forty extracted teeth were divided into equal groups of carious and non-carious teeth, as determined by visual inspection. After radiographs and OCT imaging, teeth were randomly assigned for sealant placement with one of four commonly purchased dental sealants: Clinpro™, Fuji Triage™, Embrace Wet Bond™, and Delton™. Following sealant placement, teeth were radiographed, imaged with OCT, sectioned, examined histologically, and scored as healthy/not healthy. OCT and radiographic images were scored separately. The gold standard was histopathological diagnosis from the serial sections. Cohen’s Kappa, sensitivity, negative predictive value and positive predictive value were computed for all measures. Results After 90 mins training, pre-standardized dentists were able to detect tooth decay more accurately using OCT than with visual or radiographic examination. Detection using OCT was somewhat better prior to sealant placement than afterwards. This effect varied in size depending on the type of sealant used. Radiographic diagnosis was also less accurate after sealant placement. Of the four dental sealants, Delton provided excellent positive predictive value and the best post-sealant negative predictive values. Conclusion In this ex vivo study, dentists were able to detect tooth decay beneath four commonly used dental sealants based on OCT images. Clinical investigations are now underway to determine the usefulness of this approach in vivo. PMID:20848554

Rh blood phenotyping (D, E, e, C, c) microarrays using multichannel surface plasmon resonance imaging.

PubMed

Pipatpanukul, Chinnawut; Takeya, Sasaki; Baba, Akira; Amarit, Ratthasart; Somboonkaew, Armote; Sutapun, Boonsong; Kitpoka, Pimpun; Kunakorn, Mongkol; Srikhirin, Toemsak

2018-04-15

The application of Surface Plasmon Resonance Imaging (SPRi) for the detection of transmembrane antigen of the Rhesus (Rh) blood group system is demonstrated. Clinically significant Rh blood group system antigens, including D, C, E, c, and e, can be simultaneously identified via solid phase immobilization assay, which offers significant time savings and assay simplification. Red blood cells (RBCs) flowed through the micro-channel, where a suitable condition for Rh blood group detection was an RBC dilution of 1:10 with a stop-flow condition. Stop flow showed an improvement in specific binding compared to continuous flow. Rh antigens required a longer incubation time to react with the immobilized antibody than A and B antigens due to the difference in antigen type and their location on the RBC. The interaction between the immobilized antibodies and their specific antigenic counterpart on the RBC showed a significant difference in RBC removal behavior using shear flow, measured from the decay of the SPR signal. The strength of the interaction between the immobilized antibody and RBC antigen was determined from the minimum wall shear stress required to start the decay process in the SPR signal. For a given range of immobilized antibody surface densities, the Rh antigen possesses a stronger interaction than A, B, and AB antigens. Identification of 82 samples of ABO and Rh blood groups using SPRi showed good agreement with the standard micro-column agglutination technique. A wider coverage of antigenic recognition for RBC when using the solid phase immobilization assay was demonstrated for the RBC with the antigenic site located on the transmembrane protein of the clinically significant Rh antigen. Given the level of accuracy and precision, the technique showed potential for the detection of the Rh minor blood group system. Copyright © 2017 Elsevier B.V. All rights reserved.

Liquid argon scintillation read-out with silicon devices

NASA Astrophysics Data System (ADS)

Canci, N.; Cattadori, C.; D'Incecco, M.; Lehnert, B.; Machado, A. A.; Riboldi, S.; Sablone, D.; Segreto, E.; Vignoli, C.

2013-10-01

Silicon photosensors represent a viable alternative to standard photomultipliers in fields such as communications and medical imaging. We explored the interesting possibility of using these sensors in combination with liquid argon (LAr) for astroparticle physics applications such as neutrino, dark matter and double beta decay experiments. In fact, silicon photosensors have detection efficiencies comparable with those of the highest performance PMTs and can be manufactured with high level of radiopurity. In particular within the on-going R&D activity of the SILENT project (Low background and low noise techniques for double beta decay physics funded by ASPERA) a large area SiPM (Silicon PhotoMultiplier - Hamamatsu S11828-3344M - 1.7 cm2 area) has been installed in a LAr scintillation chamber of 0.5 liters volume together with a cryogenic photomultiplier tube (Hamamatsu R11065) used as a reference. The liquid argon chamber has been exposed to many gamma sources of different energies and single photoelectron response and light yield for the SiPM and PMT have been measured and compared. In this contribution the results of the tests, and the ongoing R&D to optimize the SiPM for cryogenic and for ultralow background applications, are reported, as well as the possible application in the GERDA experiment on Double Beta Decay Searches of 76Ge.

Emergency Dose Estimation Using Optically Stimulated Luminescence from Human Tooth Enamel

PubMed Central

Sholom, S.; DeWitt, R.; Simon, S.L.; Bouville, A.; McKeever, S.W.S.

2011-01-01

Human teeth were studied for potential use as emergency Optically Stimulated Luminescence (OSL) dosimeters. By using multiple-teeth samples in combination with a custom-built sensitive OSL reader, 60Co-equivalent doses below 0.64 Gy were measured immediately after exposure with the lowest value being 27 mGy for the most sensitive sample. The variability of OSL sensitivity, from individual to individual using multiple-teeth samples, was determined to be 53%. X-ray and beta exposure were found to produce OSL curves with the same shape that differed from those due to ultraviolet (UV) exposure; as a result, correlation was observed between OSL signals after X-ray and beta exposure and was absent if compared to OSL signals after UV exposure. Fading of the OSL signal was “typical” for most teeth with just a few of incisors showing atypical behavior. Typical fading dependences were described by a bi-exponential decay function with “fast” (decay time around of 12 min) and “slow” (decay time about 14 h) components. OSL detection limits, based on the techniques developed to-date, were found to be satisfactory from the point-of-view of medical triage requirements if conducted within 24 hours of the exposure. PMID:21949479

Natural radioactivity of the tar-sand deposits of Ondo State, Southwestern Nigeria

NASA Astrophysics Data System (ADS)

Fasasi, M. K.; Oyawale, A. A.; Mokobia, C. E.; Tchokossa, P.; Ajayi, T. R.; Balogun, F. A.

2003-06-01

A combination of gamma spectrometry and energy dispersive X-ray fluorescence was used to determine the presence and level of radioactivity of radionuclides in bituminous sand and overburden obtained from bituminous sand deposits in Ondo State Nigeria for the purpose of providing baseline data and assessing its impact on the environment. The radionuclides identified with reliable regularity belong to the decay series of naturally occurring radionuclides headed by 238U and 232Th. The non-decay series of naturally occurring 40K was found to be below the limit of detection. The average specific activity concentration values obtained for 214 Bi, 208Tl, and 226Ra in the overburden are 165.64±2.91, 150.25±2.91 and 60.97±2.27 Bq kg -1, respectively. The measured activity in the bituminous sand layer is so low that it can be said to be non-radioactive. The result of the EDXRF supports the presence of radioelements in the overburden, which are likely to be embedded in accessory minerals like zircon and tourmaline. Thus, surface exploration technique using soil-gas radon measurement will not yield the desired result. Furthermore, the level of radioelements and associated decay daughter 222Rn is not expected to cause any health hazard.

Photon activation-15O decay studies of tumor blood flow.

PubMed

Ten Haken, R K; Nussbaum, G H; Emami, B; Hughes, W L

1981-01-01

A direct, noninvasive method for measuring absolute values of specific capillary blood flow in living tissue is described. The method is based on the photon activation, in situ, of tissue elements and the measurement of the subsequent decay of the positron activity induced, employing coincidence detection of the photon pairs produced in positron annihilation. Analysis of the time-dependent coincidence spectrum reveals the contribution to the total signal from the decay of 15O, from which the specific capillary blood flow in the imaged, activated volume is ultimately determined. By virtue of its introduction of the radioisotope of interest (15O) directly and uniformly into the tissue volume under investigation, the method described permits both the nonperfused and well perfused fractions of an activated volume to be estimated and hence, the average specific blood flow within imaged tumor volumes to be computed. The model employed to describe and analyze the data is discussed in detail. Results of application of the technique to measurement of specific blood flow in rhabdomyosarcoma tumors grown in WAG/Rij rats are presented and discussed. The method is shown to be reliable and well suited to studies designed to determined the effects of various agents, such as heat, radiation and drugs, on tumor blood flow.

M$^3$: A New Muon Missing Momentum Experiment to Probe $$(g-2)_{\\mu}$$ and Dark Matter at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kahn, Yonatan; Krnjaic, Gordan; Tran, Nhan

New light, weakly-coupled particles are commonly invoked to address the persistentmore » $$\\sim 4\\sigma$$ anomaly in $$(g-2)_\\mu$$ and serve as mediators between dark and visible matter. If such particles couple predominantly to heavier generations and decay invisibly, much of their best-motivated parameter space is inaccessible with existing experimental techniques. In this paper, we present a new fixed-target, missing-momentum search strategy to probe invisibly decaying particles that couple preferentially to muons. In our setup, a relativistic muon beam impinges on a thick active target. The signal consists of events in which a muon loses a large fraction of its incident momentum inside the target without initiating any detectable electromagnetic or hadronic activity in downstream veto systems. We propose a two-phase experiment, M$^3$ (Muon Missing Momentum), based at Fermilab. Phase 1 with $$\\sim 10^{10}$$ muons on target can test the remaining parameter space for which light invisibly-decaying particles can resolve the $$(g-2)_\\mu$$ anomaly, while Phase 2 with $$\\sim 10^{13}$$ muons on target can test much of the predictive parameter space over which sub-GeV dark matter achieves freeze-out via muon-philic forces, including gauged $$U(1)_{L_\\mu - L_\\tau}$$.« less

Report on the Brookhaven Solar Neutrino Experiment

DOE R&D Accomplishments Database

Davis, R. Jr.; Evans, J. C. Jr.

1976-09-22

This report is intended as a brief statement of the recent developments and results of the Brookhaven Solar Neutrino Experiment communicated through Professor G. Kocharov to the Leningrad conference on active processes on the sun and the solar neutrino problem. The report summarizes the results of experiments performed over a period of 6 years, from April 1970 to January 1976. Neutrino detection depends upon the neutrino capture reaction /sup 37/Cl(..nu..,e/sup -/)/sup 37/Ar producing the isotope /sup 37/Ar (half life of 35 days). The detector contains 3.8 x 10/sup 5/ liters of C/sub 2/Cl/sub 4/ (2.2 x 10/sup 30/ atoms of /sup 37/Cl) and is located at a depth of 4400 meters of water equivalent (m.w.e.) in the Homestake Gold Mine at Lead, South Dakota, U.S.A. The procedures for extracting /sup 37/Ar and the counting techniques used were described in previous reports. The entire recovered argon sample was counted in a small gas proportional counter. Argon-37 decay events were characterized by the energy of the Auger electrons emitted following the electron capture decay and by the rise-time of the pulse. Counting measurements were continued for a period sufficiently long to observe the decay of /sup 37/Ar.

Long-term measurements of 36Cl to investigate potential solar influence on the decay rate

NASA Astrophysics Data System (ADS)

Kossert, Karsten; Nähle, Ole J.

2014-03-01

Recently, Jenkins et al. [6] reported on fluctuations in the detected decay events of 36Cl which were measured with a Geiger-Müller counter. Experimental data of 32Si measured by means of an end-window gas-flow proportional counter at the Brookhaven National Laboratory show similar periodicity, albeit a different amplitude. Jenkins et al. interpret the fluctuations as evidence of solar influence on the decay rates of beta-decaying radionuclides.

Radiative decay of massious neutrinos: Implications for physics and astrophysics

NASA Technical Reports Server (NTRS)

Stecker, F. W.

1981-01-01

The radiative lifetime tau for the decay of massious neutrinos is calculated using various physical models for neutrino decay. The results are related to the astrophysical problem of the detectability of the decay photons from cosmic neutrinos. Conversely, the astrophysical data are used to place lower limits on tau. However, an observed feature at approximately 1700 A in the ultraviolet background radiation at high galactic latitudes may be from the decay of neutrinos with mass approximately 14 eV. This would require a decay rate much larger than the predictions of standard models but could be indicative of a decay rate possible in composite models. It is considered that this may be an important test for substructure in leptons and quarks.

Tomographic Image Reconstruction Using an Interpolation Method for Tree Decay Detection

Treesearch

Hailin Feng; Guanghui Li; Sheng Fu; Xiping Wang

2014-01-01

Stress wave velocity has been traditionally regarded as an indicator of the extent of damage inside wood. This paper aimed to detect internal decay of urban trees through reconstructing tomographic image of the cross section of a tree trunk. A grid model covering the cross section area of a tree trunk was defined with some assumptions. Stress wave data were processed...

Accuracy, reliability, and timing of visual evaluations of decay in fresh-cut lettuce

PubMed Central

Hayes, Ryan J.

2018-01-01

Visual assessments are used for evaluating the quality of food products, such as fresh-cut lettuce packaged in bags with modified atmosphere. We have compared the accuracy and the reliability of visual evaluations of decay on fresh-cut lettuce performed with experienced and inexperienced raters. In addition, we have analyzed decay data from over 4.5 thousand bags to determine the optimum timing for evaluations to detect differences among accessions. Lin’s concordance coefficient (ρc) that takes into consideration both the closeness of the data and the conformance to the identity line showed high repeatability (intra-rater reliability, ρc = 0.97), reproducibility (inter-rater reliability, ρc = 0.92), and accuracy (ρc = 0.96) for experienced raters. Inexperienced raters did not perform as well and their ratings showed decreased repeatability (ρc = 0.93), but even larger reduction in reproducibility (ρc = 0.80) and accuracy (ρc = 0.90). We have detected that 5.3% of ratings were outside of the 95% limits of agreement. These under- or overestimates were predominantly found for bags with intermediate levels of decay, which corresponds to the middle of the rating scale. This occurs because intermediate amounts of decay are more difficult to discriminate than extremes. The frequencies of aberrant ratings for experienced raters ranged from 0.6% to 4.4% (mean = 2.1%), for inexperienced raters the frequencies were substantially higher, ranging from 6.1% to 15.6% (mean = 9.4%). Therefore, we recommend that new raters receive training that includes practical examples in this range of decay, use of standard area diagrams, and continuing interaction with experienced raters (consultation during actual rating). Very high agreement among experienced raters indicate that visual ratings can be successfully used for evaluations of decay, until a more objective, rapid, and affordable method is developed. We recommend evaluating samples at multiple time points until 42 days after processing (about 80% decay on average) and then combining these individual ratings into the area under the decay progress stairs (AUDePS) score. Applying this approach, experienced evaluators can accurately detect difference among lettuce accessions and identify lettuce cultivars with reduced decay. PMID:29664945

Non-Destructive Approaches for the Validation of Visually Observed Spatial Patterns of Decay

NASA Astrophysics Data System (ADS)

Johnston, Brian; McKinley, Jennifer; Warke, Patricia; Ruffell, Alastair

2017-04-01

Historical structures are regarded as a built legacy that is passed down through the generations and as such the conservation and restoration of these buildings is of great importance to governmental, religious and charitable organisations. As these groups play the role of custodians of this built heritage, they are therefore keen that the approaches employed in these studies of stone condition are non-destructive in nature. Determining sections of facades requiring repair work is often achieved through a visual conditional inspection of the stonework by a specialist. However, these reports focus upon the need to identify blocks requiring restorative action rather than the determination of spatial trends that lead to the identification of causes. This fixation on decay occurring at the block scale results in the spatial distribution of weathering present at the larger 'wall' scale appearing to have developed chaotically. Recent work has shown the importance of adopting a geomorphological focus when undertaking visual inspection of the facades of historical buildings to overcome this issue. Once trends have been ascertained, they can be used to bolster remedial strategies that target the sources of decay rather than just undertaking an aesthetic treatment of symptoms. Visual inspection of the study site, Fitzroy Presbyterian Church in Belfast, using the geomorphologically driven approach revealed three features suggestive of decay extending beyond the block scale. Firstly, the influence of architectural features on the susceptibility of blocks to decay. Secondly, the impact of the fluctuation in groundwater rise over the seasons and the influence of aspect upon this process. And finally, the interconnectivity of blocks, due to deteriorating mortar and poor repointing, providing conduits for the passage of moisture. Once these patterns were identified, it has proven necessary to validate the outcome of the visual inspection using other techniques. In this study, three complimentary approaches were employed, ground penetrating radar (GPR), probe permeametry and 3D modelling. Each of these strategies were selected as they were both capable of substantiating the suggested causes of visible decay trends and non-destructive in nature. GPR was employed to detect variations in the wall corresponding to the presence of hollows or moisture within the wall sections. The returns support the conclusions that empty spaces, created through the deterioration of mortar exist within the wall, allowing the passage of moisture. Using probe permeametry, the surface permeability of the wall surface was measured, analysis of which was carried out using kriging. The variograms created for this purpose suggest a significant directional element. 3D Models created by scanning the wall sections was used to calculate a measurement of roughness for the surfaces of the study area. Due to the stonework at the church being hammer dressed, the effectiveness of the determination of changing roughness was restricted, however some variation was identified. Through the combined use of these techniques, the wall scale trends suggested by the results of the visual inspection were validated. Thus, the apparent potential of these techniques, in particular the use of GPR, in supporting future studies of decay is promising.

Machine learning techniques in searches for$$t\\bar{t}$$h in the h → $$b\\bar{b}$$ decay channel

DOE PAGES

Santos, Robert; Nguyen, M.; Webster, Jordan; ...

2017-04-10

Study of the production of pairs of top quarks in association with a Higgs boson is one of the primary goals of the Large Hadron Collider over the next decade, as measurements of this process may help us to understand whether the uniquely large mass of the top quark plays a special role in electroweak symmetry breaking. Higgs bosons decay predominantly to bmore » $$\\bar{_b}$$, yielding signatures for the signal that are similar to t$$\\bar{_t}$$ + jets with heavy flavor. Though particularly challenging to study due to the similar kinematics between signal and background events, such final states (t$$\\bar{_t}$$b$$\\bar{b}$$) are an important channel for studying the top quark Yukawa coupling. This paper presents a systematic study of machine learning (ML) methods for detecting t$$\\bar{_t}$$h in the h → b$$\\bar{b}$$ decay channel. Among the seven ML methods tested, we show that neural network models outperform alternative methods. In addition, two neural models used in this paper outperform NeuroBayes, one of the standard algorithms used in current particle physics experiments. We further study the effectiveness of ML algorithms by investigating the impact of feature set and data size, as well as the depth of the networks for neural models. We demonstrate that an extended feature set leads to improvement of performance over basic features. Furthermore, the availability of large samples for training is found to be important for improving the performance of the techniques. For the features and the data set studied here, neural networks of more layers deliver comparable performance to their simpler counterparts.« less

Machine learning techniques in searches for$$t\\bar{t}$$h in the h → $$b\\bar{b}$$ decay channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos, Robert; Nguyen, M.; Webster, Jordan

Study of the production of pairs of top quarks in association with a Higgs boson is one of the primary goals of the Large Hadron Collider over the next decade, as measurements of this process may help us to understand whether the uniquely large mass of the top quark plays a special role in electroweak symmetry breaking. Higgs bosons decay predominantly to bmore » $$\\bar{_b}$$, yielding signatures for the signal that are similar to t$$\\bar{_t}$$ + jets with heavy flavor. Though particularly challenging to study due to the similar kinematics between signal and background events, such final states (t$$\\bar{_t}$$b$$\\bar{b}$$) are an important channel for studying the top quark Yukawa coupling. This paper presents a systematic study of machine learning (ML) methods for detecting t$$\\bar{_t}$$h in the h → b$$\\bar{b}$$ decay channel. Among the seven ML methods tested, we show that neural network models outperform alternative methods. In addition, two neural models used in this paper outperform NeuroBayes, one of the standard algorithms used in current particle physics experiments. We further study the effectiveness of ML algorithms by investigating the impact of feature set and data size, as well as the depth of the networks for neural models. We demonstrate that an extended feature set leads to improvement of performance over basic features. Furthermore, the availability of large samples for training is found to be important for improving the performance of the techniques. For the features and the data set studied here, neural networks of more layers deliver comparable performance to their simpler counterparts.« less

Probing the photon polarization in B → K*γ with conversion

DOE PAGES

Bishara, Fady; Robinson, Dean J.

2015-09-02

We re-examine the possibility to measure the photon polarization in B → K*γ decays, via decays in which the photon subsequently undergoes nuclear conversion to a lepton pair. We obtain compact expressions for the full decay-plus-conversion amplitude. With these results we show that interference between the B → (K* → Kπ)γ decay and the γN → ℓ + ℓ – N conversion permits both the ratio and relative weak phase between the left- and right-handed photon amplitudes to be probed by an angular observable, constructed from the final state dilepton, kaon and pion kinematic configuration. Exploiting this technique will bemore » experimentally challenging. However, we present special kinematic cuts that enhance the statistical power of this technique by an O(1) factor. Furthermore, we verify this effect and extract pertinent angular kinematic distributions with dedicated numerical simulations.« less

Modifications to a Cavity Ringdown Spectrometer to Improve Data Acquisition Rates

NASA Astrophysics Data System (ADS)

Bostrom, Gregory Alan

Cavity ringdown spectroscopy (CRDS) makes use of light retention in an optical cavity to enhance the sensitivity to absorption or extinction of light from a sample inside the cavity. When light entering the cavity is stopped, the output is an exponential decay with a decay constant that can be used to determine the quantity of the analyte if the extinction or absorption coefficient is known. The precision of the CRDS is dependent on the rate at which the system it acquires and processes ringdowns, assuming randomly distributed errors. We have demonstrated a CRDS system with a ringdown acquisition rate of 1.5 kHz, extendable to a maximum of 3.5 kHz, using new techniques that significantly changed the way in which the ringdowns are both initiated and processed. On the initiation side, we combined a custom high-resolution laser controller with a linear optical feedback configuration and a novel optical technique for initiating a ringdown. Our optical injection "unlock" method switches the laser off-resonance, while allowing the laser to immediately return to resonance, after terminating the unlock, to allow for another ringdown (on the same cavity resonance mode). This part of the system had a demonstrated ringdown initiation rate of 3.5 kHz. To take advantage of this rate, we developed an optimized cost-effective FGPA-based data acquisition and processing system for CRDS, capable of determining decay constants at a maximum rate of 4.4 kHz, by modifying a commercial ADC-FPGA evaluation board and programming it to apply a discrete Fourier transform-based algorithm for determining decay constants. The entire system shows promise with a demonstrated ability to determine gas concentrations for H2O with a measured concentration accuracy of +/-3.3%. The system achieved an absorption coefficient precision of 0.1% (95% confidence interval). It also exhibited a linear response for varying H2O concentrations, a 2.2% variation (1sigma) for repeated measurements at the same H2O concentration, and a corresponding precision of 0.6% (standard error of the mean). The absorption coefficient limit of detection was determined to be 1.6 x 10-8 cm -1 (root mean square of the baseline residual). Proposed modifications to our prototype system offer the promise of more substantial gains in both precision and limit of detection. The system components developed here for faster ringdown acquisition and processing have broader applications for CRDS in atmospheric science and other fields that need fast response systems operating at high-precision.

High-Resolution and -Efficiency Gamma-Ray Detection for the FRIB Decay Station

NASA Astrophysics Data System (ADS)

Grover, Hannah; Leach, Kyle; Natzke, Connor; FRIB Decay Station Collaboration Collaboration

2017-09-01

As we push our knowledge of nuclear structure to the frontier of the unknown with FRIB, a new high-efficiency, -resolution, and -sensitivity photon-detection device is critical. The FRIB Decay Station Collaboration is working to create a new detector array that meets the needs of the exploratory nature of FRIB by minimizing cost and maximizing efficiency. GEANT4 simulations are being utilized to combine detectors in various configurations to test their feasibility. I will discuss these simulations and how they compare to existing simulations of past-generation decay-spectroscopy equipment. This work has been funded by the DOE Office of Science, Office of Nuclear Physics.

Developing a chloramine decay index to understand nitrification: A case study of two chloraminated drinking water distribution systems.

PubMed

Moradi, Sina; Liu, Sanly; Chow, Christopher W K; van Leeuwen, John; Cook, David; Drikas, Mary; Amal, Rose

2017-07-01

The management of chloramine decay and the prevention of nitrification are some of the critical issues faced by water utilities that use chloramine as a disinfectant. In this study, potential association between high performance size exclusion chromatography (HPSEC) data obtained with multiple wavelength Ultraviolet (UV) detection from two drinking water distribution systems in Australia and nitrification occurrence was investigated. An increase in the absorbance signal of HPSEC profiles with UV detection at λ=230nm between apparent molecular weights of 200 to 1000Da was observed at sampling sites that experienced rapid chloramine decay and nitrification while its absorbance signal at λ=254nm decreased. A chloramine decay index (C.D.I) defined as the ratio of area beneath the HPSEC spectra at two different wavelengths of 230 and 254nm, was used in assessing chloramine decay occurrences. The C.D.Is of waters at locations that experienced nitrification were consistently higher than locations not experiencing nitrification. A simulated laboratory study showed that the formation of nitrite/nitrate and/or soluble microbial products and/or the release of extracellular polymeric substances (EPS) during nitrification may contribute to the C.D.I. increase. These findings suggest that C.D.I derived from HPSEC with multiple wavelength UV detection could be an informative index to track the occurrence of rapid chloramine decay and nitrification. Copyright © 2016. Published by Elsevier B.V.

Laser-induced breakdown spectroscopy of dental lesions: diagnostic and therapeutic monitoring tool

NASA Astrophysics Data System (ADS)

Borisova, Ekaterina; Uzunov, Tzonko; Penev, Dimitar; Genova, Tsanislava; Avramov, Latchezar

2016-01-01

The carious decay develops a tiny area of demineralization on the enamel, which could be detected by element analytic techniques such as laser-induced breakdown spectroscopy (LIBS). That demineralization can quickly turn into a large lesion inside the tooth, it is often discovered too late to prevent the kind of decay that leads to cavities. The same optical LIBS detection approach could be used for monitoring of the caries removal using laser ablation or drilling techniques. For LIBS measurements we applied LIBS 2500Plus (Ocean Optics Inc., Dunedin, USA) system, which consists of seven spectrometric channels, covering spectral region from 200 to 980 nm, which optical resolution 0,05 nm, the spectrometers are connected with sample fiber bundle for 7-channels spectral system to the chamber for solid and liquid samples, Q-switched Nd:YAG laser, at 1 064 nm, with energy per pulse - 40 mJ, which is applied to induce plasma in the samples. LIBS spectra were obtained after single shot of the laser in the region of pathology. Samples investigated by LIBS are extracted teeth from patients, with periodontal problems on different stage of carious lesions, and their LIBS spectra are compared with the LIBS signals obtained from normal enamel and dentine tissues to receive complete picture of the carious lesion development. The major line of our investigations is related to the development of a methodology for real-time optical feedback control during selective ablation of tooth tissues using LIBS. Tooth structures, with and without pathological changes, are compared and their LIBS element analysis is used to differentiate major changes, which occur during tooth carious process and growth.

Gain-assisted broadband ring cavity enhanced spectroscopy

NASA Astrophysics Data System (ADS)

Selim, Mahmoud A.; Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

2017-02-01

Incoherent broadband cavity enhanced spectroscopy can significantly increase the effective path length of light-matter interaction to detect weak absorption lines over broad spectral range, for instance to detect gases in confined environments. Broadband cavity enhancement can be based on the decay time or the intensity drop technique. Decay time measurement is based on using tunable laser source that is expensive and suffers from long scan time. Intensity dependent measurement is usually reported based on broadband source using Fabry-Perot cavity, enabling short measurement time but suffers from the alignment tolerance of the cavity and the cavity insertion loss. In this work we overcome these challenges by using an alignment-free ring cavity made of an optical fiber loop and a directional coupler, while having a gain medium pumped below the lasing threshold to improve the finesse and reduce the insertion loss. Acetylene (C2H2) gas absorption is measured around 1535 nm wavelength using a semiconductor optical amplifier (SOA) gain medium. The system is analyzed for different ring resonator forward coupling coefficient and loses, including the 3-cm long gas cell insertion loss and fiber connector losses used in the experimental verification. The experimental results are obtained for a coupler ratio of 90/10 and a fiber length of 4 m. The broadband source is the amplified spontaneous emission of another SOA and the output is measured using a 70pm-resolution optical spectrum analyzer. The absorption depth and the effective interaction length are improved about an order of magnitude compared to the direct absorption of the gas cell. The presented technique provides an engineering method to improve the finesse and, consequently the effective length, while relaxing the technological constraints on the high reflectivity mirrors and free-space cavity alignment.

Infrared Absorption Spectroscopy and Chemical Kinetics of Free Radicals. Final Performance Report, August 1, 1985--July 31, 1994

DOE R&D Accomplishments Database

Curl, R. F.; Glass, G. P.

1995-06-01

This research was directed at the detection, monitoring, and study (by infrared absorption spectroscopy) of the chemical kinetic behavior of small free radical species thought to be important intermediates in combustion. The work typically progressed from the detection and analysis of the infrared spectrum of combustion radical to the utilization of the infrared spectrum thus obtained in the investigation of chemical kinetics of the radical species. The methodology employed was infrared kinetic spectroscopy. In this technique the radical is produced by UV flash photolysis using an excimer laser and then its transient infrared absorption is observed using a single frequency cw laser as the source of the infrared probe light. When the probe laser frequency is near the center of an absorption line of the radical produced by the flash, the transient infrared absorption rises rapidly and then decays as the radical reacts with the precursor or with substances introduced for the purpose of studying the reaction kinetics or with itself. The decay times observed in these studies varied from less than one microsecond to more than one millisecond. By choosing appropriate time windows after the flash and the average infrared detector signal in a window as data channels, the infrared spectrum of the radical may be obtained. By locking the infrared probe laser to the center of the absorption line and measuring the rate of decay of the transient infrared absorption signal as the chemical composition of the gas mixture is varied, the chemical kinetics of the radical may be investigated. In what follows the systems investigated and the results obtained are outlined.

Simulation of double beta decay in the ''SeXe'' TPC

NASA Astrophysics Data System (ADS)

Mauger, F.

2007-04-01

In 2004, the NEMO collaboration has started some preliminary studies for a next-generation double beta decay experiment: SuperNEMO. The possibility to use a large gaseous TPC has been investigated using simulation and extrapolation of former experiments. In this talk, I report on the reasons why such techniques have not been selected in 2004 and led the NEMO collaboration to reuse the techniques implemented within the NEMO3 detector.

A multiplex PCR-based method for the detection and early identification of wood rotting fungi in standing trees.

PubMed

Guglielmo, F; Bergemann, S E; Gonthier, P; Nicolotti, G; Garbelotto, M

2007-11-01

The goal of this research was the development of a PCR-based assay to identify important decay fungi from wood of hardwood tree species in northern temperate regions. Eleven taxon-specific primers were designed for PCR amplification of either nuclear or mitochondrial ribosomal DNA regions of Armillaria spp., Ganoderma spp., Hericium spp., Hypoxylon thouarsianum var. thouarsianum, Inonotus/Phellinus-group, Laetiporus spp., Perenniporia fraxinea, Pleurotus spp., Schizophyllum spp., Stereum spp. and Trametes spp. Multiplex PCR reactions were developed and optimized to detect fungal DNA and identify each taxon with a sensitivity of at least 1 pg of target DNA in the template. This assay correctly identified the agents of decay in 82% of tested wood samples. The development and optimization of multiplex PCRs allowed for reliable identification of wood rotting fungi directly from wood. Early detection of wood decay fungi is crucial for assessment of tree stability in urban landscapes. Furthermore, this method may prove useful for prediction of the severity and the evolution of decay in standing trees.

Study of the $$\\beta $$ Decay of Fission Products with the DTAS Detector

DOE PAGES

Guadilla, V.; Algora, A.; Tain, J. L.; ...

2017-01-01

Total Absorption Spectroscopy measurements of the β decay of 103Mo and 103Tc, important contributors to the decay heat summation calculation in reactors, are reported in this work. Furthermore, the analysis of the experiment, performed at IGISOL with the new DTAS detector, show new β intensity that was not detected in previous measurements with Ge detectors.

Apparatuses and methods for detecting, identifying and quantitating radioactive nuclei and methods of distinguishing neutron stimulation of a radiation particle detector from gamma-ray stimulation of a detector

DOEpatents

Cole, Jerald D.; Drigert, Mark W.; Reber, Edward L.; Aryaeinejad, Rahmat

2001-01-01

In one aspect, the invention encompasses a method of detecting radioactive decay, comprising: a) providing a sample comprising a radioactive material, the radioactive material generating decay particles; b)providing a plurality of detectors proximate the sample, the detectors comprising a first set and a second set, the first set of the detectors comprising liquid state detectors utilizing liquid scintillation material coupled with photo tubes to generate a first electrical signal in response to decay particles stimulating the liquid scintillation material, the second set of the detectors comprising solid state detectors utilizing a crystalline solid to generate a second electrical signal in response to decay particles stimulating the crystalline solid; c) stimulating at least one of the detectors to generate at least one of the first and second electrical signals, the at least one of the first and second electrical signals being indicative of radioactive decay in the sample. In another aspect, the invention encompasses an apparatus for identifying and quantitating radioactive nuclei of a sample comprising radioactive material that decays to generate neutrons and high-energy .gamma.-rays.

A Novel Computational Method to Reduce Leaky Reaction in DNA Strand Displacement.

PubMed

Li, Xin; Wang, Xun; Song, Tao; Lu, Wei; Chen, Zhihua; Shi, Xiaolong

2015-01-01

DNA strand displacement technique is widely used in DNA programming, DNA biosensors, and gene analysis. In DNA strand displacement, leaky reactions can cause DNA signals decay and detecting DNA signals fails. The mostly used method to avoid leakage is cleaning up after upstream leaky reactions, and it remains a challenge to develop reliable DNA strand displacement technique with low leakage. In this work, we address the challenge by experimentally evaluating the basic factors, including reaction time, ratio of reactants, and ion concentration to the leakage in DNA strand displacement. Specifically, fluorescent probes and a hairpin structure reporting DNA strand are designed to detect the output of DNA strand displacement, and thus can evaluate the leakage of DNA strand displacement reactions with different reaction time, ratios of reactants, and ion concentrations. From the obtained data, mathematical models for evaluating leakage are achieved by curve derivation. As a result, it is obtained that long time incubation, high concentration of fuel strand, and inappropriate amount of ion concentration can weaken leaky reactions. This contributes to a method to set proper reaction conditions to reduce leakage in DNA strand displacement.

Accelerator-based neutrino oscillation experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Deborah A.; /Fermilab

2007-12-01

Neutrino oscillations were first discovered by experiments looking at neutrinos coming from extra-terrestrial sources, namely the sun and the atmosphere, but we will be depending on earth-based sources to take many of the next steps in this field. This article describes what has been learned so far from accelerator-based neutrino oscillation experiments, and then describe very generally what the next accelerator-based steps are. In section 2 the article discusses how one uses an accelerator to make a neutrino beam, in particular, one made from decays in flight of charged pions. There are several different neutrino detection methods currently in use,more » or under development. In section 3 these are presented, with a description of the general concept, an example of such a detector, and then a brief discussion of the outstanding issues associated with this detection technique. Finally, section 4 describes how the measurements of oscillation probabilities are made. This includes a description of the near detector technique and how it can be used to make the most precise measurements of neutrino oscillations.« less

Physical Characterization of Orthorhombic AgInS2 Nanocrystalline Thin Films

NASA Astrophysics Data System (ADS)

El Zawawi, I. K.; Mahdy, Manal A.

2017-11-01

Nanocrystalline thin films of AgInS2 were synthesized using an inert gas condensation technique. The grazing incident in-plane x-ray diffraction technique was used to detect the crystal structure of the deposited and annealed thin films. The results confirmed that the as-deposited film shows an amorphous behavior and that the annealed film has a single phase crystallized in an orthorhombic structure. The orthorhombic structure and particle size were detected using high-resolution transmission electron microscopy. The particle size ( P_{{s}}) estimated from micrograph images of the nanocrystalline films were increased from 6 nm to 12 nm as the film thickness increased from 11 nm to 110 nm. Accordingly, increasing the film thickness up to 110 nm reflects varying the optical band gap from 2.75 eV to 2.1 eV. The photocurrent measurements were studied where the fast rise and decay of the photocurrent are governed by the recombination mechanism. The electrical conductivity behavior was demonstrated by two transition mechanisms: extrinsic transition for a low-temperature range (300-400 K) and intrinsic transition for the high-temperature region above 400 K.

On the advance of non-invasive techniques implementation for monitoring moisture distribution in cultural heritage: a case study

NASA Astrophysics Data System (ADS)

Inmaculada Martínez Garrido, María; Gómez Heras, Miguel; Fort González, Rafael; Valles Iriso, Javier; José Varas Muriel, María

2015-04-01

This work presents a case study developed in San Juan Bautista church in Talamanca de Jarama (12th -16th Century), which have been selected as an example of a historical church with a complex construction with subsequent combination of architectural styles and building techniques and materials. These materials have a differential behavior under the influence of external climatic conditions and constructive facts. Many decay processes related to humidity are affecting the building's walls and also have influence in the environmental dynamics inside the building. A methodology for monitoring moisture distribution on stone and masonry walls and floors was performed with different non-invasive techniques as thermal imaging, wireless sensor networks (WSN), portable moisture meter, electrical resistivity tomography (ERT) and ground-penetrating radar (GPR), in order to the evaluate the effectiveness of these techniques for the knowledge of moisture distribution inside the walls and the humidity origin. North and south oriented sections, both on walls and floors, were evaluated and also a general inspection in the church was carried out with different non-invasive techniques. This methodology implies different monitoring stages for a complete knowledge of the implication of outdoors and indoors conditions on the moisture distribution. Each technique is evaluated according to its effectiveness in the detection of decay processes and maintenance costs. Research funded by Geomateriales (S2013/MIT-2914) and Deterioration of stone materials in the interior of historic buildings as a result induced variation of its microclimate (CGL2011-27902) projects. The cooperation received from the Complutense University of Madrid's Research Group Alteración y Conservación de los Materiales Pétreos del Patrimonio (ref. 921349), the Laboratory Network in Science and Technology for Heritage Conservation (RedLabPat, CEI Moncloa) and the Diocese of Alcalá is gratefully acknowledged. MI Martínez-Garrido and M. Gomez-Heras are funded by Moncloa Campus of International Excellence (UPM-UCM, CSIC) PICATA fellowships.

Analog detection for cavity lifetime spectroscopy

DOEpatents

Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

2001-05-15

An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

Analog detection for cavity lifetime spectroscopy

DOEpatents

Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

2003-01-01

An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

Detection of discoloration and decay in living trees and utility poles

Treesearch

Alex L. Shigo; Alex Shigo

1974-01-01

A method is described for detecting discoloration and decay in living trees and creosoted utility poles. The method and devices have come from research involving many people over a seven-year period. A probe was inserted into a 3/32-inch (2.4 mm) diameter hole made by drill bits 8 inches (20.32 cm) and 12 inches (30.48 cm) long mounted in a portable, light-weight,...

Probing r-Process Production of Nuclei Beyond 209Bi with Gamma Rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Y.-Z.; Vogel, P.; Wasserburg, G. J.

We estimate gamma-ray fluxes due to the decay of nuclei beyond 209Bi from a supernova or a supernova remnant assuming that the r-process occurs in supernovae. We find that a detector with a sensitivity of {approx}10-7 {gamma} cm-2 s-1 at energies from {approx}40 keV to {approx}3 MeV may detect fluxes due to the decay of 226Ra, 229Th, 241Am, 243Am, 249Cf, and 251Cf in the newly discovered supernova remnant near Vela. In addition, such a detector may detect fluxes due to the decay of 227Ac and 228Ra produced in a future supernova at a distance of {approx}1 kpc. Because nuclei withmore » mass numbers A>209 are produced solely by the r-process, such detections are the best proof for a supernova r-process site. Further, they provide the most direct information on yields of progenitor nuclei with A>209 at r-process freeze-out. Finally, detection of fluxes due to the decay of r-process nuclei over a range of masses from a supernova or a supernova remnant provides the opportunity to compare yields in a single supernova event with the solar r-process abundance pattern. (c) (c) 1999. The American Astronomical Society.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Algora, A.; Rice, S.; Guadilla, V.

Preliminary results from beta decay studies of nuclei that are important for reactor applications are presented. The beta decays have been studied using the total absorption technique (TAS) and the pure beams provided by the JYFLTRAP system at the IGISOL facility of the University of Jyväskylä.

Two-Color Pump-Probe Measurement of Photonic Quantum Correlations Mediated by a Single Phonon

NASA Astrophysics Data System (ADS)

Anderson, Mitchell D.; Tarrago Velez, Santiago; Seibold, Kilian; Flayac, Hugo; Savona, Vincenzo; Sangouard, Nicolas; Galland, Christophe

2018-06-01

We propose and demonstrate a versatile technique to measure the lifetime of the one-phonon Fock state using two-color pump-probe Raman scattering and spectrally resolved, time-correlated photon counting. Following pulsed laser excitation, the n =1 phonon Fock state is probabilistically prepared by projective measurement of a single Stokes photon. The detection of an anti-Stokes photon generated by a second, time-delayed laser pulse probes the phonon population with subpicosecond time resolution. We observe strongly nonclassical Stokes-anti-Stokes correlations, whose decay maps the single phonon dynamics. Our scheme can be applied to any Raman-active vibrational mode. It can be modified to measure the lifetime of n ≥1 Fock states or the phonon quantum coherences through the preparation and detection of two-mode entangled vibrational states.

Two-Color Pump-Probe Measurement of Photonic Quantum Correlations Mediated by a Single Phonon.

PubMed

Anderson, Mitchell D; Tarrago Velez, Santiago; Seibold, Kilian; Flayac, Hugo; Savona, Vincenzo; Sangouard, Nicolas; Galland, Christophe

2018-06-08

We propose and demonstrate a versatile technique to measure the lifetime of the one-phonon Fock state using two-color pump-probe Raman scattering and spectrally resolved, time-correlated photon counting. Following pulsed laser excitation, the n=1 phonon Fock state is probabilistically prepared by projective measurement of a single Stokes photon. The detection of an anti-Stokes photon generated by a second, time-delayed laser pulse probes the phonon population with subpicosecond time resolution. We observe strongly nonclassical Stokes-anti-Stokes correlations, whose decay maps the single phonon dynamics. Our scheme can be applied to any Raman-active vibrational mode. It can be modified to measure the lifetime of n≥1 Fock states or the phonon quantum coherences through the preparation and detection of two-mode entangled vibrational states.

Microbial community changes with decaying chloramine residuals in a lab-scale system.

PubMed

Bal Krishna, K C; Sathasivan, Arumugam; Ginige, Maneesha P

2013-09-01

When chloramine is used as a disinfectant, managing an acceptable "residual" throughout the water distribution systems particularly once nitrification has set in is challenging. Managing chloramine decay prior to the onset of nitrification through effective control strategies is important and to-date the strategies developed around nitrification has been ineffective. This study aimed at developing a more holistic knowledge on how decaying chloramine and nitrification metabolites impact microbial communities in chloraminated systems. Five lab-scale reactors (connected in series) were operated to simulate a full-scale chloraminated distribution system. Culture independent techniques (cloning and qPCR) were used to characterise and quantify the mixed microbial communities in reactors maintaining a residual of high to low (2.18-0.03 mg/L). The study for the first time associates chloramine residuals and nitrification metabolites to different microbial communities. Bacterial classes Solibacteres, Nitrospira, Sphingobacteria and Betaproteobacteria dominated at low chloramine residuals whereas Actinobacteria and Gammaproteobacteria dominated at higher chloramine residuals. Prior to the onset of nitrification bacterial genera Pseudomonas, Methylobacterium and Sphingomonas were found to be dominant and Sphingomonas in particular increased with the onset of nitrification. Nitrosomonas urea, oligotropha, and two other novel ammonia-oxidizing bacteria were detected once the chloramine residuals had dropped below 0.65 mg/L. Additionally nitrification alone failed to explain chloramine decay rates observed in these reactors. The finding of this study is expected to re-direct the focus from nitrifiers to heterotrophic bacteria, which the authors believe could hold the key towards developing a control strategy that would enable better management of chloramine residuals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Temporal binning of time-correlated single photon counting data improves exponential decay fits and imaging speed

PubMed Central

Walsh, Alex J.; Sharick, Joe T.; Skala, Melissa C.; Beier, Hope T.

2016-01-01

Time-correlated single photon counting (TCSPC) enables acquisition of fluorescence lifetime decays with high temporal resolution within the fluorescence decay. However, many thousands of photons per pixel are required for accurate lifetime decay curve representation, instrument response deconvolution, and lifetime estimation, particularly for two-component lifetimes. TCSPC imaging speed is inherently limited due to the single photon per laser pulse nature and low fluorescence event efficiencies (<10%) required to reduce bias towards short lifetimes. Here, simulated fluorescence lifetime decays are analyzed by SPCImage and SLIM Curve software to determine the limiting lifetime parameters and photon requirements of fluorescence lifetime decays that can be accurately fit. Data analysis techniques to improve fitting accuracy for low photon count data were evaluated. Temporal binning of the decays from 256 time bins to 42 time bins significantly (p<0.0001) improved fit accuracy in SPCImage and enabled accurate fits with low photon counts (as low as 700 photons/decay), a 6-fold reduction in required photons and therefore improvement in imaging speed. Additionally, reducing the number of free parameters in the fitting algorithm by fixing the lifetimes to known values significantly reduced the lifetime component error from 27.3% to 3.2% in SPCImage (p<0.0001) and from 50.6% to 4.2% in SLIM Curve (p<0.0001). Analysis of nicotinamide adenine dinucleotide–lactate dehydrogenase (NADH-LDH) solutions confirmed temporal binning of TCSPC data and a reduced number of free parameters improves exponential decay fit accuracy in SPCImage. Altogether, temporal binning (in SPCImage) and reduced free parameters are data analysis techniques that enable accurate lifetime estimation from low photon count data and enable TCSPC imaging speeds up to 6x and 300x faster, respectively, than traditional TCSPC analysis. PMID:27446663

Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms

PubMed Central

Mantilla-Calderon, David

2017-01-01

ABSTRACT The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic resistance gene was detected in the aerobic sludge by a cultivation method. A subpopulation of persister E. coli cells was also detected in the aerobic sludge. The findings of this study suggest potential areas of concern arising from pathogenic and antibiotic-resistant E. coli during both anaerobic and aerobic sludge treatment processes. PMID:28411227

Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms.

PubMed

Mantilla-Calderon, David; Hong, Pei-Ying

2017-07-01

The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic resistance gene was detected in the aerobic sludge by a cultivation method. A subpopulation of persister E. coli cells was also detected in the aerobic sludge. The findings of this study suggest potential areas of concern arising from pathogenic and antibiotic-resistant E. coli during both anaerobic and aerobic sludge treatment processes. Copyright © 2017 Mantilla-Calderon and Hong.

Mitigating Backgrounds with a Novel Thin-Film Cathode in the DRIFT-IId Dark Matter Detector

NASA Astrophysics Data System (ADS)

Miller, Eric H.

The nature of dark matter, which comprises 85% of the matter density in the universe, is a major outstanding question in physics today. The standard hypothesis is that the dark matter is a new weakly interacting massive particle, which is present throughout the galaxy. These particles could interact within detectors on Earth, producing low-energy nuclear recoils. Two distinctive signatures arise from the solar motion through the galaxy. The DRIFT experiment aims to measure one of these, the directional signature that is based on the sidereal modulation of the nuclear recoil directions. Although DRIFT has demonstrated its capability for detecting this signature, it has been plagued by a large number of backgrounds that have limited its reach. The focus of this thesis is on characterizing these backgrounds and describing techniques that have essentially eliminated them. The background events in the DRIFT-IId detector are predominantly caused by alpha decays on the central cathode in which the alpha particles completely or partially absorbed by the cathode material. This thesis describes the installation a 0.9 mum thick aluminized-mylar cathode as a way to reduce the probability of producing these backgrounds. We study three generations of cathode (wire, thin-film, and radiologically clean thin-film) with a focus on identifying and quantifying the sources of alpha decay backgrounds, as well as their contributions to the background rate in the detector. This in-situ study is based on alpha range spectroscopy and the determination of the absolute alpha detection efficiency. The results for the final radiologically clean version of the cathode give a contamination of 3.3 +/- 0.1 ppt 234U and 73 +/- 2 ppb 238U, and an efficiency for rejecting an RPR from an alpha decay that is a factor 70 +/- 20 higher than for the original wire cathode. Along with other background reduction measures, the thin-film cathode has reduced the observed background rate from 130/day to 1.7/day in the DRIFT experiment. The complete elimination of the remaining RPR backgrounds requires fiducialization of the detector along the drift direction. We describe two methods for doing this: one involving the detection of positive ions at the cathode, and the other using multiple species of charge carriers with variable drift speeds. With the recent successful implementation of the latter technique, the DRIFT experiment has run background-free for 46 days.

Gaseous time projection chambers for rare event detection: results from the T-REX project. I. Double beta decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Irastorza, I.G.; Aznar, F.; Castel, J., E-mail: igor.irastorza@cern.ch, E-mail: faznar@unizar.es, E-mail: jfcastel@unizar.es

2016-01-01

As part of the T-REX project, a number of R and D and prototyping activities have been carried out during the last years to explore the applicability of gaseous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) in rare event searches like double beta decay, axion research and low-mass WIMP searches. In both this and its companion paper, we compile the main results of the project and give an outlook of application prospects for this detection technique. While in the companion paper we focus on axions and WIMPs, in this paper we focus on the results regarding the measurementmore » of the double beta decay (DBD) of {sup 136}Xe in a high pressure Xe (HPXe) TPC. Micromegas of the microbulk type have been extensively studied in high pressure Xe and Xe mixtures. Particularly relevant are the results obtained in Xe + trimethylamine (TMA) mixtures, showing very promising results in terms of gain, stability of operation, and energy resolution at high pressures up to 10 bar. The addition of TMA at levels of ∼ 1% reduces electron diffusion by up to a factor of 10 with respect to pure Xe, improving the quality of the topological pattern, with a positive impact on the discrimination capability. Operation with a medium size prototype of 30 cm diameter and 38 cm of drift (holding about 1 kg of Xe at 10 bar in the fiducial volume, enough to contain high energy electron tracks in the detector volume) has allowed to test the detection concept in realistic experimental conditions. Microbulk Micromegas are able to image the DBD ionization signature with high quality while, at the same time, measuring its energy deposition with a resolution of at least a ∼ 3% FWHM @ Q{sub ββ}. This value was experimentally demonstrated for high-energy extended tracks at 10 bar, and is probably improvable down to the ∼ 1% FWHM levels as extrapolated from low energy events. In addition, first results on the topological signature information (one straggling track ending in two blobs) show promising background discrimination capabilities out of reach of other experimental implementations. Moreover, microbulk Micromegas have very low levels of intrinsic radioactivity, and offer cost-effective scaling-up options. All these results demonstrate that Micromegas-read HPXe TPC remains a very competitive technique for the next generation DBD experiments.« less

Geant4 Developments for the Radon Electric Dipole Moment Search at TRIUMF

NASA Astrophysics Data System (ADS)

Rand, E. T.; Bangay, J. C.; Bianco, L.; Dunlop, R.; Finlay, P.; Garrett, P. E.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S.; Svensson, C. E.; Wong, J.

2011-09-01

An experiment is being developed at TRIUMF to search for a time-reversal violating electric dipole moment (EDM) in odd-A isotopes of Rn. Extensive simulations of the experiment are being performed with GEANT4 to study the backgrounds and sensitivity of the proposed measurement technique involving the detection of γ rays emitted following the β decay of polarized Rn nuclei. GEANT4 developments for the RnEDM experiment include both realistic modelling of the detector geometry and full tracking of the radioactive β, γ, internal conversion, and x-ray processes, including the γ-ray angular distributions essential for measuring an atomic EDM.

RADIUM AND MESOTHORIUM POISONING AND DOSIMETRY AND INSTRUMENTATION TECHNIQUES IN APPLIED RADIOACTIVITY. Annual Progress Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

The study of the toxicity of radium and radium decay products was continued. Special emphasis was placed on the acquisition of data on patients selected by record of exposure. Data are tabulated on the radium body burden of about 40 individuals. About half the measurements were made on living persons and about half on tooth or bone specimens. Case history summaries and all available medical data are summarized for persons under study. An investigation of the gamma shielding properties of dunite was continued. Design modifications and calibration of radiation detection instruments are discussed. (For preceding period see AECU-3504.) (C.H.)

Mass transport on adsorbate multilayers studied by surface plasmon polariton wave excitation

NASA Astrophysics Data System (ADS)

Wang, X.; Fei, Y. Y.; Zhu, X. D.

2011-12-01

We excited surface-plasmon polariton waves (SPPW) on Cu(111) by coupling a monochromatic optical beam with a xenon multilayer thickness grating on the metal. The SPPW excitation was detected with an angle-resolved oblique-incidence reflectivity difference technique (OI-RD). The amplitude of the resonance OI-RD signal was a quadratic function of the grating modulation depth. By monitoring the decay of the resonance OI-RD signal as a function of time and temperature, we were able to study the mass transport of xenon that plays a key role in the annealing of a "rough" Xe multilayer crystalline film.

Label-free monitoring of interaction between DNA and oxaliplatin in aqueous solution by terahertz spectroscopy

NASA Astrophysics Data System (ADS)

Wu, Xiaojun; E, Yiwen; Xu, Xinlong; Wang, Li

2012-07-01

We demonstrated the feasibility of applying terahertz time-domain spectroscopy (THz-TDS) to monitor the molecular reactions in aqueous solutions of anticancer drug oxaliplatin with λ-DNA and macrophages DNA. The reaction time dependent refractive index and absorption coefficient were extracted and analyzed. The reaction half-decaying time of about 4.0 h for λ-DNA and 12.9 h for M-DNA was established. The results suggest that the THz-TDS detection could be an effective label-free technique to sense the molecular reaction in aqueous solutions and could be very useful in biology, medicine, and pharmacy industry.

Direct Observation of Two Proton Radioactivity Using Digital Photography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rykaczewski, Krzysztof Piotr; Pfutzner, M.; Dominik, Wojciech

2007-01-01

Recently the observation of a new type of spontaneous radioactive decay has been claimed in which two protons are simultaneously ejected by an atomic nucleus from the ground state1,2,3. Experimental data obtained for the extremely neutron-deficient nuclei 45Fe and 54Zn, were interpreted as the first evidence of such a decay mode which has been sought since 1960.4 However, the technique applied in those studies allowed only measurements of the decay time and the total energy released. Particles emitted in the decay were not identified and the conclusions had to be supported by theoretical arguments. Here we show for the firstmore » time, directly and unambiguously, that 45Fe indeed disintegrates by two-proton decay. Furthermore, we demonstrate that the decay branch of this isotope leads to various particle emission channels including two-proton and three-proton emission. To achieve this result we have developed a new type of detector V the Optical Time Projection Chamber (OTPC) in which digital photography is applied to nuclear physics for the first time. The detector records images of tracks from charged particles, allowing for their unambiguous identification and the reconstruction of decay events in three dimensions. This new and simple technique provides a powerful method to identify exotic decay channels involving emission of charged particles. It is expected that further studies with the OTPC device will yield important information on nuclei located at and beyond the proton drip-line, thus providing new material for testing and improving models of very unstable atomic nuclei.« less

Nanophotonic force microscopy: characterizing particle-surface interactions using near-field photonics.

PubMed

Schein, Perry; Kang, Pilgyu; O'Dell, Dakota; Erickson, David

2015-02-11

Direct measurements of particle-surface interactions are important for characterizing the stability and behavior of colloidal and nanoparticle suspensions. Current techniques are limited in their ability to measure pico-Newton scale interaction forces on submicrometer particles due to signal detection limits and thermal noise. Here we present a new technique for making measurements in this regime, which we refer to as nanophotonic force microscopy. Using a photonic crystal resonator, we generate a strongly localized region of exponentially decaying, near-field light that allows us to confine small particles close to a surface. From the statistical distribution of the light intensity scattered by the particle we are able to map out the potential well of the trap and directly quantify the repulsive force between the nanoparticle and the surface. As shown in this Letter, our technique is not limited by thermal noise, and therefore, we are able to resolve interaction forces smaller than 1 pN on dielectric particles as small as 100 nm in diameter.

Damage Assessment of Creep Tested and Thermally Aged Metallic Alloys Using Acousto-Ultrasonics

NASA Technical Reports Server (NTRS)

Gyekenyesi, Andrew L.; Kautz, Harold E.; Baaklini, George Y.

2001-01-01

In recent years emphasis has been placed on the early detection of material changes experienced in turbine powerplant components. During the scheduled overhaul of a turbine, the current techniques of examination of various hot section components aim to find flaws such as cracks, wear, and erosion, as well as excessive deformations. Thus far, these localized damage modes have been detected with satisfactory results. However, the techniques used to find these flaws provide no information on life until the flaws are actually detected. Major improvements in damage assessment, safety, as well as more accurate life prediction could be achieved if nondestructive evaluation (NDE) techniques could be utilized to sense material changes that occur prior to the localized defects mentioned. Because of elevated temperatures and excessive stresses, turbine components may experience creep behavior. As a result, it is desirable to monitor and access the current condition of such components. Research at the NASA Glenn Research Center involves developing and utilizing an NDE technique that discloses distributed material changes that occur prior to the localized damage detected by the current methods of inspection. In a recent study, creep processes in a nickel-base alloy were the life-limiting condition of interest, and the NDE technique was acousto-ultrasonics (AU). AU is an NDE technique that utilizes two ultrasonic transducers to interrogate the condition of a test specimen. The sending transducer introduces an ultrasonic pulse at a point on the surface of the specimen while a receiving transducer detects the signal after it has passed through the material. The goal of the method is to correlate certain parameters of the detected waveform to characteristics of the material between the two transducers. Here, the waveform parameter of interest is the attenuation due to internal damping for which information is being garnered from the frequency domain. The parameters utilized to indirectly quantify the attenuation are the ultrasonic decay rate as well as various moments of the frequency power spectrum. A new, user-friendly, graphical interface AU system was developed at NASA Glenn. This system is an all-inclusive, multifunction system that controls the sending and receiving ultrasonic transducers as well as all posttest signal analysis. The system's postprocessing software calculates the multiple parameters used to study the material of interest.

Measurement of time-dependent CP asymmetries and constraints on sin(2beta+gamma) with partial reconstruction of B0-->D*-/+pi+/- decays.

PubMed

Aubert, B; Barate, R; Boutigny, D; Couderc, F; Gaillard, J-M; Hicheur, A; Karyotakis, Y; Lees, J P; Robbe, P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; LeClerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Romosan, A; Ronan, M T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Knowles, D J; Morgan, S E; Penny, R C; Watson, A T; Watson, N K; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmuecker, H; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Mackay, C; Wilson, F F; Abe, K; Cuhadar-Donszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; McKemey, A K; Teodorescu, L; Blinov, V E; Bukin, A D; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Gary, J W; Layter, J; Shen, B C; Wang, K; del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, Sh; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Beringer, J; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Spradlin, P; Turri, M; Walkowiak, W; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Erwin, R J; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Roy, J; Smith, J G; van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Soffer, A; Toki, W H; Wilson, R J; Zhang, J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Dubitzky, R S; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Schubert, J; Schubert, K R; Schwierz, R; Spaan, B; Wilden, L; Bernard, D; Bonneaud, G R; Brochard, F; Cohen-Tanugi, J; Grenier, P; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Khan, A; Lavin, D; Muheim, F; Playfer, S; Swain, J E; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Falciai, D; Finocchiaro, G; Patteri, P; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Morii, M; Won, E; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Eschrich, I; Gaillard, J R; Morton, G W; Nash, J A; Taylor, G P; Grenier, G J; Lee, S-J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Diberder, F Le; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Brigljević, V; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, E; Gamet, R; Kay, M; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Harrison, P F; Shorthouse, H W; Vidal, P B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; George, S; Green, M G; Kurup, A; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Jackson, F; Lafferty, G D; Lyon, A J; Weatherall, J H; Williams, J C; Farbin, A; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Cote-Ahern, D; Taras, P; Nicholson, H; Cartaro, C; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; LoSecco, J M; Gabriel, T A; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; de la Vaissière, Ch; Del Buono, L; Hamon, O; John, M J J; Leruste, Ph; Ocariz, J; Pivk, M; Roos, L; Stark, J; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Anulli, F; Biasini, M; Peruzzi, I M; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Del Gamba, V; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martinez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lu, C; Miftakov, V; Olsen, J; Smith, A J S; Tanaka, H A; Varnes, E W; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; SafaiTehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Geddes, N I; Gopal, G P; Olaiya, E O; Xella, S M; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P-F; Hamel de Monchenault, G; Kozanecki, W; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yeche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Convery, M R; Cristinziani, M; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Elsen, E E; Field, R C; Glanzman, T; Gowdy, S J; Grauges-Pous, E; Hadig, T; Halyo, V; Hryn'ova, T; Innes, W R; Jessop, C P; Kelsey, M H; Kim, P; Kocian, M L; Langenegger, U; Leith, D W G S; Libby, J; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Va'vra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wright, D H; Young, C C; Burchat, P R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihalyi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; von Wimmersperg-Toeller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H

2004-06-25

We present a measurement of time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D(*-/+)pi(+/-), using approximately 82x10(6) BBmacr; events recorded by the BABAR experiment at the PEP-II e(+)e(-) storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum pi(+/-) from the B decay and the low-momentum pi(-/+) from the D(*-/+) decay are used. We measure the amplitude of the asymmetry to be -0.063+/-0.024(stat)+/-0.014(syst) and compute bounds on |sin((2beta+gamma)|.

A novel method for rapid and non-invasive detection of plants senescence using delayed fluorescence technique

NASA Astrophysics Data System (ADS)

Zhang, Lingrui; Xing, Da; Wang, Junsheng; Zeng, Lizhang; Li, Qiang

2007-05-01

Plants senescence is a phase of plants ontogeny marked by declining photosynthetic activity that is paralleled by a decline in chloroplast function. The photosystem II ( PSII ) in a plant is considered the primary site where light-induced delayed fluorescence (DF) is produced. With the leaves of Catharanthus roseus (Catharanthus roseus (L.) G.Don) as testing models, we have studied the effects of plants senescence induced by dark and/or exogenous hormones treatments on characteristics of DF by using a home-made portable DF detection system, which can enable various DF parameters, such as DF decay kinetic curve and DF intensity, to be rapidly produced for the plants in a short time. The results show that the changes in DF intensity of green plants can truly reflect the changes in photosynthetic capacity and chlorophyll content. Therefore, DF may be used an important means of evaluating in vivo plants senescence physiology. The changes in DF intensity may provide a new approach for the rapid and early detection of plants senescence caused by age or other senescence-related factors. DF technique could be potential useful for high throughput screening and less time-consuming and automated identifying the interesting mutants with genetic modifications that change plants senescence progress.

Abundant aftershock sequence of the 2015 Mw7.5 Hindu Kush intermediate-depth earthquake

NASA Astrophysics Data System (ADS)

Li, Chenyu; Peng, Zhigang; Yao, Dongdong; Guo, Hao; Zhan, Zhongwen; Zhang, Haijiang

2018-05-01

The 2015 Mw7.5 Hindu Kush earthquake occurred at a depth of 213 km beneath the Hindu Kush region of Afghanistan. While many early aftershocks were missing from the global earthquake catalogues, this sequence was recorded continuously by eight broad-band stations within 500 km. Here we use a waveform matching technique to systematically detect earthquakes around the main shock. More than 3000 events are detected within 35 d after the main shock, as compared with 42 listed in the Advanced National Seismic System catalogue (or 196 in the International Seismological Centre catalogue). The aftershock sequence generally follows the Omori's law with a decay constant p = 0.92. We also apply the recently developed double-pair double-difference technique to relocate all detected aftershocks. Most of them are located to the west of the hypocentre of the main shock, consistent with the westward propagation of the main-shock rupture. The aftershocks outline a nearly vertical southward dipping plane, which matches well with one of the nodal planes of the main shock. We conclude that the aftershock sequence of this intermediate-depth earthquake shares many similarities with those for shallow earthquakes and infer that there are some common mechanisms responsible for shallow and intermediate-depth earthquakes.

Astrophysical tests for radiative decay of neutrinos and fundamental physics implications

NASA Technical Reports Server (NTRS)

Stecker, F. W.; Brown, R. W.

1981-01-01

The radiative lifetime tau for the decay of massious neutrinos was calculated using various physical models for neutrino decay. The results were then related to the astrophysical problem of the detectability of the decay photons from cosmic neutrinos. Conversely, the astrophysical data were used to place lower limits on tau. These limits are all well below predicted values. However, an observed feature at approximately 1700 A in the ultraviolet background radiation at high galactic latitudes may be from the decay of neutrinos with mass approximately 14 eV. This would require a decay rate much larger than the predictions of standard models but could be indicative of a decay rate possible in composite models or other new physics. Thus an important test for substructure in leptons and quarks or other physics beyond the standard electroweak model may have been found.

Search for the β decay of 96Zr

NASA Astrophysics Data System (ADS)

Finch, S. W.; Tornow, W.

2016-01-01

96Zr and 48Ca are unique among double-β decay candidate nuclides in that they may also undergo single-β decay. In the case of 96Zr, the single-β decay mode is dominated by the fourth-forbidden β decay with a 119 keV Q value. A search was conducted for the β decay of 96Zr by observing the decay of the daughter 96Nb nucleus. Two coaxial high-purity germanium detectors were used in coincidence to detect the γ-ray cascade produced by the daughter nucleus as it de-excited to the ground state. The experiment was carried out at the Kimballton Underground Research Facility and produced 685.7 days of data with a 17.91 g enriched sample. No counts were seen above background, producing a limit of T1/2 > 2.4 ×1019 year. This is the first experimental search that is able to discern between the β decay and the double-β decay to an excited state of 96Zr.

Using Sound To Study the Effect of Frothers on the Breakaway of Air Bubbles at an Underwater Capillary.

PubMed

Chu, Pengbo; Pax, Randolph; Li, Ronghao; Langlois, Ray; Finch, James A

2017-04-04

Frothers, a class of surfactants, are widely employed in froth flotation to aid the generation of small bubbles. Their action is commonly explained by their ability to hinder coalescence. There are occasional references suggesting that the frother may also play a role in the initial breakup of the injected air mass. This work investigates the possible effect of the frother on breakup by monitoring air bubbles produced quasi-statically at an underwater capillary. Under this condition, breakup is isolated from coalescence and an impact of frothers on the detached bubble can be ascribed to an impact on breakup. The breakaway process was monitored by an acoustic technique along with high-speed cinematography. The results showed that the presence of frothers did influence the breakaway process and that the acoustic technique was able to detect the impact. It was demonstrated that the acoustic frequency and acoustic damping ratio depend upon the frother type and concentration and that they are associated with a liquid jet, which initially excites the bubble and then decays to form a surface wave. The addition of the frother did not influence the formation of the jet but did increase its decay rate, hence, dampening the surface wave. It is postulated that the action of the frother is related to an effect on the magnitude of surface tension gradients.

Decay spectroscopy for nuclear astrophysics: β- and β-delayed proton decay

NASA Astrophysics Data System (ADS)

Trache, L.; Banu, A.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B. T.; Simmons, E.; Spiridon, A.; Tribble, R. E.; Saastamoinen, A.; Jokinen, A.; Äysto, J.; Davinson, T.; Lotay, G.; Woods, P. J.; Pollacco, E.

2012-02-01

In several radiative proton capture reactions important in novae and XRBs, the resonant parts play the capital role. We use decay spectroscopy techniques to find these resonances and study their properties. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A&M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. This allows us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of 23Al, 27P, 31Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions 22Na(p,γ)23Mg (crucial for the depletion of 22Na in novae), 26mAl(p,γ)27Si and 30P(p,γ)31S (bottleneck in novae and XRB burning), respectively. Lastly, results with a new detector that allowed us to measure down to about 80 keV proton energy are announced.

Radioisotope studies of the farmville meteorite using γγ-coincidence spectrometry.

PubMed

Howard, Chris; Ferm, Megan; Cesaratto, John; Daigle, Stephen; Iliadis, Christian

2014-12-01

Radionuclides are cosmogenically produced in meteorites before they fall to the surface of the Earth. Measurement of the radioactive decay of such nuclides provides a wealth of information on the irradiation conditions of the meteorite fragment, the intensity of cosmic rays in the inner solar system, and the magnetic activity of the Sun. We report here on the detection of (26)Al using a sophisticated spectrometer consisting of a HPGe detector and a NaI(Tl) annulus. It is shown that modern γ-ray spectrometers represent an interesting alternative to other detection techniques. Data are obtained for a fragment of the Farmville meteorite and compared to results from Geant4 simulations. In particular, we report on optimizing the detection sensitivity by using suitable coincidence gates for deposited energy and event multiplicity. We measured an (26)Al activity of 48.5±3.5dpm/kg for the Farmville meteorite, in agreement with previously reported values for other H chondrites. Copyright © 2014 Elsevier Ltd. All rights reserved.

Improved L-C resonant decay technique for Q measurement of quasilinear power inductors: New results for MPP and ferrite powdered cores

NASA Technical Reports Server (NTRS)

Niedra, Janis M.; Gerber, Scott S.

1995-01-01

The L-C resonant decay technique for measuring circuit Q or losses is improved by eliminating the switch from the inductor-capacitor loop. A MOSFET switch is used instead to momentarily connect the resonant circuit to an existing voltage source, which itself is gated off during the decay transient. Very reproducible, low duty cycle data could be taken this way over a dynamic voltage range of at least 10:1. Circuit Q is computed from a polynomial fit to the sequence of the decaying voltage maxima. This method was applied to measure the losses at 60 kHz in inductors having loose powder cores of moly permalloy and an Mn-Zn power ferrite. After the copper and capacitor losses are separated out, the resulting specific core loss is shown to be roughly as expected for the MPP powder, but anomalously high for the ferrite powder. Possible causes are mentioned.

Finding Mass Constraints Through Third Neutrino Mass Eigenstate Decay

NASA Astrophysics Data System (ADS)

Gangolli, Nakul; de Gouvêa, André; Kelly, Kevin

2018-01-01

In this paper we aim to constrain the decay parameter for the third neutrino mass utilizing already accepted constraints on the other mixing parameters from the Pontecorvo-Maki-Nakagawa-Sakata matrix (PMNS). The main purpose of this project is to determine the parameters that will allow the Jiangmen Underground Neutrino Observatory (JUNO) to observe a decay parameter with some statistical significance. Another goal is to determine the parameters that JUNO could detect in the case that the third neutrino mass is lighter than the first two neutrino species. We also replicate the results that were found in the JUNO Conceptual Design Report (CDR). By utilizing Χ2-squared analysis constraints have been put on the mixing angles, mass squared differences, and the third neutrino decay parameter. These statistical tests take into account background noise and normalization corrections and thus the finalized bounds are a good approximation for the true bounds that JUNO can detect. If the decay parameter is not included in our models, the 99% confidence interval lies within The bounds 0s to 2.80x10-12s. However, if we account for a decay parameter of 3x10-5 ev2, then 99% confidence interval lies within 8.73x10-12s to 8.73x10-11s.

The use of γ-rays analysis by HPGe detector to assess the gross alpha and beta activities in waters.

PubMed

Casagrande, M F S; Bonotto, D M

2018-07-01

This paper describes an alternative method for evaluating gross alpha and beta radioactivity in waters by using γ-rays analysis performed with hyper-pure germanium detector (HPGe). Several gamma emissions related to α and β - decays were used to provide the activity concentration data due to natural radionuclides commonly present in waters like 40 K and those belonging to the 238 U and 232 Th decay series. The most suitable gamma emissions related to β - decays were 214 Bi (1120.29 keV, 238 U series) and 208 Tl (583.19 keV, 232 Th series) as the equation in activity concentration yielded values compatible to those generated by the formula taking into account the detection efficiency. The absence of isolated and intense γ-rays peaks associated to α decays limited the choice to 226 Ra (186.21 keV, 238 U series) and 224 Ra (240.99 keV, 232 Th series). In these cases, it was adopted appropriate correction factors involving the absolute intensities and specific activities for avoiding the interferences of other γ-rays energies. The critical level of detection across the 186-1461 keV energy region corresponded to 0.010, 0.023, 0.038, 0.086, and 0.042 Bq/L, respectively, for 226 Ra, 224 Ra, 208 Tl, 214 Bi and 40 K. It is much lower than the WHO guideline reference value for gross alpha (0.5 Bq/L) and beta (1.0 Bq/L) in waters. The method applicability was checked by the analysis of groundwater samples from different aquifer systems occurring in the Brazilian states of São Paulo, Minas Gerais and Mato Grosso do Sul. The waters exhibit very different chemical composition and the samples with the highest radioactivity levels were those associated with lithotypes possessing enhanced uranium and thorium levels. The technique allowed directly discard the 40 K contribution to the gross beta activity as potassium is an essential element for humans. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dynamics of monochromatically generated nonequilibrium phonons in LaF3:Pr3+

NASA Astrophysics Data System (ADS)

Tolbert, W. A.; Dennis, W. M.; Yen, W. M.

1990-07-01

The temporal evolution of nonequilibrium phonon populations in LaF3:Pr3+ is investigated at low temperatures (1.8 K) utilizing pulsed, tunable, monochromatic generation and time-resolved, tunable, narrow-band detection. High occupation number, narrow-band phonon populations are generated via far-infrared pumping of defect-induced one-phonon absorption. Time-resolved, frequency-selective detection is provided by optical sideband absorption. Nonequilibrium phonon decay times are measured and attributed to anharmonic decay.

Sensitivity quantification of remote detection NMR and MRI

NASA Astrophysics Data System (ADS)

Granwehr, J.; Seeley, J. A.

2006-04-01

A sensitivity analysis is presented of the remote detection NMR technique, which facilitates the spatial separation of encoding and detection of spin magnetization. Three different cases are considered: remote detection of a transient signal that must be encoded point-by-point like a free induction decay, remote detection of an experiment where the transient dimension is reduced to one data point like phase encoding in an imaging experiment, and time-of-flight (TOF) flow visualization. For all cases, the sensitivity enhancement is proportional to the relative sensitivity between the remote detector and the circuit that is used for encoding. It is shown for the case of an encoded transient signal that the sensitivity does not scale unfavorably with the number of encoded points compared to direct detection. Remote enhancement scales as the square root of the ratio of corresponding relaxation times in the two detection environments. Thus, remote detection especially increases the sensitivity of imaging experiments of porous materials with large susceptibility gradients, which cause a rapid dephasing of transverse spin magnetization. Finally, TOF remote detection, in which the detection volume is smaller than the encoded fluid volume, allows partial images corresponding to different time intervals between encoding and detection to be recorded. These partial images, which contain information about the fluid displacement, can be recorded, in an ideal case, with the same sensitivity as the full image detected in a single step with a larger coil.

Atomic mass and double-β-decay Q value of 48Ca

NASA Astrophysics Data System (ADS)

Redshaw, Matthew; Bollen, Georg; Brodeur, Maxime; Bustabad, Scott; Lincoln, David L.; Novario, Samuel J.; Ringle, Ryan; Schwarz, Stefan

2012-10-01

The possibility of detecting neutrinoless double-β-decay (0νββ-decay) in experiments that are currently in operation or under development provides the exciting opportunity to determine the Dirac or Majorana nature of the neutrino and its absolute mass scale. An important datum for interpreting 0νββ-decay experimental results is the Q value of the decay. Using Penning trap mass spectrometry we have measured the atomic mass of 48Ca to be M[48Ca] = 47.952 522 76(21) u which, combined with the mass of 48Ti evaluated by Audi [Nucl. Phys. ANUPABL0375-947410.1016/j.nuclphysa.2003.11.003 729, 337 (2003)], provides a new determination of the 48Ca ββ-decay Q value: Qββ = 4262.96(84) keV.

Thoron detection with an active Radon exposure meter—First results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Irlinger, J., E-mail: josef.irlinger@helmholtz-muenchen.de; Wielunski, M.; Rühm, W.

For state-of-the-art discrimination of Radon and Thoron several measurement techniques can be used, such as active sampling, electrostatic collection, delayed coincidence method, and alpha-particle-spectroscopy. However, most of the devices available are bulky and show high power consumption, rendering them unfeasible for personal exposition monitoring. Based on a Radon exposure meter previously realized at the Helmholtz Center Munich (HMGU), a new electronic prototype for Radon/Thoron monitoring is currently being developed, which features small size and weight. Operating with pin-diode detectors, the low-power passive-sampling device can be used for continuous concentration measurements, employing alpha-particle-spectroscopy and coincidence event registration to distinguish decays originatingmore » either from Radon or Thoron isotopes and their decay products. In open geometry, preliminary calibration measurements suggest that one count per hour is produced by a 11 Bq m{sup −3} Radon atmosphere or by a 15 Bq m{sup −3} Thoron atmosphere. Future efforts will concentrate on measurements in mixed Radon/Thoron atmospheres.« less

Half-life of the superallowed β+ emitter Ne18

NASA Astrophysics Data System (ADS)

Grinyer, G. F.; Smith, M. B.; Andreoiu, C.; Andreyev, A. N.; Ball, G. C.; Bricault, P.; Chakrawarthy, R. S.; Daoud, J. J.; Finlay, P.; Garrett, P. E.; Hackman, G.; Hyland, B.; Leslie, J. R.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Schumaker, M. A.; Svensson, C. E.; Valiente-Dobón, J. J.; Williams, S. J.; Zganjar, E. F.

2007-08-01

The half-life of Ne18 has been determined by detecting 1042-keV γ rays in the daughter F18 following the superallowed-Fermi β+ decay of samples implanted at the center of the 8πγ-ray spectrometer, a spherical array of 20 HPGe detectors. Radioactive Ne18 beams were produced on-line, mass-separated, and ionized using an electron-cyclotron-resonance ionization source at the ISAC facility at TRIUMF in Vancouver, Canada. This is the first high-precision half-life measurement of a superallowed Fermi β decay to utilize both a large-scale HPGe spectrometer and the isotope separation on-line technique. The half-life of Ne18, 1.6656 ± 0.0019 s, deduced following a 1.4σ correction for detector pulse pile-up, is four times more precise than the previous world average. As part of an investigation into potential systematic effects, the half-life of the heavier isotope Ne23 was determined to be 37.11 ± 0.06 s, a factor of 2 improvement over the previous precision.

Half-life of the superallowed {beta}{sup +} emitter {sup 18}Ne

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grinyer, G. F.; Andreoiu, C.; Finlay, P.

The half-life of {sup 18}Ne has been determined by detecting 1042-keV {gamma} rays in the daughter {sup 18}F following the superallowed-Fermi {beta}{sup +} decay of samples implanted at the center of the 8{pi}{gamma}-ray spectrometer, a spherical array of 20 HPGe detectors. Radioactive {sup 18}Ne beams were produced on-line, mass-separated, and ionized using an electron-cyclotron-resonance ionization source at the ISAC facility at TRIUMF in Vancouver, Canada. This is the first high-precision half-life measurement of a superallowed Fermi {beta} decay to utilize both a large-scale HPGe spectrometer and the isotope separation on-line technique. The half-life of {sup 18}Ne, 1.6656 {+-} 0.0019 s,more » deduced following a 1.4{sigma} correction for detector pulse pile-up, is four times more precise than the previous world average. As part of an investigation into potential systematic effects, the half-life of the heavier isotope {sup 23}Ne was determined to be 37.11 {+-} 0.06 s, a factor of 2 improvement over the previous precision.« less

Real-time method and apparatus for measuring the decay-time constant of a fluorescing phosphor

DOEpatents

Britton, Jr., Charles L.; Beshears, David L.; Simpson, Marc L.; Cates, Michael R.; Allison, Steve W.

1999-01-01

A method for determining the decay-time constant of a fluorescing phosphor is provided, together with an apparatus for performing the method. The apparatus includes a photodetector for detecting light emitted by a phosphor irradiated with an excitation pulse and for converting the detected light into an electrical signal. The apparatus further includes a differentiator for differentiating the electrical signal and a zero-crossing discrimination circuit that outputs a pulse signal having a pulse width corresponding to the time period between the start of the excitation pulse and the time when the differentiated electrical signal reaches zero. The width of the output pulse signal is proportional to the decay-time constant of the phosphor.

Photoluminescence kinetics in CdS nanoclusters formed by the Langmuir-Blodgett technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zarubanov, A. A., E-mail: alexsundr@mail.ru; Zhuravlev, K. S.

2015-03-15

The photoluminescence kinetics in CdS nanocrystals produced by the Langmuir-Blodgett technique is studied at a temperature of 5 K. The photoluminescence kinetics is described by the sum of two exponential functions, with characteristic times of about 30 and 160 ns. It is found that the fast and slow decay times become longer, as the nanocrystal size increases. Analysis of the data shows that the fast decay time is controlled by trion recombination in nanocrystals with defects, whereas the slow decay time is controlled by the annihilation of optically inactive excitons in nanocrystals without defects. It is established that, as themore » nanocrystal size is decreased, the fraction of imperfect nanocrystals is reduced because of an increase in the energy of defect formation.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rice, S.; Algora, A.; Tain, J. L.

The beta decays of Br-86 and Rb-91 have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the Ion Guide Isotope Separator On-Line facility in Jyvaskyla and further purified using the JYFLTRAP. Br-86 and Rb-91 are considered to be major contributors to the decay heat in reactors. In addition, Rb-91 was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decaywas well known from high-resolution measurements. Our results show that both decays were suffering from the Pandemoniummore » effect and that the results of Rudstam et al. should be renormalized. The relative impact of the studied decays in the prediction of the decay heat and antineutrino spectrum from reactors has been evaluated.« less

Measurement of the shape of the Λb0→Λc+μ-ν¯μ differential decay rate

NASA Astrophysics Data System (ADS)

Aaij, R.; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Alfonso Albero, A.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Archilli, F.; d'Argent, P.; Arnau Romeu, J.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Babuschkin, I.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baker, S.; Balagura, V.; Baldini, W.; Baranov, A.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Baryshnikov, F.; Baszczyk, M.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Beiter, A.; Bel, L. J.; Beliy, N.; Bellee, V.; Belloli, N.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Beranek, S.; Berezhnoy, A.; Bernet, R.; Berninghoff, D.; Bertholet, E.; Bertolin, A.; Betancourt, C.; Betti, F.; Bettler, M.-O.; van Beuzekom, M.; Bezshyiko, Ia.; Bifani, S.; Billoir, P.; Birnkraut, A.; Bitadze, A.; Bizzeti, A.; Bjoern, M. B.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Boettcher, T.; Bondar, A.; Bondar, N.; Bonivento, W.; Bordyuzhin, I.; Borgheresi, A.; Borghi, S.; Borisyak, M.; Borsato, M.; Borysova, M.; Bossu, F.; Boubdir, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britton, T.; Brodzicka, J.; Brundu, D.; Buchanan, E.; Burr, C.; Bursche, A.; Buytaert, J.; Byczynski, W.; Cadeddu, S.; Cai, H.; Calabrese, R.; Calladine, R.; Calvi, M.; Calvo Gomez, M.; Camboni, A.; Campana, P.; Campora Perez, D. H.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cavallero, G.; Cenci, R.; Chamont, D.; Charles, M.; Charpentier, Ph.; Chatzikonstantinidis, G.; Chefdeville, M.; Chen, S.; Cheung, S. F.; Chitic, S.-G.; Chobanova, V.; Chrzaszcz, M.; Chubykin, A.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collins, P.; Colombo, T.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombs, G.; Coquereau, S.; Corti, G.; Corvo, M.; Costa Sobral, C. M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Currie, R.; D'Ambrosio, C.; Da Cunha Marinho, F.; Dall'Occo, E.; Dalseno, J.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Serio, M.; De Simone, P.; Dean, C. T.; Decamp, D.; Del Buono, L.; Dembinski, H.-P.; Demmer, M.; Dendek, A.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Nezza, P.; Dijkstra, H.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Douglas, L.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dungs, K.; Durante, P.; Dzhelyadin, R.; Dziewiecki, M.; Dziurda, A.; Dzyuba, A.; Déléage, N.; Easo, S.; Ebert, M.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Farley, N.; Farry, S.; Fay, R.; Fazzini, D.; Federici, L.; Ferguson, D.; Fernandez, G.; Fernandez Declara, P.; Fernandez Prieto, A.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fini, R. A.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fleuret, F.; Fohl, K.; Fontana, M.; Fontanelli, F.; Forshaw, D. C.; Forty, R.; Franco Lima, V.; Frank, M.; Frei, C.; Fu, J.; Funk, W.; Furfaro, E.; Färber, C.; Gabriel, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; Garcia Martin, L. M.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Garsed, P. J.; Gascon, D.; Gaspar, C.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianı, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gizdov, K.; Gligorov, V. V.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gorelov, I. V.; Gotti, C.; Govorkova, E.; Grabowski, J. P.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greim, R.; Griffith, P.; Grillo, L.; Gruber, L.; Gruberg Cazon, B. R.; Grünberg, O.; Gushchin, E.; Guz, Yu.; Gys, T.; Göbel, C.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hamilton, B.; Han, X.; Hancock, T.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; Hatch, M.; He, J.; Hecker, M.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hombach, C.; Hopchev, P. H.; Huard, Z.-C.; Hulsbergen, W.; Humair, T.; Hushchyn, M.; Hutchcroft, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jalocha, J.; Jans, E.; Jawahery, A.; Jiang, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Karacson, M.; Kariuki, J. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenzie, M.; Ketel, T.; Khairullin, E.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Klimkovich, T.; Koliiev, S.; Kolpin, M.; Komarov, I.; Kopecna, R.; Koppenburg, P.; Kosmyntseva, A.; Kotriakhova, S.; Kozeiha, M.; Kravchuk, L.; Kreps, M.; Krokovny, P.; Kruse, F.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lanfranchi, G.; Langenbruch, C.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Leflat, A.; Lefrançois, J.; Lefèvre, R.; Lemaitre, F.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, T.; Li, Y.; Li, Z.; Likhomanenko, T.; Lindner, R.; Lionetto, F.; Liu, X.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusiani, A.; Lyu, X.; Machefert, F.; Maciuc, F.; Macko, V.; Maddock, B.; Maddrell-Mander, S.; Maev, O.; Maguire, K.; Maisuzenko, D.; Majewski, M. W.; Malde, S.; Malinin, A.; Maltsev, T.; Manca, G.; Mancinelli, G.; Manning, P.; Marangotto, D.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marinangeli, M.; Marino, P.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massacrier, L. M.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurice, E.; Maurin, B.; Mazurov, A.; McCann, M.; McNab, A.; McNulty, R.; Mead, J. V.; Meadows, B.; Meaux, C.; Meier, F.; Meinert, N.; Melnychuk, D.; Merk, M.; Merli, A.; Michielin, E.; Milanes, D. A.; Millard, E.; Minard, M.-N.; Minzoni, L.; Mitzel, D. S.; Mogini, A.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morello, M. J.; Morgunova, O.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Mulder, M.; Mussini, M.; Müller, D.; Müller, J.; Müller, K.; Müller, V.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, T. D.; Nguyen-Mau, C.; Nieswand, S.; Niet, R.; Nikitin, N.; Nikodem, T.; Nogay, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Oldeman, R.; Onderwater, C. J. G.; Ossowska, A.; Otalora Goicochea, J. M.; Owen, P.; Oyanguren, A.; Pais, P. R.; Palano, A.; Palutan, M.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Pappenheimer, C.; Parker, W.; Parkes, C.; Passaleva, G.; Pastore, A.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petrov, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pikies, M.; Pinci, D.; Pistone, A.; Piucci, A.; Placinta, V.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poli Lener, M.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Pomery, G. J.; Ponce, S.; Popov, A.; Popov, D.; Poslavskii, S.; Potterat, C.; Price, E.; Prisciandaro, J.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Pullen, H.; Punzi, G.; Qian, W.; Quagliani, R.; Quintana, B.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Ramos Pernas, M.; Rangel, M. S.; Raniuk, I.; Ratnikov, F.; Raven, G.; Ravonel Salzgeber, M.; Reboud, M.; Redi, F.; Reichert, S.; dos Reis, A. C.; Remon Alepuz, C.; Renaudin, V.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Rogozhnikov, A.; Roiser, S.; Rollings, A.; Romanovskiy, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Rudolph, M. S.; Ruf, T.; Ruiz Valls, P.; Ruiz Vidal, J.; Saborido Silva, J. J.; Sadykhov, E.; Sagidova, N.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Gonzalo, D.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarpis, G.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schellenberg, M.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schreiner, H. F.; Schubert, K.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Siddi, B. G.; Silva Coutinho, R.; Silva de Oliveira, L.; Simi, G.; Simone, S.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Lavra, l. Soares; Sokoloff, M. D.; Soler, F. J. P.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefko, P.; Stefkova, S.; Steinkamp, O.; Stemmle, S.; Stenyakin, O.; Stevens, H.; Stone, S.; Storaci, B.; Stracka, S.; Stramaglia, M. E.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Syropoulos, V.; Szczekowski, M.; Szumlak, T.; Szymanski, M.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Tellarini, G.; Teubert, F.; Thomas, E.; van Tilburg, J.; Tilley, M. J.; Tisserand, V.; Tobin, M.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Toriello, F.; Tourinho Jadallah Aoude, R.; Tournefier, E.; Traill, M.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tully, A.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagner, A.; Vagnoni, V.; Valassi, A.; Valat, S.; Valenti, G.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Venkateswaran, A.; Verlage, T. A.; Vernet, M.; Vesterinen, M.; Viana Barbosa, J. V.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Viemann, H.; Vilasis-Cardona, X.; Vitti, M.; Volkov, V.; Vollhardt, A.; Voneki, B.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Vázquez Sierra, C.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wang, J.; Ward, D. R.; Wark, H. M.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wicht, J.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Winn, M. A.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wraight, K.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yang, Z.; Yao, Y.; Yin, H.; Yu, J.; Yuan, X.; Yushchenko, O.; Zarebski, K. A.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zheng, Y.; Zhu, X.; Zhukov, V.; Zonneveld, J. B.; Zucchelli, S.; LHCb Collaboration

2017-12-01

A measurement of the shape of the differential decay rate and the associated Isgur-Wise function for the decay Λb0→Λc+μ-ν¯μ is reported, using data corresponding to 3 fb-1 collected with the LHCb detector in proton-proton collisions. The Λc+μ-ν¯ μ(+anything ) final states are reconstructed through the detection of a muon and a Λc+ baryon decaying into p K-π+, and the decays Λb0→Λc+π+π-μ-ν¯μ are used to determine contributions from Λb0→Λc*+μ-ν¯μ decays. The measured dependence of the differential decay rate upon the squared four-momentum transfer between the heavy baryons, q2, is compared with expectations from heavy-quark effective theory and from unquenched lattice QCD predictions.

Dental hard tissue characterization using laser-based ultrasonics

NASA Astrophysics Data System (ADS)

Blodgett, David W.; Massey, Ward L.

2003-07-01

Dental health care and research workers require a means of imaging the structures within teeth in vivo. One critical need is the detection of tooth decay in its early stages. If decay can be detected early enough, the process can be monitored and interventional procedures, such as fluoride washes and controlled diet, can be initiated to help re-mineralize the tooth. Currently employed x-ray imaging is limited in its ability to visualize interfaces and incapable of detecting decay at a stage early enough to avoid invasive cavity preparation followed by a restoration. To this end, non-destructive and non-contact in vitro measurements on extracted human molars using laser-based ultrasonics are presented. Broadband ultrasonic waves are excited in the extracted sections by using a pulsed carbon-dioxide (CO2) laser operating in a region of high optical absorption in the dental hard tissues. Optical interferometric detection of the ultrasonic wave surface displacements in accomplished with a path-stabilized Michelson-type interferometer. Results for bulk and surface in-vitro characterization of caries are presented on extracted molars with pre-existing caries.

Application of the mass-spectrometer MASHA for mass-spectrometry and laser-spectroscopy

NASA Astrophysics Data System (ADS)

Rodin, A. M.; Belozerov, A. V.; Dmitriev, S. N.; Oganessian, Yu. Ts.; Sagaidak, R. N.; Salamatin, V. S.; Stepantsov, S. V.; Vanin, D. V.

2010-02-01

We report the present status of the mass-spectrometer MASHA (Mass-Analyzer of Supper Heavy Atoms) designed for determination of the masses of superheavy elements. The mass-spectrometer is connected to the U-400M cyclotron of the Flerov Laboratory for Nuclear Reactions (FLNR) JINR, Dubna. The first experiments on mass-measurements for 112 and 114 elements will be performed in the upcoming 2010. For this purpose a hot catcher, based on a graphite stopper, is constructed. The α-decay of the superheavy nuclides or spontaneous fission products will be detected with a silicon 192 strips detector. The experimental program of future investigations using the technique of a gas catcher is discussed. It should be regarded as an alternative of the classical ISOL technique. The possibilities are considered for using this mass-spectrometer for laser spectroscopy of nuclei far off-stability.

Picosecond acoustic phonon dynamics in LaF3:Pr3+

NASA Astrophysics Data System (ADS)

Kirkpatrick, Sean M.; Yang, Ho-Soon; Dennis, W. M.

1998-09-01

A plasma switching technique is used to generate subnanosecond, far-infrared (FIR) pulses with frequency 113 cm-1. The generation of subnanosecond FIR pulses enables us to improve the time resolution of phonon spectroscopic measurements from 50 ns to 350 ps. As an application of this technique, we investigate the subnanosecond dynamics of high-frequency phonons in 0.5% LaF3:Pr3+. In particular, we report on the generation and detection of a subnanosecond nonequilibrium phonon population at 113 cm-1, and the temporal evolution of the resulting decay products. The frequency dependence of the phonon relaxation rates of acoustic phonons in this material is found to deviate from the ω5 frequency dependence predicted by an isotropic model with linear dispersion. A more realistic model based on the actual dispersion curves of the material is presented and compared with the data.

Enhanced Higgs boson to τ(+)τ(-) search with deep learning.

PubMed

Baldi, P; Sadowski, P; Whiteson, D

2015-03-20

The Higgs boson is thought to provide the interaction that imparts mass to the fundamental fermions, but while measurements at the Large Hadron Collider (LHC) are consistent with this hypothesis, current analysis techniques lack the statistical power to cross the traditional 5σ significance barrier without more data. Deep learning techniques have the potential to increase the statistical power of this analysis by automatically learning complex, high-level data representations. In this work, deep neural networks are used to detect the decay of the Higgs boson to a pair of tau leptons. A Bayesian optimization algorithm is used to tune the network architecture and training algorithm hyperparameters, resulting in a deep network of eight nonlinear processing layers that improves upon the performance of shallow classifiers even without the use of features specifically engineered by physicists for this application. The improvement in discovery significance is equivalent to an increase in the accumulated data set of 25%.

Near-surface structural examination of human tooth enamel subject to in vitro demineralization and remineralization

NASA Astrophysics Data System (ADS)

Gaines, Carmen Veronica

The early stages of chemical tooth decay are governed by dynamic processes of demineralization and remineralization of dental enamel that initiates along the surface of the tooth. Conventional diagnostic techniques lack the spatial resolution required to analyze near-surface structural changes in enamel at the submicron level. In this study, slabs of highly-polished, decay-free human enamel were subjected to 0.12M EDTA and buffered lactic acid demineralizing agents and MI Paste(TM) and calcifying (0.1 ppm F) remineralizing treatments in vitro. Grazing incidence x-ray diffraction (GIXD), a technique typically used for thin film analysis, provided depth profiles of crystallinity changes in surface enamel with a resolution better than 100 nm. In conjunction with nanoindentation, a technique gaining acceptance as a means of examining the mechanical properties of sound enamel, these results were corroborated with well-established microscopy and Raman techniques to assess the nanohardness, morphologies and chemical nature of treated enamel. Interestingly, the average crystallite size of surface enamel along its c-axis dimension increased by nearly 40% after a 60 min EDTA treatment as detected by GIXD. This result was in direct contrast to the obvious surface degradation observed by microscopic and confocal Raman imaging. A decrease in nanohardness from 4.86 +/- 0.44 GPa to 0.28 +/- 0.10 GPa was observed. Collective results suggest that mineral dissolution characteristics evident on the micron scale may not be fully translated to the nanoscale in assessing the integrity of chemically-modified tooth enamel. While an intuitive decrease in enamel crystallinity was observed with buffered lactic acid-treated samples, demineralization was too slow to adequately quantify the enamel property changes seen. MI Paste(TM) treatment of EDTA-demineralized enamel showed preferential growth along the a-axis direction. Calcifying solution treatments of both demineralized sample types appeared to have negligible effects on enamel crystallinity. Both remineralizing agents provided an increase in resiliency within the enamel surface layers. Findings from this study may prove useful in identifying more effective methods to prevent enamel demineralization and to promote and/or enhance remineralization for the treatment of tooth decay. Careful consideration of the nanoscale properties of treated surface enamel may lead to an understanding of how to truly regenerate decomposed enamel mineral from the inside out.

Prospecting for new physics in the Higgs and flavor sectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishara, Fady

We explore two directions in beyond the standard model physics: dark matter model building and probing new sources of CP violation. In dark matter model building, we consider two scenarios where the stability of dark matter derives from the flavor symmetries of the standard model. The first model contains a flavor singlet dark matter candidate whose couplings to the visible sector are proportional to the flavor breaking parameters. This leads to a metastable dark matter with TeV scale mediators. In the second model, we consider a fully gauged SU(3) 3 flavor model with a flavor triplet dark matter. Consequently, the dark matter multiplet is charged while the standard model fields are neutral under a remnant Z 3 which ensures dark matter stability. We show that a Dirac fermion dark matter with radiative splitting in the multiplet must have a mass in the range [0:5; 5] TeV in order to satisfy all experimental constraints. We then turn our attention to Higgs portal dark matter and investigate the possibility of obtaining bounds on the up, down, and strange quark Yukawa couplings. If Higgs portal dark matter is discovered, we find that direct detection rates are insensitive to vanishing light quark Yukawa couplings. We then review flavor models and give the expected enhancement or suppression of the Yukawa couplings in those models. Finally, in the last two chapters, we develop techniques for probing CP violation in the Higgs coupling to photons and in rare radiative decays of B mesons. While theoretically clean, we find that these methods are not practical with current and planned detectors. However, these techniques can be useful with a dedicated detector (e.g., a gaseous TPC). In the case of radiative B meson decay B 0 → (K* → Kππ) γ, the techniques we develop also allow the extraction of the photon polarization fraction which is sensitive to new physics contributions since, in the standard model, the right(left) handed polarization fraction is of O( Λ QCD=m b) formore » $$\\bar{B}^{0}$$(B 0) meson decays.« less

Single-electron detection and spectroscopy via relativistic cyclotron radiation

DOE PAGES

Asner, D. M.; Bradley, R. F.; de Viveiros, L.; ...

2015-04-20

Since 1897, we've understood that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. We demonstrate single-electron detection in a novel radiofrequency spec- trometer. Here, we observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precisemore » electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.« less

Laser restorative dentistry in children and adolescents.

PubMed

Olivi, G; Genovese, M D

2011-04-01

The idea of substituting a drill with a laser light, has led to its introduction in dentistry. Besides being more accepted to patients, in paediatric dentistry the laser has demonstrated safety compared with rotating instruments. A review of the past 20 years of the dental literature concerning laser use in dentistry, including paediatric dentistry was completed. The findings of that review are presented. The various types of lasers and their uses for caries detection, tooth sealing and caries removal are described. Laser caries detection demonstrated a good reproducibility, reliability and predictability to monitor the caries process over time. Erbium lasers have been found to be efficient for caries removal, tooth cleaning and decontamination. The laser erbium technology represents a safe device to effectively and selectively remove carious tissues from decayed teeth. For children, all the recognized advantages of this technique play a decisive role in the successful day-to-day treatment of dental caries.

Optical Properties of Heterostructures and Superlattices.

DTIC Science & Technology

1985-05-01

High intensity studies, from 104 to 106 W/cm2 were performed using near or on resonant excitation techniques, i.e., the excitation energy hv was... rhb mediat for the subsequent LO phonon emisasion decay. The free ecuitons; in Al. Gal - As, evidently decay via the The exact detailed mechaniu of

Extending the use of ultraviolet light for fruit quality sorting in citrus packinghouses

USDA-ARS?s Scientific Manuscript database

Illumination with ultraviolet light (UV) is commonly used in citrus packinghouses as a means to aid in the identification and removal of decayed oranges from the packline. This technique is effective because areas of decay strongly fluoresce under UV illumination. It was observed that oranges often ...

The Majorana Project

ScienceCinema

Orrell, John; Hoppe, Eric

2018-01-26

Working as part of a collaborative team, PNNL is bringing its signature capability in ultra-low-level detection to help search for a rare form of radioactive decay-never before detected-called "neutrinoless double beta decay" in germanium. If observed, it would demonstrate neutrinos are Majorana-type particles. This discovery would show neutrinos are unique among fundamental particles, having a property whereby the matter and anti-matter version of this particle are indistinguishable. Physicist John L. Orrell explains how they rely on the Shallow Underground Laboratory to conduct the research.

Computational Age Dating of Special Nuclear Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

2012-06-30

This slide-show presented an overview of the Constrained Progressive Reversal (CPR) method for computing decays, age dating, and spoof detecting. The CPR method is: Capable of temporal profiling a SNM sample; Precise (compared with known decay code, such a ORIGEN); Easy (for computer implementation and analysis). We have illustrated with real SNM data using CPR for age dating and spoof detection. If SNM is pure, may use CPR to derive its age. If SNM is mixed, CPR will indicate that it is mixed or spoofed.

X-ray lines from dark matter: the good, the bad, and the unlikely

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frandsen, Mads T.; Sannino, Francesco; Shoemaker, Ian M.

2014-05-01

We consider three classes of dark matter (DM) models to account for the recently observed 3.5 keV line: metastable excited state DM, annihilating DM, and decaying DM. We study two examples of metastable excited state DM. The first, millicharged composite DM, has both inelasticity and photon emission built in, but with a very constrained parameter space. In the second example, up-scattering and decay come from separate sectors and is thus less constrained. The decay of the excited state can potentially be detectable at direct detection experiments. However we find that CMB constraints are at the border of excluding this asmore » an interpretation of the DAMA signal. The annihilating DM interpretation of the X-ray line is found to be in mild tension with CMB constraints. Lastly, a generalized version of decaying DM can account for the data with a lifetime exceeding the age of the Universe for masses ∼<10{sup 6} GeV.« less

Mobility and fluorescence of barium ions in xenon gas for the exo experiment

NASA Astrophysics Data System (ADS)

Benitez Medina, Julio Cesar

The Enriched Xenon Observatory (EXO) is an experiment which aims to observe the neutrinoless double beta decay of 136Xe. The measurement of this decay would give information about the absolute neutrino mass and whether or not the neutrino is its own antiparticle. Since this is a very rare decay, the ability to reject background events by detecting the barium ion daughter from the double beta decay would be a major advantage. EXO is currently operating a detector with 200 kg of enriched liquid xenon, and there are plans to build a ton scale xenon detector. Measurements of the purity of liquid xenon in our liquid xenon test cell are reported. These results are relevant to the research on detection of single barium ions by our research group at Colorado State University. Details of the operation of the purity monitor are described. The effects of using a purifier, recirculation and laser ablation on the purity of liquid xenon are discussed. Mobility measurements of barium in xenon gas are reported for the first time. The variation of mobility with xenon gas pressure suggests that a significant fraction of molecular ions are formed when barium ions interact with xenon gas at high pressures. The measured mobility of Ba+ in Xe gas at different pressures is compared with the predicted theoretical value, and deviations are explained by a model that describes the fraction of molecular ions in Xe gas as a function of pressure. The results are useful for the analysis of experiments of fluorescence of Ba+ in xenon gas. It is also important to know the mobility of the ions in order to calculate the time they interact with an excitation laser in fluorescence experiments and in proposed 136 Ba+ daughter detection schemes. This thesis presents results of detection of laser induced fluorescence of Ba+ ions in Xe gas. Measurements of the pressure broadening of the excitation spectra of Ba+ in xenon gas are presented. Nonradiative decays due to gas collisions and optical pumping affect the number of fluorescence counts detected. A model that treats the barium ion as a three level system is used to predict the total number of fluorescence counts and correct for optical pumping. A pressure broadening coefficient for Ba+ in xenon gas is extracted and limits for p-d and d-s nonradiative decay rates are extracted. Although fluorescence is reduced significantly at 5-10 atm xenon pressure, the measurements in this thesis indicate that it is still feasible to detect 136Ba+ ions directly in high pressure xenon gas, e.g. in a double beta decay detector.

Possible Detection of Pi(exp 0)-Decay Gamma-Ray Emission from Cyg OB2 by EGRET

NASA Technical Reports Server (NTRS)

Chen, W.; White, R. L.; Bertsch, D.

1996-01-01

We report possible detection of pi (exp 0) decay radiation from Cyg OB2, a nearby (1.7 kpc) massive OB star association. The EGRET flux (greater than 100 MeV) maps clearly indicate a point source whose error circle includes both Cyg OB2 and Cyg X-3. We show that Cyg X-3 is unlikely to be the counterpart for the EGRET source, because of the marginal spatial consistency and the lack of the 4.8 hour modulation seen in other high energy emissions from Cyg X-3. If confirmed, this will be the first detection by EGRET of massive stars.

Detection of weak signals in memory thermal baths.

PubMed

Jiménez-Aquino, J I; Velasco, R M; Romero-Bastida, M

2014-11-01

The nonlinear relaxation time and the statistics of the first passage time distribution in connection with the quasideterministic approach are used to detect weak signals in the decay process of the unstable state of a Brownian particle embedded in memory thermal baths. The study is performed in the overdamped approximation of a generalized Langevin equation characterized by an exponential decay in the friction memory kernel. A detection criterion for each time scale is studied: The first one is referred to as the receiver output, which is given as a function of the nonlinear relaxation time, and the second one is related to the statistics of the first passage time distribution.

Possible detection of π^0^-decay γ-ray emission from CYG OB2 by EGRET.

NASA Astrophysics Data System (ADS)

Chen, W.; White, R. L.; Bertsch, D.

1996-12-01

We report possible detection of π^0^-decay radiation from Cyg OB2, a nearby (1.7kpc) massive OB star association. The EGRET flux (>100MeV) maps clearly indicate a point source whose error circle includes both Cyg OB2 and Cyg X-3. We show that Cyg X-3 is unlikely to be the counterpart for the EGRET source, because of the marginal spatial consistency and the lack of the 4.8-hour modulation seen in other high energy emissions from Cyg X-3. If confirmed, this will be the first detection by EGRET of massive stars.

Comparative analysis of optical coherence tomography signal and microhardness for demineralization evaluation of human tooth enamel

NASA Astrophysics Data System (ADS)

de Cara, Ana Claudia Ballet; Zezell, Denise Maria; Ana, Patricia A.; Deana, Alessandro Melo; Amaral, Marcello Magri; Dias Vieira, Nilson, Jr.; de Freitas, Anderson Zanardi

2012-06-01

The diagnosis of dental caries at an early stage enables the implementation of conservative treatments based on dental preservation. Several diagnostic methods have been developed, like visual-tactile and radiographic are the most commons but are limited for this application. The Optical Coherence Tomography is a technique that provides information of optical properties of enamel, which may change due to the decay process. The objective of this study was to evaluate the ability of OCT to detect different stages of demineralization of tooth enamel during the development of artificial caries lesions, taking as a reference standard for comparison sectional microhardness testing. Different stages of caries lesions were simulated using the pH cycling model suggested Feathestone and modified by Argenta. The samples were exposed to 0 (control group), 5, 10, 15, 20 and 25 days at a daily regimen of three hours demineralization followed by remineralization during 20 hours. It was used an OCT system with at 930nm. Sectional images were generated in all lesion region. The results obtained from the OCT technique presented similar behavior to microhardness, except for the group 25 days, due to inability to perform indentations reading in areas of more intense demineralization. A linear relationship was observed between the OCT and microhardness techniques for detection of demineralization in enamel. This relationship will allow the use of OCT technique in quantitative assessment of mineral loss and for the evaluation of incipient caries lesions.

The long-term optical evolution of the black hole candidate MAXI J1659-152

NASA Astrophysics Data System (ADS)

Corral-Santana, Jesús M.; Torres, Manuel A. P.; Shahbaz, Tariq; Bartlett, Elizabeth S.; Russell, David M.; Kong, Albert K. H.; Casares, Jorge; Muñoz-Darias, Teodoro; Bauer, Franz E.; Homan, Jeroen; Jonker, Peter G.; Mata Sánchez, Daniel; Wevers, Thomas; Rodríguez-Gil, Pablo; Lewis, Fraser; Schreuder, Laurien

2018-03-01

We present 5 yr of optical and infrared data of the black hole candidate MAXI J1659-152 covering its 2010 outburst, decay, and quiescence. Combining optical data taken during the outburst decay, we obtain an orbital period of 2.414 ± 0.005 h, in perfect agreement with the value previously measured from X-ray dips. In addition, we detect a clear H α excess in MAXI J1659-152 with data taken during the outburst decay. We also detect a single hump modulation most likely produced by irradiation. Assuming that the maximum occurs at orbital phase 0.5, we constrain the phase of the X-ray dips to be ˜0.65. We also detect the quiescent optical counterpart at r΄ = 24.20 ± 0.08, I = 23.32 ± 0.02, and H = 20.7 ± 0.1. These magnitudes provide colour indices implying an M2-M5 donor star assuming 60 per cent contribution from a disc component in the r΄ band.

Investigation of Periodic Nuclear Decay Data with Spectral Analysis Techniques

NASA Astrophysics Data System (ADS)

Javorsek, D.; Sturrock, P.; Buncher, J.; Fischbach, E.; Gruenwald, T.; Hoft, A.; Horan, T.; Jenkins, J.; Kerford, J.; Lee, R.; Mattes, J.; Morris, D.; Mudry, R.; Newport, J.; Petrelli, M.; Silver, M.; Stewart, C.; Terry, B.; Willenberg, H.

2009-12-01

We provide the results from a spectral analysis of nuclear decay experiments displaying unexplained periodic fluctuations. The analyzed data was from 56Mn decay reported by the Children's Nutrition Research Center in Houston, 32Si decay reported by an experiment performed at the Brookhaven National Laboratory, and 226Ra decay reported by an experiment performed at the Physikalisch-Technische-Bundesanstalt in Germany. All three data sets possess the same primary frequency mode consisting of an annual period. Additionally a spectral comparison of the local ambient temperature, atmospheric pressure, relative humidity, Earth-Sun distance, and the plasma speed and latitude of the heliospheric current sheet (HCS) was performed. Following analysis of these six possible causal factors, their reciprocals, and their linear combinations, a possible link between nuclear decay rate fluctuations and the linear combination of the HCS latitude and 1/R motivates searching for a possible mechanism with such properties.

Recent advances in biomedical applications of accelerator mass spectrometry.

PubMed

Hah, Sang Soo; Henderson, Paul T; Turteltaub, Kenneth W

2009-06-17

The use of radioisotopes has a long history in biomedical science, and the technique of accelerator mass spectrometry (AMS), an extremely sensitive nuclear physics technique for detection of very low-abundant, stable and long-lived isotopes, has now revolutionized high-sensitivity isotope detection in biomedical research, because it allows the direct determination of the amount of isotope in a sample rather than measuring its decay, and thus the quantitative analysis of the fate of the radiolabeled probes under the given conditions. Since AMS was first used in the early 90's for the analysis of biological samples containing enriched 14C for toxicology and cancer research, the biomedical applications of AMS to date range from in vitro to in vivo studies, including the studies of 1) toxicant and drug metabolism, 2) neuroscience, 3) pharmacokinetics, and 4) nutrition and metabolism of endogenous molecules such as vitamins. In addition, a new drug development concept that relies on the ultrasensitivity of AMS, known as human microdosing, is being used to obtain early human metabolism information of candidate drugs. These various aspects of AMS are reviewed and a perspective on future applications of AMS to biomedical research is provided.

Particle Dark Matter Searches Outside the Local Group.

PubMed

Regis, Marco; Xia, Jun-Qing; Cuoco, Alessandro; Branchini, Enzo; Fornengo, Nicolao; Viel, Matteo

2015-06-19

If dark matter (DM) is composed by particles which are nongravitationally coupled to ordinary matter, their annihilations or decays in cosmic structures can result in detectable radiation. We show that the most powerful technique to detect a particle DM signal outside the Local Group is to study the angular cross-correlation of nongravitational signals with low-redshift gravitational probes. This method allows us to enhance the signal to noise from the regions of the Universe where the DM-induced emission is preferentially generated. We demonstrate the power of this approach by focusing on GeV-TeV DM and on the recent cross-correlation analysis between the 2MASS galaxy catalogue and the Fermi-LAT γ-ray maps. We show that this technique is more sensitive than other extragalactic γ-ray probes, such as the energy spectrum and angular autocorrelation of the extragalactic background, and emission from clusters of galaxies. Intriguingly, we find that the measured cross-correlation can be well fitted by a DM component, with a thermal annihilation cross section and mass between 10 and 100 GeV, depending on the small-scale DM properties and γ-ray production mechanism. This solicits further data collection and dedicated analyses.

A Novel Computational Method to Reduce Leaky Reaction in DNA Strand Displacement

PubMed Central

Li, Xin; Wang, Xun; Song, Tao; Lu, Wei; Chen, Zhihua; Shi, Xiaolong

2015-01-01

DNA strand displacement technique is widely used in DNA programming, DNA biosensors, and gene analysis. In DNA strand displacement, leaky reactions can cause DNA signals decay and detecting DNA signals fails. The mostly used method to avoid leakage is cleaning up after upstream leaky reactions, and it remains a challenge to develop reliable DNA strand displacement technique with low leakage. In this work, we address the challenge by experimentally evaluating the basic factors, including reaction time, ratio of reactants, and ion concentration to the leakage in DNA strand displacement. Specifically, fluorescent probes and a hairpin structure reporting DNA strand are designed to detect the output of DNA strand displacement, and thus can evaluate the leakage of DNA strand displacement reactions with different reaction time, ratios of reactants, and ion concentrations. From the obtained data, mathematical models for evaluating leakage are achieved by curve derivation. As a result, it is obtained that long time incubation, high concentration of fuel strand, and inappropriate amount of ion concentration can weaken leaky reactions. This contributes to a method to set proper reaction conditions to reduce leakage in DNA strand displacement. PMID:26491602

2D XAFS-XEOL Spectroscopy - Some recent developments

NASA Astrophysics Data System (ADS)

Ward, M. J.; Smith, J. G.; Regier, T. Z.; Sham, T. K.

2013-03-01

The use of optical photons to measure the modulation of the absorption coefficient upon X-ray excitation, or optical XAFS, is of particular interest for application to the study of light emitting semiconducting nanomaterials due to the additional information that may be gained. The potential for site-selectivity, elemental and excitation energy specific luminescence decay channels, and surface vs. bulk effects all make the use of X-ray excited optical luminescence (XEOL) desirable as a detection method. Previous experiments have made use of a monochromator to select the optical emission wavelength used to monitor optical XAFS. This method of detection suffers from the primary limitation of only being able to monitor the optical response at one emission wavelength. By combining the high resolution soft X-ray Spherical Grating Monochromator beam-line at the Canadian Light Source with an Ocean Optics QE 65000 fast CCD spectrophotometer and custom integration software we have developed a technique for collecting 2D XAFS-XEOL spectra, in which the excitation energy is scanned and a XEOL spectra is collected for every energy value. Herein we report the development of this technique and its capabilities using the study of the luminescence emitted from single crystal zinc oxide as an example.

Particle Dark Matter Searches Outside the Local Group

NASA Astrophysics Data System (ADS)

Regis, Marco; Xia, Jun-Qing; Cuoco, Alessandro; Branchini, Enzo; Fornengo, Nicolao; Viel, Matteo

2015-06-01

If dark matter (DM) is composed by particles which are nongravitationally coupled to ordinary matter, their annihilations or decays in cosmic structures can result in detectable radiation. We show that the most powerful technique to detect a particle DM signal outside the Local Group is to study the angular cross-correlation of nongravitational signals with low-redshift gravitational probes. This method allows us to enhance the signal to noise from the regions of the Universe where the DM-induced emission is preferentially generated. We demonstrate the power of this approach by focusing on GeV-TeV DM and on the recent cross-correlation analysis between the 2MASS galaxy catalogue and the Fermi-LAT γ -ray maps. We show that this technique is more sensitive than other extragalactic γ -ray probes, such as the energy spectrum and angular autocorrelation of the extragalactic background, and emission from clusters of galaxies. Intriguingly, we find that the measured cross-correlation can be well fitted by a DM component, with a thermal annihilation cross section and mass between 10 and 100 GeV, depending on the small-scale DM properties and γ -ray production mechanism. This solicits further data collection and dedicated analyses.

Recent advances in biomedical applications of accelerator mass spectrometry

PubMed Central

Hah, Sang Soo

2009-01-01

The use of radioisotopes has a long history in biomedical science, and the technique of accelerator mass spectrometry (AMS), an extremely sensitive nuclear physics technique for detection of very low-abundant, stable and long-lived isotopes, has now revolutionized high-sensitivity isotope detection in biomedical research, because it allows the direct determination of the amount of isotope in a sample rather than measuring its decay, and thus the quantitative analysis of the fate of the radiolabeled probes under the given conditions. Since AMS was first used in the early 90's for the analysis of biological samples containing enriched 14C for toxicology and cancer research, the biomedical applications of AMS to date range from in vitro to in vivo studies, including the studies of 1) toxicant and drug metabolism, 2) neuroscience, 3) pharmacokinetics, and 4) nutrition and metabolism of endogenous molecules such as vitamins. In addition, a new drug development concept that relies on the ultrasensitivity of AMS, known as human microdosing, is being used to obtain early human metabolism information of candidate drugs. These various aspects of AMS are reviewed and a perspective on future applications of AMS to biomedical research is provided. PMID:19534792

THE DISTURBANCE OF A MILLISECOND PULSAR MAGNETOSPHERE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shannon, R. M.; Kerr, M.; Dai, S.

2016-09-01

Pulsar timing has enabled some of the strongest tests of fundamental physics. Central to the technique is the assumption that the detected radio pulses can be used to accurately measure the rotation of the pulsar. Here, we report on a broadband variation in the pulse profile of the millisecond pulsar J1643−1224. A new component of emission suddenly appears in the pulse profile, decays over four months, and results in a permanently modified pulse shape. Profile variations such as these may be the origin of timing noise observed in other millisecond pulsars. The sensitivity of pulsar-timing observations to gravitational radiation canmore » be increased by accounting for this variability.« less

Monopoles, cosmology, and astrophysics - Update 1985

NASA Technical Reports Server (NTRS)

Turner, Michael S.

1986-01-01

The characteristics of the superheavy magnetic monopoles (MMs) predicted by GUTs are reviewed, and recent developments in astrophysical MM search techniques are surveyed. Theoretical models of the birth, current distribution, and motion of MMs are examined; the observational implications of MM mass, magnetic charge, and ability to catalyze nucleon decay are considered; estimates of the average and local flux limits for MMs of 10 to the 25th eV are given (less than about 3 x 10 to the -15th and less than about 3 x 10 to the -11th/sq cm sr sec, respectively); and the possibility of detecting MMs in the sun (if they can escape annihilation there) is discussed.

Development of Functional Fluorescent Molecular Probes for the Detection of Biological Substances

PubMed Central

Suzuki, Yoshio; Yokoyama, Kenji

2015-01-01

This review is confined to sensors that use fluorescence to transmit biochemical information. Fluorescence is, by far, the most frequently exploited phenomenon for chemical sensors and biosensors. Parameters that define the application of such sensors include intensity, decay time, anisotropy, quenching efficiency, and luminescence energy transfer. To achieve selective (bio)molecular recognition based on these fluorescence phenomena, various fluorescent elements such as small organic molecules, enzymes, antibodies, and oligonucleotides have been designed and synthesized over the past decades. This review describes the immense variety of fluorescent probes that have been designed for the recognitions of ions, small and large molecules, and their biological applications in terms of intracellular fluorescent imaging techniques. PMID:26095660

Characterization of the intrinsic scintillator Cs 2LiCeCl 6

DOE Office of Scientific and Technical Information (OSTI.GOV)

James, R.

2017-10-02

In this work, we report on the scintillation properties of the intrinsic scintillator Cs 2LiCeCl 6 (CLCC), which is potentially useful for dual gamma-ray and neutron detection. CLCC is from the elpasolite family with a cubic structure. We grew the crystals at BNL by the vertical Bridgman growth technique. The luminescence spectrum of CLCC showed a doublet with peak maxima at 384 nm and 402 nm. The light yield of CLCC was approximately 20,000 photons/MeV, and the energy resolution was about 6% for 662-keV gamma radiation. A scintillation decay of ~81% of the total light was observed to be ~more » 90 nanoseconds.« less

Identifying phase-space boundaries with Voronoi tessellations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Debnath, Dipsikha; Gainer, James S.; Kilic, Can

Determining the masses of new physics particles appearing in decay chains is an important and longstanding problem in high energy phenomenology. Recently it has been shown that these mass measurements can be improved by utilizing the boundary of the allowed region in the fully differentiable phase space in its full dimensionality. Here in this paper we show that the practical challenge of identifying this boundary can be solved using techniques based on the geometric properties of the cells resulting from Voronoi tessellations of the relevant data. The robust detection of such phase-space boundaries in the data could also be usedmore » to corroborate a new physics discovery based on a cut-and-count analysis.« less

Identifying phase-space boundaries with Voronoi tessellations

DOE PAGES

Debnath, Dipsikha; Gainer, James S.; Kilic, Can; ...

2016-11-24

Determining the masses of new physics particles appearing in decay chains is an important and longstanding problem in high energy phenomenology. Recently it has been shown that these mass measurements can be improved by utilizing the boundary of the allowed region in the fully differentiable phase space in its full dimensionality. Here in this paper we show that the practical challenge of identifying this boundary can be solved using techniques based on the geometric properties of the cells resulting from Voronoi tessellations of the relevant data. The robust detection of such phase-space boundaries in the data could also be usedmore » to corroborate a new physics discovery based on a cut-and-count analysis.« less

Frequency selective detection of nuclear quadrupole resonance (NQR) spin echoes

NASA Astrophysics Data System (ADS)

Somasundaram, Samuel D.; Jakobsson, Andreas; Smith, John A. S.; Althoefer, Kaspar A.

2006-05-01

Nuclear Quadrupole Resonance (NQR) is a radio frequency (RF) technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. The technique has been hampered by low signal-to-noise ratios and is further aggravated by the presence of RF interference (RFI). To ensure accurate detection, proposed detectors should exploit the rich form of the NQR signal. Furthermore, the detectors should also be robust to any remaining residual interference, left after suitable RFI mitigation has been employed. In this paper, we propose a new NQR data model, particularly for the realistic case where multiple pulse sequences are used to generate trains of spin echoes. Furthermore, we refine two recently proposed approximative maximum likelihood (AML) detectors, enabling the algorithm to optimally exploit the data model of the entire echo train and also incorporate knowledge of the temperature dependent spin-echo decay time. The AML-based detectors ensure accurate detection and robustness against residual RFI, even when the temperature of the sample is not precisely known, by exploiting the dependencies of the NQR resonant lines on temperature. Further robustness against residual interference is gained as the proposed detector is frequency selective; exploiting only those regions of the spectrum where the NQR signal is expected. Extensive numerical evaluations based on both simulated and measured NQR data indicate that the proposed Frequency selective Echo Train AML (FETAML) detector offers a significant improvement as compared to other existing detectors.

Indirect detection of dark matter with γ rays.

PubMed

Funk, Stefan

2015-10-06

The details of what constitutes the majority of the mass that makes up dark matter in the Universe remains one of the prime puzzles of cosmology and particle physics today-80 y after the first observational indications. Today, it is widely accepted that dark matter exists and that it is very likely composed of elementary particles, which are weakly interacting and massive [weakly interacting massive particles (WIMPs)]. As important as dark matter is in our understanding of cosmology, the detection of these particles has thus far been elusive. Their primary properties such as mass and interaction cross sections are still unknown. Indirect detection searches for the products of WIMP annihilation or decay. This is generally done through observations of γ-ray photons or cosmic rays. Instruments such as the Fermi large-area telescope, high-energy stereoscopic system, major atmospheric gamma-ray imaging Cherenkov, and very energetic radiation imaging telescope array, combined with the future Cherenkov telescope array, will provide important complementarity to other search techniques. Given the expected sensitivities of all search techniques, we are at a stage where the WIMP scenario is facing stringent tests, and it can be expected that WIMPs will be either be detected or the scenario will be so severely constrained that it will have to be rethought. In this sense, we are on the threshold of discovery. In this article, I will give a general overview of the current status and future expectations for indirect searches of dark matter (WIMP) particles.

Indirect detection of dark matter with γ rays

PubMed Central

Funk, Stefan

2015-01-01

The details of what constitutes the majority of the mass that makes up dark matter in the Universe remains one of the prime puzzles of cosmology and particle physics today—80 y after the first observational indications. Today, it is widely accepted that dark matter exists and that it is very likely composed of elementary particles, which are weakly interacting and massive [weakly interacting massive particles (WIMPs)]. As important as dark matter is in our understanding of cosmology, the detection of these particles has thus far been elusive. Their primary properties such as mass and interaction cross sections are still unknown. Indirect detection searches for the products of WIMP annihilation or decay. This is generally done through observations of γ-ray photons or cosmic rays. Instruments such as the Fermi large-area telescope, high-energy stereoscopic system, major atmospheric gamma-ray imaging Cherenkov, and very energetic radiation imaging telescope array, combined with the future Cherenkov telescope array, will provide important complementarity to other search techniques. Given the expected sensitivities of all search techniques, we are at a stage where the WIMP scenario is facing stringent tests, and it can be expected that WIMPs will be either be detected or the scenario will be so severely constrained that it will have to be rethought. In this sense, we are on the threshold of discovery. In this article, I will give a general overview of the current status and future expectations for indirect searches of dark matter (WIMP) particles. PMID:24821791

Curve fitting air sample filter decay curves to estimate transuranic content.

PubMed

Hayes, Robert B; Chiou, Hung Cheng

2004-01-01

By testing industry standard techniques for radon progeny evaluation on air sample filters, a new technique is developed to evaluate transuranic activity on air filters by curve fitting the decay curves. The industry method modified here is simply the use of filter activity measurements at different times to estimate the air concentrations of radon progeny. The primary modification was to not look for specific radon progeny values but rather transuranic activity. By using a method that will provide reasonably conservative estimates of the transuranic activity present on a filter, some credit for the decay curve shape can then be taken. By carrying out rigorous statistical analysis of the curve fits to over 65 samples having no transuranic activity taken over a 10-mo period, an optimization of the fitting function and quality tests for this purpose was attained.

Decay of Solar Wind Turbulence behind Interplanetary Shocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pitňa, Alexander; Šafránková, Jana; Němeček, Zdeněk

We investigate the decay of magnetic and kinetic energies behind IP shocks with motivation to find a relaxation time when downstream turbulence reaches a usual solar wind value. We start with a case study that introduces computation techniques and quantifies a contribution of kinetic fluctuations to the general energy balance. This part of the study is based on high-time (31 ms) resolution plasma data provided by the Spektr-R spacecraft. On the other hand, a statistical part is based on 92 s Wind plasma and magnetic data and its results confirm theoretically established decay laws for kinetic and magnetic energies. Wemore » observe the power-law behavior of the energy decay profiles and we estimated the power-law exponents of both kinetic and magnetic energy decay rates as −1.2. We found that the decay of MHD turbulence does not start immediately after the IP shock ramp and we suggest that the proper decay of turbulence begins when a contribution of the kinetic processes becomes negligible. We support this suggestion with a detailed analysis of the decay of turbulence at the kinetic scale.« less

Demonstrating the saturation of stimulated Brillouin scattering by ion acoustic decay using fully kinetic simulations

DOE PAGES

Chapman, T.; Winjum, B. J.; Brunner, S.; ...

2015-09-01

The saturation of stimulated Brillouin scattering (SBS) by the decay to turbulence of the ion acoustic wave (IAW) that participates in the three-wave SBS interaction is demonstrated using a quasi-noiseless one-dimensional numerical solution to the Vlasov-Maxwell system of equations. This simulation technique permits careful examination of the decay process and its role in the complex evolution of SBS. Here, the IAW decay process is shown to be an effective SBS saturation mechanism. In our example, the instantaneous plasma reflectivity saturates at ~30% and drops to ~0% as a direct consequence of IAW decay. A contrasting example where the reflectivity ismore » controlled by dephasing due to the nonlinear frequency of the IAW is also discussed.« less

Preventing Advanced Carious Lesions with Caries Atraumatic Restorative Technique.

PubMed

Byrd, Tammi O

2016-06-01

An alternative approach to controlling dental caries and preventing the associated pain, called atraumatic restorative technique (ART), is described for populations in need, where dental hygienists restore decayed teeth with glass ionomer restorations without prior removal of all decayed tooth structure. There are populations whose decay needs are not adequately being met within the current oral health care delivery system. These include those in poverty conditions, vulnerable children, and the elderly who are often in long-term care facilities without adequate resources or opportunities for traditional dentistry. ART provides a viable option for controlling caries and relieving the pain of untreated decay. The purpose of this article is to suggest that the evidence surrounding ART be viewed objectively and that dental hygienists, with additional education in this approach, can contribute to relieving the pain of untreated dental decay. Evidence suggests that teeth can be effectively restored with ART. Dental hygienists represent an appropriate workforce to provide ART with their current background and education combined plus a brief training program; it is suggested that dental hygiene educational programs include ART within the curriculum. Along with dental sealants and fluoride varnish application, ART can be an important component of a comprehensive preventive program to address the unmet needs of vulnerable populations. Copyright © 2016 Elsevier Inc. All rights reserved.

β-delayed p-decay of proton-rich nuclei ^23Al and ^31Cl and explosive H-burning in novae

NASA Astrophysics Data System (ADS)

Trache, L.; Banu, A.; Hardy, J. C.; McCleskey, M.; Simmons, E.; Tabacaru, G.; Tribble, R. E.; Aysto, J.; Jokinen, A.; Saastamoinen, A.; Davinson, T.; Woods, P. J.; Achouri, L.; Roeder, B.

2008-10-01

We developed a technique to measure β-delayed proton-decay of proton-rich nuclei produced and separated with MARS at TAMU. In particular, we studied the decay of ^23Al and ^31Cl, both important for understanding explosive H-burning in novae. We have pulsed the beam, implanting the source nuclei moving at about 40 MeV/u in a thin Si strip detector, and then measured β-p and β-γ coincidences simultaneously. The states populated above the proton threshold in ^23Mg and ^31S, respectively, may proton decay. They are resonances in the reaction ^22Na(p,γ)^23Mg (crucial for the depletion of ^22Na in ONe novae) and in ^30P(p,γ)^31S (critical point in explosive H-burning in novae), but the protons emitted have very low energies, starting at about 200 keV, an experimental challenge. The setup and the results are described. The β-decay schemes were established for both nuclei, and IAS identified. The technique has shown a remarkable selectivity to β-delayed charged particle emission and shown to work even at radioactive beam rates of a few pps, for rare isotopes with lifetimes as low as 10s msec.

Spectral dimension controlling the decay of the quantum first-detection probability

NASA Astrophysics Data System (ADS)

Thiel, Felix; Kessler, David A.; Barkai, Eli

2018-06-01

We consider a quantum system that is initially localized at xin and that is repeatedly projectively probed with a fixed period τ at position xd. We ask for the probability Fn that the system is detected at xd for the very first time, where n is the number of detection attempts. We relate the asymptotic decay and oscillations of Fn with the system's energy spectrum, which is assumed to be absolutely continuous. In particular, Fn is determined by the Hamiltonian's measurement spectral density of states (MSDOS) f (E ) that is closely related to the density of energy states (DOS). We find that Fn decays like a power law whose exponent is determined by the power-law exponent dS of f (E ) around its singularities E*. Our findings are analogous to the classical first passage theory of random walks. In contrast to the classical case, the decay of Fn is accompanied by oscillations with frequencies that are determined by the singularities E*. This gives rise to critical detection periods τc at which the oscillations disappear. In the ordinary case dS can be identified with the spectral dimension associated with the DOS. Furthermore, the singularities E* are the van Hove singularities of the DOS in this case. We find that the asymptotic statistics of Fn depend crucially on the initial and detection state and can be wildly different for out-of-the-ordinary states, which is in sharp contrast to the classical theory. The properties of the first-detection probabilities can alternatively be derived from the transition amplitudes. All our results are confirmed by numerical simulations of the tight-binding model, and of a free particle in continuous space both with a normal and with an anomalous dispersion relation. We provide explicit asymptotic formulas for the first-detection probability in these models.

Nondestructive evaluation of oriented strand board exposed to decay fungi.

Treesearch

Barbara L. Illman; Vina W. Yang; Robert J. Ross; William J. Nelson

2002-01-01

Stress wave nondestructive evaluation (NDE) technologies are being used in our laboratory to evaluate the performance properties of engineered wood. These techniques have proven useful in the inspection of timber structures to locate internal voids and decayed or deteriorated areas in large timbers. But no information exists concerning NDE and important properties of...

Decay Of Bacterial Pathogens, Fecal Indicators, And Real-Time Quantitative PCR Genetic Markers In Manure-Amended Soils

EPA Science Inventory

This study examined persistence and decay of bacterial pathogens, fecal indicator bacteria (FIB), and emerging real-time quantitative PCR (qPCR) genetic markers for rapid detection of fecal pollution in manure-amended agricultural soils. Known concentrations of transformed green...

Decay Of Bacterial Pathogen, Fecal Indicators, And Real-Time Quantitative PCR Genetic Markers In Manure Amended Soils

EPA Science Inventory

This study examined persistence and decay of bacterial pathogens, fecal indicator bacteria, and emerging real-time quantitative PCR (qPCR) genetic markers for rapid detection of fecal pollution in manre-amended agricultural soils. Known concentrations of transformed green fluore...

Search for top squarks decaying via four-body or chargino-mediated modes in single-lepton final states in proton-proton collisions at $$\\sqrt{s} =$$ 13 TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sirunyan, Albert M; et al.

A search for the pair production of the lightest supersymmetric partner of the top quark (more » $$\\widetilde{\\mathrm{t}}_1$$) is presented. The search focuses on a compressed scenario where the mass difference between the top squark and the lightest supersymmetric particle, often considered to be the lightest neutralino ($$\\widetilde{\\chi}^0_1$$), is smaller than the mass of the W boson. The proton-proton collision data were recorded by the CMS experiment at a centre-of-mass energy of 13 TeV, and correspond to an integrated luminosity of 35.9 fb$$^{-1}$$. In this search, two decay modes of the top squark are considered: a four-body decay into a bottom quark, two additional fermions, and a $$\\widetilde{\\chi}^0_1$$; and a decay via an intermediate chargino. Events are selected using the presence of a high-momentum jet, significant missing transverse momentum, and a low transverse momentum electron or muon. Two analysis techniques are used, targeting different decay modes of the $$\\widetilde{\\mathrm{t}}_1$$: a sequential selection and a multivariate technique. No evidence for the production of top squarks is found, and mass limits at 95% confidence level are set that reach up to 560 GeV, depending on the $$m(\\widetilde{\\mathrm{t}}_1) - m(\\widetilde{\\chi}^0_1)$$ mass difference and the decay mode.« less

A mass reconstruction technique for a heavy resonance decaying to τ + τ -

NASA Astrophysics Data System (ADS)

Xia, Li-Gang

2016-11-01

For a resonance decaying to τ + τ -, it is difficult to reconstruct its mass accurately because of the presence of neutrinos in the decay products of the τ leptons. If the resonance is heavy enough, we show that its mass can be well determined by the momentum component of the τ decay products perpendicular to the velocity of the τ lepton, p ⊥, and the mass of the visible/invisible decay products, m vis/inv, for τ decaying to hadrons/leptons. By sampling all kinematically allowed values of p ⊥ and m vis/inv according to their joint probability distributions determined by the MC simulations, the mass of the mother resonance is assumed to lie at the position with the maximal probability. Since p ⊥ and m vis/inv are invariant under the boost in the τ lepton direction, the joint probability distributions are independent upon the τ’s origin. Thus this technique is able to determine the mass of an unknown resonance with no efficiency loss. It is tested using MC simulations of the physics processes pp → Z/h(125)/h(750) + X → ττ + X at 13 TeV. The ratio of the full width at half maximum and the peak value of the reconstructed mass distribution is found to be 20%-40% using the information of missing transverse energy. Supported by General Financial Grant from the China Postdoctoral Science Foundation (2015M581062)

Microwave Three-Wave Mixing Experiments for Chirality Determination: Current Status

NASA Astrophysics Data System (ADS)

Perez, Cristobal; Shubert, V. Alvin; Schmitz, David; Medcraft, Chris; Krin, Anna; Schnell, Melanie

2015-06-01

Microwave three-wave mixing experiments have been shown to provide a novel and sensitive way to generate and measure enantiomer-specific molecular signatures. The handedness of the sample can be obtained from the phase of the molecular free induction decay whereas the enantiomeric excess can be determined by the amplitude of the chiral signal. After the introduction of this technique by Patterson et al. remarkable improvements have been realized and experimental strategies for both absolute phase determination and enantiomeric excess have been presented. This technique has been also successfully implemented at higher microwave frequencies. Here we present the current status of this technique as well future directions and perspectives. This will be illustrated through our systematic study of chiral terpenes as well as preliminary results in molecular clusters. Patterson, D.; Schnell, M.; Doyle, J. M. Enantiomer-Specific Detection of Chiral Molecules via Microwave Spectroscopy. Nature 2013, 497, 475-477. Patterson, D.; Doyle, J. M. Sensitive Chiral Analysis via Microwave Three-Wave Mixing. Phys. Rev. Lett. 2013, 111, 023008. Shubert, V. A.; Schmitz, D.; Patterson, D.; Doyle, J. M.; Schnell, M. Identifying Enantiomers in Mixtures of Chiral Molecules with Broadband Microwave Spectroscopy. Angew. Chem. Int. Ed. 2014, 53, 1152-1155. Lobsiger, S.; Perez, C.; Evangelisti, L.; Lehmann, K. K.; Pate, B. H. Molecular Structure and Chirality Detection by Fourier Transform Microwave Spectroscopy. J. Phys. Chem. Lett. 2014, 6, 196-200.

Human-Associated Bacteroides spp. and Human Polyomaviruses as Microbial Source Tracking Markers in Hawaii

PubMed Central

Caffaro-Filho, Roberto A.; Wong, Mayee; Harwood, Valerie J.; Moravcik, Philip; Fujioka, Roger S.

2016-01-01

ABSTRACT Identification of sources of fecal contaminants is needed to (i) determine the health risk associated with recreational water use and (ii) implement appropriate management practices to mitigate this risk and protect the environment. This study evaluated human-associated Bacteroides spp. (HF183TaqMan) and human polyomavirus (HPyV) markers for host sensitivity and specificity using human and animal fecal samples collected in Hawaii. The decay rates of those markers and indicator bacteria were identified in marine and freshwater microcosms exposed and not exposed to sunlight, followed by field testing of the usability of the molecular markers. Both markers were strongly associated with sewage, although the cross-reactivity of the HF183TaqMan (also present in 82% of canine [n = 11], 30% of mongoose [n = 10], and 10% of feline [n = 10] samples) needs to be considered. Concentrations of HF183TaqMan in human fecal samples exceeded those in cross-reactive animals at least 1,000-fold. In the absence of sunlight, the decay rates of both markers were comparable to the die-off rates of enterococci in experimental freshwater and marine water microcosms. However, in sunlight, the decay rates of both markers were significantly lower than the decay rate of enterococci. While both markers have their individual limitations in terms of sensitivity and specificity, these limitations can be mitigated by using both markers simultaneously; ergo, this study supports the concurrent use of HF183TaqMan and HPyV markers for the detection of sewage contamination in coastal and inland waters in Hawaii. IMPORTANCE This study represents an in-depth characterization of microbial source tracking (MST) markers in Hawaii. The distribution and concentrations of HF183TaqMan and HPyV markers in human and animal fecal samples and in wastewater, coupled with decay data obtained from sunlight-exposed and unexposed microcosms, support the concurrent application of HF183TaqMan and HPyV markers for sewage contamination detection in Hawaii waters. Both markers are more conservative and more specific markers of sewage than fecal indicator bacteria (enterococci and Escherichia coli). Analysis of HF183TaqMan (or newer derivatives) is recommended for inclusion in future epidemiological studies concerned with beach water quality, while better concentration techniques are needed for HPyV. Such epidemiological studies can be used to develop new recreational water quality criteria, which will provide direct information on the absence or presence of sewage contamination in water samples as well as reliable measurements of the risk of waterborne disease transmission to swimmers. PMID:27613686

DN/DG Screening of Environmental Swipe Samples: FY2016 Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glasgow, David C.; Croft, Stephen; Venkataraman, Ramkumar

The Delayed Neutron Delayed Gamma (DNDG) technique provides a new analytical capability to the International Atomic Energy Agency (IAEA) for detecting undeclared nuclear activities. IAEA’s Long Term R&D (LTRD) plan has a stated high urgency need to develop elemental and isotopic signatures of nuclear fuel cycle activities and processes (LTRD 2.2). The new DNDG capability is used to co-detect both uranium and plutonium as an extension of a DN only method that is already being utilized by the IAEA for the analysis of swipes to inform on undeclared nuclear activities. Analytical method involving irradiation of swipe samples potentially containing tracemore » quantities of fissile material in a thermal neutron field, followed by the counting of delayed neutrons, is a well-known technique in the field of safeguards and nonproliferation. It is used for detecting the presence of microscopic amounts of fissile material, (typically a linear combination of 233U, 235U, 239Pu, and 241Pu)and quantifying it in terms of the equivalent mass of 235U. The delayed neutron (DN) technique is very sensitive and is been routinely employed at the High Flux Isotope Reactor (HFIR) facility at Oak Ridge National Laboratory (ORNL). Both uranium and plutonium are of high safeguards value. However, the DN technique is not well suited for distinguishing between U and Pu isotopes since the decay curves overlap closely. The delayed gamma (DG) technique will help detect the presence of 239Pu in a mixture of U and Pu. Thus the DNDG approach combines the best of both worlds; the sensitivity of DN counting and the isotopic specificity of DG counting. The present work seeks to build on the delayed neutron and delayed gamma methods that have been developed at ORNL. It is recognized that the distribution profile of heavy fission products remains fairly invariant for the fissile nuclides whereas the distribution of light fission products varies from one isotope to another. That is, the ratio of the yield of a light fission fragment to a heavy fission fragments is isotope specific. Measurement of the ratio of the net full energy peak (FEP) from low/high mass fission products is an elegant way to characterize the fraction of fissile materials present in a mixture. By empirically calibrating the ratio of the net FEP as a function of known concentration of the binary mixture, one can determine the fraction of fissile isotopes in an unknown sample. In the work done in fiscal year (FY) 2016, samples of single fissile material isotopes as well as binary mixtures were irradiated in a well thermalized irradiation field in the HFIR. Delayed neutron counting was performed using the neutron counter at the HFIR Neutron Activation Analysis (NAA) laboratory. Delayed gamma counting was performed using a shielded high purity germanium (HPGe) detector. Delayed neutron decay curve results highlighted the difficulty of distinguishing between U and Pu isotopes, and the need for including the delayed gamma component. Based on delayed gamma spectrometry, twelve ratios of low mass/high fission product gamma ray FEP have been identified as valid candidates. Linearity of the ratios, as a function of 239Pu fraction in 235U+ 239Pu mixtures, was confirmed for the low mass/high mass candidates that were selected. The DNDG method we are spearheading allows not only the presence of total fissile content to be detected, but whether the material is predominantly U or predominantly Pu, or a mixture. This provides additional SG relevant information.« less

MEASUREMENTS OF AIRBORNE CONCENTRATIONS OF RADON AND THORON DECAY PRODUCTS.

PubMed

Chalupnik, S; Skubacz, K; Urban, P; Wysocka, M

2017-11-01

Liquid scintillation counting (LSC) is a measuring technique, broadly applied in environmental monitoring of radionuclides. One of the possible applications of LSC is the measurement of radon and thoron decay products. But this method is suitable only for grab sampling. For long-term measurements a different technique can be applied-monitors of potential alpha energy concentration (PAEC) with thermoluminescent detectors (TLD). In these devices, called Alfa-2000 sampling probe, TL detectors (CaSO4:Dy) are applied for alpha particles counting. Three independent heads are placed over the membrane filter in a dust sampler's microcyclone. Such solution enables simultaneous measurements of PAEC and dust content. Moreover, the information which is stored in TLD chips is the energy of alpha particles, not the number of counted particles. Therefore, the readout of TL detector shows directly potential alpha energy, with no dependence on equilibrium factor, etc. This technique, which had been used only for radon decay products measurements, was modified by author to allow simultaneous measurements of radon and thoron PAEC. The LSC method can be used for calibration of portable radon decay products monitors. The LSC method has the advantage to be an absolute one, the TLD method to measure directly the (dose relevant) deposited energy. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Weak decay of hypernuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grace, R.

1983-01-01

The Moby Dick spectrometer (at BNL) in coincidence with a range spectrometer and a TOF neutron detector will be used to study the weak decay modes of /sup 12/C. The Moby Dick spectrometer will be used to reconstruct and tag events in which specific hypernuclear states are formed in the reaction K/sup -/ + /sup 12/C ..-->.. ..pi../sup -/ + /sup 12/C. Subsequent emission of decay products (pions, protons and neutrons) in coincidence with the fast forward pion will be detected in a time and range spectrometer, and a neutron detector.

Physics Division annual report, 1 January-31 December 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-10-01

A brief overview of each of the several areas of research is given with a list of resulting publications. Areas of research include electron-positron annihilation, neutrino interactions, neutrinoless double beta decay of /sup 100/Mo, double beta decay of /sup 76/Ge, antiproton-proton interactions, right-handed gauge boson effects, muon decay asymmetry parameter measurements, supernovae detection, Nemesis search, and detector development. Areas of theoretical research include electroweak interactions, strong interactions, nonperturbative dynamics, supersymmetry, and cosmology and particle physics. 34 figs. (WRF)

Constraining heavy decaying dark matter with the high energy gamma-ray limits

NASA Astrophysics Data System (ADS)

Kalashev, O. E.; Kuznetsov, M. Yu.

2016-09-01

We consider decaying dark matter with masses 1 07≲M ≲1 016 GeV as a source of ultrahigh energy (UHE) gamma rays. Using recent limits on UHE gamma-ray flux for energies Eγ>2 ×1 014 eV , provided by extensive air shower observatories, we put limits on masses and lifetimes of the dark matter. We also discuss possible dark matter decay origin of tentative 100 PeV photon flux detected with the EAS-MSU experiment.

Modeling the Production of Beta-Delayed Gamma Rays for the Detection of Special Nuclear Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hall, J M; Pruet, J A; Brown, D A

2005-02-14

The objective of this LDRD project was to develop one or more models for the production of {beta}-delayed {gamma} rays following neutron-induced fission of a special nuclear material (SNM) and to define a standardized formatting scheme which will allow them to be incorporated into some of the modern, general-purpose Monte Carlo transport codes currently being used to simulate inspection techniques proposed for detecting fissionable material hidden in sea-going cargo containers. In this report, we will describe a Monte Carlo model for {beta}-delayed {gamma}-ray emission following the fission of SNM that can accommodate arbitrary time-dependent fission rates and photon collection histories.more » The model involves direct sampling of the independent fission yield distributions of the system, the branching ratios for decay of individual fission products and spectral distributions representing photon emission from each fission product and for each decay mode. While computationally intensive, it will be shown that this model can provide reasonably detailed estimates of the spectra that would be recorded by an arbitrary spectrometer and may prove quite useful in assessing the quality of evaluated data libraries and identifying gaps in the libraries. The accuracy of the model will be illustrated by comparing calculated and experimental spectra from the decay of short-lived fission products following the reactions {sup 235}U(n{sub th}, f) and {sup 239}Pu(n{sub th}, f). For general-purpose transport calculations, where a detailed consideration of the large number of individual {gamma}-ray transitions in a spectrum may not be necessary, it will be shown that a simple parameterization of the {gamma}-ray source function can be defined which provides high-quality average spectral distributions that should suffice for calculations describing photons being transported through thick attenuating media. Finally, a proposal for ENDF-compatible formats that describe each of the models and allow for their straightforward use in Monte Carlo codes will be presented.« less

Large mass bolometers for neutrinoless double beta decay detection: model and last results

NASA Astrophysics Data System (ADS)

Pedretti, Marisa; Barucci, Marco; Giuliani, Andrea; Pasca, Edoardo; Risegari, Lara; Olivieri, Emiliano; Ventura, Guglielmo

2004-01-01

Milano collaboration has been developing for many years large mass bolometers for particle detection, and in particular for the study of neutrinoless double beta decay of 130Te. The active components of the detectors are large mass (340 g and 790 g) TeO2 crystals, while Neutron Transmutation Doped Ge thermistors are used as phonon sensors. These devices work at low temperatures, about 5-10 mK. The mechanical and thermal connections of the detector to the thermal bath are made with PTFE pieces that hold the crystal on copper frames. Gold wires are used as electric connections. We have developed a complete thermal model for the bolometers and "ad hoc" measurements of the thermal parameters involved were performed in the Florence cryogenic laboratory. These studies have permitted to simulate the static and dynamic behaviours of the detectors. A satisfactory agreement between simulated and the experimental response has been obtained as far as the static behaviour is concerned, while the dynamic behaviour is not yet fully understood. These preliminary results however will enable us to design new detector structures in order to improve the signal-to-noise ratio and the reproducibility. Given the good performances of these devices (excellent energy resolutions were obtained, of the order of 2 keV at 911 keV and of 5 keV at 2615 keV), this technique is particularly suitable to detectors for gamma ray spectroscopy. Encouraged by this results, the Milano-Como group has joined a large international collaboration for the realization of CUORE (Cryogenic Underground Observatory for Rare Events), seraching for Dark Matter and neutrinoless Double Beta Decay, a crucial phenomenon for neutrino physics. The Cuoricino detector, a small scale test of CUORE detector, is an array of 62 large mass bolometers like those already described, and it is now in operation in the Gran Sasso undergrand laboratory, Italy). It is the largest array of bolometric detectors ever constructed.

Inference of the ring current ion composition by means of charge exchange decay

NASA Technical Reports Server (NTRS)

Smith, P. H.; Bewtra, N. K.; Hoffman, R. A.

1978-01-01

The analysis of the measured ion fluxes during the several day storm recovery period and the assumption that beside hydrogen other ions were present and that the decays were exponential in nature, it was possible to establish three separate lifetimes for the ions. These fitted decay lifetimes are in excellent agreement with the expected charge exchange decay lifetimes for H(+), O(+), and He(+) in the energy and L-value range of the data. This inference technique, thus, establishes the presence of measurable and appreciable quantities of oxygen and helium ions as well as protons in the storm-time ring current. Indications that He(+) may also be present under these same conditions were found.

Decay rates of inner-valence excitations in noble gas atoms.

PubMed

Gokhberg, K; Averbukh, V; Cederbaum, L S

2007-04-21

A Fano - algebraic diagrammatic construction - Stieltjes method has been recently developed for ab initio calculations of nonradiative decay rates [V. Averbukh and L. S. Cederbaum, J. Chem. Phys. 123, 204107 (2005)] of singly ionized states. In the present work this method is generalized for the case of electronic decay of excited states. The decay widths of autoionizing inner-valence-excited states of Ne, Ar, and Kr are calculated. Apart from the lowest excitation of Kr, they are found to be in good to excellent agreement with the experimental values. Comparison with the other theoretical studies shows that in many cases the new method performs better than the previously available techniques.

Magnetic relaxometry as applied to sensitive cancer detection and localization

DOE PAGES

De Haro, Leyma P.; Karaulanov, Todor; Vreeland, Erika C.; ...

2015-06-02

Abstract Here we describe superparamagnetic relaxometry (SPMR), a technology that utilizes highly sensitive magnetic sensors and superparamagnetic nanoparticles for cancer detection. Using SPMR, we sensitively and specifically detect nanoparticles conjugated to biomarkers for various types of cancer. SPMR offers high contrast In SPMR measurements, a brief magnetizing pulse is used to align superparamagnetic nanoparticles of a discrete size. Following the pulse, an array of superconducting quantum interference detectors (SQUID) sensors detect the decaying magnetization field. NP size is chosen so that, when bound, the induced field decays in seconds. They are functionalized with specific biomarkers and incubated with cancer cellsmore » As a result, superparamagnetic NPs developed here have small size dispersion. Cell incubation studies measure specificity for different cell lines and antibodies with very high contrast.« less

Radiochemistry in the twenty-first century: Strenghts, weaknesses, opportunities and threats

NASA Astrophysics Data System (ADS)

de Goeij, J. J. M.

2003-01-01

Strengths, weaknesses, opportunities and threats of radiochemistry and associated nuclear chemistry are discussed. For that purpose radiochemistry is subdivided into three categories. The first category covers fundamental aspects, e.g. nuclear reaction cross-sections, production routes with associated yields and radionuclidic impurities, decay schemes, radiochemical separations, recoil and hot-atom chemistry, isotope effects and fractionation, and interaction of radiation with matter and detection. The second category covers topics where radioactivity is inextricably involved, e.g. the nuclear fuel cycle, very heavy elements and other actinides, primordial and cosmogenic radioactivity, and radionuclide techniques for dating. The third category involves radioactivity as essential part of a technique. On one hand radioactivity is used here as source of ionising radiation for food conservation, polymerisation of plastics, sterilisation, radiotherapy and pain palliation. On the other hand it is used to get information on systems and materials, via radiotracer methods and nuclear activation techniques. In particular the latter field is experiencing strong competition with other, non-nuclear methods. In this frame it is indicated what is required to achieve a situation where nuclear analytical techniques may successfully be exploited to the full extent of their potentials, particularly in providing valuable and sometimes unique information.

Nanophotonic force microscopy: Characterizing particle–surface interactions using near-field photonics

DOE PAGES

Schein, Perry; Kang, Pilgyu; O’Dell, Dakota; ...

2015-01-27

Direct measurements of particle–surface interactions are important for characterizing the stability and behavior of colloidal and nanoparticle suspensions. Current techniques are limited in their ability to measure pico-Newton scale interaction forces on submicrometer particles due to signal detection limits and thermal noise. In this paper, we present a new technique for making measurements in this regime, which we refer to as nanophotonic force microscopy. Using a photonic crystal resonator, we generate a strongly localized region of exponentially decaying, near-field light that allows us to confine small particles close to a surface. From the statistical distribution of the light intensity scatteredmore » by the particle we are able to map out the potential well of the trap and directly quantify the repulsive force between the nanoparticle and the surface. Finally, as shown in this Letter, our technique is not limited by thermal noise, and therefore, we are able to resolve interaction forces smaller than 1 pN on dielectric particles as small as 100 nm in diameter.« less

New limits for the 2 νββ decay of 96Zr to excited nuclear states of 96Mo

NASA Astrophysics Data System (ADS)

Finch, Sean; Tornow, Werner

2015-10-01

The final results from our search for the 2 νββ decay of 96Zr to excited 0+ and 2+ states of 96Mo are presented. Such measurements provide valuable test cases for 2 νββ -decay nuclear matrix element calculations, which in turn are used to tune 0 νββ -decay nuclear matrix element calculations. After undergoing double- β decay to an excited state, the excited daughter nucleus decays to the ground state, emitting two coincident γ rays. These two γ rays are detected in coincidence by two HPGe detectors sandwiching the 96Zr sample, with a NaI veto in anti-coincidence. This experimental apparatus, located at the Kimballton Underground Research Facility (KURF), has previously measured the 2 νββ decay of 100Mo and 150Nd to excited nuclear states. Experimental limits on the T1 / 2 and corresponding nuclear matrix element are presented for each of these decays. As a byproduct of this experiment, limits were also set on the single- β decay of 96Zr. Supported by DOE Grant: DE-FG02-97ER41033.

Statistical Study of Rapid Penumbral Decay Associated with Flares

NASA Astrophysics Data System (ADS)

Chen, W.; Liu, C.; Wang, H.

2005-05-01

We present results of statistical study of rapid penumbral decay associated with flares. In total, we investigated 402 events from 05/09/98 to 07/17/04, including 40 X-class, 173 M-class and 189 C-class flares. We show strong evidence that penumbral segments decayed rapidly and permanently right after many flares. The rapid changes, which can be identified in the time profiles of white-light(WL) mean intensity are permanent, not transient, thus are not due to flare emissions. Our study shows that penumbral decay is more likely to be detected when associated with large solar flares. The larger the flare magnitude, the stronger the penumbral decay is. For X-class flares, almost 50% events show distinct decay. But for M- and C-class flares, this percentage drops to 16% and 10%, respectively. For all the events that clear decay can be observed, we find that the locations of penumbral decay are associated with flare emissions and are connected by prominent TRACE post-flare loops. To explain these observations, we propose a reconnection picture in that the penumbral fields change from a highly inclined to a more vertical configuration, leading to penumbral decay.

Precise measurement of the half-life of the Fermi {beta} decay of {sup 26}Al{sup m}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, Rebecca J.; Thompson, Maxwell N.; Rassool, Roger P.

2011-08-15

State-of-the-art signal digitization and analysis techniques have been used to measure the half-life of the Fermi {beta} decay of {sup 26}Al{sup m}. The half-life was determined to be 6347.8 {+-} 2.5 ms. This new datum contributes to the experimental testing of the conserved-vector-current hypothesis and the required unitarity of the Cabibbo-Kobayashi-Maskawa matrix: two essential components of the standard model. Detailed discussion of the experimental techniques and data analysis and a thorough investigation of the statistical and systematic uncertainties are presented.

High-precision branching ratio measurement for the superallowed β+ emitter Ga62

NASA Astrophysics Data System (ADS)

Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-08-01

A high-precision branching ratio measurement for the superallowed β+ decay of Ga62 was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8π spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the γ rays emitted following Gamow-Teller and nonanalog Fermi β+ decays of Ga62, and the SCEPTAR plastic scintillator array was used to detect the emitted β particles. Thirty γ rays were identified following Ga62 decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for Ga62, this branching ratio yields an ft value of 3074.3±1.1 s, making Ga62 among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected F tmacr value allows the large nuclear-structure-dependent correction for Ga62 decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A⩾62 superallowed decays.

Photoacoustic microscopy of human teeth

NASA Astrophysics Data System (ADS)

Rao, Bin; Cai, Xin; Favazza, Christopher; Yao, Junjie; Li, Li; Duong, Steven; Liaw, Lih-Huei; Holtzman, Jennifer; Wilder-Smith, Petra; Wang, Lihong V.

2011-03-01

Photoacoustic microscopy (PAM) utilizes short laser pulses to deposit energy into light absorbers and sensitively detects the ultrasonic waves the absorbers generate in response. PAM directly renders a three-dimensional spatial distribution of sub-surface optical absorbers. Unlike other optical imaging technologies, PAM features label-free optical absorption contrast and excellent imaging depths. Standard dental imaging instruments are limited to X-ray and CCD cameras. Subsurface optical dental imaging is difficult due to the highly-scattering enamel and dentin tissue. Thus, very few imaging methods can detect dental decay or diagnose dental pulp, which is the innermost part of the tooth, containing the nerves, blood vessels, and other cells. Here, we conducted a feasibility study on imaging dental decay and dental pulp with PAM. Our results showed that PAM is sensitive to the color change associated with dental decay. Although the relative PA signal distribution may be affected by surface contours and subsurface reflections from deeper dental tissue, monitoring changes in the PA signals (at the same site) over time is necessary to identify the progress of dental decay. Our results also showed that deep-imaging, near-infrared (NIR) PAM can sensitively image blood in the dental pulp of an in vitro tooth. In conclusion, PAM is a promising tool for imaging both dental decay and dental pulp.

Superpartner mass measurement technique using 1D orthogonal decompositions of the Cambridge transverse mass variable M(T2).

PubMed

Konar, Partha; Kong, Kyoungchul; Matchev, Konstantin T; Park, Myeonghun

2010-07-30

We propose a new model-independent technique for mass measurements in missing energy events at hadron colliders. We illustrate our method with the most challenging case of a single-step decay chain. We consider inclusive same-sign chargino pair production in supersymmetry, followed by leptonic decays to sneutrinos χ+ χ+ → ℓ+ ℓ'+ ν(ℓ)ν(ℓ') and invisible decays ν(ℓ) → ν(ℓ) χ(1)(0). We introduce two one-dimensional decompositions of the Cambridge MT2 variable: M(T2∥) and M(T2⊥), on the direction of the upstream transverse momentum P→T and the direction orthogonal to it, respectively. We show that the sneutrino mass Mc can be measured directly by minimizing the number of events N(Mc) in which MT2 exceeds a certain threshold, conveniently measured from the end point M(T2⊥)(max) (Mc).

Superpartner Mass Measurement Technique using 1D Orthogonal Decompositions of the Cambridge Transverse Mass Variable MT2

NASA Astrophysics Data System (ADS)

Konar, Partha; Kong, Kyoungchul; Matchev, Konstantin T.; Park, Myeonghun

2010-07-01

We propose a new model-independent technique for mass measurements in missing energy events at hadron colliders. We illustrate our method with the most challenging case of a single-step decay chain. We consider inclusive same-sign chargino pair production in supersymmetry, followed by leptonic decays to sneutrinos χ+χ+→ℓ+ℓ'+ν˜ℓν˜ℓ' and invisible decays ν˜ℓ→νℓχ˜10. We introduce two one-dimensional decompositions of the Cambridge MT2 variable: MT2∥ and MT2⊥, on the direction of the upstream transverse momentum P→T and the direction orthogonal to it, respectively. We show that the sneutrino mass Mc can be measured directly by minimizing the number of events N(M˜c) in which MT2 exceeds a certain threshold, conveniently measured from the end point MT2⊥max⁡(M˜c).

Identification techniques for highly boosted W bosons that decay into hadrons

DOE PAGES

Khachatryan, Vardan

2014-12-02

In searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that result in a single jet, such as those from highly boosted Z and Higgs bosons. The efficiency for tagging W jets is measured in data collected with the CMSmore » detector at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb -1. The performance of W tagging in data is compared with predictions from several Monte Carlo simulators.« less

Recombination algorithms and jet substructure: Pruning as a tool for heavy particle searches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, Stephen D.; Vermilion, Christopher K.; Walsh, Jonathan R.

2010-05-01

We discuss jet substructure in recombination algorithms for QCD jets and single jets from heavy particle decays. We demonstrate that the jet algorithm can introduce significant systematic effects into the substructure. By characterizing these systematic effects and the substructure from QCD, splash-in, and heavy particle decays, we identify a technique, pruning, to better identify heavy particle decays into single jets and distinguish them from QCD jets. Pruning removes protojets typical of soft, wide-angle radiation, improves the mass resolution of jets reconstructing heavy particle decays, and decreases the QCD background to these decays. We show that pruning provides significant improvements overmore » unpruned jets in identifying top quarks and W bosons and separating them from a QCD background, and may be useful in a search for heavy particles.« less

Measurement Of Molecular Mobilities Of Polymers

NASA Technical Reports Server (NTRS)

Kim, Soon Sam; Tsay, Fun-Dow

1989-01-01

New molecular-probe technique used to measure molecular mobility of polymer. Method based on use of time-resolved electron-spin resonance (ESR) spectroscopy to monitor decay of transient nutation amplitudes from photoexcited triplet states of probe molecules with which polymer is doped. The higher molecular mobility of polymer matrix, the faster nutation amplitudes of the probe molecules decay.

Changes in wood microstructure through progressive stages of decay

Treesearch

W. Wayne Wilcox

1968-01-01

Successive stages of decay in the sapwood of sweetgum (Liquidambar styraciflua L.), a hardwood, and of southern pine (Pinus sp.), a softwood, were observed microscopically. The white-rot fungus. Polyporus versicolor L., and the brown-rot fungus, Poria monticola Murr., were the fungi used or the observations, light microscopy, plus the techniques of polarization and...

21 CFR 872.1740 - Caries detection device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Caries detection device. 872.1740 Section 872.1740...) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1740 Caries detection device. (a) Identification. The caries detection device is a device intended to show the existence of decay in a patient's tooth...

Decay of quadrupole-octupole 1- states in 40Ca and 140Ce

NASA Astrophysics Data System (ADS)

Derya, V.; Tsoneva, N.; Aumann, T.; Bhike, M.; Endres, J.; Gooden, M.; Hennig, A.; Isaak, J.; Lenske, H.; Löher, B.; Pietralla, N.; Savran, D.; Tornow, W.; Werner, V.; Zilges, A.

2016-03-01

Background: Two-phonon excitations originating from the coupling of two collective one-phonon states are of great interest in nuclear structure physics. One possibility to generate low-lying E 1 excitations is the coupling of quadrupole and octupole phonons. Purpose: In this work, the γ -decay behavior of candidates for the (21+⊗31-)1- state in the doubly magic nucleus 40Ca and in the heavier and semimagic nucleus 140Ce is investigated. Methods: (γ ⃗,γ') experiments have been carried out at the High Intensity γ -ray Source (HI γ S ) facility in combination with the high-efficiency γ -ray spectroscopy setup γ3 consisting of HPGe and LaBr3 detectors. The setup enables the acquisition of γ -γ coincidence data and, hence, the detection of direct decay paths. Results: In addition to the known ground-state decays, for 40Ca the decay into the 31- state was observed, while for 140Ce the direct decays into the 21+ and the 02+ state were detected. The experimentally deduced transition strengths and excitation energies are compared to theoretical calculations in the framework of EDF theory plus QPM approach and systematically analyzed for N =82 isotones. In addition, negative parities for two J =1 states in 44Ca were deduced simultaneously. Conclusions: The experimental findings together with the theoretical calculations support the two-phonon character of the 11- excitation in the light-to-medium-mass nucleus 40Ca as well as in the stable even-even N =82 nuclei.

Quantile regression applied to spectral distance decay

USGS Publications Warehouse

Rocchini, D.; Cade, B.S.

2008-01-01

Remotely sensed imagery has long been recognized as a powerful support for characterizing and estimating biodiversity. Spectral distance among sites has proven to be a powerful approach for detecting species composition variability. Regression analysis of species similarity versus spectral distance allows us to quantitatively estimate the amount of turnover in species composition with respect to spectral and ecological variability. In classical regression analysis, the residual sum of squares is minimized for the mean of the dependent variable distribution. However, many ecological data sets are characterized by a high number of zeroes that add noise to the regression model. Quantile regressions can be used to evaluate trend in the upper quantiles rather than a mean trend across the whole distribution of the dependent variable. In this letter, we used ordinary least squares (OLS) and quantile regressions to estimate the decay of species similarity versus spectral distance. The achieved decay rates were statistically nonzero (p < 0.01), considering both OLS and quantile regressions. Nonetheless, the OLS regression estimate of the mean decay rate was only half the decay rate indicated by the upper quantiles. Moreover, the intercept value, representing the similarity reached when the spectral distance approaches zero, was very low compared with the intercepts of the upper quantiles, which detected high species similarity when habitats are more similar. In this letter, we demonstrated the power of using quantile regressions applied to spectral distance decay to reveal species diversity patterns otherwise lost or underestimated by OLS regression. ?? 2008 IEEE.

Spectral distance decay: Assessing species beta-diversity by quantile regression

USGS Publications Warehouse

Rocchinl, D.; Nagendra, H.; Ghate, R.; Cade, B.S.

2009-01-01

Remotely sensed data represents key information for characterizing and estimating biodiversity. Spectral distance among sites has proven to be a powerful approach for detecting species composition variability. Regression analysis of species similarity versus spectral distance may allow us to quantitatively estimate how beta-diversity in species changes with respect to spectral and ecological variability. In classical regression analysis, the residual sum of squares is minimized for the mean of the dependent variable distribution. However, many ecological datasets are characterized by a high number of zeroes that can add noise to the regression model. Quantile regression can be used to evaluate trend in the upper quantiles rather than a mean trend across the whole distribution of the dependent variable. In this paper, we used ordinary least square (ols) and quantile regression to estimate the decay of species similarity versus spectral distance. The achieved decay rates were statistically nonzero (p < 0.05) considering both ols and quantile regression. Nonetheless, ols regression estimate of mean decay rate was only half the decay rate indicated by the upper quantiles. Moreover, the intercept value, representing the similarity reached when spectral distance approaches zero, was very low compared with the intercepts of upper quantiles, which detected high species similarity when habitats are more similar. In this paper we demonstrated the power of using quantile regressions applied to spectral distance decay in order to reveal species diversity patterns otherwise lost or underestimated by ordinary least square regression. ?? 2009 American Society for Photogrammetry and Remote Sensing.

Multiwavelength FLIM: new applications and algorithms

NASA Astrophysics Data System (ADS)

Rück, A.; Strat, D.; Dolp, F.; von Einem, B.; von Arnim, C. A. F.

2011-03-01

The combination of time-resolved and spectral resolved techniques as achieved by SLIM (spectrally resolved fluorescence lifetime imaging) improves the analysis of complex situations, when different fluorophores have to be distinguished. This could be the case when endogenous fluorophores of living cells and tissues are observed to identify the redox state and oxidative metabolic changes of the mitochondria. Other examples are FRET (resonant energy transfer) measurements, when different donor/acceptor pairs are observed simultaneously. SLIM is working in the time domain employing excitation with short light pulses and detection of the fluorescence intensity decay in many cases with time-correlated single photon counting (TCSPC). Spectral resolved detection is achieved by a polychromator in the detection path and a 16-channel multianode photomultiplier tube with the appropriate routing electronics. Within this paper special attention will be focused on FRET measurements with respect to protein interactions in Alzheimers disease. Using global analysis as the phasor plot approach or integration of the kinetic equations taking into account the multidimensional datasets in every spectral channel we could demonstrate considerable improvement of our calculations.

Detection of bifurcations in noisy coupled systems from multiple time series

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williamson, Mark S., E-mail: m.s.williamson@exeter.ac.uk; Lenton, Timothy M.

We generalize a method of detecting an approaching bifurcation in a time series of a noisy system from the special case of one dynamical variable to multiple dynamical variables. For a system described by a stochastic differential equation consisting of an autonomous deterministic part with one dynamical variable and an additive white noise term, small perturbations away from the system's fixed point will decay slower the closer the system is to a bifurcation. This phenomenon is known as critical slowing down and all such systems exhibit this decay-type behaviour. However, when the deterministic part has multiple coupled dynamical variables, themore » possible dynamics can be much richer, exhibiting oscillatory and chaotic behaviour. In our generalization to the multi-variable case, we find additional indicators to decay rate, such as frequency of oscillation. In the case of approaching a homoclinic bifurcation, there is no change in decay rate but there is a decrease in frequency of oscillations. The expanded method therefore adds extra tools to help detect and classify approaching bifurcations given multiple time series, where the underlying dynamics are not fully known. Our generalisation also allows bifurcation detection to be applied spatially if one treats each spatial location as a new dynamical variable. One may then determine the unstable spatial mode(s). This is also something that has not been possible with the single variable method. The method is applicable to any set of time series regardless of its origin, but may be particularly useful when anticipating abrupt changes in the multi-dimensional climate system.« less

Detection of bifurcations in noisy coupled systems from multiple time series

NASA Astrophysics Data System (ADS)

Williamson, Mark S.; Lenton, Timothy M.

2015-03-01

We generalize a method of detecting an approaching bifurcation in a time series of a noisy system from the special case of one dynamical variable to multiple dynamical variables. For a system described by a stochastic differential equation consisting of an autonomous deterministic part with one dynamical variable and an additive white noise term, small perturbations away from the system's fixed point will decay slower the closer the system is to a bifurcation. This phenomenon is known as critical slowing down and all such systems exhibit this decay-type behaviour. However, when the deterministic part has multiple coupled dynamical variables, the possible dynamics can be much richer, exhibiting oscillatory and chaotic behaviour. In our generalization to the multi-variable case, we find additional indicators to decay rate, such as frequency of oscillation. In the case of approaching a homoclinic bifurcation, there is no change in decay rate but there is a decrease in frequency of oscillations. The expanded method therefore adds extra tools to help detect and classify approaching bifurcations given multiple time series, where the underlying dynamics are not fully known. Our generalisation also allows bifurcation detection to be applied spatially if one treats each spatial location as a new dynamical variable. One may then determine the unstable spatial mode(s). This is also something that has not been possible with the single variable method. The method is applicable to any set of time series regardless of its origin, but may be particularly useful when anticipating abrupt changes in the multi-dimensional climate system.

High-precision branching-ratio measurement for the superallowed β+ emitter 74Rb

NASA Astrophysics Data System (ADS)

Dunlop, R.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Andreoiu, C.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Finlay, P.; Garnsworthy, A. B.; Garrett, P. E.; Glister, J.; Hackman, G.; Hadinia, B.; Leach, K. G.; Rand, E. T.; Starosta, K.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2013-10-01

A high-precision branching-ratio measurement for the superallowed β+ decay of 74Rb was performed at the TRIUMF Isotope Separator and Accelerator (ISAC) radioactive ion-beam facility. The scintillating electron-positron tagging array (SCEPTAR), composed of 10 thin plastic scintillators, was used to detect the emitted β particles; the 8π spectrometer, an array of 20 Compton-suppressed HPGe detectors, was used for detecting γ rays that were emitted following Gamow-Teller and nonanalog Fermi β+ decays of 74Rb; and the Pentagonal Array of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) detectors, was employed for measuring β-delayed conversion electrons. Twenty-three excited states were identified in 74Kr following 8.241(4)×108 detected 74Rb β decays. A total of 58 γ-ray and electron transitions were placed in the decay scheme, allowing the superallowed branching ratio to be determined as B0=99.545(31)%. Combined with previous half-life and Q-value measurements, the superallowed branching ratio measured in this work leads to a superallowed ft value of 3082.8(65) s. Comparisons between this superallowed ft value and the world-average-corrected Ft¯ value, as well as the nonanalog Fermi branching ratios determined in this work, provide guidance for theoretical models of the isospin-symmetry-breaking corrections in this mass region.

Search for two-neutrino double-β decay of 96Zr to excited states of 96Mo

NASA Astrophysics Data System (ADS)

Finch, S. W.; Tornow, W.

2015-10-01

Background: Double-β decay is a rare second-order nuclear decay. The importance of this decay stems from the possibility of neutrinoless double-β decay and its applications to neutrino physics. Purpose: A search was conducted for the 2 ν β β decay of 96Zr to excited final states of the daughter nucleus, 96Mo. Measurements of this decay are important to test nuclear matrix element calculations, which are necessary to extract the neutrino mass from a measurement of the neutrinoless double-β decay half-life. Method: Two coaxial high-purity germanium detectors were used in coincidence to detect γ rays produced by the daughter nucleus as it de-excited to the ground state. The experiment was carried out at the Kimballton Underground Research Facility and produced 685.7 d of data with a 17.91 g enriched sample. Results: No counts were seen above background. For the decay to the first excited 0+ state, a limit of T1 /2>3.1 ×1020 yr was produced. Limits to higher excited states are also reported. Conclusion: The new limits on double-β decay are an improvement over previous experiments by a factor of 2 to 5 for the various excited states. The nuclear matrix element for the double-β decay to the first excited 0+ state is found to be <0.13 .

A comparison of radiative capture with decay gamma-ray method in bore hole logging for economic minerals

USGS Publications Warehouse

Senftle, F.E.; Moxham, R.M.; Tanner, A.B.

1972-01-01

The recent availability of borehole logging sondes employing a source of neutrons and a Ge(Li) detector opens up the possibility of analyzing either decay or capture gamma rays. The most efficient method for a given element can be predicted by calculating the decay-to-capture count ratio for the most prominent peaks in the respective spectra. From a practical point of view such a calculation must be slanted toward short irradiation and count times at each station in a borehole. A simplified method of computation is shown, and the decay-to-capture count ratio has been calculated and tabulated for the optimum value in the decay mode irrespective of the irradiation time, and also for a ten minute irradiation time. Based on analysis of a single peak in each spectrum, the results indicate the preferred technique and the best decay or capture peak to observe for those elements of economic interest. ?? 1972.

Methods to Improve the Maintenance of the Earth Catalog of Satellites During Severe Solar Storms

NASA Technical Reports Server (NTRS)

Wilkin, Paul G.; Tolson, Robert H.

1998-01-01

The objective of this thesis is to investigate methods to improve the ability to maintain the inventory of orbital elements of Earth satellites during periods of atmospheric disturbance brought on by severe solar activity. Existing techniques do not account for such atmospheric dynamics, resulting in tracking errors of several seconds in predicted crossing time. Two techniques are examined to reduce of these tracking errors. First, density predicted from various atmospheric models is fit to the orbital decay rate for a number of satellites. An orbital decay model is then developed that could be used to reduce tracking errors by accounting for atmospheric changes. The second approach utilizes a Kalman filter to estimate the orbital decay rate of a satellite after every observation. The new information is used to predict the next observation. Results from the first approach demonstrated the feasibility of building an orbital decay model based on predicted atmospheric density. Correlation of atmospheric density to orbital decay was as high as 0.88. However, it is clear that contemporary: atmospheric models need further improvement in modeling density perturbations polar region brought on by solar activity. The second approach resulted in a dramatic reduction in tracking errors for certain satellites during severe solar Storms. For example, in the limited cases studied, the reduction in tracking errors ranged from 79 to 25 percent.

Background-free search for neutrinoless double-β decay of 76Ge with GERDA.

PubMed

2017-04-05

Many extensions of the Standard Model of particle physics explain the dominance of matter over antimatter in our Universe by neutrinos being their own antiparticles. This would imply the existence of neutrinoless double-β decay, which is an extremely rare lepton-number-violating radioactive decay process whose detection requires the utmost background suppression. Among the programmes that aim to detect this decay, the GERDA Collaboration is searching for neutrinoless double-β decay of 76 Ge by operating bare detectors, made of germanium with an enriched 76 Ge fraction, in liquid argon. After having completed Phase I of data taking, we have recently launched Phase II. Here we report that in GERDA Phase II we have achieved a background level of approximately 10 -3 counts keV -1 kg -1 yr -1 . This implies that the experiment is background-free, even when increasing the exposure up to design level. This is achieved by use of an active veto system, superior germanium detector energy resolution and improved background recognition of our new detectors. No signal of neutrinoless double-β decay was found when Phase I and Phase II data were combined, and we deduce a lower-limit half-life of 5.3 × 10 25 years at the 90 per cent confidence level. Our half-life sensitivity of 4.0 × 10 25 years is competitive with the best experiments that use a substantially larger isotope mass. The potential of an essentially background-free search for neutrinoless double-β decay will facilitate a larger germanium experiment with sensitivity levels that will bring us closer to clarifying whether neutrinos are their own antiparticles.

Background-free search for neutrinoless double-β decay of 76Ge with GERDA

NASA Astrophysics Data System (ADS)

Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; di Marco, N.; di Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.; GERDA Collaboration

2017-04-01

Many extensions of the Standard Model of particle physics explain the dominance of matter over antimatter in our Universe by neutrinos being their own antiparticles. This would imply the existence of neutrinoless double-β decay, which is an extremely rare lepton-number-violating radioactive decay process whose detection requires the utmost background suppression. Among the programmes that aim to detect this decay, the GERDA Collaboration is searching for neutrinoless double-β decay of 76Ge by operating bare detectors, made of germanium with an enriched 76Ge fraction, in liquid argon. After having completed Phase I of data taking, we have recently launched Phase II. Here we report that in GERDA Phase II we have achieved a background level of approximately 10-3 counts keV-1 kg-1 yr-1. This implies that the experiment is background-free, even when increasing the exposure up to design level. This is achieved by use of an active veto system, superior germanium detector energy resolution and improved background recognition of our new detectors. No signal of neutrinoless double-β decay was found when Phase I and Phase II data were combined, and we deduce a lower-limit half-life of 5.3 × 1025 years at the 90 per cent confidence level. Our half-life sensitivity of 4.0 × 1025 years is competitive with the best experiments that use a substantially larger isotope mass. The potential of an essentially background-free search for neutrinoless double-β decay will facilitate a larger germanium experiment with sensitivity levels that will bring us closer to clarifying whether neutrinos are their own antiparticles.

Quantum walks: The first detected passage time problem

NASA Astrophysics Data System (ADS)

Friedman, H.; Kessler, D. A.; Barkai, E.

2017-03-01

Even after decades of research, the problem of first passage time statistics for quantum dynamics remains a challenging topic of fundamental and practical importance. Using a projective measurement approach, with a sampling time τ , we obtain the statistics of first detection events for quantum dynamics on a lattice, with the detector located at the origin. A quantum renewal equation for a first detection wave function, in terms of which the first detection probability can be calculated, is derived. This formula gives the relation between first detection statistics and the solution of the corresponding Schrödinger equation in the absence of measurement. We illustrate our results with tight-binding quantum walk models. We examine a closed system, i.e., a ring, and reveal the intricate influence of the sampling time τ on the statistics of detection, discussing the quantum Zeno effect, half dark states, revivals, and optimal detection. The initial condition modifies the statistics of a quantum walk on a finite ring in surprising ways. In some cases, the average detection time is independent of the sampling time while in others the average exhibits multiple divergences as the sampling time is modified. For an unbounded one-dimensional quantum walk, the probability of first detection decays like (time)(-3 ) with superimposed oscillations, with exceptional behavior when the sampling period τ times the tunneling rate γ is a multiple of π /2 . The amplitude of the power-law decay is suppressed as τ →0 due to the Zeno effect. Our work, an extended version of our previously published paper, predicts rich physical behaviors compared with classical Brownian motion, for which the first passage probability density decays monotonically like (time)-3 /2, as elucidated by Schrödinger in 1915.

Multistate photo-induced relaxation and photoisomerization ability of fumaramide threads: a computational and experimental study.

PubMed

Altoè, Piero; Haraszkiewicz, Natalia; Gatti, Francesco G; Wiering, Piet G; Frochot, Céline; Brouwer, Albert M; Balkowski, Grzegorz; Shaw, Daniel; Woutersen, Sander; Buma, Wybren Jan; Zerbetto, Francesco; Orlandi, Giorgio; Leigh, David A; Garavelli, Marco

2009-01-14

Fumaric and maleic amides are the photoactive units of an important and widely investigated class of photocontrollable rotaxanes as they trigger ring shuttling via a cis-trans photoisomerization. Here, ultrafast decay and photoinduced isomerization in isolated fumaramide and solvated nitrogen-substituted fumaramides (that are employed as threads in those rotaxanes) have been investigated by means of CASPT2//CASSCF computational and time-resolved spectroscopic techniques, respectively. A complex multistate network of competitive deactivation channels, involving both internal conversion and intersystem crossing (ISC) processes, has been detected and characterized that accounts for the picosecond decay and photochemical/photophysical properties observed in the singlet as well as triplet (photosensitized) photochemistry of fumaramides threads. Interestingly, singlet photochemistry appears to follow a non-Kasha rule model, where nonequilibrium dynamical factors control the outcome of the photochemical process: accessible high energy portions of extended crossing seams turn out to drive the deactivation process and ground-state recovery. Concurrently, extended singlet/triplet degenerate regions of twisted molecular structures with significant spin-orbit-coupling values account for ultrafast (picosecond time scale) ISC processes that lead to higher photoisomerization efficiencies. This model discloses the principles behind the intrinsic photochemical reactivity of fumaramide and its control.

Laser Measurements of the H Atom + Ozone Rate Constant at Atmospheric Temperatures

NASA Astrophysics Data System (ADS)

Liu, Y.; Smith, G. P.; Peng, J.; Reppert, K. J.; Callahan, S. L.

2015-12-01

The exothermic H + O3 reaction produces OH(v) Meinel band emissions, used to derive mesospheric H concentrations and chemical heating rates. We have remeasured its rate constant to reduce resulting uncertainties and the measurement extend to lower mesospheric temperatures using modern laser techniques. H atoms are produced by pulsed ultraviolet laser trace photolysis of O3, followed by reaction of O(D) with added H2. A second, delayed, frequency-mixed dye laser measures the reaction decay rate with the remaining ozone by laser induced fluorescence. We monitor either the H atom decay by 2 photon excitation at 205 nm and detection of red fluorescence, or the OH(v=9) product time evolution with excitation of the B-X (0,9) band at 237 nm and emission in blue B-A bands. By cooling the enclosed low pressure flow cell we obtained measurements from 146-305 K. Small kinetic modeling corrections are made for secondary regeneration of H atoms. The results fully confirm the current NASA JPL recommendation for this rate constant, and establish its extrapolation down to the lower temperatures of the mesosphere. This work was supported by the NSF Aeronomy Program and an NSF Physics summer REU student grant.

Present and future challenges of urban systems affected by seawater and its intrusion: the case of Venice, Italy

NASA Astrophysics Data System (ADS)

di Sipio, Eloisa; Zezza, Fulvio

2011-11-01

In lagoonal and marine environments, both historic monuments and recent buildings suffer from severe salt damage caused by sea flooding, sea-level rise and frequent storm events. Salt-water contamination of groundwater systems, a widespread phenomenon typical of coastal areas, can lead to a deterioration not only of the quality of fresh groundwater resources, but also of building materials in urban settlements. A general overview is given of the hydrogeological configuration of the subsoil of Venice (Italy), with particular reference to the shallow groundwater circulation. The relationship between the seawater in the subsoil and salt decay processes, due to salt crystallization, is highlighted. These processes affect civil constructions in Venice's historic center. Perched aquifers, influenced by tide variations and characterized by salt-water intrusion, favor the transport of salts within masonry walls through the action of rising damp. In fact, foundations, in direct contact with the aquifers, may become a preferential vehicle for the transportation of salt within buildings. Decay patterns of different building materials can be detected through non-destructive techniques, which can identify sea-salt damage and therefore assist in the preservation of cultural heritage in coastal areas.

Ultrafast Method for the Analysis of Fluorescence Lifetime Imaging Microscopy Data Based on the Laguerre Expansion Technique

PubMed Central

Jo, Javier A.; Fang, Qiyin; Marcu, Laura

2007-01-01

We report a new deconvolution method for fluorescence lifetime imaging microscopy (FLIM) based on the Laguerre expansion technique. The performance of this method was tested on synthetic and real FLIM images. The following interesting properties of this technique were demonstrated. 1) The fluorescence intensity decay can be estimated simultaneously for all pixels, without a priori assumption of the decay functional form. 2) The computation speed is extremely fast, performing at least two orders of magnitude faster than current algorithms. 3) The estimated maps of Laguerre expansion coefficients provide a new domain for representing FLIM information. 4) The number of images required for the analysis is relatively small, allowing reduction of the acquisition time. These findings indicate that the developed Laguerre expansion technique for FLIM analysis represents a robust and extremely fast deconvolution method that enables practical applications of FLIM in medicine, biology, biochemistry, and chemistry. PMID:19444338

A Review of Interface Electronic Systems for AT-cut Quartz Crystal Microbalance Applications in Liquids

PubMed Central

Arnau, Antonio

2008-01-01

From the first applications of AT-cut quartz crystals as sensors in solutions more than 20 years ago, the so-called quartz crystal microbalance (QCM) sensor is becoming into a good alternative analytical method in a great deal of applications such as biosensors, analysis of biomolecular interactions, study of bacterial adhesion at specific interfaces, pathogen and microorganism detection, study of polymer film-biomolecule or cell-substrate interactions, immunosensors and an extensive use in fluids and polymer characterization and electrochemical applications among others. The appropriate evaluation of this analytical method requires recognizing the different steps involved and to be conscious of their importance and limitations. The first step involved in a QCM system is the accurate and appropriate characterization of the sensor in relation to the specific application. The use of the piezoelectric sensor in contact with solutions strongly affects its behavior and appropriate electronic interfaces must be used for an adequate sensor characterization. Systems based on different principles and techniques have been implemented during the last 25 years. The interface selection for the specific application is important and its limitations must be known to be conscious of its suitability, and for avoiding the possible error propagation in the interpretation of results. This article presents a comprehensive overview of the different techniques used for AT-cut quartz crystal microbalance in in-solution applications, which are based on the following principles: network or impedance analyzers, decay methods, oscillators and lock-in techniques. The electronic interfaces based on oscillators and phase-locked techniques are treated in detail, with the description of different configurations, since these techniques are the most used in applications for detection of analytes in solutions, and in those where a fast sensor response is necessary. PMID:27879713

Mass measurement using energy spectra in three-body decays

DOE PAGES

Agashe, Kaustubh; Franceschini, Roberto; Kim, Doojin; ...

2016-05-24

In previous works we have demonstrated how the energy distribution of massless decay products in two body decays can be used to measure the mass of decaying particles. In this study, we show how such results can be generalized to the case of multi-body decays. The key ideas that allow us to deal with multi-body final states are an extension of our previous results to the case of massive decay products and the factorization of the multi-body phase space. The mass measurement strategy that we propose is distinct from alternative methods because it does not require an accurate reconstruction ofmore » the entire event, as it does not involve, for instance, the missing transverse momentum, but rather requires measuring only the visible decay products of the decay of interest. To demonstrate the general strategy, we study a supersymmetric model wherein pair-produced gluinos each decay to a stable neutralino and a bottom quark-antiquark pair via an off -shell bottom squark. The combinatorial background stemming from the indistinguishable visible final states on both decay sides can be treated by an “event mixing” technique, the performance of which is discussed in detail. In conclusion, taking into account dominant backgrounds, we are able to show that the mass of the gluino and, in favorable cases, that of the neutralino can be determined by this mass measurement strategy.« less

High-Performance Acousto-Ultrasonic Scan System Being Developed

NASA Technical Reports Server (NTRS)

Roth, Don J.; Martin, Richard E.; Cosgriff, Laura M.; Gyekenyesi, Andrew L.; Kautz, Harold E.

2003-01-01

Acousto-ultrasonic (AU) interrogation is a single-sided nondestructive evaluation (NDE) technique employing separated sending and receiving transducers. It is used for assessing the microstructural condition and distributed damage state of the material between the transducers. AU is complementary to more traditional NDE methods, such as ultrasonic cscan, x-ray radiography, and thermographic inspection, which tend to be used primarily for discrete flaw detection. Throughout its history, AU has been used to inspect polymer matrix composites, metal matrix composites, ceramic matrix composites, and even monolithic metallic materials. The development of a high-performance automated AU scan system for characterizing within-sample microstructural and property homogeneity is currently in a prototype stage at NASA. This year, essential AU technology was reviewed. In addition, the basic hardware and software configuration for the scanner was developed, and preliminary results with the system were described. Mechanical and environmental loads applied to composite materials can cause distributed damage (as well as discrete defects) that plays a significant role in the degradation of physical properties. Such damage includes fiber/matrix debonding (interface failure), matrix microcracking, and fiber fracture and buckling. Investigations at the NASA Glenn Research Center have shown that traditional NDE scan inspection methods such as ultrasonic c-scan, x-ray imaging, and thermographic imaging tend to be more suited to discrete defect detection rather than the characterization of accumulated distributed micro-damage in composites. Since AU is focused on assessing the distributed micro-damage state of the material in between the sending and receiving transducers, it has proven to be quite suitable for assessing the relative composite material state. One major success story at Glenn with AU measurements has been the correlation between the ultrasonic decay rate obtained during AU inspection and the mechanical modulus (stiffness) seen during fatigue experiments with silicon carbide/silicon carbide (SiC/SiC) ceramic matrix composite samples. As shown in the figure, ultrasonic decay increased as the modulus decreased for the ceramic matrix composite tensile fatigue samples. The likely microstructural reason for the decrease in modulus (and increase in ultrasonic decay) is the matrix microcracking that commonly occurs during fatigue testing of these materials. Ultrasonic decay has shown the capability to track the pattern of transverse cracking and fiber breakage in these composites.

High-Performance Acousto-Ultrasonic Scan System Being Developed

NASA Technical Reports Server (NTRS)

Roth, Don J.; Martin, Richard E.; Cosgriff, Laura M.; Gyekenyesi, Andrew L.; Kautz, Harold E.

2003-01-01

Acousto-ultrasonic (AU) interrogation is a single-sided nondestructive evaluation (NDE) technique employing separated sending and receiving transducers. It is used for assessing the microstructural condition and distributed damage state of the material between the transducers. AU is complementary to more traditional NDE methods, such as ultrasonic cscan, x-ray radiography, and thermographic inspection, which tend to be used primarily for discrete flaw detection. Throughout its history, AU has been used to inspect polymer matrix composites, metal matrix composites, ceramic matrix composites, and even monolithic metallic materials. The development of a high-performance automated AU scan system for characterizing within-sample microstructural and property homogeneity is currently in a prototype stage at NASA. This year, essential AU technology was reviewed. In addition, the basic hardware and software configuration for the scanner was developed, and preliminary results with the system were described. Mechanical and environmental loads applied to composite materials can cause distributed damage (as well as discrete defects) that plays a significant role in the degradation of physical properties. Such damage includes fiber/matrix debonding (interface failure), matrix microcracking, and fiber fracture and buckling. Investigations at the NASA Glenn Research Center have shown that traditional NDE scan inspection methods such as ultrasonic c-scan, x-ray imaging, and thermographic imaging tend to be more suited to discrete defect detection rather than the characterization of accumulated distributed microdamage in composites. Since AU is focused on assessing the distributed microdamage state of the material in between the sending and receiving transducers, it has proven to be quite suitable for assessing the relative composite material state. One major success story at Glenn with AU measurements has been the correlation between the ultrasonic decay rate obtained during AU inspection and the mechanical modulus (stiffness) seen during fatigue experiments with silicon carbide/silicon carbide (SiC/SiC) ceramic matrix composite samples. As shown in the figure, ultrasonic decay increased as the modulus decreased for the ceramic matrix composite tensile fatigue samples. The likely microstructural reason for the decrease in modulus (and increase in ultrasonic decay) is the matrix microcracking that commonly occurs during fatigue testing of these materials. Ultrasonic decay has shown the capability to track the pattern of transverse cracking and fiber breakage in these composites.

Determination of decay coefficients for combustors with acoustic absorbers

NASA Technical Reports Server (NTRS)

Mitchell, C. E.; Espander, W. R.; Baer, M. R.

1972-01-01

An analytical technique for the calculation of linear decay coefficients in combustors with acoustic absorbers is presented. Tuned circumferential slot acoustic absorbers were designed for the first three transverse modes of oscillation, and decay coefficients for these absorbers were found as a function of backing distance for seven different chamber configurations. The effectiveness of the absorbers for off-design values of the combustion response and acoustic mode is also investigated. Results indicate that for tuned absorbers the decay coefficient increases approximately as the cube of the backing distance. For most off-design situations the absorber still provides a damping effect. However, if an absorber designed for some higher mode of oscillation is used to damp lower mode oscillations, a driving effect is frequently found.

Current observations with a decaying cosmological constant allow for chaotic cyclic cosmology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, George F.R.; Platts, Emma; Weltman, Amanda

2016-04-01

We use the phase plane analysis technique of Madsen and Ellis [1] to consider a universe with a true cosmological constant as well as a cosmological 'constant' that is decaying. Time symmetric dynamics for the inflationary era allows eternally bouncing models to occur. Allowing for scalar field dynamic evolution, we find that if dark energy decays in the future, chaotic cyclic universes exist provided the spatial curvature is positive. This is particularly interesting in light of current observations which do not yet rule out either closed universes or possible evolution of the cosmological constant. We present only a proof ofmore » principle, with no definite claim on the physical mechanism required for the present dark energy to decay.« less

Improved epileptic seizure detection combining dynamic feature normalization with EEG novelty detection.

PubMed

Bogaarts, J G; Hilkman, D M W; Gommer, E D; van Kranen-Mastenbroek, V H J M; Reulen, J P H

2016-12-01

Continuous electroencephalographic monitoring of critically ill patients is an established procedure in intensive care units. Seizure detection algorithms, such as support vector machines (SVM), play a prominent role in this procedure. To correct for inter-human differences in EEG characteristics, as well as for intra-human EEG variability over time, dynamic EEG feature normalization is essential. Recently, the median decaying memory (MDM) approach was determined to be the best method of normalization. MDM uses a sliding baseline buffer of EEG epochs to calculate feature normalization constants. However, while this method does include non-seizure EEG epochs, it also includes EEG activity that can have a detrimental effect on the normalization and subsequent seizure detection performance. In this study, EEG data that is to be incorporated into the baseline buffer are automatically selected based on a novelty detection algorithm (Novelty-MDM). Performance of an SVM-based seizure detection framework is evaluated in 17 long-term ICU registrations using the area under the sensitivity-specificity ROC curve. This evaluation compares three different EEG normalization methods, namely a fixed baseline buffer (FB), the median decaying memory (MDM) approach, and our novelty median decaying memory (Novelty-MDM) method. It is demonstrated that MDM did not improve overall performance compared to FB (p < 0.27), partly because seizure like episodes were included in the baseline. More importantly, Novelty-MDM significantly outperforms both FB (p = 0.015) and MDM (p = 0.0065).

Autonomous Modal Identification of the Space Shuttle Tail Rudder

NASA Technical Reports Server (NTRS)

Pappa, Richard S.; James, George H., III; Zimmerman, David C.

1997-01-01

Autonomous modal identification automates the calculation of natural vibration frequencies, damping, and mode shapes of a structure from experimental data. This technology complements damage detection techniques that use continuous or periodic monitoring of vibration characteristics. The approach shown in the paper incorporates the Eigensystem Realization Algorithm (ERA) as a data analysis engine and an autonomous supervisor to condense multiple estimates of modal parameters using ERA's Consistent-Mode Indicator and correlation of mode shapes. The procedure was applied to free-decay responses of a Space Shuttle tail rudder and successfully identified the seven modes of the structure below 250 Hz. The final modal parameters are a condensed set of results for 87 individual ERA cases requiring approximately five minutes of CPU time on a DEC Alpha computer.

Modern Instrumental Methods to Investigate the Mechanism of Biological Decay in Wood Plastic Composites

Treesearch

Grace Sun; Rebecca Ibach; Marek Gnatowski; Jessie Glaeser; Mathew Leung; John Haight

2014-01-01

Various instrumental techniques were used to study the fungal decay process in wood plastic composite (WPC) boards. Commercial boards exposed near Hilo, Hawaii (HI) for eight years in both sun and shadow locations were inspected and tested periodically. After eight years of exposure, both boards were evaluated using magnetic resonance imaging (MRI), while a selected...

Parameterization of the Voice Source by Combining Spectral Decay and Amplitude Features of the Glottal Flow.

ERIC Educational Resources Information Center

Alku, Paavo; Vilkman, Erkki; Laukkanen, Anne-Maria

1998-01-01

A new method is presented for the parameterization of glottal volume velocity waveforms that have been estimated by inverse filtering acoustic speech pressure signals. The new technique combines two features of voice production: the AC value and the spectral decay of the glottal flow. Testing found the new parameter correlates strongly with the…

Search for high-mass Z γ resonances in proton–proton collisions at s = 8 and 13 TeV using jet substructure techniques

DOE PAGES

Sirunyan, A. M.; Tumasyan, A.; Adam, W.; ...

2017-06-28

A search for massive resonances decaying to a Z boson and a photon is performed in events with a hadronically decaying Z boson candidate, separately in light-quark and b quark decay modes, identified using jet substructure and advanced b tagging techniques. Results are based on samples of proton-proton collisions collected with the CMS detector at the LHC at center-of-mass energies of 8 and 13 TeV, corresponding to integrated luminosities of 19.7 and 2.7 inverse femtobarns, respectively. The results of the search are combined with those of a similar search in the leptonic decay modes of the Z boson, based onmore » the same data sets. Spin-0 resonances with various widths and with masses in a range between 0.2 and 3.0 TeV are considered. No significant excess is observed either in the individual analyses or the combination. The results are presented in terms of upper limits on the production cross section of such resonances and constitute the most stringent limits to date for a wide range of masses.« less

Search for a massive resonance decaying into a Higgs boson and a W or Z boson in hadronic final states in proton-proton collisions at √s = 8 TeV

DOE PAGES

Khachatryan, Vardan

2015-06-05

A search for a massive resonance decaying into a standard-model-like Higgs boson (H) and a W or Z boson is reported. The analysis is performed on a data sample corresponding to an integrated luminosity of 19.7 fb –1, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. Signal events, in which the decay products of Higgs, W, or Z bosons at high Lorentz boost are contained within single reconstructed jets, are identified using jet substructure techniques, including the tagging of b hadrons. This is the first search for heavy resonances decayingmore » in HW or HZ resulting in an all-jet final state, as well as the first application of jet substructure techniques to identify H → WW* → 4q decays at high Lorentz boost. Furthermore, no significant signal is observed and limits are set at 95% confidence level on the production cross section of W' and Z' in a model with mass-degenerate charged and neutral spin-1 resonances.« less

Acidification of apple and orange hosts by Penicillium digitatum and Penicillium expansum.

PubMed

Vilanova, L; Viñas, I; Torres, R; Usall, J; Buron-Moles, G; Teixidó, N

2014-05-16

New information about virulence mechanisms of Penicillium digitatum and Penicillium expansum could be an important avenue to control fungal diseases. In this study, the ability of P. digitatum and P. expansum to enhance their virulence by locally modulating the pH of oranges and apples was evaluated. For each host, pH changes with a compatible pathogen and a non-host pathogen were recorded, and the levels of different organic acids were evaluated to establish possible relationships with host pH modifications. Moreover, fruits were harvested at three maturity stages to determine whether fruit maturity could affect the pathogens' virulence. The pH of oranges and apples decreased when the compatible pathogens (P. digitatum and P. expansum, respectively) decayed the fruit. The main organic acid detected in P. digitatum-decayed oranges was galacturonic acid produced as a consequence of host maceration in the rot development process. However, the obtained results showed that this acid was not responsible for the pH decrease in decayed orange tissue. The mixture of malic and citric acids could at least contribute to the acidification of P. digitatum-decayed oranges. The pH decrease in P. expansum decayed apples is related to the accumulation of gluconic and fumaric acids. The pH of oranges and apples was not affected when the non-host pathogen was not able to macerate the tissues. However, different organic acid contents were detected in comparison to healthy tissues. The main organic acids detected in P. expansum-oranges were oxalic and gluconic and in P. digitatum-apples were citric, gluconic and galacturonic. Further research is needed to identify the pathogenicity factors of both fungi because the contribution of organic acids has profound implications. Copyright © 2014 Elsevier B.V. All rights reserved.

On the non-detection of Glashow resonance in IceCube

NASA Astrophysics Data System (ADS)

Sahu, Sarira; Zhang, Bing

2018-06-01

Electron anti-neutrinos at the Glashow resonance (GR, at Eνbare ∼ 6.3 PeV) have an enhanced probability to be detected. With three neutrinos detected by IceCube in the (1-2) PeV energy range at present, one would expect that about 1 to 4 GR νbare should have been detected. The high-energy ∼8.7 PeV muon neutrino detected by IceCube may not be a GR event. If so, we expect to detect 50 to 70 GR νbare, then one would have a "missing Glashow-resonance problem". This would suggest (1) that pγ interaction rather than pp interaction is the dominant channel to produce the observed IceCube high-energy neutrinos; (2) that multi-pion pγ interactions are suppressed; and (3) that the magnetic field and photon energy density in the pγ emission region is such that significant μ+ cooling occurs before decaying, yet π+'s essentially do not cool before decaying.

Use of geostatistics to predict virus decay rates for determination of septic tank setback distances.

PubMed Central

Yates, M V; Yates, S R; Warrick, A W; Gerba, C P

1986-01-01

Water samples were collected from 71 public drinking-water supply wells in the Tucson, Ariz., basin. Virus decay rates in the water samples were determined with MS-2 coliphage as a model virus. The correlations between the virus decay rates and the sample locations were shown by fitting a spherical model to the experimental semivariogram. Kriging, a geostatistical technique, was used to calculate virus decay rates at unsampled locations by using the known values at nearby wells. Based on the regional characteristics of groundwater flow and the kriged estimates of virus decay rates, a contour map of the area was constructed. The map shows the variation in separation distances that would have to be maintained between wells and sources of contamination to afford similar degrees of protection from viral contamination of the drinking water in wells throughout the basin. PMID:3532954

Free-decay time-domain modal identification for large space structures

NASA Technical Reports Server (NTRS)

Kim, Hyoung M.; Vanhorn, David A.; Doiron, Harold H.

1992-01-01

Concept definition studies for the Modal Identification Experiment (MIE), a proposed space flight experiment for the Space Station Freedom (SSF), have demonstrated advantages and compatibility of free-decay time-domain modal identification techniques with the on-orbit operational constraints of large space structures. Since practical experience with modal identification using actual free-decay responses of large space structures is very limited, several numerical and test data reduction studies were conducted. Major issues and solutions were addressed, including closely-spaced modes, wide frequency range of interest, data acquisition errors, sampling delay, excitation limitations, nonlinearities, and unknown disturbances during free-decay data acquisition. The data processing strategies developed in these studies were applied to numerical simulations of the MIE, test data from a deployable truss, and launch vehicle flight data. Results of these studies indicate free-decay time-domain modal identification methods can provide accurate modal parameters necessary to characterize the structural dynamics of large space structures.

Evaluating wood-based composites for incipient fungal decay with the immunodiagnostic wood decay test.

Treesearch

C.A. Clausen; L. Haughton; C. Murphy

2003-01-01

Early and accurate detection of the extent of fungal deterioration during forensic inspection of the building envelope would eliminate excessive or unnecessary replacement of wood-based building materials. Areas of water infiltration in wood-framed building envelopes in the Pacific Northwest were evaluated visually and sampled for moisture content. Wood samples were...

Experimental medium energy physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnes, P.D.

1991-01-01

This report discusses the following topics: Search for the H Dibaryon at the AGS; Hypernuclear Weak Decay Studies at the AGS; Relativistic Proton-Nucleus and Heavy Ion-Nucleus Collisions at the SPS; Hyperon-Antihyperon Production studies at LEAR; Hyperon Photoproduction at CEBAF; Double Lambda Hypernuclei; Weak Decay of Light Hypernuclei; and {pi}{sup 0}/{gamma}Detection with the CMU Scintillator Arrays.

Dark Matter Limits from Dwarf Spheroidal Galaxies with the HAWC Gamma-Ray Observatory

NASA Astrophysics Data System (ADS)

Albert, A.; Alfaro, R.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Avila Rojas, D.; Ayala Solares, H. A.; Bautista-Elivar, N.; Becerril, A.; Belmont-Moreno, E.; BenZvi, S. Y.; Bernal, A.; Braun, J.; Brisbois, C.; Caballero-Mora, K. S.; Capistrán, T.; Carramiñana, A.; Casanova, S.; Castillo, M.; Cotti, U.; Cotzomi, J.; Coutiño de León, S.; De León, C.; De la Fuente, E.; Diaz Hernandez, R.; Dingus, B. L.; DuVernois, M. A.; Díaz-Vélez, J. C.; Ellsworth, R. W.; Engel, K.; Fiorino, D. W.; Fraija, N.; García-González, J. A.; Garfias, F.; González, M. M.; Goodman, J. A.; Hampel-Arias, Z.; Harding, J. P.; Hernandez, S.; Hernandez-Almada, A.; Hona, B.; Hüntemeyer, P.; Iriarte, A.; Jardin-Blicq, A.; Joshi, V.; Kaufmann, S.; Kieda, D.; Lauer, R. J.; Lennarz, D.; León Vargas, H.; Linnemann, J. T.; Longinotti, A. L.; Longo Proper, M.; Raya, G. Luis; Luna-García, R.; López-Coto, R.; Malone, K.; Marinelli, S. S.; Martinez-Castellanos, I.; Martínez-Castro, J.; Martínez-Huerta, H.; Matthews, J. A.; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nellen, L.; Newbold, M.; Nisa, M. U.; Noriega-Papaqui, R.; Pelayo, R.; Pretz, J.; Pérez-Pérez, E. G.; Ren, Z.; Rho, C. D.; Rivière, C.; Rosa-González, D.; Rosenberg, M.; Ruiz-Velasco, E.; Salesa Greus, F.; Sandoval, A.; Schneider, M.; Schoorlemmer, H.; Sinnis, G.; Smith, A. J.; Springer, R. W.; Surajbali, P.; Taboada, I.; Tibolla, O.; Tollefson, K.; Torres, I.; Vianello, G.; Weisgarber, T.; Westerhoff, S.; Wood, J.; Yapici, T.; Younk, P. W.; Zhou, H.

2018-02-01

The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field of view observatory sensitive to 500 GeV–100 TeV gamma-rays and cosmic rays. It can also perform diverse indirect searches for dark matter annihilation and decay. Among the most promising targets for the indirect detection of dark matter are dwarf spheroidal galaxies. These objects are expected to have few astrophysical sources of gamma-rays but high dark matter content, making them ideal candidates for an indirect dark matter detection with gamma-rays. Here we present individual limits on the annihilation cross section and decay lifetime for 15 dwarf spheroidal galaxies within the field of view, as well as their combined limit. These are the first limits on the annihilation cross section and decay lifetime using data collected with HAWC. We also present the HAWC flux upper limits of the 15 dwarf spheroidal galaxies in half-decade energy bins.

Recoil ions from the β decay of 134Sb confined in a Paul trap

NASA Astrophysics Data System (ADS)

Siegl, K.; Scielzo, N. D.; Czeszumska, A.; Clark, J. A.; Savard, G.; Aprahamian, A.; Caldwell, S. A.; Alan, B. S.; Burkey, M. T.; Chiara, C. J.; Greene, J. P.; Harker, J.; Marley, S. T.; Morgan, G. E.; Munson, J. M.; Norman, E. B.; Orford, R.; Padgett, S.; Galván, A. Perez; Sharma, K. S.; Strauss, S. Y.

2018-03-01

The low-energy recoiling ions from the β decay of 134Sb were studied by using the Beta-decay Paul Trap. Using this apparatus, singly charged ions were suspended in vacuum at the center of a detector array used to detect emitted β particles, γ rays, and recoil ions in coincidence. The recoil ions emerge from the trap with negligible scattering, allowing β -decay properties and the charge-state distribution of the daughter ions to be determined from the β -ion coincidences. First-forbidden β -decay theory predicts a β -ν correlation coefficient of nearly unity for the 0- to 0+ transition from the ground state of 134Sb to the ground state of 134Te. Although this transition was expected to have a nearly 100% branching ratio, an additional 17.2(52)% of the β -decay strength must populate high-lying excited states to obtain an angular correlation consistent with unity. The extracted charge-state distribution of the recoiling ions was compared with existing β -decay results and the average charge state was found to be consistent with the results from lighter nuclei.

Neutron induced radio-isotopes and background for Ge double beta decay experiments

NASA Astrophysics Data System (ADS)

Chu, Pinghan; Majorana Collaboration

2015-10-01

Environmental neutrons, mostly produced by muons in the cosmic rays, might contribute backgrounds to the search for neutrinoless double beta decays. These neutrons can interact with materials and generate radio-isotopes, which can decay and produce radioactive backgrounds. Some of these neutron-induced isotopes have a signature of a time-delayed coincidence, allowing us to study these infrequent events. For example, such isotopes can decay by beta decay to metastable states and then decay by gamma decay to the ground state. Considering the time-delayed coincidence of these two processes, we can determine candidates for these neutron-induced isotopes in the data and estimate the flux of neutrons in the deep underground environment. In this report, we will list possible neutron-induced isotopes and the methodology to detect them, especially those that can affect the search for neutrinoless double beta decays in 76Ge. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

Measurement of Neutral-Current K+ Production by Neutrinos using MINERvA

NASA Astrophysics Data System (ADS)

Marshall, C. M.; Aliaga, L.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Cai, T.; Carneiro, M. F.; da Motta, H.; Dytman, S. A.; Díaz, G. A.; Dunkman, M.; Eberly, B.; Endress, E.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Gallagher, H.; Ghosh, A.; Golan, T.; Gran, R.; Harris, D. A.; Higuera, A.; Hurtado, K.; Kleykamp, J.; Kordosky, M.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Caicedo, D. A. Martinez; McFarland, K. S.; McGivern, C. L.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Norrick, A.; Nuruzzaman; Paolone, V.; Patrick, C. E.; Perdue, G. N.; Ramírez, M. A.; Ransome, R. D.; Ray, H.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schmitz, D. W.; Solano Salinas, C. J.; Sultana, M.; Sánchez Falero, S.; Valencia, E.; Walton, T.; Wolcott, J.; Wospakrik, M.; Yaeggy, B.; Zhang, D.; Minerva Collaboration

2017-07-01

Neutral-current production of K+ by atmospheric neutrinos is a background in searches for the proton decay p →K+ν ¯. Reactions such as ν p →ν K+Λ are indistinguishable from proton decays when the decay products of the Λ are below detection threshold. Events with K+ are identified in MINERvA by reconstructing the timing signature of a K+ decay at rest. A sample of 201 neutrino-induced neutral-current K+ events is used to measure differential cross sections with respect to the K+ kinetic energy, and the non-K+ hadronic visible energy. An excess of events at low hadronic visible energy is observed relative to the prediction of the neut event generator. Good agreement is observed with the cross section prediction of the genie generator. A search for photons from π0 decay, which would veto a neutral-current K+ event in a proton decay search, is performed, and a 2 σ deficit of detached photons is observed relative to the genie prediction.

Measurement of Neutral-Current K + Production by Neutrinos using MINERvA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, C. M.; Aliaga, L.; Altinok, O.

Neutral-current production of K+ by atmospheric neutrinos is a background in searches for the proton decay p→K+ν¯. Reactions such as νp→νK+Λ are indistinguishable from proton decays when the decay products of the Λ are below detection threshold. Events with K+ are identified in MINERvA by reconstructing the timing signature of a K+ decay at rest. A sample of 201 neutrino-induced neutral-current K+ events is used to measure differential cross sections with respect to the K+ kinetic energy, and the non-K+ hadronic visible energy. An excess of events at low hadronic visible energy is observed relative to the prediction of themore » neut event generator. Good agreement is observed with the cross section prediction of the genie generator. A search for photons from π0 decay, which would veto a neutral-current K+ event in a proton decay search, is performed, and a 2σ deficit of detached photons is observed relative to the genie prediction.« less

Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

DOE PAGES

Khatavkar, Sanchit; Muniappan, Kulasekaran; Kannan, Chinna V.; ...

2017-11-10

Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment.more » For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.« less

Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khatavkar, Sanchit; Muniappan, Kulasekaran; Kannan, Chinna V.

Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment.more » For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.« less

Stochastic mass-reconstruction: a new technique to reconstruct resonance masses of heavy particles decaying into tau lepton pairs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maruyama, Sho

2015-12-15

The invariant mass of tau lepton pairs turns out to be smaller than the resonant mass of their mother particle and the invariant mass distribution is stretched wider than the width of the resonant mass as significant fraction of tau lepton momenta are carried away by neutrinos escaping undetected at collider experiments. This paper describes a new approach to reconstruct resonant masses of heavy particles decaying to tau leptons at such experiments. A typical example is a Z or Higgs boson decaying to a tau pair. Although the new technique can be used for each tau lepton separately, I combinemore » two tau leptons to improve mass resolution by requiring the two tau leptons are lined up in a transverse plane. The method is simple to implement and complementary to the collinear approximation technique that works well when tau leptons are not lined up in a transverse plane. The reconstructed mass can be used as another variable in analyses that already use a visible tau pair mass and missing transverse momentum as these variables are not explicitly used in the stochastic mass-reconstruction to select signal-like events.« less

Absolute measurement of hadronic branching fractions of the Ds+ meson.

PubMed

Alexander, J P; Berkelman, K; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Libby, J; Powell, A; Wilkinson, G; Ecklund, K M; Love, W; Savinov, V; Lopez, A; Mendez, H; Ramirez, J; Ge, J Y; Miller, D H; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Rademacker, J; Asner, D M; Edwards, K W; Naik, P; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L

2008-04-25

The branching fractions of D(s)(+/-) meson decays serve to normalize many measurements of processes involving charm quarks. Using 298 pb(-1) of e(+)e(-) collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight D(s)(+/-) decays with a double tag technique. In particular we determine the branching fraction B(D(s)(+)-->K(-)K(+}pi(+))=(5.50+/-0.23+/-0.16)%, where the uncertainties are statistical and systematic, respectively. We also provide partial branching fractions for kinematic subsets of the K(-)K(+)pi(+) decay mode.

Decay of the 3D viscous liquid-gas two-phase flow model with damping

NASA Astrophysics Data System (ADS)

Zhang, Yinghui

2016-08-01

We establish the optimal Lp - L2(1 ≤ p < 6/5) time decay rates of the solution to the Cauchy problem for the 3D viscous liquid-gas two-phase flow model with damping and analyse the influences of the damping on the qualitative behaviors of solution. It is observed that the fraction effect of the damping affects the dispersion of fluids and enhances the time decay rate of solution. Our method of proof consists of Hodge decomposition technique, Lp - L2 estimates for the linearized equations, and delicate energy estimates.

Absolute Measurement of Hadronic Branching Fractions of the Ds+ Meson

NASA Astrophysics Data System (ADS)

Alexander, J. P.; Berkelman, K.; Cassel, D. G.; Duboscq, J. E.; Ehrlich, R.; Fields, L.; Gibbons, L.; Gray, R.; Gray, S. W.; Hartill, D. L.; Heltsley, B. K.; Hertz, D.; Jones, C. D.; Kandaswamy, J.; Kreinick, D. L.; Kuznetsov, V. E.; Mahlke-Krüger, H.; Mohapatra, D.; Onyisi, P. U. E.; Patterson, J. R.; Peterson, D.; Riley, D.; Ryd, A.; Sadoff, A. J.; Shi, X.; Stroiney, S.; Sun, W. M.; Wilksen, T.; Athar, S. B.; Patel, R.; Yelton, J.; Rubin, P.; Eisenstein, B. I.; Karliner, I.; Mehrabyan, S.; Lowrey, N.; Selen, M.; White, E. J.; Wiss, J.; Mitchell, R. E.; Shepherd, M. R.; Besson, D.; Pedlar, T. K.; Cronin-Hennessy, D.; Gao, K. Y.; Hietala, J.; Kubota, Y.; Klein, T.; Lang, B. W.; Poling, R.; Scott, A. W.; Zweber, P.; Dobbs, S.; Metreveli, Z.; Seth, K. K.; Tomaradze, A.; Libby, J.; Powell, A.; Wilkinson, G.; Ecklund, K. M.; Love, W.; Savinov, V.; Lopez, A.; Mendez, H.; Ramirez, J.; Ge, J. Y.; Miller, D. H.; Sanghi, B.; Shipsey, I. P. J.; Xin, B.; Adams, G. S.; Anderson, M.; Cummings, J. P.; Danko, I.; Hu, D.; Moziak, B.; Napolitano, J.; He, Q.; Insler, J.; Muramatsu, H.; Park, C. S.; Thorndike, E. H.; Yang, F.; Artuso, M.; Blusk, S.; Khalil, S.; Li, J.; Mountain, R.; Nisar, S.; Randrianarivony, K.; Sultana, N.; Skwarnicki, T.; Stone, S.; Wang, J. C.; Zhang, L. M.; Bonvicini, G.; Cinabro, D.; Dubrovin, M.; Lincoln, A.; Rademacker, J.; Asner, D. M.; Edwards, K. W.; Naik, P.; Briere, R. A.; Ferguson, T.; Tatishvili, G.; Vogel, H.; Watkins, M. E.; Rosner, J. L.

2008-04-01

The branching fractions of Ds± meson decays serve to normalize many measurements of processes involving charm quarks. Using 298pb-1 of e+e- collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight Ds± decays with a double tag technique. In particular we determine the branching fraction B(Ds+→K-K+π+)=(5.50±0.23±0.16)%, where the uncertainties are statistical and systematic, respectively. We also provide partial branching fractions for kinematic subsets of the K-K+π+ decay mode.

Direct imaging of explosives.

PubMed

Knapp, E A; Moler, R B; Saunders, A W; Trower, W P

2000-01-01

Any technique that can detect nitrogen concentrations can screen for concealed explosives. However, such a technique would have to be insensitive to metal, both encasing and incidental. If images of the nitrogen concentrations could be captured, then, since form follows function, a robust screening technology could be developed. However these images would have to be sensitive to the surface densities at or below that of the nitrogen contained in buried anti-personnel mines or of the SEMTEX that brought down Pan Am 103, approximately 200 g. Although the ability to image in three-dimensions would somewhat reduce false positives, capturing collateral images of carbon and oxygen would virtually assure that nitrogenous non-explosive material like fertilizer, Melmac dinnerware, and salami could be eliminated. We are developing such an instrument, the Nitrogen Camera, which has met experimentally these criteria with the exception of providing oxygen images, which awaits the availability of a sufficiently energetic light source. Our Nitrogen Camera technique uses an electron accelerator to produce photonuclear reactions whose unique decays it registers. Clearly if our Nitrogen Camera is made mobile, it could be effective in detecting buried mines, either in an active battlefield situation or in the clearing of abandoned military munitions. Combat operations require that a swathe the width of an armored vehicle, 5 miles deep, be screened in an hour, which is within our camera's scanning speed. Detecting abandoned munitions is technically easier as it is free from the onerous speed requirement. We describe here our Nitrogen Camera and show its 180 pixel intensity images of elemental nitrogen in a 200 g mine simulant and in a 125 g stick of SEMTEX. We also report on our progress in creating a lorry transportable 70 MeV electron racetrack microtron, the principal enabling technology that will allow our Nitrogen Camera to be deployed in the field.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Compostella, Gabriele

This thesis is focused on an inclusive search of the tmore » $$\\bar{t}$$ → E T + jets decay channel by means of neural network tools in proton antiproton collisions at √s = 1.96 TeV recorded by the Collider Detector at Fermilab (CDF). At the Tevatron p$$\\bar{p}$$ collider top quarks are mainly produced in pairs through quark-antiquark annihilation and gluon-gluon fusion processes; in the Standard Model description, the top quark then decays to a W boson and a b quark almost 100% of the times, so that its decay signatures are classified according to the W decay modes. When only one W decays leptonically, the t$$\\bar{t}$$ event typically contains a charged lepton, missing transverse energy due to the presence of a neutrino escaping from the detector, and four high transverse momentum jets, two of which originate from b quarks. In this thesis we describe a t$$\\bar{t}$$ production cross section measurement which uses data collected by a 'multijet' trigger, and selects this kind of top decays by requiring a high-P T neutrino signature and by using an optimized neural network to discriminate top quark pair production from backgrounds. In Chapter 1, a brief review of the Standard Model of particle physics will be discussed, focusing on top quark properties and experimental signatures. In Chapter 2 will be presented an overview of the Tevatron accelerator chain that provides p$$\\bar{p}$$ collisions at the center-of-mass energy of √s = 1.96 TeV, and proton and antiproton beams production procedure will be discussed. The CDF detector and its components and subsystems used for the study of p{bar p} collisions provided by the Tevatron will be described in Chapter 3. Chapter 4 will detail the reconstruction procedures used in CDF to detect physical objects exploiting the features of the different detector subsystems. Chapter 5 will provide an overview of the main concepts regarding Artificial Neural Networks, one of the most important tools we will use in the analysis. Chapter 6 will be devoted to the description of the main characteristics of the t$$\\bar{t}$$ → E T + jets decay channel used to train our neural network to discriminate the top pair production from background processes. We will discuss the event selection method and the technique used for background prediction, that will rely on b-jets identification rate parameterization. Finally, Chapter 7 will provide a description of the final data sample and a detailed discussion of the systematic uncertainties before determining the cross section measurement by means of a likelihood maximization.« less

Two-neutrino double-β decay of 150Nd to excited final states in 150Sm

NASA Astrophysics Data System (ADS)

Kidd, M. F.; Esterline, J. H.; Finch, S. W.; Tornow, W.

2014-11-01

Background: Double-β decay is a rare nuclear process in which two neutrons in the nucleus are converted to two protons with the emission of two electrons and two electron antineutrinos. Purpose: We measured the half-life of the two-neutrino double-β decay of 150Nd to excited final states of 150Sm by detecting the deexcitation γ rays of the daughter nucleus. Method: This study yields the first detection of the coincidence γ rays from the 0 1+ excited state of 150Sm. These γ rays have energies of 333.97 and 406.52 keV and are emitted in coincidence through a 01+→21+→0gs+ transition. Results: The enriched Nd2O3 sample consisted of 40.13 g 150Nd and was observed for 642.8 days at the Kimballton Underground Research Facility, producing 21.6 net events in the region of interest. This count rate gives a half-life of T1 /2=[1 .07-0.25+0.45(stat ) ±0.07 (syst ) ] ×1020 yr. The effective nuclear matrix element was found to be 0.0465 -0.0054+0.0098. Finally, lower limits were obtained for decays to higher excited final states. Conclusions: Our half-life measurement agrees within uncertainties with another recent measurement in which no coincidence was employed. Our nuclear matrix element calculation may have an impact on a recent neutrinoless double-β decay nuclear matrix element calculation which implies that the decay to the first excited state in 150Sm is favored over that to the ground state.

Performance of the Versatile Array of Neutron Detectors at Low Energy (VANDLE)

DOE PAGES

Peters, W. A.; Ilyushkin, S.; Madurga, M.; ...

2016-08-26

The Versatile Array of Neutron Detectors at Low Energy (VANDLE) is a new, highly efficient plastic-scintillator array constructed for decay and transfer reaction experimental setups that require neutron detection. The versatile and modular design allows for customizable experimental setups including beta-delayed neutron spectroscopy and (d,n) transfer reactions in normal and inverse kinematics. The neutron energy and prompt-photon discrimination is determined through the time of flight technique. Fully digital data acquisition electronics and integrated triggering logic enables some VANDLE modules to achieve an intrinsic efficiency over 70% for 300-keV neutrons, measured through two different methods. A custom Geant4 simulation models aspectsmore » of the detector array and the experimental setups to determine efficiency and detector response. Lastly, a low detection threshold, due to the trigger logic and digitizing data acquisition, allowed us to measure the light-yield response curve from elastically scattered carbon nuclei inside the scintillating plastic from incident neutrons with kinetic energies below 2 MeV.« less

Pressure jump relaxation setup with IR detection and millisecond time resolution

NASA Astrophysics Data System (ADS)

Schiewek, Martin; Krumova, Marina; Hempel, Günter; Blume, Alfred

2007-04-01

An instrument is described that allows the use of Fourier transform infrared (FTIR) spectroscopy as a detection system for kinetic processes after a pressure jump of up to 100bars. The pressure is generated using a high performance liquid chromatography (HPLC) pump and water as a pressure transducing medium. A flexible membrane separates the liquid sample in the IR cell from the pressure transducing medium. Two electromagnetic switching valves in the setup enable pressure jumps with a decay time of 4ms. The FTIR spectrometer is configured to measure time resolved spectra in the millisecond time regime using the rapid scan mode. All components are computer controlled. For a demonstration of the capability of the method first results on the kinetics of a phase transition between two lamellar phases of an aqueous phospholipid dispersion are presented. This combination of FTIR spectroscopy with the pressure jump relaxation technique can also be used for other systems which display cooperative transitions with concomitant volume changes.

Efficient removal of UDMH from dilute nitride MOCVD exhaust streams

NASA Astrophysics Data System (ADS)

Pahle, Jörg; Czerniak, Mike; Seeley, Andy; Baker, Derek

2004-12-01

Unsymmetrical dimethyl hydrazine (UDMH) (CH 3) 2N 2H 2 is often used in the deposition of dilute nitride semiconductors because it provides a source of nitrogen with a low thermal decomposition temperature (Temperature-dependent carrier lifetime in GaNAs using resonant-coupled photoconductive decay, NCPV Program Review Meeting, Lakewood, Colorado, 14-17 October, 2001). The problems with using this material, however, are its significant toxicity (0.01 ppm compared to ammonia's 25 ppm) and also the fact that it blocks the action of conventional dosed wet scrubbers sometimes used on nitride applications, resulting in diminished efficiency in removing arsine (the source of arsenic), and arsine being similarly toxic (TLV of 0.05 ppm). Efficient removal of UDMH, AsH 3 and hydrogen (which, though not toxic poses a potential safety hazard) by means of a combined thermal oxidation reaction and wet scrubber in series is described at input gas flow rates exceeding those typically encountered in practice. The detection technique employed was Fourier transform infra red spectroscopy (FTIR), and the calibration and resolution techniques will be described. For input UDMH flows of up to 445 sccm (i.e. 1.85×10 -2 mol/min), destructive reaction efficiencies (DREs) of >99.9% were demonstrated, corresponding to the background detection resolution of 0.4 ppm.

New methods for time-resolved fluorescence spectroscopy data analysis based on the Laguerre expansion technique--applications in tissue diagnosis.

PubMed

Jo, J A; Marcu, L; Fang, Q; Papaioannou, T; Qiao, J H; Fishbein, M C; Beseth, B; Dorafshar, A H; Reil, T; Baker, D; Freischlag, J

2007-01-01

A new deconvolution method for the analysis of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) data is introduced and applied for tissue diagnosis. The intrinsic TR-LIFS decays are expanded on a Laguerre basis, and the computed Laguerre expansion coefficients (LEC) are used to characterize the sample fluorescence emission. The method was applied for the diagnosis of atherosclerotic vulnerable plaques. At a first stage, using a rabbit atherosclerotic model, 73 TR-LIFS in-vivo measurements from the normal and atherosclerotic aorta segments of eight rabbits were taken. The Laguerre deconvolution technique was able to accurately deconvolve the TR-LIFS measurements. More interesting, the LEC reflected the changes in the arterial biochemical composition and provided discrimination of lesions rich in macrophages/foam-cells with high sensitivity (> 85%) and specificity (> 95%). At a second stage, 348 TR-LIFS measurements were obtained from the explanted carotid arteries of 30 patients. Lesions with significant inflammatory cells (macrophages/foam-cells and lymphocytes) were detected with high sensitivity (> 80%) and specificity (> 90%), using LEC-based classifiers. This study has demonstrated the potential of using TR-LIFS information by means of LEC for in vivo tissue diagnosis, and specifically for detecting inflammation in atherosclerotic lesions, a key marker of plaque vulnerability.

Search for Dinucleon Decay into Kaons in Super-Kamiokande

NASA Astrophysics Data System (ADS)

Litos, M.; Abe, K.; Hayato, Y.; Iida, T.; Ikeda, M.; Iyogi, K.; Kameda, J.; Kobayashi, K.; Koshio, Y.; Kozuma, Y.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakayama, S.; Obayashi, Y.; Ogawa, H.; Sekiya, H.; Shiozawa, M.; Suzuki, Y.; Takeda, A.; Takenaga, Y.; Takeuchi, Y.; Ueno, K.; Ueshima, K.; Watanabe, H.; Yamada, S.; Yokozawa, T.; Hazama, S.; Ishihara, C.; Kaji, H.; Kajita, T.; Kaneyuki, K.; McLachlan, T.; Okumura, K.; Shimizu, Y.; Tanimoto, N.; Vagins, M. R.; Kearns, E.; Stone, J. L.; Sulak, L. R.; Dufour, F.; Raaf, J. L.; Henning, B.; Goldhaber, M.; Bays, K.; Casper, D.; Cravens, J. P.; Kropp, W. R.; Mine, S.; Regis, C.; Smy, M. B.; Sobel, H. W.; Ganezer, K. S.; Hill, J.; Keig, W. E.; Jang, J. S.; Kim, J. Y.; Lim, I. T.; Albert, J. B.; Wongjirad, T.; Wendell, R.; Scholberg, K.; Walter, C. W.; Tasaka, S.; Learned, J. G.; Matsuno, S.; Watanabe, Y.; Hasegawa, T.; Ishida, T.; Ishii, T.; Kobayashi, T.; Nakadaira, T.; Nakamura, K.; Nishikawa, K.; Nishino, H.; Oyama, Y.; Sakashita, K.; Sekiguchi, T.; Tsukamoto, T.; Suzuki, A. T.; Minamino, A.; Nakaya, T.; Fukuda, Y.; Itow, Y.; Mitsuka, G.; Tanaka, T.; Jung, C. K.; Lopez, G.; McGrew, C.; Terri, R.; Yanagisawa, C.; Tamura, N.; Ishino, H.; Kibayashi, A.; Mino, S.; Mori, T.; Sakuda, M.; Toyota, H.; Kuno, Y.; Yoshida, M.; Kim, S. B.; Yang, B. S.; Ishizuka, T.; Okazawa, H.; Choi, Y.; Nishijima, K.; Yokosawa, Y.; Koshiba, M.; Yokoyama, M.; Totsuka, Y.; Chen, S.; Heng, Y.; Yang, Z.; Zhang, H.; Kielczewska, D.; Mijakowski, P.; Connolly, K.; Dziomba, M.; Thrane, E.; Wilkes, R. J.; Super-Kamiokande Collaboration

2014-04-01

A search for the dinucleon decay pp→K+K+ has been performed using 91.6 kton .yr data from Super-Kamiokande-I. This decay provides a sensitive probe of the R-parity-violating parameter λ112''. A boosted decision tree analysis found no signal candidates in the data. The expected background was 0.28±0.19 atmospheric neutrino induced events and the estimated signal detection efficiency was 12.6%±3.2%. A lower limit of 1.7×1032 years has been placed on the partial lifetime of the decay O16→C14K+K+ at 90% C.L. A corresponding upper limit of 7.8×10-9 has been placed on the parameter λ112''.

Short-lived particle search procedure in the OPERA experiment. Application to charm decays

NASA Astrophysics Data System (ADS)

del Amo Sánchez, Pablo; OPERA Collaboration

2016-04-01

The OPERA experiment has recently provided evidence of νμ →ντ neutrino oscillations in appearance mode through the detection of tau leptons produced in ντ Charged Current interactions. The OPERA detector collected data from 2008 to 2012, when it was exposed to the CNGS muon neutrino beam from CERN to Gran Sasso, 730 km away from the source. We report on the search procedure for short-lived particles and on its validation with charmed hadron decays. The latter, produced in about 4% of the neutrino interactions in OPERA, are an important background to the νμ →ντ channel and an ideal control sample as their decay exhibits topological and kinematical features strongly resembling the tau's decay.

Predictions on the modes of decay of even Z superheavy isotopes within the range 104 ≤ Z ≤ 136

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Nithya, C.

2018-01-01

The decay modes and half lives of all the even Z isotopes of superheavy elements within the range 104 ≤ Z ≤ 136 have been predicted by comparing the alpha decay half-lives with the spontaneous fission half-lives. The Coulomb and proximity potential model for deformed nuclei (CPPMDN) and the shell-effect-dependent formula of Santhosh et al. are used to calculate the alpha half-lives and spontaneous fission half-lives respectively. For theoretical comparison the alpha decay half-lives are also calculated using Coulomb and proximity potential model (CPPM), the Viola-Seaborg-Sobiczewski semi-empirical (VSS) relation, the universal (UNIV) curve of Poenaru et al., the analytical formula of Royer and the universal decay law (UDL) of Qi et al. Another tool used for the evaluation of spontaneous fission half-lives is the semi-empirical formula of Xu et al. The nuclei with alpha decay half-lives less than spontaneous fission half-lives will survive fission and hence decay through alpha emission. The predicted half lives and decay modes are compared with the available experimental results. The one-proton and two-proton separation energies of all the isotopes are calculated to find nuclei which lie beyond the proton drip line. Among 1119 even Z nuclei within the range 104 ≤ Z ≤ 136, 164 nuclei show sequential alpha emission followed by subsequent spontaneous fission. Since the isotopes decay through alpha decay chain and the half-lives are in measurable range, these isotopes are predicted to be synthesized and detected in laboratory via alpha decay. 2 nuclei will decay by alpha decay followed by proton emission, 54 nuclei show full alpha chains, 642 nuclei will decay through spontaneous fission, 166 nuclei exhibit proton decay and 91 isotopes are found to be stable against alpha decay. All the isotopes are tabulated according to their decay modes. The study is intended to enhance further experimental investigations in superheavy region.

Coatings for minimally processed fruits and vegetables

USDA-ARS?s Scientific Manuscript database

Fresh-cut fruit and vegetables are gaining increasing popularity and market share. Techniques to enhance stability of fresh cut produce are reviewed. Among these techniques, edibles coatings can provide protection against dehydration, microbial decay and decrease events related to physiological sene...

Use of sonic tomography to detect and quantify wood decay in living trees1

PubMed Central

Gilbert, Gregory S.; Ballesteros, Javier O.; Barrios-Rodriguez, Cesar A.; Bonadies, Ernesto F.; Cedeño-Sánchez, Marjorie L.; Fossatti-Caballero, Nohely J.; Trejos-Rodríguez, Mariam M.; Pérez-Suñiga, José Moises; Holub-Young, Katharine S.; Henn, Laura A. W.; Thompson, Jennifer B.; García-López, Cesar G.; Romo, Amanda C.; Johnston, Daniel C.; Barrick, Pablo P.; Jordan, Fulvia A.; Hershcovich, Shiran; Russo, Natalie; Sánchez, Juan David; Fábrega, Juan Pablo; Lumpkin, Raleigh; McWilliams, Hunter A.; Chester, Kathleen N.; Burgos, Alana C.; Wong, E. Beatriz; Diab, Jonathan H.; Renteria, Sonia A.; Harrower, Jennifer T.; Hooton, Douglas A.; Glenn, Travis C.; Faircloth, Brant C.; Hubbell, Stephen P.

2016-01-01

Premise of the study: Field methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes. Methods and Results: Living trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness. Conclusions: Sonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees. PMID:28101433

α decay and cluster radioactivity of nuclei of interest to the synthesis of Z =119 , 120 isotopes

NASA Astrophysics Data System (ADS)

Poenaru, D. N.; Gherghescu, R. A.

2018-04-01

Super-heavy nuclei of interest for the forthcoming synthesis of the isotopes with Z =119 , 120 are investigated. One of the very interesting latest experiments was performed at the velocity filter SHIP (GSI Darmstadt) trying to produce 299120 in a fusion reaction 248Cm(54Cr,3 n )299120 . We report calculations of α -decay half-lives using four models: AKRA (Akrawy), ASAF (analytical superasymmetric fission), UNIV (universal formula), and semFIS (semi-empirical formula based on fission theory). The released energy, Q , is calculated using the theoretical model of atomic masses, WS4. For Sr,9492 cluster radioactivity of 120,302300 we predict a branching ratio relative to α decay of -0.10 and 0.49, respectively, meaning that it is worth trying to detect such kinds of decay modes in competition with α decay.

Retrospective Imaging and Characterization of Nuclear Material.

PubMed

Hayes, Robert B; Sholom, Sergey

2017-08-01

Modern techniques for detection of covert nuclear material requires some combination of real time measurement and/or sampling of the material. More common is real time measurement of the ionizing emission caused by radioactive decay or through the materials measured in response to external interrogation radiation. One can expose the suspect material with various radiation types, including high energy photons such as x rays or with larger particles such as neutrons and muons, to obtain images or measure nuclear reactions induced in the material. Stand-off detection using imaging modalities similar to those in the medical field can be accomplished, or simple collimated detectors can be used to localize radioactive materials. In all such cases, the common feature is that some or all of the nuclear materials have to be present for the measurement, which makes sense; as one might ask, "How you can measure something that is not there?" The current work and results show how to do exactly that: characterize nuclear materials after they have been removed from an area leaving no chemical trace. This new approach is demonstrated to be fully capable of providing both previous source spatial distribution and emission energy grouping. The technique uses magnetic resonance for organic insulators and/or luminescence techniques on ubiquitous refractory materials similar in theory to the way the nuclear industry carries out worker personnel dosimetry. Spatial information is obtained by acquiring gridded samples for dosimetric measurements, while energy information comes through dose depth profile results that are functions of the incident radiation energies.

Long-time correlation for the chaotic orbit in the two-wave Hamiltonian

NASA Astrophysics Data System (ADS)

Hatori, Tadatsugu; Irie, Haruyuki

1987-03-01

The time correlation function of velocity is found to decay with the power law for the orbit governed by a Hamiltonian, H=v sup 2/2 - Mcosx - Pcos (k(x-t)). The renormalization group technique can predict the power of decay for the correlation function defined by the ensemble average. The power spectrum becomes the 1/f-type for a special case.

Assessment of decay in standing timber using stress wave timing nondestructive evaluation tools : a guide for use and interpretation

Treesearch

Xiping Wang; Ferenc Divos; Crystal Pilon; Brian K. Brashaw; Robert J. Ross; Roy F. Pellerin

2004-01-01

This guide was prepared to assist field foresters in the use of stress wave timing instruments to locate and define areas of decay in standing timber. The first three sections provide background information, the principles of stress wave nondestructive testing, and measurement techniques for stress wave nondestructive testing. The last section is a detailed description...

Detecting defects in conifers with ground penetrating radar: applications and challenges

Treesearch

J.R. Butnor; M.L. Pruyn; D.C. Shaw; M.E. Harmon; A.N. Mucciardi; M.G. Ryan

2009-01-01

Our objective was to test ground penetrating radar (GPR) to non-destructively estimate decay volumes in living coniferous trees. GPR is geophysical tool which uses an antenna to propagate short bursts of electromagnetic energy in solid materials and measure the two-way travel time and amplitude of reflected signals. We compared estimates hof bole decay from data...

Heavy particle decay studies using different versions of nuclear potentials

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Sukumaran, Indu

2017-10-01

The heavy particle decay from 212-240Pa , 219-245Np , 228-246Pu , 230-249Am , and 232-252Cm leading to doubly magic 208Pb and its neighboring nuclei have been studied using fourteen versions of nuclear potentials. The study has shown that the barrier penetrability as well as the decay half-lives are found to vary with the nuclear potential used. The investigated decay events of the emission of the clusters 22Ne , 24Ne , 26Mg , 28Mg , 32Si and 33Si are not experimentally detected yet but may be detectable in the future. As most of the half-lives predicted are found to lie within the experimental upper limit, T 1/2 < 1030 s, our predictions will be a guide to future experimental design. The GN plots studied are linear for different cluster emissions from different parents with varying slopes and intercepts. Also, it is to be noted that the linearity of the GN plots is unaltered using different nuclear potentials. The universal curve studied ( log10 T 1/2 vs. -ln P for various clusters emitted from various parents shows a linear behavior with the same slope and intercept irrespective of the nuclear potential used.

Optically Stimulated Luminescence (OSL) of dental enamel for retrospective assessment of radiation exposure

PubMed Central

Yukihara, E.G.; Mittani, J.; McKeever, S.W.S.; Simon, S.L.

2009-01-01

This paper briefly reviews the optically stimulated luminescence (OSL) properties of dental enamel and discusses the potential and challenges of OSL for filling the technology gap in biodosimetry required for medical triage following a radiological/nuclear accident or terrorist event. The OSL technique uses light to stimulate a radiation-induced luminescence signal from materials previously exposed to ionizing radiation. This luminescence originates from radiation-induced defects in insulating crystals and is proportional to the absorbed dose of ionizing radiation. In our research conducted to date, we focused on fundamental investigations of the OSL properties of dental enamel using extracted teeth and tabletop OSL readers. The objective was to obtain information to support the development of the necessary instrumentation for retrospective dosimetry using dental enamel in laboratory, or for in situ and non-invasive accident dosimetry using dental enamel in emergency triage. An OSL signal from human dental enamel was detected using blue, green, or IR stimulation. Blue/green stimulation associated with UV emission detection seems to be the most appropriate combination in the sense that there is no signal from un-irradiated samples and the shape of the OSL decay is clear. Improvements in the minimum detection level were achieved by incorporating an ellipsoidal mirror in the OSL system to maximize light collection. Other possibilities to improve the sensitivity and research steps necessary to establish the feasibility of the technique for retrospective assessment of radiation exposure are also discussed. PMID:19623269

The shock waves in decaying supersonic turbulence

NASA Astrophysics Data System (ADS)

Smith, M. D.; Mac Low, M.-M.; Zuev, J. M.

2000-04-01

We here analyse numerical simulations of supersonic, hypersonic and magnetohydrodynamic turbulence that is free to decay. Our goals are to understand the dynamics of the decay and the characteristic properties of the shock waves produced. This will be useful for interpretation of observations of both motions in molecular clouds and sources of non-thermal radiation. We find that decaying hypersonic turbulence possesses an exponential tail of fast shocks and an exponential decay in time, i.e. the number of shocks is proportional to t exp (-ktv) for shock velocity jump v and mean initial wavenumber k. In contrast to the velocity gradients, the velocity Probability Distribution Function remains Gaussian with a more complex decay law. The energy is dissipated not by fast shocks but by a large number of low Mach number shocks. The power loss peaks near a low-speed turn-over in an exponential distribution. An analytical extension of the mapping closure technique is able to predict the basic decay features. Our analytic description of the distribution of shock strengths should prove useful for direct modeling of observable emission. We note that an exponential distribution of shocks such as we find will, in general, generate very low excitation shock signatures.

Tunneling decay of false vortices with gravitation

NASA Astrophysics Data System (ADS)

Dupuis, Éric; Gobeil, Yan; Lee, Bum-Hoon; Lee, Wonwoo; MacKenzie, Richard; Paranjape, Manu B.; Yajnik, Urjit A.; Yeom, Dong-han

2017-11-01

We study the effect of vortices on the tunneling decay of a symmetry-breaking false vacuum in three spacetime dimensions with gravity. The scenario considered is one in which the initial state, rather than being the homogeneous false vacuum, contains false vortices. The question addressed is whether, and, if so, under which circumstances, the presence of vortices has a significant catalyzing effect on vacuum decay. After studying the existence and properties of vortices, we study their decay rate through quantum tunneling using a variety of techniques. In particular, for so-called thin-wall vortices we devise a one-parameter family of configurations allowing a quantum-mechanical calculation of tunneling. Also for thin-wall vortices, we employ the Israel junction conditions between the interior and exterior spacetimes. Matching these two spacetimes reveals a decay channel which results in an unstable, expanding vortex. We find that the tunneling exponent for vortices, which is the dominant factor in the decay rate, is half that for Coleman-de Luccia bubbles. This implies that vortices are short-lived, making them cosmologically significant even for low vortex densities. In the limit of the vanishing gravitational constant we smoothly recover our earlier results for the decay of the false vortex in a model without gravity.

Thermoelectric detection and imaging of propagating graphene plasmons.

PubMed

Lundeberg, Mark B; Gao, Yuanda; Woessner, Achim; Tan, Cheng; Alonso-González, Pablo; Watanabe, Kenji; Taniguchi, Takashi; Hone, James; Hillenbrand, Rainer; Koppens, Frank H L

2017-02-01

Controlling, detecting and generating propagating plasmons by all-electrical means is at the heart of on-chip nano-optical processing. Graphene carries long-lived plasmons that are extremely confined and controllable by electrostatic fields; however, electrical detection of propagating plasmons in graphene has not yet been realized. Here, we present an all-graphene mid-infrared plasmon detector operating at room temperature, where a single graphene sheet serves simultaneously as the plasmonic medium and detector. Rather than achieving detection via added optoelectronic materials, as is typically done in other plasmonic systems, our device converts the natural decay product of the plasmon-electronic heat-directly into a voltage through the thermoelectric effect. We employ two local gates to fully tune the thermoelectric and plasmonic behaviour of the graphene. High-resolution real-space photocurrent maps are used to investigate the plasmon propagation and interference, decay, thermal diffusion, and thermoelectric generation.

Mid-Infrared Lifetime Imaging for Viability Evaluation of Lettuce Seeds Based on Time-Dependent Thermal Decay Characterization

PubMed Central

Kim, Ghiseok; Kim, Geon Hee; Ahn, Chi-Kook; Yoo, Yoonkyu; Cho, Byoung-Kwan

2013-01-01

An infrared lifetime thermal imaging technique for the measurement of lettuce seed viability was evaluated. Thermal emission signals from mid-infrared images of healthy seeds and seeds aged for 24, 48, and 72 h were obtained and reconstructed using regression analysis. The emission signals were fitted with a two-term exponential model that had two amplitudes and two time variables as lifetime parameters. The lifetime thermal decay parameters were significantly different for seeds with different aging times. Single-seed viability was visualized using thermal lifetime images constructed from the calculated lifetime parameter values. The time-dependent thermal signal decay characteristics, along with the decay amplitude and delay time images, can be used to distinguish aged lettuce seeds from normal seeds. PMID:23529120

Long-term starvation and subsequent recovery of nitrifiers in aerated submerged fixed-bed biofilm reactors.

PubMed

Elawwad, Abdelsalam; Sandner, Hendrik; Kappelmeyer, Uwe; Koeser, Heinz

2013-01-01

The effectiveness of three operational strategies for maintaining nitrifiers in bench-scale, aerated, submerged fixed-bed biofilm reactors (SFBBRs) during long-term starvation at 20 degrees C were evaluated. The operational strategies were characterized by the resulting oxidation-reduction potential (ORP) in the SFBBRs. The activity rates of the nitrifiers were measured and the activity decay was expressed by half-life times. It was found that anoxic and alternating anoxic/aerobic conditions were the best ways to preserve ammonia-oxidizing bacteria (AOB) during long starvation periods and resulted in half-life times of up to 34 and 28 days, respectively. Extended anaerobic conditions caused the half-life for AOB to decrease to 21 days. In comparison, the activity decay of nitrite-oxidizing bacteria (NOB) tended to be slightly faster. The activity of AOB biofilms that were kept for 97 days under anoxic conditions could be completely recovered in less than one week, while over 4 weeks was needed for AOB kept under anaerobic conditions. NOB were more sensitive to starvation and required longer recovery periods than AOB. For complete recovery, NOB needed approximately 7 weeks, regardless of the starvation conditions applied. Using the fluorescence in situ hybridization (FISH) technique, Nitrospira was detected as the dominant NOB genus. Among the AOB, the terminal restriction fragment length polymorphism (TRFLP) technique showed that during starvation and recovery periods, the relative frequency of species shifted to Nitrosomonas europaea/eutropha, regardless of the starvation condition. The consequences of these findings for the operation of SFBBRs under low-load and starvation conditions are discussed.

Development of the new trigger for VANDLE neutron detector

NASA Astrophysics Data System (ADS)

Hasse, Adam; Taylor, Steven; Daugherty, Hadyn; Grzywacz, Robert

2014-09-01

Beta-delayed neutron emission (βn) is the dominant decay channel for the majority of very neutron-rich nuclei. In order to study these decays a new detector system called the Versatile Array of Neutron Detectors at Low Energy (VANDLE) was constructed. A critical part of this neutron time of flight detector is a trigger unit. This trigger is sensitive to electron from beta decay down to very low energies, insensitive to gamma rays and have a good timing performance, better than 1 ns. In order to satisfy these condition, we have developed a new system, which utilizes plastic scintillator but uses recently developed light readout technique, based on the so called Silicon Photomultiplier, manufactured by Sensl. New system has been developed and performance tested using digital data acquisition system at the University of Tennessee and will be utilized in future experiments involving VANDLE. Beta-delayed neutron emission (βn) is the dominant decay channel for the majority of very neutron-rich nuclei. In order to study these decays a new detector system called the Versatile Array of Neutron Detectors at Low Energy (VANDLE) was constructed. A critical part of this neutron time of flight detector is a trigger unit. This trigger is sensitive to electron from beta decay down to very low energies, insensitive to gamma rays and have a good timing performance, better than 1 ns. In order to satisfy these condition, we have developed a new system, which utilizes plastic scintillator but uses recently developed light readout technique, based on the so called Silicon Photomultiplier, manufactured by Sensl. New system has been developed and performance tested using digital data acquisition system at the University of Tennessee and will be utilized in future experiments involving VANDLE. Department of Physics and Astronomy, University of Tennessee, Knoxville, USA.

Search for a massive resonance decaying into a Higgs boson and a W or Z boson in hadronic final states in proton-proton collisions at √{s}=8 TeV

NASA Astrophysics Data System (ADS)

Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Knünz, V.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Ochesanu, S.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; De Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Van Parijs, I.; Barria, P.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Delannoy, H.; Dobur, D.; Fasanella, G.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Léonard, A.; Mohammadi, A.; Perniè, L.; Randle-conde, A.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Zenoni, F.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Fagot, A.; Garcia, G.; Gul, M.; Mccartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Nuttens, C.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Caebergs, T.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Dos Reis Martins, T.; Hensel, C.; Mora Herrera, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santaolalla, J.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Genchev, V.; Hadjiiska, R.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Shaheen, S. M.; Tao, J.; Wang, C.; Wang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Zhang, F.; Zhang, L.; Zou, W.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Bodlak, M.; Finger, M.; Finger, M.; Ali, A.; Aly, R.; Aly, S.; Elgammal, S.; Ellithi Kamel, A.; Lotfy, A.; Mahmoud, M. A.; Radi, A.; Salama, E.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Dahms, T.; Davignon, O.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Merlin, J. A.; Skovpen, K.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Beaupere, N.; Bernet, C.; Boudoul, G.; Bouvier, E.; Brochet, S.; Carrillo Montoya, C. A.; Chasserat, J.; Chierici, R.; Contardo, D.; Courbon, B.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Laktineh, I. B.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Bagaturia, I.; Autermann, C.; Beranek, S.; Edelhoff, M.; Feld, L.; Heister, A.; Kiesel, M. K.; Klein, K.; Lipinski, M.; Ostapchuk, A.; Preuten, M.; Raupach, F.; Sammet, J.; Schael, S.; Schulte, J. F.; Verlage, T.; Weber, H.; Wittmer, B.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Endres, M.; Erdmann, M.; Erdweg, S.; Esch, T.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Klingebiel, D.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Olschewski, M.; Padeken, K.; Papacz, P.; Pook, T.; Radziej, M.; Reithler, H.; Rieger, M.; Schmitz, S. A.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Haj Ahmad, W.; Hoehle, F.; Kargoll, B.; Kress, T.; Kuessel, Y.; Künsken, A.; Lingemann, J.; Nowack, A.; Nugent, I. M.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asin, I.; Bartosik, N.; Behnke, O.; Behrens, U.; Bell, A. J.; Borras, K.; Burgmeier, A.; Cakir, A.; Calligaris, L.; Campbell, A.; Choudhury, S.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Karacheban, O.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Korol, I.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Mankel, R.; Marfin, I.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Ribeiro Cipriano, P. M.; Roland, B.; Sahin, M. Ö.; Salfeld-Nebgen, J.; Saxena, P.; Schoerner-Sadenius, T.; Schröder, M.; Seitz, C.; Spannagel, S.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Gonzalez, D.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Junkes, A.; Kirschenmann, H.; Klanner, R.; Kogler, R.; Lapsien, T.; Lenz, T.; Marchesini, I.; Marconi, D.; Nowatschin, D.; Ott, J.; Peiffer, T.; Perieanu, A.; Pietsch, N.; Poehlsen, J.; Rathjens, D.; Sander, C.; Schettler, H.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Seidel, M.; Sola, V.; Stadie, H.; Steinbrück, G.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Akbiyik, M.; Barth, C.; Baus, C.; Berger, J.; Böser, C.; Butz, E.; Chwalek, T.; Colombo, F.; De Boer, W.; Descroix, A.; Dierlamm, A.; Feindt, M.; Frensch, F.; Giffels, M.; Gilbert, A.; Hartmann, F.; Husemann, U.; Katkov, I.; Kornmayer, A.; Lobelle Pardo, P.; Mozer, M. U.; Müller, T.; Müller, Th.; Plagge, M.; Quast, G.; Rabbertz, K.; Röcker, S.; Roscher, F.; Simonis, H. J.; Stober, F. M.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weiler, T.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Markou, A.; Psallidas, A.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Tziaferi, E.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Bencze, G.; Hajdu, C.; Hazi, A.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Molnar, J.; Palinkas, J.; Szillasi, Z.; Bartók, M.; Makovec, A.; Raics, P.; Trocsanyi, Z. L.; Mal, P.; Mandal, K.; Sahoo, N.; Swain, S. K.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Gupta, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Mehta, A.; Mittal, M.; Nishu, N.; Singh, J. B.; Walia, G.; Kumar, Ashok; Kumar, Arun; Bhardwaj, A.; Choudhary, B. C.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, R.; Sharma, V.; Banerjee, S.; Bhattacharya, S.; Chatterjee, K.; Dutta, S.; Gomber, B.; Jain, Sa.; Jain, Sh.; Khurana, R.; Majumdar, N.; Modak, A.; Mondal, K.; Mukherjee, S.; Mukhopadhyay, S.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Abdulsalam, A.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Banerjee, S.; Bhowmik, S.; Chatterjee, R. M.; Dewanjee, R. K.; Dugad, S.; Ganguly, S.; Ghosh, S.; Guchait, M.; Gurtu, A.; Kole, G.; Kumar, S.; Maity, M.; Majumder, G.; Mazumdar, K.; Mohanty, G. B.; Parida, B.; Sudhakar, K.; Sur, N.; Sutar, B.; Wickramage, N.; Sharma, S.; Bakhshiansohi, H.; Behnamian, H.; Etesami, S. M.; Fahim, A.; Goldouzian, R.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Chhibra, S. S.; Colaleo, A.; Creanza, D.; Cristella, L.; De Filippis, N.; De Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Sharma, A.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Battilana, C.; Benvenuti, A. C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Travaglini, R.; Cappello, G.; Chiorboli, M.; Costa, S.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Gallo, E.; Gonzi, S.; Gori, V.; Lenzi, P.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Tropiano, A.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Calvelli, V.; Ferro, F.; Lo Vetere, M.; Robutti, E.; Tosi, S.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Gerosa, R.; Ghezzi, A.; Govoni, P.; Lucchini, M. T.; Malvezzi, S.; Manzoni, R. A.; Marzocchi, B.; Menasce, D.; Moroni, L.; Paganoni, M.; Pedrini, D.; Ragazzi, S.; Redaelli, N.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; Di Guida, S.; Esposito, M.; Fabozzi, F.; Iorio, A. O. 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V.; Maksimovic, P.; Martin, C.; Nash, K.; Osherson, M.; Swartz, M.; Xiao, M.; Xin, Y.; Baringer, P.; Bean, A.; Benelli, G.; Bruner, C.; Gray, J.; Kenny, R. P.; Majumder, D.; Malek, M.; Murray, M.; Noonan, D.; Sanders, S.; Stringer, R.; Wang, Q.; Wood, J. S.; Chakaberia, I.; Ivanov, A.; Kaadze, K.; Khalil, S.; Makouski, M.; Maravin, Y.; Saini, L. K.; Skhirtladze, N.; Svintradze, I.; Lange, D.; Rebassoo, F.; Wright, D.; Anelli, C.; Baden, A.; Baron, O.; Belloni, A.; Calvert, B.; Eno, S. C.; Gomez, J. A.; Hadley, N. J.; Jabeen, S.; Kellogg, R. G.; Kolberg, T.; Lu, Y.; Mignerey, A. C.; Pedro, K.; Shin, Y. H.; Skuja, A.; Tonjes, M. B.; Tonwar, S. C.; Apyan, A.; Barbieri, R.; Baty, A.; Bierwagen, K.; Brandt, S.; Busza, W.; Cali, I. A.; Di Matteo, L.; Gomez Ceballos, G.; Goncharov, M.; Gulhan, D.; Klute, M.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Mcginn, C.; Niu, X.; Paus, C.; Ralph, D.; Roland, C.; Roland, G.; Stephans, G. S. F.; Sumorok, K.; Varma, M.; Velicanu, D.; Veverka, J.; Wang, J.; Wang, T. W.; Wyslouch, B.; Yang, M.; Zhukova, V.; Dahmes, B.; Finkel, A.; Gude, A.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Mans, J.; Nourbakhsh, S.; Rusack, R.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Keller, J.; Knowlton, D.; Kravchenko, I.; Lazo-Flores, J.; Meier, F.; Monroy, J.; Ratnikov, F.; Snow, G. R.; Alyari, M.; Dolen, J.; George, J.; Godshalk, A.; Iashvili, I.; Kaisen, J.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira De Lima, R.; Trocino, D.; Wang, R.-J.; Wood, D.; Zhang, J.; Hahn, K. A.; Kubik, A.; Mucia, N.; Odell, N.; Pollack, B.; Pozdnyakov, A.; Schmitt, M.; Stoynev, S.; Sung, K.; Trovato, M.; Velasco, M.; Won, S.; Brinkerhoff, A.; Dev, N.; Hildreth, M.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Lynch, S.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Pearson, T.; Planer, M.; Ruchti, R.; Smith, G.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Hart, A.; Hill, C.; Hughes, R.; Kotov, K.; Ling, T. Y.; Liu, B.; Luo, W.; Puigh, D.; Rodenburg, M.; Winer, B. L.; Wulsin, H. W.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Koay, S. A.; Lujan, P.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Piroué, P.; Quan, X.; Saka, H.; Stickland, D.; Tully, C.; Werner, J. S.; Zuranski, A.; Barnes, V. E.; Benedetti, D.; Bortoletto, D.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, K.; Kress, M.; Leonardo, N.; Miller, D. H.; Neumeister, N.; Primavera, F.; Radburn-Smith, B. C.; Shi, X.; Shipsey, I.; Silvers, D.; Sun, J.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Zablocki, J.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Redjimi, R.; Roberts, J.; Tu, Z.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Goldenzweig, P.; Han, J.; Harel, A.; Hindrichs, O.; Khukhunaishvili, A.; Petrillo, G.; Verzetti, M.; Vishnevskiy, D.; Demortier, L.; Arora, S.; Barker, A.; Chou, J. P.; Contreras-Campana, C.; Contreras-Campana, E.; Duggan, D.; Ferencek, D.; Gershtein, Y.; Gray, R.; Halkiadakis, E.; Hidas, D.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Lath, A.; Panwalkar, S.; Park, M.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Foerster, M.; Rose, K.; Spanier, S.; York, A.; Bouhali, O.; Castaneda Hernandez, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Flanagan, W.; Gilmore, J.; Kamon, T.; Krutelyov, V.; Montalvo, R.; Mueller, R.; Osipenkov, I.; Pakhotin, Y.; Patel, R.; Perloff, A.; Roe, J.; Rose, A.; Safonov, A.; Suarez, I.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kovitanggoon, K.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Undleeb, S.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Sheldon, P.; Snook, B.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Boutle, S.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Wolfe, E.; Wood, J.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Christian, A.; Dasu, S.; Dodd, L.; Duric, S.; Friis, E.; Grothe, M.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ross, I.; Ruggles, T.; Sarangi, T.; Savin, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.

2016-02-01

A search for a massive resonance decaying into a standard-model-like Higgs boson (H) and a W or Z boson is reported. The analysis is performed on a data sample corresponding to an integrated luminosity of 19.7 fb-1, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. Signal events, in which the decay products of Higgs, W, or Z bosons at high Lorentz boost are contained within single reconstructed jets, are identified using jet substructure techniques, including the tagging of b hadrons. This is the first search for heavy resonances decaying into HW or HZ resulting in an all-jet final state, as well as the first application of jet substructure techniques to identify H → WW* → 4q decays at high Lorentz boost. No significant signal is observed and limits are set at 95% confidence level on the production cross sections of W' and Z' in a model with mass-degenerate charged and neutral spin-1 resonances. Resonance masses are excluded for W' in the interval [1.0, 1.6] TeV, for Z' in the intervals [1.0, 1.1] and [1.3, 1.5] TeV, and for mass-degenerate W' and Z' in the interval [1.0, 1.7] TeV. [Figure not available: see fulltext.

Direct measurement of the 3d{}^{2}{D}_{3/2} to 3d{}^{2}{D}_{5/2} lifetime ratio in a single trapped {}^{40}{{\\rm{Ca}}}^{+}

NASA Astrophysics Data System (ADS)

Shao, H.; Huang, Y.; Guan, H.; Gao, K.

2018-02-01

We present for the first time a direct measurement of the lifetime ratio between the 3d{}2{D}3/2 and 3d{}2{D}5/2 metastable states in a single trapped 40Ca+. A high-efficiency quantum state detection technique is adopted to monitor the quantum jumps, and a high precision and synchronized measurement sequence is used for laser control to study the rule of spontaneous decay. Our method shows that the lifetime ratio is a constant and is irrelevant to the dwell time; it is only determined by the spontaneous decay probabilities of the two metastable states at one random decay time, independent of the lifetimes of the two metastable states. Systematic errors such as collisions with background gases, heating effects, impurity components, the shelving and pumping rates and the photon counts are analyzed, and the lifetime ratio between the 3d{}2{D}3/2 and 3d{}2{D}5/2 states is directly measured to be 1.0257(43) with an uncertainty of 0.42%. Our result is in good agreement with the most precise many-body atomic structure calculations. Our method can be used to obtain the lifetime of a state which is usually difficult to measure and can be used to determine the magnetic dipole transition matrix elements in heavy ions such as Ba+ and Ra+, and can also be universally applied to lifetime ratio measurements of other single atoms and ions with a similar structure.

Direct measurements of the lifetime of medium-heavy hypernuclei

NASA Astrophysics Data System (ADS)

Qiu, X.; Tang, L.; Chen, C.; Margaryan, A.; Wood, S. A.; Achenbach, P.; Ahmidouch, A.; Albayrak, I.; Androic, D.; Asaturyan, A.; Asaturyan, R.; Ates, O.; Badui, R.; Baturin, P.; Boeglin, W.; Bono, J.; Brash, E.; Carter, P.; Chen, X.; Chiba, A.; Christy, M. E.; Dalton, M. M.; Danagoulian, S.; De Leo, R.; Doi, D.; Elaasar, M.; Ent, R.; Fenker, H.; Fujii, Y.; Furic, M.; Gabrielyan, M.; Gan, L.; Garibaldi, F.; Gaskell, D.; Gasparian, A.; Gogami, T.; Hashimoto, O.; Horn, T.; Hu, B.; Hungerford, Ed V.; Jones, M.; Kanda, H.; Kaneta, M.; Kawama, D.; Khanal, H.; Kohl, M.; Liyanage, A.; Luo, W.; Maeda, K.; Markowitz, P.; Marikyan, G.; Maruta, T.; Matsumura, A.; Maxwell, V.; Mkrtchyan, A.; Mkrtchyan, H.; Nagao, S.; Nakamura, S. N.; Narayan, A.; Neville, C.; Niculescu, G.; Niculescu, M. I.; Nunez, A.; Nuruzzaman; Okayasu, Y.; Petkovic, T.; Pochodzalla, J.; Reinhold, J.; Rodriguez, V. M.; Samanta, C.; Sawatzky, B.; Seva, T.; Shichijo, A.; Tadevosyan, V.; Taniya, N.; Tsukada, K.; Veilleux, M.; Vulcan, W.; Wesselmann, F. R.; Yamamoto, T.; Ye, Z.; Yokota, K.; Yuan, L.; Zhamkochyan, S.; Zhu, L.; HKS (JLab E02-017) Collaboration

2018-05-01

The lifetime of a Λ particle embedded in a nucleus (hypernucleus) decreases from that of free Λ decay mainly due to the opening of the ΛN → NN weak decay channel. However, it is generally believed that the lifetime of a hypernucleus attains a constant value (saturation) for medium to heavy hypernuclear masses, yet this hypothesis has been difficult to verify. This paper presents a direct measurement of the lifetime of medium-heavy hypernuclei that were hyper-fragments produced by fission or break-up from heavy hypernuclei initially produced with a 2.34 GeV photon-beam incident on thin Fe, Cu, Ag, and Bi target foils. For each event, fragments were detected in coincident pairs by a low-pressure multi-wire proportional chamber system. The lifetime was extracted from decay time spectrum formed by the difference of the time zeros between the pairs. The measured lifetime from each target is actually a statistical average over a range of mass with mean about 1/2 of the target mass and appears to be a constant of about 200 ps. Although this result cannot exclude unexpected shorter or longer lifetimes for some specific hypernuclei or hypernuclear states, it shows that a systematic decrease in lifetime as hypernuclear mass increases is not a general feature for hypernuclei with mean mass up to A ≈ 130. On the other hand, the success of this experiment and its technique shows that the time delayed fissions observed and used by all the lifetime measurements done so far on heavy hypernuclei could likely have originated from hyper-fragments lighter than the assumed masses.

Measurement of scintillation and ionization yield with high-pressure gaseous mixtures of Xe and TMA for improved neutrinoless double beta decay and dark matter searches

DOE PAGES

Nakajima, Y.; Goldschmidt, A.; Matis, H. S.; ...

2016-03-18

The gaseous Xenon(Xe) time projection chamber (TPC) is an attractive detector technique for neutrinoless double beta decay and WIMP dark matter searches. While it is less dense compared to Liquid Xe detectors, it has intrinsic advantages in tracking capability and better energy resolution. The performance of gaseous Xe can be further improved by molecular additives such as trimethylamine(TMA), which is expected to (1) cool down the ionization electrons, (2) convert Xe excitation energy to TMA ionizations through Penning transfer, and (3) produce scintillation and electroluminescence light in a more easily detectable wavelength (300 nm). In order to test the feasibilitymore » of the performance improvements with TMA, in this paper we made the first direct measurement of Penning and fluorescence transfer efficiency with gaseous mixtures of Xe and TMA. While we observed a Penning transfer efficiency up to ~35%, we found strong suppression of primary scintillation light with TMA. We also found that the primary scintillation light with Xe and TMA mixture can be well characterized by ~3% fluorescence transfer from Xe to TMA, with further suppression due to TMA self-quenching. No evidence of the scintillation light produced by recombination of TMA ions was found. This strong suppression of scintillation light makes dark matter searches quite challenging, while the possibility of improved neutrinoless double beta decay searches remains open. Finally, this work has been carried out within the context of the NEXT collaboration.« less

Time-Domain Fluorescence Lifetime Imaging Techniques Suitable for Solid-State Imaging Sensor Arrays

PubMed Central

Li, David Day-Uei; Ameer-Beg, Simon; Arlt, Jochen; Tyndall, David; Walker, Richard; Matthews, Daniel R.; Visitkul, Viput; Richardson, Justin; Henderson, Robert K.

2012-01-01

We have successfully demonstrated video-rate CMOS single-photon avalanche diode (SPAD)-based cameras for fluorescence lifetime imaging microscopy (FLIM) by applying innovative FLIM algorithms. We also review and compare several time-domain techniques and solid-state FLIM systems, and adapt the proposed algorithms for massive CMOS SPAD-based arrays and hardware implementations. The theoretical error equations are derived and their performances are demonstrated on the data obtained from 0.13 μm CMOS SPAD arrays and the multiple-decay data obtained from scanning PMT systems. In vivo two photon fluorescence lifetime imaging data of FITC-albumin labeled vasculature of a P22 rat carcinosarcoma (BD9 rat window chamber) are used to test how different algorithms perform on bi-decay data. The proposed techniques are capable of producing lifetime images with enough contrast. PMID:22778606

Alloying of steel and graphite by hydrogen in nuclear reactor

NASA Astrophysics Data System (ADS)

Krasikov, E.

2017-02-01

In traditional power engineering hydrogen may be one of the first primary source of equipment damage. This problem has high actuality for both nuclear and thermonuclear power engineering. Study of radiation-hydrogen embrittlement of the steel raises the question concerning the unknown source of hydrogen in reactors. Later unexpectedly high hydrogen concentrations were detected in irradiated graphite. It is necessary to look for this source of hydrogen especially because hydrogen flakes were detected in reactor vessels of Belgian NPPs. As a possible initial hypothesis about the enigmatical source of hydrogen one can propose protons generation during beta-decay of free neutrons поскольку inasmuch as protons detected by researches at nuclear reactors as witness of beta-decay of free neutrons.

On the nature of χ c2(2P): two-gluon decay

NASA Astrophysics Data System (ADS)

Achasov, N. N.; Kang, Xian-Wei

2017-12-01

We expect that BR(χ c2(2P)→gluongluon)≳2% if the Particle Data Group as well as the BaBar and Belle collaborations have correctly identified the state. In reality, this branching ratio corresponds to the one for χ c2(2P) decaying into light hadrons. We also discuss the detection possibilities of these decays. N.N. Achasov was supported in part by RFBR, (16-02-00065), and by Presidium of the Russian Academy of Sciences, Project (0314-2015-0011), XWK’s work is supported by MOST, Taiwan, (104-2112-M-001-022)

Search for doubly charged Higgs bosons with lepton-flavor-violating decays involving tau leptons.

PubMed

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Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shalhout, S Z; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner-Kuhr, J; Wagner, W; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zheng, Y; Zucchelli, S

2008-09-19

We search for pair production of doubly charged Higgs particles (H+/- +/-) followed by decays into electron-tau (etau) and muon-tau (mutau) pairs using data (350 pb(-1) collected from [over]pp collisions at sqrt[s]=1.96 TeV by the CDF II experiment. We search separately for cases where three or four final-state leptons are detected, and combine results for exclusive decays to left-handed etau (mutau) pairs. We set an H+/- +/- lower mass limit of 114(112) GeV/c(2) at the 95% confidence level.

Search for long-lived, weakly interacting particles that decay to displaced hadronic jets in proton-proton collisions at s = 8 TeV with the ATLAS detector

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2015-07-17

A search for the decay of neutral, weakly interacting, long-lived particles using data collected by the ATLAS detector at the LHC is presented. This analysis uses the full data set recorded in 2012: 20.3 fb –1 of proton-proton collision data at √s = 8 TeV. The search employs techniques for reconstructing decay vertices of long-lived particles decaying to jets in the inner tracking detector and muon spectrometer. Signal events require at least two reconstructed vertices. No significant excess of events over the expected background is found, and limits as a function of proper lifetime are reported for the decay ofmore » the Higgs boson and other scalar bosons to long-lived particles and for Hidden Valley Z' and Stealth SUSY benchmark models. The first search results for displaced decays in Z' and Stealth SUSY models are presented. The upper bounds of the excluded proper lifetimes are the most stringent to date.« less

Method and apparatus for detecting dilute concentrations of radioactive xenon in samples of xenon extracted from the atmosphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warburton, William K.; Hennig, Wolfgang G.

A method and apparatus for measuring the concentrations of radioxenon isotopes in a gaseous sample wherein the sample cell is surrounded by N sub-detectors that are sensitive to both electrons and to photons from radioxenon decays. Signal processing electronics are provided that can detect events within the sub-detectors, measure their energies, determine whether they arise from electrons or photons, and detect coincidences between events within the same or different sub-detectors. The energies of detected two or three event coincidences are recorded as points in associated two or three-dimensional histograms. Counts within regions of interest in the histograms are then usedmore » to compute estimates of the radioxenon isotope concentrations. The method achieves lower backgrounds and lower minimum detectable concentrations by using smaller detector crystals, eliminating interference between double and triple coincidence decay branches, and segregating double coincidences within the same sub-detector from those occurring between different sub-detectors.« less

Human-Associated Bacteroides spp. and Human Polyomaviruses as Microbial Source Tracking Markers in Hawaii.

PubMed

Kirs, Marek; Caffaro-Filho, Roberto A; Wong, Mayee; Harwood, Valerie J; Moravcik, Philip; Fujioka, Roger S

2016-11-15

Identification of sources of fecal contaminants is needed to (i) determine the health risk associated with recreational water use and (ii) implement appropriate management practices to mitigate this risk and protect the environment. This study evaluated human-associated Bacteroides spp. (HF183TaqMan) and human polyomavirus (HPyV) markers for host sensitivity and specificity using human and animal fecal samples collected in Hawaii. The decay rates of those markers and indicator bacteria were identified in marine and freshwater microcosms exposed and not exposed to sunlight, followed by field testing of the usability of the molecular markers. Both markers were strongly associated with sewage, although the cross-reactivity of the HF183TaqMan (also present in 82% of canine [n = 11], 30% of mongoose [n = 10], and 10% of feline [n = 10] samples) needs to be considered. Concentrations of HF183TaqMan in human fecal samples exceeded those in cross-reactive animals at least 1,000-fold. In the absence of sunlight, the decay rates of both markers were comparable to the die-off rates of enterococci in experimental freshwater and marine water microcosms. However, in sunlight, the decay rates of both markers were significantly lower than the decay rate of enterococci. While both markers have their individual limitations in terms of sensitivity and specificity, these limitations can be mitigated by using both markers simultaneously; ergo, this study supports the concurrent use of HF183TaqMan and HPyV markers for the detection of sewage contamination in coastal and inland waters in Hawaii. This study represents an in-depth characterization of microbial source tracking (MST) markers in Hawaii. The distribution and concentrations of HF183TaqMan and HPyV markers in human and animal fecal samples and in wastewater, coupled with decay data obtained from sunlight-exposed and unexposed microcosms, support the concurrent application of HF183TaqMan and HPyV markers for sewage contamination detection in Hawaii waters. Both markers are more conservative and more specific markers of sewage than fecal indicator bacteria (enterococci and Escherichia coli). Analysis of HF183TaqMan (or newer derivatives) is recommended for inclusion in future epidemiological studies concerned with beach water quality, while better concentration techniques are needed for HPyV. Such epidemiological studies can be used to develop new recreational water quality criteria, which will provide direct information on the absence or presence of sewage contamination in water samples as well as reliable measurements of the risk of waterborne disease transmission to swimmers. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

High Energy Phenomenology - Proceedings of the Workshop

NASA Astrophysics Data System (ADS)

Pérez, Miguel A.; Huerta, Rodrigo

1992-06-01

The Table of Contents for the full book PDF is as follows: * Preface * Radiative Corrections in the Electroweak Standard Model * Introduction * The Electroweak Standard Model and its Renormalization * Basic Properties of the Standard Model * Renormalization of the Standard Model * Calculation of Radiative Corrections * One-Loop Integrals * Corrected Matrix Elements and Cross Sections * Photonic Corrections * Physical Applications and Results * Parameter Relations in Higher Orders * Decay Widths * Z Physics * W-Pair Production * Higgs Production in e+e- Annihilation * Conclusion * Appendix: Feynman Rules * References * Hadron Collider Physics * Introduction * e+ e- Annihilation * The Standard Model * The Drell-Yan Process in Hadronic Collisions * The Structure Functions * Hadronic Z Production * Hadronic W Production * The Transverse Mass * Quark Decays of W's * Weak Interactions * Neutrino Scattering * Weak Neutral Currents * The Standard Model * Symmetries and Lagrangians * Spontaneous Symmetry Breaking * The Standard Model Again * Experimental Situation * Appendix * References * Lectures on Heavy Quark Effective Theory * Introduction * Motivation * Physical Intuition * The Heavy Quark Effective Theory * The Effective Lagrangian and its Feynman Rules * What is an Effective Theory? * The Effective Theory Beyond Tree Level * External Currents * Leading-Logs or No Leading-Logs; A digression * Sample Calculations * Symmetries * Flavor-SU(N) * Spin-SU(2) * Spectrum * Strong Transitions * Covariant Representation of States * Meson Decay Constants * Preliminaries * Formal Derivation: Green Functions * Quick and Dirty Derivation: States in the HQET * Vector Meson Decay Constant * Corrections * Form Factors in overline {B} rightarrow Deν and overline {B} rightarrow D ^ast {e}ν * Preliminaries * Form Factors in the HQET * Form Factors in order αs * 1/MQ * The Correcting Lagrangian * The Corrected Currents * Corrections of order mc/mb * Corrections of order overline {Λ} /m_c and overline {Λ} /m_c * Conclusions and More * Inclusive Semileptonic Decay Rates * overline {B} rightarrow Π {e} overline {ν} and overline {B} rightarrow Π {e} overline {ν} * Rare overline {B} decays * e^+ e^- rightarrow {B} overline {B} * λb → λcDs vs λb → λc D*s * Factorization * A Last Word (or Two) * References * An Overview of Nonleptonic Decays of B, D, K Mesons and CP-Noninvariance * Generic Ways to Study Nonleptonic Decays and CP-Noninvariance * The Quark-Diagram Scheme * Invariants of the CKM and the Universal Decay-Amplitude CP-Noninvariance Factor Xcp * Implications of Measuring Partial-Decay-Rate Asymmetries in B± Decays and in Neutral B Decays such as B0, overline {B}^{0} rightarrow K_sJ/{Ψ} * Nonleptonic Decays of D Mesons: From the CKM Non- and Singly-Suppressed Decays to the Predictions of Doubly-Suppressed Decays * Charm Meson D Decays into Vector and Pseudoscalar Bosons, D → VP * Charm Meson Decays into Pseudoscalar-Pseudoscalar Mesons, D → PP * Charm Meson Decays into Vector-Vector Mesons, D → VV * Nonleptonic Decays of B Mesons * The CKM Non-Suppressed Decays * Interesting Features in the Rare B Meson Decays * CP-Noninvariance in K Meson Decays * Implications of Measurement of Re( ɛ'/ɛ) * Other Important Searches for Decay-Amplitude CP Noninvariance in Strange Particles * Some Generic Properties of Decay-Amplitude CP-Noninvariance * References * Top Quark Physics * Introduction * The Top Quark Exists * Upper Limit on Mt * Other Constraints on Mt * Production of Top * Hadron Colliders * SM Top Decays * Detecting SM Tops-Signatures * Model-Independent Lower Limit on Mt * Determining the Charge of a New Heavy Quark * When the Top Quark is Detected * Top Decays - A Window to New Physics? * - Decay to Supersymmetric Partners * - Decay to Charged Higgs Bosons * - Flavor-Changing Neutral Current Decays * - Other possibilities * New Information Once Top is Observed * Studying the Top Decays Couplings * The Top Quark at N LC * Measuring Mt - How Well? * Sharper Predictions for Many Observables * Measuring Vts, Vtd, Vtb and Γ(t → bW) * Top Polarization Predictions - A New Observable * Testing QCD Polarization Predictions * Correlation of Top Spin Direction with Final b, l+ Directions and Top Mass Measurements * Measuring P_{pm} ^ t * General Top Couplings * One Loop Corrections to Top Decay * Decay Helicity Amplitudes * New Sources of CP Violation at the Weak Scale? * The Effect of Top Loops on Higgs Masses * Is t → Wb a Background for Studying TeV WW Interactions? * Predictions for Mt * Final Remarks * References * High Precision Radiative Corrections in the Semileptonic Decays of Hyperons * On the Decay W± → P±γ * The Decay H0 → γγ and Physics Beyond the Standard Model * Neutrino Masses and Double Beta Decay * Neutrino Oscillations in a Medium: Analytic Calculation of Nonadiabatic Transitions * Gauge-Invariant Perturbation Theory Near a Gauge Resonance * Lower Dimensional Divergences in Gauge Theories * Strange Stars: Which is the Ground State of QCD at Finite Baryon Number? * Experimental Signatures of the SU(5)c Color Model * Generalized Supersymmetric Quantum Mechanics * Chern-Simons Theories in 2 + 1 Dimensions * List of participants

Precision Gamma-Ray Branching Ratios for Long-Lived Radioactive Nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tonchev, Anton

Many properties of the high-energy-density environments in nuclear weapons tests, advanced laser-fusion experiments, the interior of stars, and other astrophysical bodies must be inferred from the resulting long-lived radioactive nuclei that are produced. These radioactive nuclei are most easily and sensitively identified by studying the characteristic gamma rays emitted during decay. Measuring a number of decays via detection of the characteristic gamma-rays emitted during the gamma-decay (the gamma-ray branching ratio) of the long-lived fission products is one of the most straightforward and reliable ways to determine the number of fissions that occurred in a nuclear weapon test. The fission productsmore » 147Nd, 144Ce, 156Eu, and certain other long-lived isotopes play a crucial role in science-based stockpile stewardship, however, the large uncertainties (about 8%) on the branching ratios measured for these isotopes are currently limiting the usefulness of the existing data [1,2]. We performed highly accurate gamma-ray branching-ratio measurements for a group of high-atomic-number rare earth isotopes to greatly improve the precision and reliability with which the fission yield and reaction products in high-energy-density environments can be determined. We have developed techniques that take advantage of new radioactive-beam facilities, such as DOE's CARIBU located at Argonne National Laboratory, to produce radioactive samples and perform decay spectroscopy measurements. The absolute gamma-ray branching ratios for 147Nd and 144Ce are reduced <2% precision. In addition, high-energy monoenergetic neutron beams from the FN Tandem accelerator in TUNL at Duke University was used to produce 167Tm using the 169Tm(n,3n) reaction. Fourtime improved branching ratio of 167Tm is used now to measure reaction-in-flight (RIF) neutrons from a burning DT capsule at NIF [10]. This represents the first measurement of RIF neutrons in any laboratory fusion system, and the magnitude of the signal has important implications for fundamental plasma science and for weapons physics.« less

Fermi and Swift as supernova alarms: Alert, localization, and diagnosis of future Galactic Type Ia explosions

NASA Astrophysics Data System (ADS)

Wang, Xilu; Fields, Brian D.; Lien, Amy Y.

2017-01-01

A Galactic SNIa event could go entirely unnoticed due to the large optical and near-IR extinction in the Milky Way plane, low radio and X-ray luminosities, and a weak neutrino signal. But the recent SN2014J confirms that Type Ia supernovae emit nuclear γ- ray lines, from the 56Ni → 56Co → 56Fe radioactive decay. The energy released in these decays powers the SNIa UVOIR light curve at times after ~1 week, leading to an exponential decline. Importantly for Swift and Fermi, these decays are accompanied by γ-ray line emission, with distinct series of lines for both the 56Ni and 56Co decays, spanning 158 keV to 2.6 MeV. These lines are squarely within the Fermi/GBM energy range, and the 56Ni 158 keV line is detectable by Swift/BAT. The Galaxy is optically thin to γ-rays, so the supernova line flux will suffer negligible extinction. Both GBM and BAT have continuous and nearly all-sky coverage. Thus GBM and BAT are ideal Galactic SNIa monitors and early warning systems. We will illustrate expected GBM and BAT light curves and spectra, based on our model for SNIa γ-ray emission and transfer. We show that the supernova signal emerges as distinct from the GBM background within days after the explosion in the SN2014J shell model. Therefore, if a Galactic SNIa were to explode, there are two possibilities of confirming and sounding the alert: 1) Swift/BAT discovers the SNIa first and localizes it within arcminutes; 2) Fermi/GBM finds the SNIa first and localizes it to within ~1 degree, using the Earth occultation technique, followed up by BAT to localize it within arcminutes. After the alert of either BAT or GBM, Swift localizes it to take spectra in optical, UV, soft and hard X-rays simultaneously with both XRT and UVOT instruments.

Radon Diffusion Measurement in Polyethylene based on Alpha Detection

NASA Astrophysics Data System (ADS)

Rau, Wolfgang

2011-04-01

We present a method to measure the diffusion of Radon in solid materials based on the alpha decay of the radon daughter products. In contrast to usual diffusion measurements which detect the radon that penetrates a thin barrier, we let the radon diffuse into the material and then measure the alpha decays of the radon daughter products in the material. We applied this method to regular and ultra high molecular weight poly ethylene and find diffusion lengths of order of mm as expected. However, the preliminary analysis shows significant differences between two different approaches we have chosen. These differences may be explained by the different experimental conditions.

Measurement of DT neutron-induced activity in glass-microshell laser fusion targets

NASA Astrophysics Data System (ADS)

Lane, S. M.; Campbell, E. M.; Bennett, C.

1980-10-01

Laser fusion targets consisting of DT gas contained in Teflon-coated glass microshells produce 14.1-MeV neutrons that can interact with the (Si-28) nuclei in the glass to produce radioactive (Al-28). Using a very efficient collection-detection scheme that could detect the decay of 10% of the (Al-28) created, these nuclei are identified by their 1.78-MeV gamma ray, which decayed with a 2.2-min half-life. From the number of (Al-28) nuclei created and the neutron yield the compressed glass areal density was found to be 0.0059 g/sq cm.

Erosion measurement techniques for plasma-driven railgun barrels

NASA Astrophysics Data System (ADS)

Jamison, K. A.; Niiler, Andrus

1987-04-01

Plasma-driven railguns are now in operation at several locations throughout the world. All share common problems in barrel erosion arising from the fact that the bore surface must contain a high temperature plasma armature which transmits the acceleration force to a projectile. The plasma temperature at the core of the armature is estimated to be 30 000 K or higher. Such conditions are erosive to most materials even when the exposure time is 100 μs or less. We have adapted two accelerator based techniques to aid in the study of this erosion. The first technique involves the collection and analysis of material ablated and left behind by the plasma. This analysis is based on the unfolding of the Rutherford backscattered (RBS) spectra of 1 MeV deuterons incident on residue collected from a railgun bore. The second technique is an erosion measurement involving thin layer activation (TLA) of surfaces. In this process, the copper rail surface is activated by 2.4 MeV protons creating a relatively thin (3 m) layer sparsely seeded with a long lived zinc isotope. Monitoring the decay of the activated sample before and after a firing can detect surface wear of about 0. 1 m. Results from the RBS and TLA experiments on the BRL plasma driven railgun are described.

Alpha decay studies on Po isotopes using different versions of nuclear potentials

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Sukumaran, Indu

2017-12-01

The alpha decays from 186-224Po isotopes have been studied using 25 different versions of nuclear potentials so as to select a suitable nuclear potential for alpha decay studies. The computed standard deviation of the calculated half-lives in comparison with the experimental data suggested that proximity 2003-I is the apt form of nuclear potential for alpha decay studies as it possesses the least standard deviation, σ =0.620 . Among the different proximity potentials, proximity 1966 ( σ =0.630 and proximity 1977 ( σ =0.636 , are also found to work well in alpha decay studies with low deviation. Among other versions of nuclear potentials (other than proximity potentials), Bass 1980 is suggested to be a significant form of nuclear potential because of its good predictive power. However, while the other forms of potentials are able to reproduce the experimental data to some extent, these potentials cannot be considered as apposite potentials for alpha decay studies in their present form. Since the experimental correlation of the models is noticed to be satisfying, the alpha decay half-lives of certain Po isotopes that are not detected experimentally yet have been predicted.

Proton-proton correlations observed in two-proton radioactivity of 94Ag.

PubMed

Mukha, Ivan; Roeckl, Ernst; Batist, Leonid; Blazhev, Andrey; Döring, Joachim; Grawe, Hubert; Grigorenko, Leonid; Huyse, Mark; Janas, Zenon; Kirchner, Reinhard; La Commara, Marco; Mazzocchi, Chiara; Tabor, Sam L; Van Duppen, Piet

2006-01-19

The stability and spontaneous decay of naturally occurring atomic nuclei have been much studied ever since Becquerel discovered natural radioactivity in 1896. In 1960, proton-rich nuclei with an odd or an even atomic number Z were predicted to decay through one- and two-proton radioactivity, respectively. The experimental observation of one-proton radioactivity was first reported in 1982, and two-proton radioactivity has now also been detected by experimentally studying the decay properties of 45Fe (refs 3, 4) and 54Zn (ref. 5). Here we report proton-proton correlations observed during the radioactive decay of a spinning long-lived state of the lightest known isotope of silver, 94Ag, which is known to undergo one-proton decay. We infer from these correlations that the long-lived state must also decay through simultaneous two-proton emission, making 94Ag the first nucleus to exhibit one- as well as two-proton radioactivity. We attribute the two-proton emission behaviour and the unexpectedly large probability for this decay mechanism to a very large deformation of the parent nucleus into a prolate (cigar-like) shape, which facilitates emission of protons either from the same or from opposite ends of the 'cigar'.

Modeling and Model Identification of Autonomous Underwater Vehicles

DTIC Science & Technology

2015-06-01

setup, based on a quadrifilar pendulum , is developed to measure the moments of inertia of the vehicle. System identification techniques, based on...parametric models of the platforms: an individual channel excitation approach and a free decay pendulum test. The former is applied to THAUS, which can...excite the system in individual channels in four degrees of freedom. These results are verified in the free decay pendulum setup, which has the

Decay of the 3D viscous liquid-gas two-phase flow model with damping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yinghui, E-mail: zhangyinghui0910@126.com

We establish the optimal L{sup p} − L{sup 2}(1 ≤ p < 6/5) time decay rates of the solution to the Cauchy problem for the 3D viscous liquid-gas two-phase flow model with damping and analyse the influences of the damping on the qualitative behaviors of solution. It is observed that the fraction effect of the damping affects the dispersion of fluids and enhances the time decay rate of solution. Our method of proof consists of Hodge decomposition technique, L{sup p} − L{sup 2} estimates for the linearized equations, and delicate energy estimates.

Barium Tagging from nEXO Using Resonance Ionization Spectroscopy

NASA Astrophysics Data System (ADS)

Twelker, K.; Kravitz, S.

nEXO is a 5-ton liquid enriched-xenon time projection chamber (TPC) to search for neutrinoless double-beta decay, designed to have the sensitivity to completely probe the inverted mass hierarchy of Majorana neutrinos. The detector will accommodate-as a background reduction technique-a system to recover and identify the barium decay product. This upgrade will allow a background-free measurement of neutrinoless double-beta decay and increase the half-life sensitivity of the experiment by at least one order of magnitude. Ongoing research and development includes a system to test barium extraction from liquid xenon using surface adsorption and Resonance Ionization Spectroscopy (RIS).

Optical spectroscopy and tooth decay

NASA Astrophysics Data System (ADS)

Misra, P.; De, T.; Singh, R.

2005-11-01

Optical spectroscopy in the ultraviolet, visible and mid-infrared spectral regions has been used to discriminate between healthy and diseased teeth of patients in the age range 15-75 years. Spectral scans of absorbance versus wavenumber and fluorescence intensity versus wavelength have been recorded and investigated for caries and periodontal disease. Such optical diagnostics can prove very useful in the early detection and treatment of tooth decay.

Data acquisition system for phase-2 KGF proton decay experiment

NASA Technical Reports Server (NTRS)

Krishnaswamy, M. R.; Menon, M. G. K.; Mondal, N. K.; Narasimham, V. S.; Sreekantan, B. V.; Hayashi, Y.; Ito, N.; Kawakami, S.; Miyake, S.

1985-01-01

Phase-2 of KGF proton decay experiment using 4000 proportional counters will start operating from middle of 1985. The detection systems, in addition to measuring the time information to an accuracy of 200 n see, also records ionization in the hit counters. It also monitors different characteristics of the counters like pulse height spectrum, pulse width spectrum and counting rate. The acquisition system is discussed.

A new scanning system for alpha decay events as calibration sources for range-energy relation in nuclear emulsion

NASA Astrophysics Data System (ADS)

Yoshida, J.; Kinbara, S.; Mishina, A.; Nakazawa, K.; Soe, M. K.; Theint, A. M. M.; Tint, K. T.

2017-03-01

A new scanning system named "Vertex picker" has been developed to rapid collect alpha decay events, which are calibration sources for the range-energy relation in nuclear emulsion. A computer-controlled optical microscope scans emulsion layers exhaustively, and a high-speed and high-resolution camera takes their micrographs. A dedicated image processing picks out vertex-like shapes. Practical operations of alpha decay search were demonstrated by emulsion sheets of the KEK-PS E373 experiment. Alpha decays of nearly 28 events were detected in eye-check work on a PC monitor per hour. This yield is nearly 20 times more effective than that by the conventional eye-scan method. The speed and quality is acceptable for the coming new experiment, J-PARC E07.

Spectroscopic analysis of XIV century wall paintings from Patriarchate of Peć Monastery, Serbia

NASA Astrophysics Data System (ADS)

Marić-Stojanović, M.; Bajuk-Bogdanović, D.; Uskoković-Marković, S.; Holclajtner-Antunović, I.

2018-02-01

The Church of the Holy Mother of God Hodegetria in Peć is decorated with wall paintings that date from the beginning of the 14th century. In terms of style they correspond to Byzantine wall paintings from the epoch of Paleologos. The painting technique and pigment pallete has been examined on micro fragments in thin cross-sections by means of optical microscopy (OM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and micro- Raman spectroscopy. Use of the fresco technique and two supporting plaster layers was noted on the majority of samples, while in large blue painted areas, a combination of fresco and secco techniques was used. The SEM-EDS results showed the presence of Ca as the main component of plaster besides the traces of Si and Mg. In some samples egg white as a binder was identified. The paint film is often multilayered. Twelve pigments were identified, mainly natural earth pigments such as red ochre, yellow ochre and green earth. A mixture of pigments was used for attaining desirable optical and aesthetical impressions. As decay product only weddelite was detected in many preparatory and painted samples.

Micro-fractures produced in the Cadalso de los Vidrios granite (Madrid) subjected to Freeze-Thaw Durability Testing

NASA Astrophysics Data System (ADS)

Freire-Lista, D. M.; Varas-Muriel, M. J.; Fort, R.

2012-04-01

A specific leucogranite (fine to medium grain sized) from Cadalso de los Vidrios, Madrid, Spain, from where it takes the name of the stone variety, which is a traditional heritage building material used in Central Spain, was subjected to freezing-thaw durability tests or accelerated artificial ageing tests (according to Spanish standard EN 12371:2001) to assess its durability by means of ultrasonic velocity measurements (a non-destructive technique), and optical and fluorescence petrography using a polarized optical microscope (destructive technique), both techniques used before, during and after laboratory ageing tests, or in other words, what is determined is the improvement or deterioration in some properties. The measurement of the ultrasonic velocity in the leucogranite cubic test specimens along the freezing-thaw cycles shown that the velocity diminishes with the number of cycles, in relation to the decay that the stones were experiencing. This deterioration can be observed by the loss of crystalline minerals in the surface of the analyzed samples and by the micro-fractures appearance up to one centimeter deep, which have been detected by the petrographic techniques previously mentioned. The images taken by means of the fluorescence microscope clearly show the micro-fractures generated during the durability test. These images have been processed and analyzed by the UTHSCSA Image Tool program with the purpose of being able to quantify the degree of decay that this type of crystalline materials undergone, when subjected to a number of freezing-thaw test cycles. It is therefore an effective, reliable and complementary technique to that of the petrography analysis, both optical and fluorescence ones. In the first cycles of the ageing test, the micro-fractures propagate along crystals edges and during the last cycles of the test, intracrystalline micro-fractures are generated, which are developed in different ways depending on the mineralogy of the crystals. Thus, the quartz crystals are those that undergo more intracrystalline micro-fractures, whereas the biotites, behave in a more ductile form and they are not micro-fractured. Both analytical techniques give information of this granite deterioration, showing a relation between the number of freezing-thaw cycles, the superficial micro-fractures proliferation and the decrease of ultrasonic waves propagation velocity produced by the ageing cycles.

Search for new resonances decaying into boosted W, Z and H bosons at CMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krohn, Michael; Vernieri, Caterina

2017-10-05

An overview of the searches for new heavy resonances decaying to standard model (SM) bosons at the TeV mass scale is presented. Results are based on data corresponding to an integrated luminosity up to aboutmore » $$36\\; \\mathrm{fb}^{-1}$$ recorded in proton-proton collisions at $$\\sqrt{s}=13$$ TeV with the CMS detector at the Large Hadron Collider at CERN. The bosons coming from the resonance decay can be W, Z, or the SM Higgs. For very heavy resonances, bosons are produced with momentum considerably higher than their mass, modifying in a very appreciable way the event topology. The quarks originated from the hadronic decay of the SM bosons will be collimated into a smaller area such that they are clustered within a single large cone jet. Dedicated reconstruction techniques are used to distinguish the merged decay products of W, Z and H bosons produced with high transverse momentum, from jets that originate from single partons.« less

Application of CRAFT (complete reduction to amplitude frequency table) in nonuniformly sampled (NUS) 2D NMR data processing.

PubMed

Krishnamurthy, Krish; Hari, Natarajan

2017-09-15

The recently published CRAFT (complete reduction to amplitude frequency table) technique converts the raw FID data (i.e., time domain data) into a table of frequencies, amplitudes, decay rate constants, and phases. It offers an alternate approach to decimate time-domain data, with minimal preprocessing step. It has been shown that application of CRAFT technique to process the t 1 dimension of the 2D data significantly improved the detectable resolution by its ability to analyze without the use of ubiquitous apodization of extensively zero-filled data. It was noted earlier that CRAFT did not resolve sinusoids that were not already resolvable in time-domain (i.e., t 1 max dependent resolution). We present a combined NUS-IST-CRAFT approach wherein the NUS acquisition technique (sparse sampling technique) increases the intrinsic resolution in time-domain (by increasing t 1 max), IST fills the gap in the sparse sampling, and CRAFT processing extracts the information without loss due to any severe apodization. NUS and CRAFT are thus complementary techniques to improve intrinsic and usable resolution. We show that significant improvement can be achieved with this combination over conventional NUS-IST processing. With reasonable sensitivity, the models can be extended to significantly higher t 1 max to generate an indirect-DEPT spectrum that rivals the direct observe counterpart. Copyright © 2017 John Wiley & Sons, Ltd.

Fiber Loop Ringdown — a Time-Domain Sensing Technique for Multi-Function Fiber Optic Sensor Platforms: Current Status and Design Perspectives

PubMed Central

Wang, Chuji

2009-01-01

Fiber loop ringdown (FLRD) utilizes an inexpensive telecommunications light source, a photodiode, and a section of single-mode fiber to form a uniform fiber optic sensor platform for sensing various quantities, such as pressure, temperature, strain, refractive index, chemical species, biological cells, and small volume of fluids. In FLRD, optical losses of a light pulse in a fiber loop induced by changes in a quantity are measured by the light decay time constants. FLRD measures time to detect a quantity; thus, FLRD is referred to as a time-domain sensing technique. FLRD sensors have near real-time response, multi-pass enhanced high-sensitivity, and relatively low cost (i.e., without using an optical spectral analyzer). During the last eight years since the introduction of the original form of fiber ringdown spectroscopy, there has been increasing interest in the FLRD technique in fiber optic sensor developments, and new application potential is being explored. This paper first discusses the challenging issues in development of multi-function, fiber optic sensors or sensor networks using current fiber optic sensor sensing schemes, and then gives a review on current fiber optic sensor development using FLRD technique. Finally, design perspectives on new generation, multi-function, fiber optic sensor platforms using FLRD technique are particularly presented. PMID:22408471

Testing the Delayed Gamma Capability in MCNP6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weldon, Robert A.; Fensin, Michael L.; McKinney, Gregg W.

The mission of the Domestic Nuclear Detection Office is to quickly and reliably detect unauthorized attempts to import or transport special nuclear material for use against the United States. Developing detection equipment to meet this objective requires accurate simulation of both the detectable signature and detection mechanism. A delayed particle capability was initially added to MCNPX 2.6.A in 2005 to sample the radioactive fission product parents and emit decay particles resulting from the decay chain. To meet the objectives of detection scenario modeling, the capability was designed to sample a particular time for emitting particular multiplicity of a particular energy.more » Because the sampling process of selecting both time and energy is interdependent, to linearize the time and emission sampling, atom densities are computed at several discrete time steps, and the time-integrated production is computed by multiplying the atom density by the decay constant and time step size to produce a cumulative distribution function for sampling the emission time, energy, and multiplicity. The delayed particle capability was initially given a time-bin structure to help reasonably reproduce, from a qualitative sense, a fission benchmark by Beddingfield, which examined the delayed gamma emission. This original benchmark was only qualitative and did not contain the magnitudes of the actual measured data but did contain relative graphical representation of the spectra. A better benchmark with measured data was later provided by Hunt, Mozin, Reedy, Selpel, and Tobin at the Idaho Accelerator Center; however, because of the complexity of the benchmark setup, sizable systematic errors were expected in the modeling, and initial results compared to MCNPX 2.7.0 showed errors outside of statistical fluctuation. Presented in this paper is a more simplified approach to benchmarking, utilizing closed form analytic solutions to the granddaughter equations for particular sets of decay systems. We examine five different decay chains (two-stage decay to stable) and show the predictability of the MCNP6 delayed gamma feature. Results do show that while the default delayed gamma calculations available in the MCNP6 1.0 release can give accurate results for some isotopes (e.g., 137Ba), the percent differences between the closed form analytic solutions and the MCNP6 calculations were often >40% ( 28Mg, 28Al, 42K, 47Ca, 47Sc, 60Co). With the MCNP6 1.1 Beta release, the tenth entry on the DBCN card allows improved calculation within <5% as compared to the closed form analytic solutions for immediate parent emissions and transient equilibrium systems. While the tenth entry on the DBCN card for MCNP6 1.1 gives much better results for transient equilibrium systems and parent emissions in general, it does little to improve daughter emissions of secular equilibrium systems. Finally, hypotheses were presented as to why daughter emissions of secular equilibrium systems might be mispredicted in some cases and not in others.« less

Measurement of Neutral-Current K + Production by Neutrinos using MINERvA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, C. M.; Aliaga, L.; Altinok, O.

Neutral-current production of K + by atmospheric neutrinos is a background in searches for the proton decay p → K +ν¯. Reactions such as νp → νK +Λ are indistinguishable from proton decays when the decay products of the Λ are below detection threshold. Events with K + are identified in MINERvA by reconstructing the timing signature of a K + decay at rest. A sample of 201 neutrino-induced neutral-current K + events is used to measure differential cross sections with respect to the K + kinetic energy, and the non-K + hadronic visible energy. An excess of events atmore » low hadronic visible energy is observed relative to the prediction of the neut event generator. Good agreement is observed with the cross section prediction of the genie generator. In conclusion, a search for photons from π 0 decay, which would veto a neutral-current K + event in a proton decay search, is performed, and a 2σ deficit of detached photons is observed relative to the genie prediction.« less

Frequency and time properties of decimeter narrowband spikes in solar flares

NASA Astrophysics Data System (ADS)

Wang, Shujuan

2013-07-01

In this paper, we focus to study the frequency and time properties of a group of spikes recorded by the 1.08-2.04 GHz spectrometer of NAOC on 27 October 2003. At the first we calculate the mean and minimum bandwidth of the spikes. We apply two different methods based on the wavelet analysis according to Messmer & Benz (2000). The first method determines the dominant spike bandwidth scale based on their scalegram, and the second method is a feature detection algorithm in the time-frequency plane. Secondly the time profile of each single spike was fitted and analyzed. In particular, we determined the e-folding rise and decay times corresponding to the ascending and decaying parts of the time profile, respectively. Several important correlations were studied and compared with the results in earlier literature, i.e. those between duration and frequency, e-folding rise time and decay time, e-folding decay time and duration, and e-folding decay time and peak flux. Finally some parameters of source region were estimated and the possible decaying mechanism was discussed.

Measurement of Neutral-Current K + Production by Neutrinos using MINERvA

DOE PAGES

Marshall, C. M.; Aliaga, L.; Altinok, O.; ...

2017-07-07

Neutral-current production of K + by atmospheric neutrinos is a background in searches for the proton decay p → K +ν¯. Reactions such as νp → νK +Λ are indistinguishable from proton decays when the decay products of the Λ are below detection threshold. Events with K + are identified in MINERvA by reconstructing the timing signature of a K + decay at rest. A sample of 201 neutrino-induced neutral-current K + events is used to measure differential cross sections with respect to the K + kinetic energy, and the non-K + hadronic visible energy. An excess of events atmore » low hadronic visible energy is observed relative to the prediction of the neut event generator. Good agreement is observed with the cross section prediction of the genie generator. In conclusion, a search for photons from π 0 decay, which would veto a neutral-current K + event in a proton decay search, is performed, and a 2σ deficit of detached photons is observed relative to the genie prediction.« less

Picosecond absorption anisotropy of polymethine and squarylium dyes in liquid and polymeric media

NASA Astrophysics Data System (ADS)

Przhonska, Olga V.; Hagan, David J.; Novikov, Evgueni; Lepkowicz, Richard; Van Stryland, Eric W.; Bondar, Mikhail V.; Slominsky, Yuriy L.; Kachkovski, Alexei D.

2001-11-01

Time-resolved excitation-probe polarization measurements are performed for polymethine and squarylium dyes in ethanol and an elastopolymer of polyurethane acrylate (PUA). These molecules exhibit strong excited-state absorption in the visible, which results in reverse saturable absorption (RSA). In pump-probe experiments, we observe a strong angular dependence of the RSA decay kinetics upon variation of the angle between pump and probe polarizations. The difference in absorption anisotropy kinetics in ethanol and PUA is detected and analyzed. Anisotropy decay curves in ethanol follow a single exponential decay leading to complete depolarization of the excited state. We also observe complete depolarization in PUA, in which case the anisotropy decay follows a double exponential behavior. Possible rotations in the PUA polymeric matrix are connected with the existence of local microcavities of free volume. We believe that the fast decay component is connected with the rotation of molecular fragments and the slower decay component is connected with the rotation of entire molecules in local microcavities, which is possible because of the elasticity of the polymeric material.

Spherical cows in dark matter indirect detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernal, Nicolás; Necib, Lina; Slatyer, Tracy R., E-mail: nicolas.bernal@uan.edu.co, E-mail: lnecib@mit.edu, E-mail: tslatyer@mit.edu

2016-12-01

Dark matter (DM) halos have long been known to be triaxial, but in studies of possible annihilation and decay signals they are often treated as approximately spherical. In this work, we examine the asymmetry of potential indirect detection signals of DM annihilation and decay, exploiting the large statistics of the hydrodynamic simulation Illustris. We carefully investigate the effects of the baryons on the sphericity of annihilation and decay signals for both the case where the observer is at 8.5 kpc from the center of the halo (exemplified in the case of Milky Way-like halos), and for an observer situated wellmore » outside the halo. In the case of Galactic signals, we find that both annihilation and decay signals are expected to be quite symmetric, with axis ratios very different from 1 occurring rarely. In the case of extragalactic signals, while decay signals are still preferentially spherical, the axis ratio for annihilation signals has a much flatter distribution, with elongated profiles appearing frequently. Many of these elongated profiles are due to large subhalos and/or recent mergers. Comparing to gamma-ray emission from the Milky Way and X-ray maps of clusters, we find that the gamma-ray background appears less spherical/more elongated than the expected DM signal from the large majority of halos, and the Galactic gamma ray excess appears very spherical, while the X-ray data would be difficult to distinguish from a DM signal by elongation/sphericity measurements alone.« less

Spherical cows in dark matter indirect detection

NASA Astrophysics Data System (ADS)

Bernal, Nicolás; Necib, Lina; Slatyer, Tracy R.

2016-12-01

Dark matter (DM) halos have long been known to be triaxial, but in studies of possible annihilation and decay signals they are often treated as approximately spherical. In this work, we examine the asymmetry of potential indirect detection signals of DM annihilation and decay, exploiting the large statistics of the hydrodynamic simulation Illustris. We carefully investigate the effects of the baryons on the sphericity of annihilation and decay signals for both the case where the observer is at 8.5 kpc from the center of the halo (exemplified in the case of Milky Way-like halos), and for an observer situated well outside the halo. In the case of Galactic signals, we find that both annihilation and decay signals are expected to be quite symmetric, with axis ratios very different from 1 occurring rarely. In the case of extragalactic signals, while decay signals are still preferentially spherical, the axis ratio for annihilation signals has a much flatter distribution, with elongated profiles appearing frequently. Many of these elongated profiles are due to large subhalos and/or recent mergers. Comparing to gamma-ray emission from the Milky Way and X-ray maps of clusters, we find that the gamma-ray background appears less spherical/more elongated than the expected DM signal from the large majority of halos, and the Galactic gamma ray excess appears very spherical, while the X-ray data would be difficult to distinguish from a DM signal by elongation/sphericity measurements alone.

Novel dark matter phenomenology at colliders

NASA Astrophysics Data System (ADS)

Wardlow, Kyle Patrick

While a suitable candidate particle for dark matter (DM) has yet to be discovered, it is possible one will be found by experiments currently investigating physics on the weak scale. If discovered on that energy scale, the dark matter will likely be producible in significant quantities at colliders like the LHC, allowing the properties of and underlying physical model characterizing the dark matter to be precisely determined. I assume that the dark matter will be produced as one of the decay products of a new massive resonance related to physics beyond the Standard Model, and using the energy distributions of the associated visible decay products, develop techniques for determining the symmetry protecting these potential dark matter candidates from decaying into lighter Standard Model (SM) particles and to simultaneously measure the masses of both the dark matter candidate and the particle from which it decays.

Nondestructive Testing Technique to Quantify Deterioration from Marine Borer Attack in Sitka Spruce and Western Hemlock Logs: Observations from a Pilot Test

Treesearch

Robert Ross; John W. Forsman; John R. Erickson; Allen M. Brackley

2014-01-01

Stress-wave nondestructive evaluation (NDE) techniques are used widely in the forest products industry—from the grading of wood veneer to inspection of timber structures. Inspection professionals frequently use stress-wave NDE techniques to locate internal voids and decayed or deteriorated areas in large timbers. Although these techniques have proven useful, little...

Toward radioguided surgery with β- decays: uptake of a somatostatin analogue, DOTATOC, in meningioma and high-grade glioma.

PubMed

Collamati, Francesco; Pepe, Alessandra; Bellini, Fabio; Bocci, Valerio; Chiodi, Giacomo; Cremonesi, Marta; De Lucia, Erika; Ferrari, Mahila E; Frallicciardi, Paola M; Grana, Chiara M; Marafini, Michela; Mattei, Ilaria; Morganti, Silvio; Patera, Vincenzo; Piersanti, Luca; Recchia, Luigi; Russomando, Andrea; Sarti, Alessio; Sciubba, Adalberto; Senzacqua, Martina; Solfaroli Camillocci, Elena; Voena, Cecilia; Pinci, Davide; Faccini, Riccardo

2015-01-01

A novel radioguided surgery (RGS) technique for cerebral tumors using β(-) radiation is being developed. Checking for a radiotracer that can deliver a β(-) emitter to the tumor is a fundamental step in the deployment of such a technique. This paper reports a study of the uptake of (90)Y-DOTATOC in meningiomas and high-grade gliomas (HGGs) and a feasibility study of the RGS technique in these types of tumor. Estimates were performed assuming the use of a β(-) probe under development with a sensitive area 2.55 mm in radius to detect 0.1-mL residuals. Uptake and background from healthy tissues were estimated on (68)Ga-DOTATOC PET scans of 11 meningioma patients and 12 HGG patients. A dedicated statistical analysis of the DICOM images was developed and validated. The feasibility study was performed using full simulation of emission and detection of the radiation, accounting for the measured uptake and background rate. All meningioma patients but one with an atypical extracranial tumor showed high uptake of DOTATOC. In terms of feasibility of the RGS technique, we estimated that by administering a 3 MBq/kg activity of radiotracer, the time needed to detect a 0.1-mL remnant with 5% false-negative and 1% false-positive rates is less than 1 s. Actually, to achieve a detection time of 1 s the required activities to administer were as low as 0.2-0.5 MBq/kg in many patients. In HGGs, the uptake was lower than in meningiomas, but the tumor-to-nontumor ratio was higher than 4, which implies that the tracer can still be effective for RGS. It was estimated that by administering 3 mBq/kg of radiotracer, the time needed to detect a 0.1-mL remnant is less than 6 s, with the exception of the only oligodendroma in the sample. Uptake of (90)Y-DOTATOC in meningiomas was high in all studied patients. Uptake in HGGs was significantly worse than in meningiomas but was still acceptable for RGS, particularly if further research and development are done to improve the performance of the β(-) probe. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

β -decay Q values among the A = 50 Ti-V-Cr isobaric triplet and atomic masses of Ti 46 , 47 , 49 , 50 , V 50 , 51 , and Cr 50 , 52 – 54

DOE PAGES

Kandegedara, R. M. E. B.; Bollen, G.; Eibach, M.; ...

2017-10-20

This manuscript describes a measurement of the Q value for the highly forbidden beta-decays of 50V and the double electron capture decay of 50Cr. The Q value corresponds to the total energy released during the decay and is equivalent to the mass difference between parent and daughter atoms. This mass difference was measured using high precision Penning trap mass spectrometry with the Low Energy Beam and Ion Trap facility at the National Superconducting Cyclotron Laboratory. The Q value enters into theoretical calculations of the half-life and beta-decay spectrum for the decay, so improves these calculations. In addition the Q valuemore » corresponds to the end point energy of the beta-decay spectrum, which has been precisely measured for several highly-forbidden decays using modern low background detector techniques. Hence, our Q value measurements provide a test of systematics for these detectors. In addition, we have measured the absolute atomic masses of 46,47,49,50Ti, 50,51V, and 50,52-52Cr, providing improvements in precision by factors of up to 3. These atomic masses help to strengthen global evaluations of all atomic mass data, such as the Atomic Mass Evaluation.« less

β -decay Q values among the A = 50 Ti-V-Cr isobaric triplet and atomic masses of Ti 46 , 47 , 49 , 50 , V 50 , 51 , and Cr 50 , 52 – 54

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kandegedara, R. M. E. B.; Bollen, G.; Eibach, M.

This manuscript describes a measurement of the Q value for the highly forbidden beta-decays of 50V and the double electron capture decay of 50Cr. The Q value corresponds to the total energy released during the decay and is equivalent to the mass difference between parent and daughter atoms. This mass difference was measured using high precision Penning trap mass spectrometry with the Low Energy Beam and Ion Trap facility at the National Superconducting Cyclotron Laboratory. The Q value enters into theoretical calculations of the half-life and beta-decay spectrum for the decay, so improves these calculations. In addition the Q valuemore » corresponds to the end point energy of the beta-decay spectrum, which has been precisely measured for several highly-forbidden decays using modern low background detector techniques. Hence, our Q value measurements provide a test of systematics for these detectors. In addition, we have measured the absolute atomic masses of 46,47,49,50Ti, 50,51V, and 50,52-52Cr, providing improvements in precision by factors of up to 3. These atomic masses help to strengthen global evaluations of all atomic mass data, such as the Atomic Mass Evaluation.« less

Wind tunnel investigation on the retention of air pollutants in three-dimensional recirculation zones in urban areas

NASA Astrophysics Data System (ADS)

Gomes, Marcos Sebastião de Paula; Isnard, André Augusto; Pinto, José Maurício do Carmo

The article discusses an experimental investigation of turbulent dispersion processes in a typical three-dimensional urban geometry, in reduced scale, in neutrally stable conditions. Wind tunnel experiments were carried out for characterizing the flow and the dispersion of a pollutant around a scaled model (1:400) of a group of eight 10-floor buildings surrounding a square. The situation corresponded to the dispersion of fine inertialess particles released from a line source positioned upstream of the urban geometry. After the sudden interruption of the source generation, the particles persisted in the recirculation cavity between the buildings, with the concentration decaying exponentially with time. This is in accordance with previous works on the dispersion process around bluff bodies of different shapes [e.g., Humphries and Vincent, 1976. An experimental investigation of the detention of airborne smoke in the wake bubble behind a disk. Journal of Fluid Mechanics 73, 453-464; Vincent, 1977. Model experiments on the nature of air pollution transport near buildings. Atmospheric Environment 11, 765-774; Fackrell, 1984. Parameters characterizing dispersion in the near wake of buildings. Journal of Wind Engineering and Industrial Aerodynamics 16, 97-118]. The main parameter in the investigation was the characteristic time constant for the concentration decay. The measurements of the variation in the concentration of the fine particles were performed by means of a photo-detection technique based on the attenuation of light. The velocity fields were evaluated with the particle image velocimetry (PIV) technique. The dimensionless residence time H for the particles ( H= τU/ L, where τ is the time constant for the concentration decay, U the free-stream velocity, and L is a characteristic dimension for the urban geometry, as defined by Humphries and Vincent [1976. An experimental investigation of the detention of airborne smoke in the wake bubble behind a disk. Journal of Fluid Mechanics 73, 453-464] was determined for various locations in the scaled model, in the range of Reynolds numbers ( Re) between 8000 and 64,000. H was found to be 6.5±1.0.

Highly sensitive detection of human papillomavirus type 16 DNA using time-resolved fluorescence microscopy and long lifetime probes

NASA Astrophysics Data System (ADS)

Wang, Xue F.; Periasamy, Ammasi; Wodnicki, Pawel; Siadat-Pajouh, M.; Herman, Brian

1995-04-01

We have been interested in the role of Human Papillomavirus (HPV) in cervical cancer and its diagnosis; to that end we have been developing microscopic imaging and fluorescent in situ hybridization (FISH) techniques to genotype and quantitate the amount of HPV present at a single cell level in cervical PAP smears. However, we have found that low levels of HPV DNA are difficult to detect accurately because theoretically obtainable sensitivity is never achieved due to nonspecific autofluorescence, fixative induced fluorescence of cells and tissues, and autofluorescence of the optical components in the microscopic system. In addition, the absorption stains used for PAP smears are intensely autofluorescent. Autofluorescence is a rapidly decaying process with lifetimes in the range of 1-100 nsec, whereas phosphorescence and delayed fluorescence have lifetimes in the range of 1 microsecond(s) ec-10 msec. The ability to discriminate between specific fluorescence and autofluorescence in the time-domain has improved the sensitivity of diagnostic test such that they perform comparably to, or even more sensitive than radioisotopic assays. We have developed a novel time-resolved fluorescence microscope to improve the sensitivity of detection of specific molecules of interest in slide based specimens. This time-resolved fluorescence microscope is based on our recently developed fluorescence lifetime imaging microscopy (FILM) in conjunction with the use of long lifetime fluorescent labels. By using fluorescence in situ hybridization and the long lifetime probe (europium), we have demonstrated the utility of this technique for detection of HPV DNA in cervicovaginal cells. Our results indicate that the use of time-resolved fluorescence microscopy and long lifetime probes increases the sensitivity of detection by removing autofluorescence and will thus lead to improved early diagnosis of cervical cancer. Since the highly sensitive detection of DNA in clinical samples using fluorescence in situ hybridization image is useful for the diagnosis of many other type of diseases, the system we have developed should find numerous applications for the diagnosis of disease states.

Identification of boosted, hadronically decaying W bosons and comparisons with ATLAS data taken at √s = 8 TeV

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2016-03-17

This paper reports a detailed study of techniques for identifying boosted, hadronically decaying W bosons using 20.3 fb –1 of proton–proton collision data collected by the ATLAS detector at the LHC at a centre-of-mass energy √s = 8 TeV. A range of techniques for optimising the signal jet mass resolution are combined with various jet substructure variables. The results of these studies in Monte Carlo simulations show that a simple pairwise combination of groomed jet mass and one substructure variable can provide a 50 % efficiency for identifying W bosons with transverse momenta larger than 200 GeV while maintaining multijetmore » background efficiencies of 2–4 % for jets with the same transverse momentum. As a result, these signal and background efficiencies are confirmed in data for a selection of tagging techniques.« less

Identification of boosted, hadronically decaying W bosons and comparisons with ATLAS data taken at [Formula: see text] TeV.

PubMed

Aad, G; Abbott, B; Abdallah, J; Abdinov, O; Aben, R; Abolins, M; AbouZeid, O S; Abramowicz, H; Abreu, H; Abreu, R; Abulaiti, Y; Acharya, B S; Adamczyk, L; Adams, D L; Adelman, J; Adomeit, S; Adye, T; Affolder, A A; Agatonovic-Jovin, T; Agricola, J; Aguilar-Saavedra, J A; Ahlen, S P; Ahmadov, F; Aielli, G; Akerstedt, H; Åkesson, T P A; Akimov, A V; Alberghi, G L; Albert, J; Albrand, S; Alconada Verzini, M J; Aleksa, M; Aleksandrov, I N; Alexa, C; Alexander, G; Alexopoulos, T; Alhroob, M; Alimonti, G; Alio, L; Alison, J; Alkire, S P; Allbrooke, B M M; Allport, P P; Aloisio, A; Alonso, A; Alonso, F; Alpigiani, C; Altheimer, A; Alvarez Gonzalez, B; Álvarez Piqueras, D; Alviggi, M G; Amadio, B T; Amako, K; Amaral Coutinho, Y; Amelung, C; Amidei, D; Amor Dos Santos, S P; Amorim, A; Amoroso, S; Amram, N; Amundsen, G; Anastopoulos, C; Ancu, L S; Andari, N; Andeen, T; Anders, C F; Anders, G; Anders, J K; Anderson, K J; Andreazza, A; Andrei, V; Angelidakis, S; Angelozzi, I; Anger, P; Angerami, A; Anghinolfi, F; Anisenkov, A V; Anjos, N; Annovi, A; Antonelli, M; Antonov, A; Antos, J; Anulli, F; Aoki, M; Aperio Bella, L; Arabidze, G; Arai, Y; Araque, J P; Arce, A T H; Arduh, F A; Arguin, J-F; Argyropoulos, S; Arik, M; Armbruster, A J; Arnaez, O; Arnold, H; Arratia, M; Arslan, O; Artamonov, A; Artoni, G; Asai, S; Asbah, N; Ashkenazi, A; Åsman, B; Asquith, L; Assamagan, K; Astalos, R; Atkinson, M; Atlay, N B; Augsten, K; Aurousseau, M; Avolio, G; Axen, B; Ayoub, M K; Azuelos, G; Baak, M A; Baas, A E; Baca, M J; Bacci, C; Bachacou, H; Bachas, K; Backes, M; Backhaus, M; Bagiacchi, P; Bagnaia, P; Bai, Y; Bain, T; Baines, J T; Baker, O K; Baldin, E M; Balek, P; Balestri, T; Balli, F; Balunas, W K; Banas, E; Banerjee, Sw; Bannoura, A A E; Barak, L; Barberio, E L; Barberis, D; Barbero, M; Barillari, T; Barisonzi, M; Barklow, T; Barlow, N; Barnes, S L; Barnett, B M; Barnett, R M; Barnovska, Z; Baroncelli, A; Barone, G; Barr, A J; Barreiro, F; Barreiro Guimarães da Costa, J; Bartoldus, R; Barton, A E; Bartos, P; Basalaev, A; Bassalat, A; Basye, A; Bates, R L; Batista, S J; Batley, J R; Battaglia, M; Bauce, M; Bauer, F; Bawa, H S; Beacham, J B; Beattie, M D; Beau, T; Beauchemin, P H; Beccherle, R; Bechtle, P; Beck, H P; Becker, K; Becker, M; Beckingham, M; Becot, C; Beddall, A J; Beddall, A; Bednyakov, V A; Bee, C P; Beemster, L J; Beermann, T A; Begel, M; Behr, J K; Belanger-Champagne, C; Bell, W H; Bella, G; Bellagamba, L; Bellerive, A; Bellomo, M; Belotskiy, K; Beltramello, O; Benary, O; Benchekroun, D; Bender, M; Bendtz, K; Benekos, N; Benhammou, Y; Benhar Noccioli, E; Benitez Garcia, J A; Benjamin, D P; Bensinger, J R; Bentvelsen, S; Beresford, L; Beretta, M; Berge, D; Bergeaas Kuutmann, E; Berger, N; Berghaus, F; Beringer, J; Bernard, C; Bernard, N R; Bernius, C; Bernlochner, F U; Berry, T; Berta, P; Bertella, C; Bertoli, G; Bertolucci, F; Bertsche, C; Bertsche, D; Besana, M I; Besjes, G J; Bessidskaia Bylund, O; Bessner, M; Besson, N; Betancourt, C; Bethke, S; Bevan, A J; 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Valderanis, C; Valencic, N; Valentinetti, S; Valero, A; Valery, L; Valkar, S; Vallecorsa, S; Valls Ferrer, J A; Van Den Wollenberg, W; Van Der Deijl, P C; van der Geer, R; van der Graaf, H; van Eldik, N; van Gemmeren, P; Van Nieuwkoop, J; van Vulpen, I; van Woerden, M C; Vanadia, M; Vandelli, W; Vanguri, R; Vaniachine, A; Vannucci, F; Vardanyan, G; Vari, R; Varnes, E W; Varol, T; Varouchas, D; Vartapetian, A; Varvell, K E; Vazeille, F; Vazquez Schroeder, T; Veatch, J; Veloce, L M; Veloso, F; Velz, T; Veneziano, S; Ventura, A; Ventura, D; Venturi, M; Venturi, N; Venturini, A; Vercesi, V; Verducci, M; Verkerke, W; Vermeulen, J C; Vest, A; Vetterli, M C; Viazlo, O; Vichou, I; Vickey, T; Vickey Boeriu, O E; Viehhauser, G H A; Viel, S; Vigne, R; Villa, M; Villaplana Perez, M; Vilucchi, E; Vincter, M G; Vinogradov, V B; Vivarelli, I; Vives Vaque, F; Vlachos, S; Vladoiu, D; Vlasak, M; Vogel, M; Vokac, P; Volpi, G; Volpi, M; von der Schmitt, H; von Radziewski, H; von Toerne, E; Vorobel, V; Vorobev, K; 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Zhou, C; Zhou, L; Zhou, L; Zhou, M; Zhou, N; Zhu, C G; Zhu, H; Zhu, J; Zhu, Y; Zhuang, X; Zhukov, K; Zibell, A; Zieminska, D; Zimine, N I; Zimmermann, C; Zimmermann, S; Zinonos, Z; Zinser, M; Ziolkowski, M; Živković, L; Zobernig, G; Zoccoli, A; Zur Nedden, M; Zurzolo, G; Zwalinski, L

This paper reports a detailed study of techniques for identifying boosted, hadronically decaying W bosons using 20.3 fb[Formula: see text] of proton-proton collision data collected by the ATLAS detector at the LHC at a centre-of-mass energy [Formula: see text]. A range of techniques for optimising the signal jet mass resolution are combined with various jet substructure variables. The results of these studies in Monte Carlo simulations show that a simple pairwise combination of groomed jet mass and one substructure variable can provide a 50 % efficiency for identifying W bosons with transverse momenta larger than 200 GeV while maintaining multijet background efficiencies of 2-4 % for jets with the same transverse momentum. These signal and background efficiencies are confirmed in data for a selection of tagging techniques.

Integration of reflectances and thermography imagery for transport infrastructures diagnostics

NASA Astrophysics Data System (ADS)

Pignatti, S.; Palombo, A.; Pascucci, S.; Santini, F.

2012-04-01

The integrated use of reflectances and thermography to study and diagnostic of transport infrastructures has been applied on the Musumeci Bridge (Potenza, Italy) test site as a fast and non-destructive tool in the framework of the Integrated System for Transport Infrastructures surveillance and Monitoring by Electromagnetic Sensing (ISTIMES) project, funded by the European Commission in the frame of a joint Call "ICT and Security" of the Seventh Framework Programme, in order to extract appropriate information and make useful decisions [1]. The applied hyperspectral imagery is primarily suited for the detection and characterization of alterations and defects in the structures' surface, whereas by means of thermography it is possible to attain near real-time information about the internal structure such as a bridge. Hyperspectral data is able to discriminate materials on the basis of their different patterns of wavelength-specific absorption; in fact, they are successfully used for identifying minerals and rocks, as well as detecting surface materials properties [2]. For this study we used the HySpex VNIR-1600 and the SWIR-320 hyperspectral scanners (see details in Table 1) located beneath the Musmeci Bridge thus being able to acquire the structure. The hyperspectral data processing has allowed to derive indication/parameters related to the status of the structure surface, i.e. by means of the detection of the surface weathering status of the iron (i.e. iron oxides such as limonite/goethite) used to reinforce the cement structure and the occurring detachments of the cement covering the iron. This assessment can be used to foresee more severe damages of the armed concrete. Concerning the rationale for using a high sensitivity Infrared camera in the MWIR range (3.5-5 micron; see Table 1) for the Musumeci test site is based on the fact that the high radiometric resolution of the thermal images time series allows analyzing the structure homogeneity and the cohesion of the cement structure layer with the substrate. As favorable environmental condition were satisfied: (a) the inner structure is thermally connected to the external surface of the bridge structure and (b) the thermal gradient at the surface does not depend on the atmospheric conditions (e.g., sun, rain, wind and so on), it was possible for the Musumeci Bridge to detect with a good accuracy the underlying structure. More specifically, the thermal series measuring sessions were executed during the night time in order to record and understand the diurnal/nocturnal thermal behavior of the structure according to the diurnal heating of the structure. Principal Components (PC) analysis and the assessment of the parameters describing the thermal decay were used. For this study the parameter that better describes the thermal decay of the bridge corresponded to the angular coefficient of the curve better interpolating the temperature decay ramp that for a limited interval of time could be approximated to a linear decay. The jointly use of the two non-destructive techniques applied for this project is encouraged by the technical and operative characteristics of the observation systems at disposal that are able to observe the variables, physical and optical parameters in near real-time and connected to the transport infrastructures status. In particular, the hyperspectral imagery processing results show that such methodology is suitable to identify reliable parameters related to the structure surface by detecting anomalies and identifying the specific signature of the material of interest. The thermal long time series processing, i.e. both the PCA and decay coefficients images, has allowed to highlight the real inner structure of the bridge. From the proposed non-destructive monitoring approach on the Musumeci test site experiences, we can conclude that the integrated use of the two sensing techniques is a valid support for a rapid and low cost evaluation of the bridge structure and also with respect to the rapidity of the sensing the output of this technology represents a powerful tool to build the first informative level in the framework of an operative decision-support system. Table 1. Characteristics of sensors used for the study. Spectral RegionSpectral ResolutionSpectral RangeIFOV Characteristics Hyspex VNIR-1600 VIS-NIR 3.7 nm 0.4÷1.0μm 0.75 mrad160 bands (1600 pixels) HySpex SWIR-320mSWIR 5.0 nm 1.3÷2.5μm 0.75 mrad240 bands (320 pixels) FLIR SC7000 MWIR integrated 3.5÷5.0μm 1.20 mrad640 - 512 (5÷300 ° C) 1

Detecting the Neutrino

NASA Astrophysics Data System (ADS)

Arns, Robert G.

In 1930 Wolfgang Pauli suggested that a new particle might be required to make sense of the radioactive-disintegration mode known as beta decay. This conjecture initially seemed impossible to verify since the new particle, which became known as the neutrino, was uncharged, had zero or small mass, and interacted only insignificantly with other matter. In 1951 Frederick Reines and Clyde L. Cowan, Jr., of the Los Alamos Scientific Laboratory undertook the difficult task of detecting the free neutrino by observing its inverse beta-decay interaction with matter. They succeeded in 1956. The neutrino was accepted rapidly as a fundamental particle despite discrepancies in reported details of the experiments and despite the absence of independent verification of the result. This paper describes the experiments, examines the nature of the discrepancies, and discusses the circumstances of the acceptance of the neutrino's detection by the physics community.

Detection of Adriamycin–DNA adducts by accelerator mass spectrometry at clinically relevant Adriamycin concentrations

PubMed Central

Coldwell, Kate E.; Cutts, Suzanne M.; Ognibene, Ted J.; Henderson, Paul T.; Phillips, Don R.

2008-01-01

Limited sensitivity of existing assays has prevented investigation of whether Adriamycin–DNA adducts are involved in the anti-tumour potential of Adriamycin. Previous detection has achieved a sensitivity of a few Adriamycin–DNA adducts/104 bp DNA, but has required the use of supra-clinical drug concentrations. This work sought to measure Adriamycin–DNA adducts at sub-micromolar doses using accelerator mass spectrometry (AMS), a technique with origins in geochemistry for radiocarbon dating. We have used conditions previously validated (by less sensitive decay counting) to extract [14C]Adriamycin–DNA adducts from cells and adapted the methodology to AMS detection. Here we show the first direct evidence of Adriamycin–DNA adducts at clinically-relevant Adriamycin concentrations. [14C]Adriamycin treatment (25 nM) resulted in 4.4 ± 1.0 adducts/107 bp (∼1300 adducts/cell) in MCF-7 breast cancer cells, representing the best sensitivity and precision reported to date for the covalent binding of Adriamycin to DNA. The exceedingly sensitive nature of AMS has enabled over three orders of magnitude increased sensitivity of Adriamycin–DNA adduct detection and revealed adduct formation within an hour of drug treatment. This method has been shown to be highly reproducible for the measurement of Adriamycin–DNA adducts in tumour cells in culture and can now be applied to the detection of these adducts in human tissues. PMID:18632763

Capillary array scanner for time-resolved detection and identification of fluorescently labelled DNA fragments.

PubMed

Neumann, M; Herten, D P; Dietrich, A; Wolfrum, J; Sauer, M

2000-02-25

The first capillary array scanner for time-resolved fluorescence detection in parallel capillary electrophoresis based on semiconductor technology is described. The system consists essentially of a confocal fluorescence microscope and a x,y-microscope scanning stage. Fluorescence of the labelled probe molecules was excited using a short-pulse diode laser emitting at 640 nm with a repetition rate of 50 MHz. Using a single filter system the fluorescence decays of different labels were detected by an avalanche photodiode in combination with a PC plug-in card for time-correlated single-photon counting (TCSPC). The time-resolved fluorescence signals were analyzed and identified by a maximum likelihood estimator (MLE). The x,y-microscope scanning stage allows for discontinuous, bidirectional scanning of up to 16 capillaries in an array, resulting in longer fluorescence collection times per capillary compared to scanners working in a continuous mode. Synchronization of the alignment and measurement process were developed to allow for data acquisition without overhead. Detection limits in the subzeptomol range for different dye molecules separated in parallel capillaries have been achieved. In addition, we report on parallel time-resolved detection and separation of more than 400 bases of single base extension DNA fragments in capillary array electrophoresis. Using only semiconductor technology the presented technique represents a low-cost alternative for high throughput DNA sequencing in parallel capillaries.

Study of the Photon Strength Functions for Gadolinium Isotopes with the DANCE Array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dashdorj, D.; Mitchell, G. E.; Baramsai, B.

2009-03-10

The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. The gadolinium isotopes have some of the largest neutron capture cross sections. As a consequence they are used in the control rod in reactor fuel assembly. From the basic science point of view, there are seven stable isotopes of gadolinium with varying degrees of deformation. Therefore they provide a good testing ground for the study of deformation dependent structure such as the scissors mode. Decay gamma rays following neutron capture on Gd isotopes are detected by the DANCE array, which is located at flight pathmore » 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a specific resonance of a specific isotope in the time-of-flight spectrum and obtain the summed energy spectrum for that isotope. The singles gamma-ray spectrum for each multiplicity can be separated by their DANCE cluster multiplicity. Various photon strength function models are used for comparison with experimentally measured DANCE data and provide insight for understanding the statistical decay properties of deformed nuclei.« less

The breakout of the Hot CNO cycle via ^18Ne resonant states

NASA Astrophysics Data System (ADS)

Almaraz-Calderon, S.; Tan, W.; Aprahamian, A.; Bucher, B.; Gorres, J.; Roberts, A.; Villano, A.; Wiescher, M.; Brune, C.; Heinen, Z.; Massey, T.; Ozkan, N.; Guray, R. T.; Mach, H.

2010-11-01

The energy generation rate in the HCNO cycle is limited by the β decay of the waiting point nuclei ^14O and ^15O. However, when the temperatures and densities are high enough (e.g. Novae and X-ray Bursts) it is possible to bypass them by p/α captures resulting in a thermonuclear runaway towards the rp-process. One of the two paths for breakouts from the HCNO cycle is the reaction chain ^14O(α,p)^17F(p,γ)^18Ne(α,p), which proceeds through resonant states on ^18Ne, making their reactions rates very sensitive on the partial and total widths, excitation energies and spins of such resonances. We studied the resonant states in ^18Ne via ^16O(^3He,n) reaction. The neutrons were measured with an array of liquid scintillators using Time-of-Flight and pulse-shape discrimination techniques. The charged particles were detected in coincidence with neutrons by an array of silicon detectors, allowing us to measure α, p, p' and 2p decay branching ratios. Tentative spin assignments were made in comparison with zero range DWBA calculations. This new information will be included in reaction network calculations to evaluate its impact on the nuclear energy generation that occurs in these stellar explosive environments.

[Assessment of mitochondrial metabolic oxidative state in living cardiomyocytes with spectrally-resolved fluorescence lifetime spectroscopy of NAD(P)H].

PubMed

Cheng, Ying; Ren, Mingming; Niu, Yanyan; Qiao, Jianhua; Aneba, S; Chorvat, D; Chorvatova, A

2009-12-01

The primary function of cardiac mitochondria is the production of ATP to support heart contraction. Examination of the mitochondrial redox state is therefore crucially important to sensitively detect early signs of mitochondrial function in pathophysiological conditions, such as ischemia, diabetes and heart failure. We study fingerprinting of mitochondrial metabolic oxidative state in living cardiomyocytes with spectrally-resolved fluorescence lifetime spectroscopy of NAD(P)H, the principal electron donor in mitochondrial respiration responsible for vital ATP supply. Here NAD(P)H is studied as a marker for non-invasive fluorescent probing of the mitochondrial function. NAD(P) H fluorescence is recorded in cardiac cells following excitation with 375nm UV-light and detection by spectrally-resolved time-correlated single photon counting (TCSPC), based on the simultaneous measurement of the fluorescence spectra and fluorescence lifetimes. Modulation of NADH production and/or mitochondrial respiration is tested to study dynamic characteristics of NAD(P) H fluorescence decay. Our results show that at least a 3-exponential decay model, with 0.4-0.7ns, 1.2-1.9ns and 8.0-13. Ons lifetime pools is necessary to describe cardiomyocyte autofluorescence (AF) within 420-560nm spectral range. Increased mitochondrial NADH production by ketone bodies enhanced the fluorescence intensity, without significant change in fluorescent lifetimes. Rotenone, the inhibitor of Complex I of the mitochondrial respiratory chain, increased AF intensity and shortened the average fluorescence lifetime. Dinitrophenol (DNP), an uncoupling agent of the mitochondrial oxidative phosphorylation, lowered AF intensity, broadened the spectral shoulder at 520 nm and increased the average fluorescence lifetime. These effects are comparable to the study of NADH fluorescence decay in vitro. In the present contribution we demonstrated that spectrally-resolved fluorescence lifetime technique provides promising new tool for analysis of mitochondrial NAD(P) H fluorescence with good reproducibility in living cardiomyocytes. This approach will enhance our knowledge about cardiomyocyte oxidative metabolism and/or its dysfunction at a cellular level. In the future, this approach can prove helpful in the clinical diagnosis and treatment of mitochondrial disorder.

Accuracy of neutron self-activation method with iodine-containing scintillators for quantifying 128I generation using decay-fitting technique

NASA Astrophysics Data System (ADS)

Nohtomi, Akihiro; Wakabayashi, Genichiro

2015-11-01

We evaluated the accuracy of a self-activation method with iodine-containing scintillators in quantifying 128I generation in an activation detector; the self-activation method was recently proposed for photo-neutron on-line measurements around X-ray radiotherapy machines. Here, we consider the accuracy of determining the initial count rate R0, observed just after termination of neutron irradiation of the activation detector. The value R0 is directly related to the amount of activity generated by incident neutrons; the detection efficiency of radiation emitted from the activity should be taken into account for such an evaluation. Decay curves of 128I activity were numerically simulated by a computer program for various conditions including different initial count rates (R0) and background rates (RB), as well as counting statistical fluctuations. The data points sampled at minute intervals and integrated over the same period were fit by a non-linear least-squares fitting routine to obtain the value R0 as a fitting parameter with an associated uncertainty. The corresponding background rate RB was simultaneously calculated in the same fitting routine. Identical data sets were also evaluated by a well-known integration algorithm used for conventional activation methods and the results were compared with those of the proposed fitting method. When we fixed RB = 500 cpm, the relative uncertainty σR0 /R0 ≤ 0.02 was achieved for R0/RB ≥ 20 with 20 data points from 1 min to 20 min following the termination of neutron irradiation used in the fitting; σR0 /R0 ≤ 0.01 was achieved for R0/RB ≥ 50 with the same data points. Reasonable relative uncertainties to evaluate initial count rates were reached by the decay-fitting method using practically realistic sampling numbers. These results clarified the theoretical limits of the fitting method. The integration method was found to be potentially vulnerable to short-term variations in background levels, especially instantaneous contaminations by spike-like noise. The fitting method easily detects and removes such spike-like noise.

HIV Type 1 (HIV-1) Proviral Reservoirs Decay Continuously Under Sustained Virologic Control in HIV-1–Infected Children Who Received Early Treatment

PubMed Central

Luzuriaga, Katherine; Tabak, Barbara; Garber, Manuel; Chen, Ya Hui; Ziemniak, Carrie; McManus, Margaret M.; Murray, Danielle; Strain, Matthew C.; Richman, Douglas D.; Chun, Tae-Wook; Cunningham, Coleen K.; Persaud, Deborah

2014-01-01

Background. Early initiation of combination antiretroviral therapy (cART) to human immunodeficiency virus type 1 (HIV-1)–infected infants controls HIV-1 replication and reduces mortality. Methods. Plasma viremia (lower limit of detection, <2 copies/mL), T-cell activation, HIV-1–specific immune responses, and the persistence of cells carrying replication-competent virus were quantified during long-term effective combination antiretroviral therapy (cART) in 4 perinatally HIV-1–infected youth who received treatment early (the ET group) and 4 who received treatment late (the LT group). Decay in peripheral blood mononuclear cell (PBMC) proviral DNA levels was also measured over time in the ET youth. Results. Plasma viremia was not detected in any ET youth but was detected in all LT youth (median, 8 copies/mL; P = .03). PBMC proviral load was significantly lower in ET youth (median, 7 copies per million PBMCs) than in LT youth (median, 181 copies; P = .03). Replication-competent virus was recovered from all LT youth but only 1 ET youth. Decay in proviral DNA was noted in all 4 ET youth in association with limited T-cell activation and with absent to minimal HIV-1–specific immune responses. Conclusions. Initiation of early effective cART during infancy significantly limits circulating levels of proviral and replication-competent HIV-1 and promotes continuous decay of viral reservoirs. Continued cART with reduction in HIV-1 reservoirs over time may facilitate HIV-1 eradication strategies. PMID:24850788

Evaluation of Accuracy of DIAGNOdent in Diagnosis of Primary and Secondary Caries in Comparison to Conventional Methods

PubMed Central

Nokhbatolfoghahaie, Hanieh; Alikhasi, Marzieh; Chiniforush, Nasim; Khoei, Farzaneh; Safavi, Nassimeh; Yaghoub Zadeh, Behnoush

2013-01-01

Introduction: Today the prevalence of teeth decays has considerably decreased. Related organizations and institutions mention several reasons for it such as improvement of decay diagnostic equipment and tools which are even capable of detecting caries in their initial stages. This resulted in reduction of costs for patients and remarkable increase in teeth life span. There are many methods for decay diagnostic, like: visual and radiographic methods, devices with fluorescence such as Quantitative light-induced fluorescence (QLF), Vista proof, Laser fluorescence (LF or DIAGNOdent), Fluorescence Camera (FC) and Digital radiography. Although DIAGNOdent is considered a valuable device for decay diagnostic ,there are concerns regarding its efficacy and accuracy. Considering the sensitivity of decaydiagnosis and the exorbitant annual expenses supported by government and people for caries treatment, finding the best method for early caries detection is of the most importance. Numerous studies were performed to compare different diagnostic methods with conflicting results. The objective of this study is a comparative review of the efficiency of DIAGNOdent in comparison to visual methods and radiographic methods in the diagnostic of teeth occlusal surfaces. Methods: Search of PubMed, Google Scholar electronic resources was performed in order to find clinical trials in English in the period between 1998 and 2013. Full texts of only 35 articles were available. Conclusion: Considering the sensitivity and specificity reported in the different studies, it seems that DIAGNOdent is an appropriate modality for caries detection as a complementary method beside other methods and its use alone to obtain treatment plan is not enough. PMID:25606325

Codecaying Dark Matter.

PubMed

Dror, Jeff Asaf; Kuflik, Eric; Ng, Wee Hao

2016-11-18

We propose a new mechanism for thermal dark matter freeze-out, called codecaying dark matter. Multicomponent dark sectors with degenerate particles and out-of-equilibrium decays can codecay to obtain the observed relic density. The dark matter density is exponentially depleted through the decay of nearly degenerate particles rather than from Boltzmann suppression. The relic abundance is set by the dark matter annihilation cross section, which is predicted to be boosted, and the decay rate of the dark sector particles. The mechanism is viable in a broad range of dark matter parameter space, with a robust prediction of an enhanced indirect detection signal. Finally, we present a simple model that realizes codecaying dark matter.

Analysis techniques for the evaluation of the neutrinoless double-β decay lifetime in 130Te with the CUORE-0 detector

DOE PAGES

Alduino, C.; Alfonso, K.; Artusa, D. R.; ...

2016-04-25

Here, we describe in detail the methods used to obtain the lower bound on the lifetime of neutrinoless double-beta (0νββ) decay in 130Te and the associated limit on the effective Majorana mass of the neutrino using the CUORE-0 detector. CUORE-0 is a bolometric detector array located at the Laboratori Nazionali del Gran Sasso that was designed to validate the background reduction techniques developed for CUORE, a next-generation experiment scheduled to come online in 2016. CUORE-0 is also a competitive 0νββ decay search in its own right and functions as a platform to further develop the analysis tools and procedures tomore » be used in CUORE. These include data collection, event selection and processing, as well as an evaluation of signal efficiency. In particular, we describe the amplitude evaluation, thermal gain stabilization, energy calibration methods, and the analysis event selection used to create our final 0νββ search spectrum. We define our high level analysis procedures, with emphasis on the new insights gained and challenges encountered. We outline in detail our fitting methods near the hypothesized 0νββ decay peak and catalog the main sources of systematic uncertainty. Finally, we derive the 0νββ decay half-life limits previously reported for CUORE-0, T 0ν 1/2 > 2.7×10 24yr, and in combination with the Cuoricino limit, T 0ν 1/2 > 4.0×10 24yr.« less

Analysis techniques for the evaluation of the neutrinoless double- β decay lifetime in Te 130 with the CUORE-0 detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alduino, C.; Alfonso, K.; Artusa, D. R.

2016-04-25

We describe in detail the methods used to obtain the lower bound on the lifetime of neutrinoless double-beta ( 0 ν β β ) decay in 130 Te and the associated limit on the effective Majorana mass of the neutrino using the CUORE-0 detector. CUORE-0 is a bolometric detector array located at the Laboratori Nazionali del Gran Sasso that was designed to validate the background reduction techniques developed for CUORE, a next-generation experiment scheduled to come online in 2016. CUORE-0 is also a competitive 0 ν β β decay search in its own right and functions as a platform tomore » further develop the analysis tools and procedures to be used in CUORE. These include data collection, event selection and processing, as well as an evaluation of signal efficiency. In particular, we describe the amplitude evaluation, thermal gain stabilization, energy calibration methods, and the analysis event selection used to create our final 0 ν β β search spectrum. We define our high level analysis procedures, with emphasis on the new insights gained and challenges encountered. We outline in detail our fitting methods near the hypothesized 0 ν β β decay peak and catalog the main sources of systematic uncertainty. Finally, we derive the 0 ν β β decay half-life limits previously reported for CUORE-0, T 0 ν 1 / 2 > 2.7 × 10 24 yr , and in combination with the Cuoricino limit, T 0 ν 1 / 2 > 4.0 × 10 24 yr .« less

Analysis of Wave Velocity Patterns in Black Cherry Trees and its Effect on Internal Decay Detection

Treesearch

Guanghui Li; Xiping Wang; Jan Wiedenbeck; Robert J. Ross

2013-01-01

In this study, we examined stress wave velocity patterns in the cross sections of black cherry trees, developed analytical models of stress wave velocity in sound healthy trees, and then tested the effectiveness of the models as a tool for tree decay diagnosis. Acoustic tomography data of the tree cross sections were collected from 12 black cherry trees at a production...

Analysis of wave velocity patterns in black cherry trees and its effect on internal decay detection

Treesearch

Guanghui Li; Xiping Wang; Hailin Feng; Jan Wiedenbeck; Robert J. Ross

2014-01-01

In this study, we examined stress wave velocity patterns in the cross sections of black cherry trees, developed analytical models of stress wave velocity in sound healthy trees, and then tested the effectiveness of the models as a tool for tree decay diagnosis. Acoustic tomography data of the tree cross sections were collected from 12 black cherry trees at a production...

VizieR Online Data Catalog: Catalog of Kepler flare stars (Van Doorsselaere+, 2017)

NASA Astrophysics Data System (ADS)

van Doorsselaere, T.; Shariati, H.; Debosscher, J.

2017-11-01

With an automated detection method, we have identified stellar flares in the long cadence observations of Kepler during quarter 15. We list each flare time for the respective Kepler objects. Furthermore, we list the flare amplitude and decay time after fitting the flare light curve with an exponential decay. Flare start times in long cadence data of Kepler during quarter 15. (1 data file).

Measurement of WZ and ZZ production in pp collisions at $$\\sqrt{s} = 8\\,\\text {TeV} $$ in final states with b-tagged jets

DOE PAGES

Chatrchyan, Serguei

2014-08-07

Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions atmore » $$\\sqrt{s}$$ = 8 TeV in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either $$W \\to e\

Tunneling effects in the unimolecular decay of (CH 3) 2COO Criegee intermediates to OH radical products

DOE PAGES

Fang, Yi; Barber, Victoria P.; Klippenstein, Stephen J.; ...

2017-04-04

Unimolecular decay of the dimethyl substituted Criegee intermediate (CH 3) 2COO is observed at energies significantly below the transition state barrier associated with hydrogen atom transfer with time-resolved detection of the resultant OH radical products. (CH 3) 2COO is prepared at specific energies in the 3900-4600 cm -1 region through IR excitation of combination bands involving CH stretch and another lower frequency mode, and the OH products are detected by UV laser-induced fluorescence. OH appearance times on the order of microseconds are observed in this deep tunneling regime, which are about 100 times slower than that in the vicinity ofmore » the barrier. The experimental rates are in good accord with Rice-Ramsperger-Kassel-Marcus (RRKM) calculations of the microcanonical dissociation rates for (CH 3) 2COO that include tunneling. Master equation modeling based on these microcanonical rates is used to predict the thermal decay rate of (CH 3) 2COO to OH products under atmospheric conditions of 276 s -1 at 298 K (high pressure limit). Furthermore, thermal unimolecular decay of (CH 3) 2COO to OH products is shown to have significant contributions from tunneling at energies much below the barrier to H-atom transfer.« less

Mesons from Laser-Induced Processes in Ultra-Dense Hydrogen H(0)

PubMed Central

2017-01-01

Large signals of charged light mesons are observed in the laser-induced particle flux from ultra-dense hydrogen H(0) layers. The mesons are formed in such layers on metal surfaces using < 200 mJ laser pulse-energy. The time variation of the signal to metal foil collectors and the magnetic deflection to a movable pin collector are now studied. Relativistic charged particles with velocity up to 500 MeV u-1 thus 0.75 c are observed. Characteristic decay time constants for meson decay are observed, for charged and neutral kaons and also for charged pions. Magnetic deflections agree with charged pions and kaons. Theoretical predictions of the decay chains from kaons to muons in the particle beam agree with the results. Muons are detected separately by standard scintillation detectors in laser-induced processes in ultra-dense hydrogen H(0) as published previously. The muons formed do not decay appreciably within the flight distances used here. Most of the laser-ejected particle flux with MeV energy is not deflected by the magnetic fields and is thus neutral, either being neutral kaons or the ultra-dense HN(0) precursor clusters. Photons give only a minor part of the detected signals. PACS: 67.63.Gh, 14.40.-n, 79.20.Ds, 52.57.-z. PMID:28081199

Tunneling effects in the unimolecular decay of (CH 3) 2COO Criegee intermediates to OH radical products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fang, Yi; Barber, Victoria P.; Klippenstein, Stephen J.

Unimolecular decay of the dimethyl substituted Criegee intermediate (CH 3) 2COO is observed at energies significantly below the transition state barrier associated with hydrogen atom transfer with time-resolved detection of the resultant OH radical products. (CH 3) 2COO is prepared at specific energies in the 3900-4600 cm -1 region through IR excitation of combination bands involving CH stretch and another lower frequency mode, and the OH products are detected by UV laser-induced fluorescence. OH appearance times on the order of microseconds are observed in this deep tunneling regime, which are about 100 times slower than that in the vicinity ofmore » the barrier. The experimental rates are in good accord with Rice-Ramsperger-Kassel-Marcus (RRKM) calculations of the microcanonical dissociation rates for (CH 3) 2COO that include tunneling. Master equation modeling based on these microcanonical rates is used to predict the thermal decay rate of (CH 3) 2COO to OH products under atmospheric conditions of 276 s -1 at 298 K (high pressure limit). Furthermore, thermal unimolecular decay of (CH 3) 2COO to OH products is shown to have significant contributions from tunneling at energies much below the barrier to H-atom transfer.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Hsin-Chia; Huang, Wei-Chih; Huang, Xiaoyuan

We consider indirect detection of meta-stable dark matter particles decaying into a stable neutral particle and a pair of standard model fermions. Due to the softer energy spectra from the three-body decay, such models could potentially explain the AMS-02 positron excess without being constrained by the Fermi-LAT gamma-ray data and the cosmic ray anti-proton measurements. We scrutinize over different final state fermions, paying special attention to handling of the cosmic ray background and including various contributions from cosmic ray propagation with the help of the LIKEDM package. It is found that primary decays into an electron-positron pair and a stablemore » neutral particle could give rise to the AMS-02 positron excess and, at the same time, stay unscathed against the gamma-ray and anti-proton constraints. Decays to a muon pair or a mixed flavor electron-muon pair may also be viable depending on the propagation models. Decays to all other standard model fermions are severely disfavored.« less

Measurement of the radiative decay branching fraction in the MEG experiment

NASA Astrophysics Data System (ADS)

Xiao, Feng

A measurement of the radiative muon decay mu+ → e+nuenumugamma branching fraction was done on the basis of the radiative decay data of MEG experiment. The data were taken periodically one day per week with the beam intensity of 1.2 x 106 mu+/ s from September to December, 2008. The positron was measured by a spectrometer with gradient magnetic field. The photon was detected by an innovative ˜900 liter liquid xenon scintillation detector. The measurement was carried out with a cut-and-count approach. We report the radiative muon decay branching fraction to be B(m→enng )=(2.84+/-0.20(stat)+/-0.05 (syst))x10-7, with Ee > 46 MeV, E gamma > 30 MeV, and the opening angle between the positron and photon thetaegamma in its full kinematic range. Distributions of three observables, Ee, Egamma, and thetaegamma, as well as their kinematic correlations were verified to be consistent with the radiative decays. The measurement is in excellent agreement with the prediction of the Standard Model.

Beta decay of exotic TZ = -1, -2 nuclei: the interesting case of 56Zn

NASA Astrophysics Data System (ADS)

Orrigo, S. E. A.; Rubio, B.; Fujita, Y.; Blank, B.; Gelletly, W.; Agramunt, J.; Algora, A.; Ascher, P.; Bilgier, B.; Cáceres, L.; Cakirli, R. B.; Fujita, H.; Ganioğlu, E.; Gerbaux, M.; Giovinazzo, J.; Grévy, S.; Kamalou, O.; Kozer, H. C.; Kucuk, L.; Kurtukian-Nieto, T.; Molina, F.; Popescu, L.; Rogers, A. M.; Susoy, G.; Stodel, C.; Suzuki, T.; Tamii, A.; Thomas, J. C.

2014-03-01

The β decay properties of the Tz = -2, 56Zn isotope and other proton-rich nuclei in the fp-shell have been investigated in an experiment performed at GANIL. The ions were produced in fragmentation reactions and implanted in a double-sided silicon strip detector surrounded by Ge EXOGAM clovers. Preliminary results for 56Zn are presented .The 56Zn decay proceeds mainly by β delayed proton emission, but β delayed gamma rays were also detected. Moreover, the exotic β delayed gamma-proton decay was observed for the first time. The 56Zn half-life and the energy levels populated in the 56Cu daughter have been determined. Knowledge of the gamma de-excitation of the mirror states in 56Co and the comparison with the results of the mirror charge exchange process, the 56Fe(3He,t) reaction (where 56Fe has Tz = +2), were important in the interpretation of the 56Zn decay data. The absolute Fermi and Gamow-Teller strengths have been deduced.

Radon detection

DOEpatents

MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

1994-01-25

A detector for atmospheric radon using a long range alpha detector as its sensing element is described. An electrostatic filter removes ions from ambient air, while allowing radon atoms to pass into a decay cavity. Here, radon atoms are allowed to decay, creating air ions. These air ions are drawn by a fan through a second electrostatic filter which can be activated or deactivated, and into the long range alpha detector. With the second electrostatic filter activated, no air ions are allowed to pass, and the signal output from the long range alpha detector consists of only the electronic background. With the second electrostatic filter deactivated, air ions and cosmic rays will be detected. The cosmic ray contribution can be minimized by shielding. 3 figures.

Radon detection

DOEpatents

MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

1994-01-01

A detector for atmospheric radon using a long range alpha detector as its sensing element. An electrostatic filter removes ions from ambient air, while allowing radon atoms to pass into a decay cavity. Here, radon atoms are allowed to decay, creating air ions. These air ions are drawn by a fan through a second electrostatic filter which can be activated or deactivated, and into the long range alpha detector. With the second electrostatic filter activated, no air ions are allowed to pass, and the signal output from the long range alpha detector consists of only the electronic background. With the second electrostatic filter deactivated, air ions and cosmic rays will be detected. The cosmic ray contribution can be minimized by shielding.

Self-Validating Thermocouple

NASA Technical Reports Server (NTRS)

Perotti, Jose M. (Inventor); Mata, Carlos T. (Inventor); Santiago, Josephine B. (Inventor); Vokrot, Peter (Inventor); Zavala, Carlos E. (Inventor); Burns, Bradley M. (Inventor)

2010-01-01

Self-Validating Thermocouple (SVT) Systems capable of detecting sensor probe open circuits, short circuits, and unnoticeable faults such as a probe debonding and probe degradation are useful in the measurement of temperatures. SVT Systems provide such capabilities by incorporating a heating or excitation element into the measuring junction of the thermocouple. By heating the measuring junction and observing the decay time for the detected DC voltage signal, it is possible to indicate whether the thermocouple is bonded or debonded. A change in the thermal transfer function of the thermocouple system causes a change in the rise and decay times of the thermocouple output. Incorporation of the excitation element does not interfere with normal thermocouple operation, thus further allowing traditional validation procedures as well.

Inversion Recovery Ultrashort Echo Time Magnetic Resonance Imaging: A Method for Simultaneous Direct Detection of Myelin and High Signal Demonstration of Iron Deposition in the Brain – A Feasibility Study

PubMed Central

Sheth, Vipul R.; Fan, Shujuan; He, Qun; Ma, Yajun; Annesse, Jacopo; Switzer, Robert; Corey-Bloom, Jody; Bydder, Graeme M; Du, Jiang

2017-01-01

Multiple sclerosis (MS)causes demyelinating lesions in the white matter and increased iron deposition in the subcortical gray matter. Myelin protons have an extremely short T2* (less than 1 ms) and are not directly detected with conventional clinical magnetic resonance (MR) imaging sequences. Iron deposition also reduces T2*, leading to reduced signal on clinical sequences. In this study we tested the hypothesis that the inversion recovery ultrashort echo time (IR-UTE) pulse sequence can directly and simultaneously image myelin and iron deposition using a clinical 3T scanner. The technique was first validated on a synthetic myelinphantom (myelin powder in D2O) and a Feridex iron phantom. This was followed by studies of cadaveric MS specimens, healthy volunteers and MS patients. UTE imaging of the synthetic myelin phantom showed an excellent bi-component signal decay with two populations of protons, one with a T2* of 1.2 ms (residual water protons) and the other with a T2* of 290 μs (myelin protons). IR-UTE imaging shows sensitivity to a wide range of iron concentrations from 0.5 to ∼30 mM. The IR-UTE signal from white matter of the brain of healthy volunteers shows a rapid signal decay with a short T2* of ∼300 μs, consistent with the T2* values of myelin protons in the synthetic myelin phantom. IR-UTE imaging in MS brain specimens and patients showed multiple white matter lesions as well as areas of high signal in subcortical gray matter. This in specimens corresponded in position to Perl's diaminobenzide staining results, consistent with increased iron deposition. IR-UTE imaging simultaneously detects lesions with myelin loss in the white matter and iron deposition in the gray matter. PMID:28038965

Evaluation of techniques for determining the density of fine woody debris

Treesearch

Becky Fasth; Mark E. Harmon; Christopher W. Woodall; Jay. Sexton

2010-01-01

Evaluated various techniques for determining the density (i.e., bulk density) of fine woody debris during forest inventory activities. It was found that only experts in dead wood inventory may be able to identify fine woody debris stages of decay. Suggests various future research directions such as...

β -delayed γ decay of P 26 : Possible evidence of a proton halo

DOE PAGES

Pérez-Loureiro, D.; Wrede, C.; Bennett, M. B.; ...

2016-06-01

Background: Measurements of β decay provide important nuclear structure information that can be used to probe isospin asymmetries and inform nuclear astrophysics studies. Purpose: To measure the β-delayed γ decay of 26P and compare the results with previous experimental results and shell-model calculations. Method: A 26P fast beam produced using nuclear fragmentation was implanted into a planar germanium detector. Its β-delayed γ-ray emission was measured with an array of 16 high-purity germanium detectors. Positrons emitted in the decay were detected in coincidence to reduce the background. Results: The absolute intensities of 26P β-delayed γ-rays were determined. A total of sixmore » new β-decay branches and 15 new γ-ray lines have been observed for the first time in 26P β-decay. A complete β-decay scheme was built for the allowed transitions to bound excited states of 26Si. ft values and Gamow-Teller strengths were also determined for these transitions and compared with shell model calculations and the mirror β-decay of 26Na, revealing significant mirror asymmetries. Conclusions: A very good agreement with theoretical predictions based on the USDB shell model is observed. The significant mirror asymmetry observed for the transition to the first excited state (δ=51(10)%) may be evidence for a proton halo in 26P.« less

Updated analysis of some two-body charmless B decays

NASA Astrophysics Data System (ADS)

Chiang, Cheng-Wei; Rosner, Jonathan L.

2002-04-01

New data from the BaBar, Belle, and CLEO Collaborations on B decays to two-body charmless final states are analyzed, with the following consequences. (1) The penguin amplitude which dominates the decay B+→π+K*0 has a magnitude similar to that dominating B+→π+K0. (2) The decay B+→π+η, a good candidate for observing direct CP violation, should be detectable at present levels of sensitivity. (3) The decays B+→η'K+ and B+→ηK*+ are sufficiently similar in rate to the corresponding decays B0→η'K0 and B0→ηK*0, respectively, that one cannot yet infer the need for “tree” amplitudes t' contributing to the B+ but not the B0 decays. Statistical requirements for observing this and other examples of tree-penguin interference are given. (4) Whereas the B+→η'K+ and B0→η'K0 rates cannot be accounted for by the penguin amplitude p' alone but require an additional flavor-singlet penguin contribution s', no such flavor-singlet penguin contribution is yet called for in the decays B+→ηK*+ or B0→ηK*0. Predictions for the rates for B+→η'K*+ and B0→η'K*0 are given which would allow one to gauge the importance of these flavor-singlet penguin amplitudes.

Beta-delayed proton emission from 20Mg

NASA Astrophysics Data System (ADS)

Lund, M. V.; Andreyev, A.; Borge, M. J. G.; Cederkäll, J.; De Witte, H.; Fraile, L. M.; Fynbo, H. O. U.; Greenlees, P. T.; Harkness-Brennan, L. J.; Howard, A. M.; Huyse, M.; Jonson, B.; Judson, D. S.; Kirsebom, O. S.; Konki, J.; Kurcewicz, J.; Lazarus, I.; Lica, R.; Lindberg, S.; Madurga, M.; Marginean, N.; Marginean, R.; Marroquin, I.; Mihai, C.; Munch, M.; Nacher, E.; Negret, A.; Nilsson, T.; Page, R. D.; Pascu, S.; Perea, A.; Pucknell, V.; Rahkila, P.; Rapisarda, E.; Riisager, K.; Rotaru, F.; Sotty, C.; Stanoiu, M.; Tengblad, O.; Turturica, A.; Van Duppen, P.; Vedia, V.; Wadsworth, R.; Warr, N.

2016-10-01

Beta-delayed proton emission from 20 Mg has been measured at ISOLDE, CERN, with the ISOLDE Decay Station (IDS) setup including both charged-particle and gamma-ray detection capabilities. A total of 27 delayed proton branches were measured including seven so far unobserved. An updated decay scheme, including three new resonances above the proton separation energy in 20 Na and more precise resonance energies, is presented. Beta-decay feeding to two resonances above the Isobaric Analogue State (IAS) in 20 Na is observed. This may allow studies of the 4032.9(2.4)keV resonance in 19 Ne through the beta decay of 20 Mg, which is important for the astrophysically relevant reaction 15O( α, γ)19Ne . Beta-delayed protons were used to obtain a more precise value for the half-life of 20 Mg, 91.4(1.0)ms.

New Result for the β-decay Asymmetry Parameter A0 from the UCNA Experiment

NASA Astrophysics Data System (ADS)

Brown, M. A.-P.; UCNA Collaboration

2017-09-01

The UCNA Experiment at the Ultracold Neutron facility at LANL uses polarized ultracold neutrons (UCN) to determine the neutron β-decay asymmetry parameter A0, the angular correlation between the neutron spin and the decay electron's momentum. A0 further determines λ =gA /gV , which, when combined with the neutron lifetime, permits extraction of the CKM matrix element Vud solely from neutron decay. In the UCNA experiment, UCN are produced in a pulsed, spallation driven solid deuterium source, polarized using a 7 T magnetic field, and transported through an Adiabatic Fast Passage (AFP) spin flipper prior to storage within a 1 T solenoidal spectrometer housing electron detectors at each end. The spin-flipper allows one to form a super-ratio of decay rates for neutron spins aligned parallel and anti-parallel to the 1 T magnetic field, eliminating to first order errors due to variations in the decay rate and detector efficiencies. Leading systematics and analysis techniques from the most recent analysis of data collected from 2011-2013 will be presented. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Number DE-SC-0014622.

Dynamics of large-wave-vector magnons and phonons in MnF2:Er3+ using a far-infrared quantum-counter technique

NASA Astrophysics Data System (ADS)

Rotter, L. D.; Dennis, W. M.; Yen, W. M.

1990-07-01

Magnons near the Brillouin zone-edge were generated in antiferromagnetic MnF2:Er3+ at 1.9 K by exciting the intrinsic two-magnon absorption band using a pulsed far-infrared laser. The lowest Stark level of the Er3+ ground state was used as a 36-cm-1 magnon and phonon detector in a quantum-counter scheme. A simple set of rate equations was used to model the system. The decay time was found to be 2.9+/-0.6 μs for 55-cm-1, 3+/-2 μs for 47.6-cm-1 magnons, and 40+/-20 ns for 36-cm-1 phonons. The sum of the 36-cm-1 magnon decay rate and the Er3+-magnon decay rate was 0.9+/-0.2 μs-1. Possible mechanisms of magnon decay are discussed. The dominant mechanism is most likely thermal magnon-magnon scattering. No evidence of large-wave-vector magnon decay to 36-cm-1 phonons was found. We suggest that magnons do not decay to phonons until they scatter into the magnetoelastic modes. Implications with respect to recent magnon-transport experiments are discussed.

Method of self-consistent evaluation of absolute emission probabilities of particles and gamma rays

NASA Astrophysics Data System (ADS)

Badikov, Sergei; Chechev, Valery

2017-09-01

In assumption of well installed decay scheme the method provides a) exact balance relationships, b) lower (compared to the traditional techniques) uncertainties of recommended absolute emission probabilities of particles and gamma rays, c) evaluation of correlations between the recommended emission probabilities (for the same and different decay modes). Application of the method for the decay data evaluation for even curium isotopes led to paradoxical results. The multidimensional confidence regions for the probabilities of the most intensive alpha transitions constructed on the basis of present and the ENDF/B-VII.1, JEFF-3.1, DDEP evaluations are inconsistent whereas the confidence intervals for the evaluated probabilities of single transitions agree with each other.

Improving LHC searches for dark photons using lepton-jet substructure

NASA Astrophysics Data System (ADS)

Barello, G.; Chang, Spencer; Newby, Christopher A.; Ostdiek, Bryan

2017-03-01

Collider signals of dark photons are an exciting probe for new gauge forces and are characterized by events with boosted lepton jets. Existing techniques are efficient in searching for muonic lepton jets but due to substantial backgrounds have difficulty constraining lepton jets containing only electrons. This is unfortunate since upcoming intensity frontier experiments are sensitive to dark photon masses which only allow electron decays. Analyzing a recently proposed model of kinetic mixing, with new scalar particles decaying into dark photons, we find that existing techniques for electron jets can be substantially improved. We show that using lepton-jet-substructure variables, in association with a boosted decision tree, improves background rejection, significantly increasing the LHC's reach for dark photons in this region of parameter space.

Flow cytometry combined with viSNE for the analysis of microbial biofilms and detection of microplastics

PubMed Central

Sgier, Linn; Freimann, Remo; Zupanic, Anze; Kroll, Alexandra

2016-01-01

Biofilms serve essential ecosystem functions and are used in different technical applications. Studies from stream ecology and waste-water treatment have shown that biofilm functionality depends to a great extent on community structure. Here we present a fast and easy-to-use method for individual cell-based analysis of stream biofilms, based on stain-free flow cytometry and visualization of the high-dimensional data by viSNE. The method allows the combined assessment of community structure, decay of phototrophic organisms and presence of abiotic particles. In laboratory experiments, it allows quantification of cellular decay and detection of survival of larger cells after temperature stress, while in the field it enables detection of community structure changes that correlate with known environmental drivers (flow conditions, dissolved organic carbon, calcium) and detection of microplastic contamination. The method can potentially be applied to other biofilm types, for example, for inferring community structure for environmental and industrial research and monitoring. PMID:27188265

Long-term behaviour of timber structures in torrent control

NASA Astrophysics Data System (ADS)

Rickli, Christian; Graf, Frank

2014-05-01

Timber is widely used for protection measures in torrent control. However, life span of woody constructions such as timber check dams is limited due to fungal decay. However, only sparse scientific information is available on the long-term behaviour of timber structures and the colonisation with decay fungi. Related to this, in practice a controversial discussion has been going on if either Norway Spruce (Picea abies) or Silver Fir (Abies alba) is more enduring and if bark removal increases resistance against fungal decay. In order to going into this matter a series of 15 timber check dams built in 1996 has been monitored. The constructions were alternatively realised with Norway Spruce and Silver Fir, half of them each with remaining and removed bark, respectively. The scientific investigations included the documentation of colonisation with rot fungi and the identification of decayed zones with a simple practical approach as well as based on drilling resistance. Colonisation by decay fungi started three years after construction (e.g. Gloeophyllum sepiarium), detecting two years later first parts with reduced wood resistance. Sixteen years after construction decay was found on all check dams but two. Wood quality was markedly better in watered sections compared to the occasionally dry lateral abutment sections. Taking the whole check dams into consideration, slightly more decay was detected in Norway Spruce compared to logs in Silver Fir and both the practical approach and the drilling resistance measurement yielded in more defects on logs without bark. However, due to limited number of replications and fungal data, it was not possible to statistically verify these results. Statistical analysis was restricted to the drilling resistance data and fruit-bodies of decay fungi of the uppermost log of each check dam. Based on this limited analysis significant differences in the effect on the drilling resistance were found for watered sections and lateral abutments, brown and white rot as well as fir with and without bark. Taking further into account that brown rot reduces wood strength faster than white rot, it may be speculated that spruce logs without bark and fir logs with bark are more resistant against fungal decay compared to logs of spruce with and fir without bark, respectively. However, this has to be treated with caution as only the uppermost logs were considered, the observation period was only 15 years and the relative abundance of the most important decay fungi considerably varied between as well as within the check dams. Consequently, for statistically sound and well-funded recommendations further investigations over a longer period are indispensable.

Retrospective Imaging and Characterization of Nuclear Material

DOE PAGES

Hayes, Robert B.; Sholom, Sergey

2017-08-01

Modern techniques for detection of covert nuclear ma-terial requires some combination of real time measurement and/or sampling of the material. More common is real time measure-ment of the ionizing emission caused by radioactive decay or through the materials measured in response to external interroga-tion radiation. One can expose the suspect material with various radiation types, including high energy photons such as x rays or with larger particles such as neutrons and muons, to obtain images or measure nuclear reactions induced in the material. Stand-off detection using imaging modalities similar to those in the medical field can be accomplished, or simplemore » collimated detec-tors can be used to localize radioactive materials. In all such cases, the common feature is that some or all of the nuclear materials have to be present for the measurement, which makes sense; as one might ask, “How you can measure something that is not there?” The current work and results show how to do exactly that: characterize nuclear materials after they have been removed from an area leaving no chemical trace. This new approach is demon-strated to be fully capable of providing both previous source spa-tial distribution and emission energy grouping. The technique uses magnetic resonance for organic insulators and/or lumines-cence techniques on ubiquitous refractory materials similar in theory to the way the nuclear industry carries out worker person-nel dosimetry. Spatial information is obtained by acquiring gridded samples for dosimetric measurements, while energy infor-mation comes through dose depth profile results that are func-tions of the incident radiation energies.« less

Retrospective Imaging and Characterization of Nuclear Material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayes, Robert B.; Sholom, Sergey

Modern techniques for detection of covert nuclear ma-terial requires some combination of real time measurement and/or sampling of the material. More common is real time measure-ment of the ionizing emission caused by radioactive decay or through the materials measured in response to external interroga-tion radiation. One can expose the suspect material with various radiation types, including high energy photons such as x rays or with larger particles such as neutrons and muons, to obtain images or measure nuclear reactions induced in the material. Stand-off detection using imaging modalities similar to those in the medical field can be accomplished, or simplemore » collimated detec-tors can be used to localize radioactive materials. In all such cases, the common feature is that some or all of the nuclear materials have to be present for the measurement, which makes sense; as one might ask, “How you can measure something that is not there?” The current work and results show how to do exactly that: characterize nuclear materials after they have been removed from an area leaving no chemical trace. This new approach is demon-strated to be fully capable of providing both previous source spa-tial distribution and emission energy grouping. The technique uses magnetic resonance for organic insulators and/or lumines-cence techniques on ubiquitous refractory materials similar in theory to the way the nuclear industry carries out worker person-nel dosimetry. Spatial information is obtained by acquiring gridded samples for dosimetric measurements, while energy infor-mation comes through dose depth profile results that are func-tions of the incident radiation energies.« less

Hybrid optimization and Bayesian inference techniques for a non-smooth radiation detection problem

DOE PAGES

Stefanescu, Razvan; Schmidt, Kathleen; Hite, Jason; ...

2016-12-12

In this paper, we propose several algorithms to recover the location and intensity of a radiation source located in a simulated 250 × 180 m block of an urban center based on synthetic measurements. Radioactive decay and detection are Poisson random processes, so we employ likelihood functions based on this distribution. Owing to the domain geometry and the proposed response model, the negative logarithm of the likelihood is only piecewise continuous differentiable, and it has multiple local minima. To address these difficulties, we investigate three hybrid algorithms composed of mixed optimization techniques. For global optimization, we consider simulated annealing, particlemore » swarm, and genetic algorithm, which rely solely on objective function evaluations; that is, they do not evaluate the gradient in the objective function. By employing early stopping criteria for the global optimization methods, a pseudo-optimum point is obtained. This is subsequently utilized as the initial value by the deterministic implicit filtering method, which is able to find local extrema in non-smooth functions, to finish the search in a narrow domain. These new hybrid techniques, combining global optimization and implicit filtering address, difficulties associated with the non-smooth response, and their performances, are shown to significantly decrease the computational time over the global optimization methods. To quantify uncertainties associated with the source location and intensity, we employ the delayed rejection adaptive Metropolis and DiffeRential Evolution Adaptive Metropolis algorithms. Finally, marginal densities of the source properties are obtained, and the means of the chains compare accurately with the estimates produced by the hybrid algorithms.« less

Correlation measurements in nuclear {beta}-decay using traps and polarized low energy beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naviliat-Cuncic, Oscar

2013-05-06

Precision measurements in nuclear {beta}-decay provide sensitive means to test discrete symmetries in the weak interaction and to determine some of the fundamental constants in semi-leptonic decays, like the coupling of the lightest quarks to charged weak bosons. The main motivation of such measurements is to find deviations from Standard Model predictions as possible indications of new physics. In this contribution I will focus on two topics related to precision measurements in nuclear {beta}-decay: i) the determination of the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix from nuclear mirror transitions and ii) the search for exotic scalar ormore » tensor contributions from {beta}{nu} angular correlations. The purpose is to underline the role being played by experimental techniques based on the confinement of radioactive species with atom and ion traps as well as the plans to use low energy polarized beams.« less

New physics with the lepton flavor violating decay τ →3 μ

NASA Astrophysics Data System (ADS)

Calcuttawala, Zaineb; Kundu, Anirban; Nandi, Soumitra; Patra, Sunando Kumar

2018-05-01

Lepton flavor violating (LFV) processes are a smoking gun signal of new physics (NP). If the semileptonic B decay anomalies are indeed due to some NP, such operators can potentially lead to LFV decays involving the second and the third generation leptons, like τ →3 μ . In this paper, we explore how far the nature of NP can be unraveled at the next generation B -factories like Belle-II, provided the decay τ →3 μ has been observed. We use four observables with which the differentiation among NP operators may be achieved to a high confidence level. Possible presence of multiple NP operators are also analyzed with the optimal observable technique. While the analysis can be improved even further if the final state muon polarizations are measured, we present this work as a motivational tool for the experimentalists, as well as a template for the analysis of similar processes.

Measuring Uranium Decay Rates for Advancement of Nuclear Forensics and Geochronology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsons-Davis, Tashi

Radioisotopic dating techniques are highly valuable tools for understanding the history of physical and chemical processes in materials related to planetary sciences and nuclear forensics, and rely on accurate knowledge of decay constants and their uncertainties. The decay constants of U-238 and U-235 are particularly important to Earth science, and often the measured values with lowest reported uncertainties are applied, although they have not been independently verified with similar precision. New direct measurements of the decay constants of U-238, Th-234, U-235, and U-234 were completed, using a range of analytical approaches. An overarching goal of the project was to ensuremore » the quality of results, including metrological traceability to facilitate implementation across diverse disciplines. This report presents preliminary results of these experiments, as a few final measurements and calculations are still in progress.« less

Towed-grid system for production and calorimetric study of homogenous quantum turbulence

NASA Astrophysics Data System (ADS)

Ciapurin, Roman; Thompson, Kyle; Ihas, Gary G.

2011-10-01

The decay of quantum turbulence is not fully understood in superfluid helium at milikelvin temperatures where the viscous normal component is absent. Vibrating grid experiments performed periously produced inhomogeneous turbulence, making the results hard to interpret. We have developed experimental methods to produce homogeneous isotropic turbulence by pulling a grid at a variable constant velocity through superfluid 4He. While using calorimetric technique to measure the energy dissipation, the Meissner effect was employed to eliminate all heat sources except from turbulent decay. A controlled divergent magnetic field provides the lift to a hollow cylindrical superconducting actuator to which the grid is attached. Position sensing is performed by measuring the inductance change of a coil when a superconductor, similar to that of the actuator, is moved inside it. This position sensing technique proved to be reliable under varying temperatures and magnetic fields, making it perfect for use in the towed-grid experiment where a rise in temperature emerges from turbulent decay. Additionally, the reproducible dependency of the grid's position on the applied magnetic field enables complete control of the actuator's motion.

High-efficiency and low-background multi-segmented proportional gas counter for β-decay spectroscopy

NASA Astrophysics Data System (ADS)

Mukai, M.; Hirayama, Y.; Watanabe, Y. X.; Schury, P.; Jung, H. S.; Ahmed, M.; Haba, H.; Ishiyama, H.; Jeong, S. C.; Kakiguchi, Y.; Kimura, S.; Moon, J. Y.; Oyaizu, M.; Ozawa, A.; Park, J. H.; Ueno, H.; Wada, M.; Miyatake, H.

2018-03-01

A multi-segmented proportional gas counter (MSPGC) with high detection efficiency and low-background event rate has been developed for β-decay spectroscopy. The MSPGC consists of two cylindrically aligned layers of 16 counters (32 counters in total). Each counter has a long active length and small trapezoidal cross-section, and the total solid angle of the 32 counters is 80% of 4 π. β-rays are distinguished from the background events including cosmic-rays by analyzing the hit patterns of independent counters. The deduced intrinsic detection efficiency of each counter was almost 100%. The measured background event rate was 0.11 counts per second using the combination of veto counters for cosmic-rays and lead block shields for background γ-rays. The MSPGC was applied to measure the β-decay half-lives of 198Ir and 199mPt. The evaluated half-lives of T1/2 = 9 . 8(7) s and 12.4(7) s for 198Ir and 199mPt, respectively, were in agreement with previously reported values. The estimated absolute detection efficiency of the MSPGC from GEANT4 simulations was consistent with the evaluated efficiency from the analysis of the β- γ spectroscopy of 199Pt, saturating at approximately 60% for Qβ > 4 MeV.

Dynamic subnanosecond time-of-flight detection for ultra-precise diffusion monitoring and optimization of biomarker preservation

NASA Astrophysics Data System (ADS)

Bauer, Daniel R.; Stevens, Benjamin; Taft, Jefferson; Chafin, David; Petre, Vinnie; Theiss, Abbey P.; Otter, Michael

2014-03-01

Recently, it has been demonstrated that the preservation of cancer biomarkers, such as phosphorylated protein epitopes, in formalin-fixed paraffin-embedded tissue is highly dependent on the localized concentration of the crosslinking agent. This study details a real-time diffusion monitoring system based on the acoustic time-of-flight (TOF) between pairs of 4 MHz focused transducers. Diffusion affects TOF because of the distinct acoustic velocities of formalin and interstitial fluid. Tissue is placed between the transducers and vertically translated to obtain TOF values at multiple locations with a spatial resolution of approximately 1 mm. Imaging is repeated for several hours until osmotic equilibrium is reached. A post-processing technique, analogous to digital acoustic interferometry, enables detection of subnanosecond TOF differences. Reference subtraction is used to compensate for environmental effects. Diffusion measurements with TOF monitoring ex vivo human tonsil tissue are well-correlated with a single exponential curve (R2>0.98) with a magnitude of up to 50 ns, depending on the tissue size (2-6 mm). The average exponential decay constant of 2 and 6 mm diameter samples are 20 and 315 minutes, respectively, although times varied significantly throughout the tissue (σmax=174 min). This technique can precisely monitor diffusion progression and could be used to mitigate effects from tissue heterogeneity and intersample variability, enabling improved preservation of cancer biomarkers distinctly sensitive to degradation during preanalytical tissue processing.

Insights into the Effects of Complement Factor H on the Assembly and Decay of the Alternative Pathway C3 Proconvertase and C3 Convertase*

PubMed Central

Bettoni, Serena; Bresin, Elena; Remuzzi, Giuseppe; Noris, Marina; Donadelli, Roberta

2016-01-01

The activated fragment of C3 (C3b) and factor B form the C3 proconvertase (C3bB), which is cleaved by factor D to C3 convertase (C3bBb). Older studies (Conrad, D. H., Carlo, J. R., and Ruddy, S. (1978) J. Exp. Med. 147, 1792–1805; Pangburn, M. K., and Müller-Eberhard, H. J. (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 2416–2420; Kazatchkine, M. D., Fearon, D. T., and Austen, K. F. (1979) J. Immunol. 122, 75–81) indicated that the complement alternative pathway regulator factor H (FH) competes with factor B for C3b binding; however, the capability of FH to prevent C3bB assembly has not been formally investigated. Moreover, in the few published studies FH did not favor C3bB dissociation. Whether FH may affect C3bBb formation from C3bB is unknown. We set up user-friendly assays based on combined microplate/Western blotting techniques that specifically detect either C3bB or C3bBb, with the aim of investigating the effect of FH on C3bB assembly and decay and C3bBb formation and decay. We document that FH does not affect C3bB assembly, indicating that FH does not efficiently compete with factor B for C3b binding. We also found that FH does not dissociate C3bB. FH showed a strong C3bBb decay-accelerating activity, as reported previously, and also exerted an apparent inhibitory effect on C3bBb formation. The latter effect was not fully attributable to a rapid FH-mediated dissociation of C3bBb complexes, because blocking decay with properdin and C3 nephritic factor did not restore C3bBb formation. FH almost completely prevented release of the smaller cleavage subunit of FB (Ba), without modifying the amount of C3bB complexes, suggesting that FH inhibits the conversion of C3bB to C3bBb. Thus, the inhibitory effect of FH on C3bBb formation is likely the sum of inhibition of C3bB conversion to C3bBb and of C3bBb decay acceleration. Further studies are required to confirm these findings in physiological cell-based settings. PMID:26903516

Novel flashlamp-based time-resolved fluorescence microscope reduces autofluorescence for 30-fold contrast enhancement in environmental samples

NASA Astrophysics Data System (ADS)

Connally, Russell; Veal, Duncan; Piper, James A.

2003-07-01

The abundance of naturally fluorescing components (autofluorophors) encountered in environmentally sourced samples can greatly hinder the detection and identification of fluorescently labeled target using fluorescence microscopy. Time-resolved fluorescence microscopy (TRFM) is a technique that reduces the effects of autofluorescence through precisely controlled time delays. Lanthanide chelates have fluorescence lifetimes many orders of magnitude greater than typical autofluorophors, and persist in their luminescence long after autofluorescence has ceased. An intense short pulse of (UV) light is used to excite fluorescence in the sample and after a short delay period the longer persisting fluorescence from the chelate is captured with an image-intensified CCD camera. The choice of pulsed excitation source for TRFM has a large impact on the price and performance of the instrument. A flashlamp with a short pulse duration was selected for our instrument because of the high spectral energy in the UV region and short pulse length. However, flash output decays with an approximate lifetime of 18μs and the TRFM requires a long-lived chelate to ensure probe fluorescence is still visible after decay of the flash plasma. We synthesized a recently reported fluorescent chelate (BHHCT) and conjugated it to a monoclonal antibody directed against the water-borne parasite Giardia lamblia. Fluorescence lifetime of the construct was determined to be 339μs +/- 14μs and provided a 45-fold enhancement of labeled Giardia over background using a gate delay of 100μs. Despite the sub-optimal decay characteristics of the light pulse, flashlamps have many advantages compared to optical chopper wheels and modulated lasers. Their low cost, lack of vibration, ease of interface and small footprint are important factors to consider in TRFM design.

Final Technical Report for ``Paths to Discovery at the LHC : Dark Matter and Track Triggering"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, Kristian

Particle Dark Matter (DM) is perhaps the most compelling and experimentally well-motivated new physics scenario anticipated at the Large Hadron Collider (LHC). The DE-SC0014073 award allowed the PI to define and pursue a path to the discovery of Dark Matter in Run-2 of the LHC with the Compact Muon Solenoid (CMS) experiment. CMS can probe regions of Dark Matter phase-space that direct and indirect detection experiments are unable to constrain. The PI’s team initiated the exploration of these regions, searching specifically for the associated production of Dark Matter with top quarks. The effort focuses on the high-yield, hadronic decays ofmore » W bosons produced in top decay, which provides the highest sensitivity to DM produced via through low-mass spin-0 mediators. The group developed identification algorithms that achieve high efficiency and purity in the selection of hadronic top decays, and analysis techniques that provide powerful signal discrimination in Run-2. The ultimate reach of new physics searches with CMS will be established at the high-luminosity LHC (HL-LHC). To fully realize the sensitivity the HL-LHC promises, CMS must minimize the impact of soft, inelastic (“pileup”) interactions on the real-time “trigger” system the experiment uses for data refinement. Charged particle trajectory information (“tracking”) will be essential for pileup mitigation at the HL-LHC. The award allowed the PI’s team to develop firmware-based data delivery and track fitting algorithms for an unprecedented, real-time tracking trigger to sustain the experiment’s sensitivity to new physics in the next decade.« less

aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay

DOE PAGES

Collett, B.; Bateman, F.; Bauder, W. K.; ...

2017-08-01

Here, we describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. This apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. We present details of the method, apparatus, detectors, data acquisition, and data reduction scheme, along with a discussion of the important systematic effects.

aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collett, B.; Bateman, F.; Bauder, W. K.

Here, we describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. This apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. We present details of the method, apparatus, detectors, data acquisition, and data reduction scheme, along with a discussion of the important systematic effects.

aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay.

PubMed

Collett, B; Bateman, F; Bauder, W K; Byrne, J; Byron, W A; Chen, W; Darius, G; DeAngelis, C; Dewey, M S; Gentile, T R; Hassan, M T; Jones, G L; Komives, A; Laptev, A; Mendenhall, M P; Nico, J S; Noid, G; Park, H; Stephenson, E J; Stern, I; Stockton, K J S; Trull, C; Wietfeldt, F E; Yerozolimsky, B G

2017-08-01

We describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. The apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. Details of the method, apparatus, detectors, data acquisition, and data reduction scheme are presented, along with a discussion of the important systematic effects.

Radioxenon Production from an Underground Nuclear Detonation

NASA Astrophysics Data System (ADS)

Sun, Y.

2016-12-01

The Comprehensive Nuclear Test Ban Treaty of 1996 has sparked the attention of many nations around the world for detecting Underground Nuclear Explosions (UNEs). The radioisotopes, specifically isotopes of xenon, Xe-131m, Xe-133m, Xe-133, and Xe-135, are being studied using their half-lives and decay networks for distinguishing civilian nuclear applications from UNEs. This study aims to simulate radioxenon concentrations and their uncertainties using analytical solutions of radioactive decay networks.