Alpha-particle spectrometer experiment

NASA Technical Reports Server (NTRS)

Gorenstein, P.; Bjorkholm, P.

1972-01-01

Mapping the radon emanation of the moon was studied to find potential areas of high activity by detection of radon isotopes and their daughter products. It was felt that based on observation of regions overflown by Apollo spacecraft and within the field of view of the alpha-particle spectrometer, a radon map could be constructed, identifying and locating lunar areas of outgassing. The basic theory of radon migration from natural concentrations of uranium and thorium is discussed in terms of radon decay and the production of alpha particles. The preliminary analysis of the results indicates no significant alpha emission.

New insights into the ligninolytic capability of a wood decay ascomycete

Treesearch

Semarjit Shary; Sally A. Ralph; Kenneth E. Hammel

2007-01-01

Wood-grown cultures of Daldinia concentrica oxidized a permethylated [beta]-14C- labeled synthetic lignin to 14CO2 and also cleaved a permethylated [alpha]-13C-labeled synthetic lignin to give C[alpha]-C[beta] cleavage products that were detected by 13C nuclear magnetic resonance spectrometry. Therefore, this ascomycete resembles white-rot basidiomycetes in attacking...

Predictions on the modes of decay of odd Z superheavy isotopes within the range 105 ≤ Z ≤ 135

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Nithya, C.

2018-05-01

The decay modes of 1051 odd Z superheavy nuclei within the range 105 ≤ Z ≤ 135, and their daughter nuclei are studied by comparing the alpha decay half-lives with the spontaneous fission half-lives. The alpha decay half-lives are calculated using the Coulomb and proximity potential model for deformed nuclei (CPPMDN) proposed by Santhosh et al. (2011) and the spontaneous fission half-lives are obtained with the shell-effect dependent formula of Santhosh et al. (Santhosh and Nithya, 2016). For a theoretical comparison, the alpha decay half-lives are also computed with the Coulomb and proximity potential model (CPPM), Viola-Seaborg-Sobiczewski semi-empirical relation (VSS), Universal curve of Poenaru et al. (UNIV), the analytical formula of Royer, and the Universal decay law of Qi et al. (UDL). The predicted decay modes and half-lives were compared with the available experimental results. The proton and neutron separation energies are calculated to identify those nuclei, which decay through proton and neutron emission. From the entire study of odd Z superheavy elements, it is seen that among 1051 nuclei, 233 nuclei exhibit proton emission and 18 nuclei exhibit neutron emission. 56 nuclei are stable against alpha decay with negative Q value for the decay. 92 nuclei show alpha decay followed by spontaneous fission and 9 nuclei show alpha decay followed by proton emission. 39 nuclei decay through full alpha chain and 595 nuclei decay through spontaneous fission. We hope that the study will be very useful for the future experimental investigations in this field.

The analysis of predictability of recent alpha decay formulae and the alpha partial half-lives of some exotic nuclei

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

Dasgupta-Schubert, N.; Reyes, M. A.; Tamez, V. A.

2009-04-20

Alpha decay is one of the two main decay modes of the heaviest nuclei, (SHE), and constitutes one of the dominant decay modes of highly neutron deficient medium mass nuclei ('exotics'). Thus identifying and characterizing the alpha decay chains form a crucial part of the identification of SHE. We report the extension of the previously developed method for the detailed and systematic investigation of the reliability of the three main extant analytical formulae of alpha decay half-lives: the generalized liquid drop model based formula of Royer et al. (FR), the Sobiczewski modified semi-empirical Viola-Seaborg formula (VSS) and the recent phenomenologicalmore » formula of Sobiczewski and Parkhomenko (SP)« less

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.

Energy-dependent etching-related impacts on CR-39 alpha detection efficiency for the Rn-222 and Rn-220 decay chains

NASA Astrophysics Data System (ADS)

Tan, Y.; Yuan, H.; Kearfott, K. J.

2018-04-01

CR-39 detectors are widely used to measure environmental levels of Rn-222, Rn-220 and their progeny. Prior research reported the CR-39 detection efficiency for alpha particles from Rn-222, Rn-220 and their progeny under a variety of etching conditions. This paper provides an explanation for interesting observations included in that work, namely that the critical incidence angle decreases with the increasing particle energy and the detection efficiency for 8.78 MeV alpha particles is zero. This paper explains these phenomena from a consideration of the interaction of alpha particles with the CR-39 detectors and the physics of etching dynamics. The proposed theory provides a rationale for an approach to optimizing the etching conditions of CR-39 detector for measuring Rn-222, Rn-220 and their progenies.

Decay studies of a long lived high spin isomer of /sup 210/Bi

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

Tuggle, D.G.

1976-08-01

A source of approximately 30 ..mu..g of pure (> 90%) /sup 210m/Bi (J..pi.. = 9-) was prepared by irradiating /sup 209/Bi in a nuclear reactor. After chemical separations to remove /sup 210/Po from the irradiated bismuth sample were completed, the /sup 210/Bi was electromagnetically separated from the /sup 209/Bi by a series of two isotope separations to create the source mentioned above. This source was then used to conduct alpha, conversion electron, gamma, gamma-gamma coincidence, and alpha-gamma coincidence spectroscopic studies of the decay of /sup 210m/Bi. The partial half life for the alpha decay of /sup 210m/Bi was measured asmore » 3.0 x 10/sup 6/ yr. A lower limit of 10/sup 13/ years was set for the partial half life for the decay of /sup 210m/Bi to /sup 210/Po. Alpha decay of /sup 210m/Bi to 8 excited states of /sup 206/Tl was observed. A lower limit of 10/sup -4/% was set for the branching ratio of the parity forbidden alpha decay of /sup 210/Bi to the /sup 206/Ti ground state. Theoretical decay rates for the alpha decays of /sup 210m/Bi, /sup 210/Bi, /sup 211/Po, and /sup 211m/Po were calculated using the method developed by Hans Mang. A comparison of the calculated and experimentally measured alpha decay rates of /sup 210m/Bi showed good agreement for the relative alpha decay rates.« less

Role of constant value of surface diffuseness in alpha decay half-lives of superheavy nuclei

NASA Astrophysics Data System (ADS)

Dehghani, V.; Alavi, S. A.; Benam, Kh.

2018-05-01

By using WKB method and considering deformed Woods-Saxon nuclear potential, deformed Coulomb potential, and centrifugal potential, the alpha decay half-lives of 68 superheavy alpha emitters have been calculated. The effect of the constant value of surface diffuseness parameter in the range of 0.1 ≤ a ≤ 0.9 (fm) on the potential barrier, tunneling probability, assault frequency, and alpha decay half-lives has been investigated. Significant differences were observed for alpha decay half-lives and decay quantities in this range of surface diffuseness. Good agreement between calculated half-lives with fitted surface diffuseness parameter a = 0.54 (fm) and experiment was observed.

INNOVATIVE EASY-TO-USE PASSIVE TECHNIQUE FOR 222RN AND 220RN DECAY PRODUCT DETECTION.

PubMed

Mishra, Rosaline; Rout, R; Prajith, R; Jalalluddin, S; Sapra, B K; Mayya, Y S

2016-10-01

The decay products of radon and thoron are essentially the radioisotopes of polonium, bismuth and lead, and are solid particulates, which deposit in different parts of the respiratory tract upon inhalation, subsequently emitting high-energy alpha particles upon their radioactive decay. Development of passive deposition-based direct progeny sensors known as direct radon and thoron progeny sensors have provided an easy-to-use technique for time-integrated measurements of the decay products only. These dosemeters are apt for large-scale population dosimetry to assign inhalation doses to the public. The paper gives an insight into the technique, the calibration, comparison with the prevalently used active grab filter paper sampling technique, alpha track diameter analysis in these progeny sensors, progeny deposition velocity measurements carried out using these detector systems in the indoor as well as outdoor environment, and applications of these sensors for time-integrated unattached fraction estimation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Estimation of the alpha decay of Platinum isotopes using different versions of theoretical formula

NASA Astrophysics Data System (ADS)

Hosseini, S. S.; Hassanabadi, H.; Sobhani, H.

The alpha decay half-lives of even-even and even-odd Platinum (Pt) nuclei have been studied within the Coulomb and proximity potential model (CPPM). The present study is restricted to even-even nuclei with A = 166-198. The results are compared with other calculations such as the Semi-empirical formula (SemFIS) from Poenaru et al. based on fission theory of alpha decay, the Viola-Seaborg (VS), Royer (R) and Brown formulae. Also, the alpha decay half-lives have been calculated using the Scaling law of Brown (SLB), the Universal Decay Law (UDL) of Qi et al., the Scaling Law of Horoi et al. (SLH), and Akrawy-Dorin formula (ADF) of Akrawy and Poenaru, which are the Royer modified formula for alpha decay half-live by adding asymmetry term.

Radiation detector

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

Taleyarkhan, Rusi P.

Alpha particle detecting devices are disclosed that have a chamber that can hold a fluid in a tensioned metastable state. The chamber is tuned with a suitable fluid and tension such that alpha emitting materials such as radon and one or more of its decay products can be detected. The devices can be portable and can be placed in areas, such as rooms in dwellings or laboratories and used to measure radon in these areas, in situ and in real time. The disclosed detectors can detect radon at and below 4 pCi/L in air; also, at and below 4,000 pCi/Lmore » or 300 pCi/L in water.« less

The BetaCage: Ultrasensitive Screener for Radioactive Backgrounds

NASA Astrophysics Data System (ADS)

Thompson, Michael; BetaCage Collaboration

2017-09-01

Rare event searches, such as dark matter detection and neutrinoless double beta decay, require screening of materials for backgrounds such as beta emission and alpha decaying isotopes. The BetaCage is a proposed ultra-sensitive time-projection chamber to screen for alpha-emitting and low energy beta-emitting (10-200 keV) contaminants. The expected sensitivity is 0.1 beta particles (perkeV -m2 - day) and 0.1 alpha particles (perm2 - day) , where the former will be limited by Compton scattering of external photons in the screening samples and the latter is expected to be signal-limited. The prototype BetaCage under commissioning at South Dakota School of Mines & Technology is filled with P10 gas (10% methane, 90% argon) in place of neon and is 40×40×20 cm in size. Details on design, construction and characterization will be presented.

alpha-decay half-lives and Q{sub a}lpha values of superheavy nuclei

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

Dong Jianmin; Graduate University of Chinese Academy of Sciences, Beijing 100049; School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000

2010-06-15

The alpha-decay half-lives of recently synthesized superheavy nuclei (SHN) are investigated by employing a unified fission model (UFM) where a new method to calculate the assault frequency of alpha emission is used. The excellent agreement with the experimental data indicates the UFM is a useful tool to investigate these alpha decays. It is found that the alpha-decay half-lives become more and more insensitive to the Q{sub a}lpha values as the atomic number increases on the whole, which is favorable for us to predict the half-lives of SHN. In addition, a formula is proposed to compute the Q{sub a}lpha values formore » the nuclei with Z>=92 and N>=140 with a good accuracy, according to which the long-lived SHN should be neutron rich. Several weeks ago, two isotopes of a new element with atomic number Z=117 were synthesized and their alpha-decay chains have been observed. The Q{sub a}lpha formula is found to work well for these nuclei, confirming its predictive power. The experimental half-lives are well reproduced by employing the UFM with the experimental Q{sub a}lpha values. This fact that the experimental half-lives are compatible with experimental Q{sub a}lpha values supports the synthesis of a new element 117 and the experimental measurements to a certain extent.« less

Search for long lived heaviest nuclei beyond the valley of stability

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

Chowdhury, P. Roy; Samanta, C.; Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284-2000

2008-04-15

The existence of long lived superheavy nuclei (SHN) is controlled mainly by spontaneous fission and {alpha}-decay processes. According to microscopic nuclear theory, spherical shell effects at Z=114, 120, 126 and N=184 provide the extra stability to such SHN to have long enough lifetime to be observed. To investigate whether the so-called 'stability island' could really exist around the above Z, N values, the {alpha}-decay half-lives along with the spontaneous fission and {beta}-decay half-lives of such nuclei are studied. The {alpha}-decay half-lives of SHN with Z=102-120 are calculated in a quantum tunneling model with DDM3Y effective nuclear interaction using Q{sub {alpha}}more » values from three different mass formulas prescribed by Koura-Uno-Tachibana-Yamada (KUTY), Myers-Swiatecki (MS), and Muntian-Hofmann-Patyk-Sobiczewski (MMM). Calculation of spontaneous fission (SF) half-lives for the same SHN are carried out using a phenomenological formula and compared with SF half-lives predicted by Smolanczuk et al. A possible source of discrepancy between the calculated {alpha}-decay half-lives of some nuclei and the experimental data of GSI, JINR-FLNR, RIKEN, is discussed. In the region of Z=106-108 with N{approx}160-164, the {beta}-stable SHN {sub 106}{sup 268}Sg{sub 162} is predicted to have highest {alpha}-decay half-life (T{sub {alpha}}{approx}3.2 h) using Q{sub {alpha}} value from MMM. Interestingly, it is much greater than the recently measured T{sub {alpha}} ({approx}22 s) of deformed doubly magic {sub 108}{sup 270}Hs{sub 162} nucleus. A few fission-survived long-lived SHN which are either {beta}-stable or having large {beta}-decay half-lives are predicted to exist near {sup 294}110{sub 184}, {sup 293}110{sub 183}, {sup 296}112{sub 184}, and {sup 298}114{sub 184}. These nuclei might decay predominantly through {alpha}-particle emission.« less

Beta/gamma and alpha backgrounds in CRESST-II Phase 2

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

Strauss, R.; Angloher, G.; Ferreiro Iachellini, N.

2015-06-01

The experiment CRESST-II aims at the detection of dark matter with scintillating CaWO{sub 4} crystals operated as cryogenic detectors. Recent results on spin-independent WIMP-nucleon scattering from the CRESST-II Phase 2 allowed to probe a new region of parameter space for WIMP masses below 3 GeV/c{sup 2}. This sensitivity was achieved after background levels were reduced significantly. We present extensive background studies of a CaWO{sub 4} crystal, called TUM40, grown at the Technische Universität München. The average beta/gamma rate of 3.51/[kg keV day] (1-40 keV) and the total intrinsic alpha activity from natural decay chains of 3.08±0.04 mBq/kg are the lowestmore » reported for CaWO{sub 4} detectors. Contributions from cosmogenic activation, surface-alpha decays, external radiation and intrinsic alpha/beta emitters are investigated in detail. A Monte-Carlo based background decomposition allows to identify the origin of the majority of beta/gamma events in the energy region relevant for dark matter search.« less

Preliminary results from the lunar prospector alpha particle spectrometer

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

Lawson, S. L.

2001-01-01

The Lunar Prospector Alpha Particle Spectrometer (LP APS) builds on Apollo heritage and maps the distribution of outgassing sites on the Moon. The APS searches for lunar surface gas release events and maps their distribution by detecting alpha particles produced by the decay of gaseous radon-222 (5.5 MeV, 3.8 day half-life) and solid polonium-210 (5.3 MeV, 138 day half-life, but remains on the surface with a 21 year half-life as lead-210), which are radioactive daughters from the decay of uranium-238. Radon is in such small quantities that it is not released directly from the lunar interior, rather it is entrainedmore » in a stream of gases and serves as a tracer for such gases. Once released, the radon spreads out by 'bouncing' across the surface on ballistic trajectories in a random-walk process. The 3.8 day half-life of radon-222 allows the gas to spread out by several 100 km before it decays and allows the APS to detect gas release events up to a few days after they occur. The long residence time (10s of years) of the lead-210 precursor to the polonium-210 allows the mapping of gas vents which have been active over the last approximately 50 years. Because radon and polonium are daughter products of the decay of uranium, the background level of alpha particle activity is a function of the lunar crustal uranium distribution. Using radioactive radon and polonium as tracers, the Apollo 15 and 16 Command Module orbital alpha particle experiments obtained evidence for the release of gases at several sites beneath the orbit tracks, especially over the Aristarchus Plateau and Mare Fecunditatis [1]. Aristarchus crater had previously been identified by ground-based observers as the site of transient optical events [2]. The Apollo 17 surface mass spectrometer showed that argon-40 is released from the lunar interior every few months, apparently in concert with some of the shallow moonquakes that are believed to be of tectonic origin [3]. The latter tectonic events could be associated with very young scarps identified in the lunar highlands [4] and are believed to indicate continued global contraction. Such quakes could open fissures leading to the release of gases that are trapped below the surface. The detection of radon-222 outgassing events at the margins of Fecunditatis basin was surprising because the observed surface distribution of uranium and thorium do not extend sufficiently eastward to cover Fecunditatis. If the Apollo detections prove sound, then those alpha particle emissions indicate substantial subsurface concentrations of uranium-238 within Fecunditatis. A primary goal of the APS was to map gas-release events, thus allowing both an appraisal of the current level of tectonic activity on the Moon and providing a probe of subsurface uranium concentrations.« less

Solar wind alpha particle capture at Mars and Venus

NASA Astrophysics Data System (ADS)

Stenberg, Gabriella; Barabash, Stas; Nilsson, Hans; Fedorov, A.; Brain, David; André, Mats

Helium is detected in the atmospheres of both Mars and Venus. It is believed that radioactive decay of uranium and thorium in the interior of the planets' is not sufficient to account for the abundance of helium observed. Alpha particles in the solar wind are suggested to be an additional source of helium, especially at Mars. Recent hybrid simulations show that as much as 30We use ion data from the ASPERA-3 and ASPERA-4 instruments on Mars and Venus Express to estimate how efficient solar wind alpha particles are captured in the atmospheres of the two planets.

Automated QA/QC Check for Beta-Gamma Coincidence Detector

DTIC Science & Technology

2007-09-01

of the ARSA, 222Rn gas can be introduced into the gas cell, along with the radioactive xenon isotopes. While this radon decays via alpha decay and...Explosion Monitoring Technologies 741 Figure 2. γ-singles spectrum from a 222Rn spike. The peaks are primarily from the radon daughter 214Pb with...National Laboratory (PNNL), can collect and detect several radioxenon isotopes. The ARSA is very sensitive to 133Xe, 131mXe, 133mXe, and 135Xe due to the

Principles of gross alpha and beta radioactivity detection in water.

PubMed

Semkow, T M; Parekh, P P

2001-11-01

A simultaneous detection of gross alpha and beta radioactivity was studied using gas proportional counting. This measurement is a part of a method mandated by US Environmental Protection Agency to screen for alpha and beta radioactivity in drinking water. Responses of a gas proportional detector to alpha and beta particles from several radionuclides were determined in drop and electroplated geometries. It is shown that, while the alpha radioactivity can be measured accurately in the presence of beta radioactivity, the opposite is not typically true due to alpha-to-beta crosstalk. The crosstalk, originating from the emission of conversion and Auger electrons as well as x rays, is shown to be dependent primarily on the particular alpha-decay scheme while the dependence on alpha energy is small but negligible. It was measured at 28-35% for 241Am, 22-24% for 230Th, and 4.9-6.5% for 239Pu. For 210Po, the crosstalk of 1.2-1.6% was observed mostly due to energy retardation. A method of reducing the crosstalk to a <3% level is proposed by absorbing the atomic electrons in a 6.2 mg cm(-2) Al absorber, at the same time decreasing the beta efficiency by 16-31%.

Recent {alpha} decay half-lives and analytic expression predictions including superheavy nuclei

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

Royer, G.; Zhang, H. F.

New recent experimental {alpha} decay half-lives have been compared with the results obtained from previously proposed formulas depending only on the mass and charge numbers of the {alpha} emitter and the Q{sub {alpha}} value. For the heaviest nuclei they are also compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The correct agreement allows us to make predictions for the {alpha} decay half-lives of other still unknown superheavy nuclei from these analytic formulas using the extrapolated Q{sub {alpha}} of G. Audi, A. H. Wapstra, and C. Thibault [Nucl. Phys. A729, 337 (2003)].

GRB 050117: Simultaneous Gamma-ray and X-ray Observations with the Swift Satellite

NASA Technical Reports Server (NTRS)

Hill, J. E.; Morris, D. C.; Sakamoto, T.; Sato, G.; Burrows, D. N.; Angelini, L.; Pagani, C.; Moretti, A.; Abbey, A. F.; Barthelmy, S.

2005-01-01

The Swift Gamma-Ray Burst Explorer performed its first autonomous, X-ray follow-up to a newly detected GRB on 2005 January 17, within 193 seconds of the burst trigger by the Swift Burst Alert Telescope. While the burst was still in progress, the X-ray Telescope obtained a position and an image for an un-catalogued X-ray source; simultaneous with the gamma-ray observation. The XRT observed flux during the prompt emission was 1.1 x 10(exp -8) ergs/sq cm/s in the 0.5-10 keV energy band. The emission in the X-ray band decreased by three orders of magnitude within 700 seconds, following the prompt emission. This is found to be consistent with the gamma-ray decay when extrapolated into the XRT energy band. During the following 6.3 hours, the XRT observed the afterglow in an automated sequence for an additional 947 seconds, until the burst became fully obscured by the Earth limb. A faint, extremely slowly decaying afterglow, alpha=-0.21, was detected. Finally, a break in the lightcurve occurred and the flux decayed with alpha<-1.2. The X-ray position triggered many follow-up observations: no optical afterglow could be confirmed, although a candidate was identified 3 arcsecs from the XRT position.

Observation of lunar radon emanation with the Apollo 15 alpha particle spectrometer.

NASA Technical Reports Server (NTRS)

Gorenstein, P.; Bjorkholm, P.

1972-01-01

The alpha particle spectrometer, a component of the orbital Sim Bay group of 'geochemistry' experiments on Apollo 15, was designed to detect alpha particles emitted during the decay of isotopes of radon gas and her daughter products. The purpose was to measure the gross activity of radon on the lunar surface and to find possible regions of increased local activity. Results are presented from a partial analysis of Apollo 15 data. For the moon as a whole, Rn220 was not observed and the upper limit on its decay rate above the lunar surface is 0.00038 disintegrations/sq cm-sec. Rn222 was marginally observed. Possible variations of radon activity on the lunar surface are being investigated. Po210 (a daughter product of Rn222) has been detected in a broad region from west of Mare Crisium to the Van de Graaff-Orlov region. The observed count rate is (4.6 plus or minus 1.4) x 0.001 disintegrations/sq cm-sec. The observed level of Po210 activity is in excess of the amount that would be in equilibrium with Rn222 by about an order of magnitude. This implies that larger levels of radon emanation have occurred on the moon within a time scale of 10 to 100 years.

Binding-dependent disorder-order transition in PKI alpha: a fluorescence anisotropy study.

PubMed

Hauer, J A; Taylor, S S; Johnson, D A

1999-05-25

The conformational flexibility of peptidyl ligands may be an essential element of many peptide-macromolecular interactions. Consequently, the alpha-carbonyl backbone flexibility of the 8 kDa protein kinase inhibitor (PKI alpha) peptide of cAMP-dependent protein kinase (cAPK) free in solution and bound to cAPK was assessed by time-resolved fluorescence anisotropy. Specifically, three full-length, single-site PKI alpha mutants (V3C, S28C, and S59C) were prepared, and fluorescein iodoacetamide (FI) was selectively conjugated to the side chains of each substituted cysteine. The time-resolved anisotropy decay profiles of the labeled mutants were well fit to a model-free nonassociative biexponential equation. Free in solution, the three labeled proteins had very similar anisotropy decays arising primarily from local alpha-carbonyl backbone movements. Only a small fraction of the anisotropy decay was associated with slower, whole-body tumbling, confirming that PKI alpha is highly disordered at all three locations. Complexation of the mutants with the catalytic (C) subunit of cAPK decreased the rate of whole-body tumbling for all three mutants. The effects on the rapid decay processes, however, were dependent upon the site of conjugation. The anisotropy decay profiles of both FI-V3C- and FI-S28C-PKI alpha were associated with significantly reduced contributions from the fast decay processes, while that of FI-S59C-PKI alpha was largely unaffected by binding to the C-subunit. The results suggest that the cAPK-binding domain of PKI alpha extends from the its N-terminus to residues beyond Ser28 but does not include the segment around Ser59, which is still part of a highly flexible domain when bound to the C-subunit.

Theoretical and experimental {alpha} decay half-lives of the heaviest odd-Z elements and general predictions

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

Zhang, H. F.; Royer, G.

Theoretical {alpha} decay half-lives of the heaviest odd-Z nuclei are calculated using the experimental Q{sub {alpha}} value. The barriers in the quasimolecular shape path are determined within a Generalized Liquid Drop Model (GLDM) and the WKB approximation is used. The results are compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The calculations provide consistent estimates for the half-lives of the {alpha} decay chains of these superheavy elements. The experimental data stand between the GLDM calculations and VSS ones in the most time. Predictions are provided for the {alpha} decay half-lives of other superheavymore » nuclei within the GLDM and VSS approaches using the recent extrapolated Q{sub {alpha}} of Audi, Wapstra, and Thibault [Nucl. Phys. A729, 337 (2003)], which may be used for future experimental assignment and identification.« less

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

Kurgalin, S. D.; Tchuvil’sky, Yu. M., E-mail: tchuvl@nucl-th.sinp.msu.ru; Churakova, T. A.

A universal theoretical model intended for calculating internal-bremsstrahlung spectra is proposed. In this model, which can be applied to describing nuclear decays of various type (such as alpha decay, cluster decay, and proton emission), use is made of realistic nucleus–nucleus potentials. Theoretical internal-bremsstrahlung spectra were obtained for the alpha decay of the {sup 214}Po nucleus, as well as for the decay of the {sup 222}Ra nucleus via the emission of a {sup 14}C cluster and for the decay of the {sup 113}Cs nucleus via proton emission, and the properties of these spectra were studied. The contributions of various regions (internal,more » subbarrier, and external) to the internal-bremsstrahlung amplitude were analyzed in detail. It is shown that the contribution of the internal region to the amplitude for internal bremsstrahlung generated in nuclear decay via proton emission is quite large, but that this is not so for alpha decay and decay via cluster emission. Thus, a process in which strong interaction of nuclear particles affects the internal-bremsstrahlung spectrum if found.« less

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.

Alpha-cluster preformation factor within cluster-formation model for odd-A and odd-odd heavy nuclei

NASA Astrophysics Data System (ADS)

Saleh Ahmed, Saad M.

2017-06-01

The alpha-cluster probability that represents the preformation of alpha particle in alpha-decay nuclei was determined for high-intensity alpha-decay mode odd-A and odd-odd heavy nuclei, 82 < Z < 114, 111 < N < 174. This probability was calculated using the energy-dependent formula derived from the formulation of clusterisation states representation (CSR) and the hypothesised cluster-formation model (CFM) as in our previous work. Our previous successful determination of phenomenological values of alpha-cluster preformation factors for even-even nuclei motivated us to expand the work to cover other types of nuclei. The formation energy of interior alpha cluster needed to be derived for the different nuclear systems with considering the unpaired-nucleon effect. The results showed the phenomenological value of alpha preformation probability and reflected the unpaired nucleon effect and the magic and sub-magic effects in nuclei. These results and their analyses presented are very useful for future work concerning the calculation of the alpha decay constants and the progress of its theory.

Determination of the volume activity concentration of alpha artificial radionuclides with alpha spectrometer.

PubMed

Liu, B; Zhang, Q; Li, Y

1997-12-01

This paper introduces a method to determine the volume activity concentration of alpha and/or beta artificial radionuclides in the environment and radon/thoron progeny background-compensation based on a Si surface-barrier detector. By measuring the alpha peak counts of 218Po and 214Po in two time intervals, the activity concentration of 218Po, 214Pb and 214Bi aerosol particles were determined; meanwhile, the total beta count of 214Pb and 214Bi aerosols was also calculated from their decay scheme. With the average equilibrium factor of thoron progeny in general environment, the alpha and beta counts of thoron progeny were approximately evaluated by 212Po alpha peak counts. The alpha count of transuranic aerosols was determined by subtracting the trail counts of radon/thoron progeny alpha peaks. The total count of beta artificial radionuclides was determined by subtracting the beta counts of radon/thoron progeny aerosol particles. In our preliminary experiments, if the radon progeny concentration is less than 15 Bq m(-3), the lower limit of detection of transuranics concentration is less than 0.1 Bq m(-3). Even if the radon progeny concentration is as high as 75 Bq m(-3), the lower limit of detection of total beta activity concentration of artificial nuclides aerosols is less than 1 Bq m(-3).

On the Numerical Analysis of Decay Rate Enhancement in Metallic Environment

NASA Astrophysics Data System (ADS)

Mehedinteanu, S.

2007-10-01

Motivated on the very recent experiments to determine the acceleration of the alpha decay of meta-stable radionuclides in metallic environment some work has been done to strengthten the importance in the process of electrons screening in metals. Thus, by combining the Gamow decay theory with electrostatic screening in Debye-Hückel approximation (jellium model) a formula for ``the shift'' in screening energy which enters in the decay enhancement factor expression that copes well with these experiments has been derived. It was established that to simulate the poly-atoms system containing decaying isotopes in QM&MD codes calculations, and to include ``the screening energy shift'' of protons, decay alpha, beta+ particles due to all surrounding interacting effects, it is sufficiently only to substitute the code ruly pseudo-potential input for hydrogen-like atoms (including alpha) by a screened Coulomb potential as from the well-known Gamow alpha decay theory. For demonstration is used the QM&MD code package which usually performs density-functional theory (DFT) total-energy calculations for materials ranging from insulators to transition metals. This package employs first-principles pseudo-potentials and a plane-wave basis-set, and it was used to do a special calculus for some metal environments (Pd) where protons-deuterons are implanted or when it is alloyed with a radionuclide-like isotopes (174Hf72), the results compare well with the existing experiments on the decay enhancement. These works give further arguments for a cheap solution to remove the transuranic waste (involving all alpha-decay) of used-up rods of fission reactors in a time period of a few years.

A comparative analysis of alpha-decay half-lives for even-even 178Pb to 234U isotopes

NASA Astrophysics Data System (ADS)

Hosseini, S. S.; Hassanabadi, H.; Zarrinkamar, S.

2018-02-01

The feasibility for the alpha decay from the even-even transitions of 178Pb to 234U isotopes has been studied within the Coulomb and proximity potential model (CPPM). The alpha decay half-lives are considered from different theoretical approaches using Semi-empirical formula of Poenaru et al. (SemFIS), the Universal Decay law (UDL) of Qi et al., Akrawy-Dorin formula of Akrawy and Poenaru (ADF), the Scaling law of Brown (SLB) and the Scaling Law of Horoi et al. (SLH). The numerical results obtained by the CPPM and compared with other method as well the experimental data.

The BetaCage, an ultra-sensitive screener for surface contamination

NASA Astrophysics Data System (ADS)

Bunker, R.; Ahmed, Z.; Bowles, M. A.; Golwala, S. R.; Grant, D. R.; Kos, M.; Nelson, R. H.; Schnee, R. W.; Rider, A.; Wang, B.; Zahn, A.

2013-08-01

Material screening for identifying low-energy electron emitters and alpha-decaying isotopes is now a prerequisite for rare-event searches (e.g., dark-matter direct detection and neutrinoless double-beta decay) for which surface radiocon-tamination has become an increasingly important background. The BetaCage, a gaseous neon time-projection chamber, is a proposed ultra-sensitive (and nondestructive) screener for alpha-and beta-emitting surface contaminants to which existing screening facilities are insufficiently sensitive. Sensitivity goals are 0.1 betas keV-1 m-2 day-1 and 0.1 alphas m-2 day-1, with the former limited by Compton scattering of photons in the screening samples and (thanks to tracking) the latter expected to be signal-limited; radioassays and simulations indicate backgrounds from detector materials and radon daughters should be subdominant. We report on details of the background simulations and detector design that provide the discrimination, shielding, and radiopurity necessary to reach our sensitivity goals for a chamber with a 95 × 95 cm2 sample area positioned below a 40 cm drift region and monitored by crisscrossed anode and cathode planes consisting of 151 wires each.

Decay properties of 256-339Ds superheavy nuclei

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Nithya, C.

2017-09-01

The decay properties of 84 isotopes of darmstadtium superheavy nuclei ( Z = 110) have been studied using various theoretical models. The proton emission half-lives, the alpha decay half-lives, the spontaneous fission half-lives and the cluster decay half-lives of all the isotopes are evaluated. The one-proton emission half-lives and the alpha decay half-lives are predicted using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The calculated alpha half-lives are compared with the available experimental results as well as with the predictions of other theoretical models. The predicted half-lives matches well with the experimental results. The one-proton half-lives are also compared with the predictions using other formalisms. The shell-effect-dependent formula of Santhosh et al. has been employed for calculating the spontaneous fission half-lives. A theoretical comparison of spontaneous fission half-lives with four different formalisms is performed. By comparing the one-proton emission half-lives, the alpha decay half-lives and the spontaneous fission half-lives decay modes are predicted for all the isotopes of Ds. It is seen that the isotopes within the range 256 ≤ A ≤ 263 and 279 ≤ A ≤ 339 decay through spontaneous fission and the isotopes 264 ≤ A ≤ 278 exhibit alpha decay. Cluster decay half-lives are calculated using different models including the Coulomb and proximity potential (CPPM), for determining the magicities in the superheavy region. The effect of magicity at N = 184 and N = 202 were confirmed from the plot of log_{10}T_{1/2} versus neutron number of the daughter nuclei for the emission of different clusters. We hope that the systematic and detailed study of all the possible decay modes of 256-339Ds using various theoretical models will be helpful in the experimental identification of the isotopes of the element in the future.

High-pressure xenon time projection Titanium chamber: a methodology for detecting background radiation in neutrinoless double-beta decay experiments

NASA Astrophysics Data System (ADS)

Bachri, A.; Elmhamdi, A.; Hawron, M.; Grant, P.; Zazoum, B.; Martin, C.

2017-10-01

The xenon time projection chamber (TPC) promises a novel detection method for neutrinoless double-beta decay (0ν β β ) experiments. The TPC is capable of discovering the rare 0ν β β ionization signal of a distinct topological signature, with a decay energy Qββ = 2.458 MeV . However, more frequent internal (within TPC) and external events are also capable of depositing energy in the range of the Qβ β -value inside the chamber, thus mimicking 0ν β β or interfering with its direct observation. In the following paper, we illustrate a methodology for background radiation evaluation, assuming a basic cylindrical design for a toy titanium TPC that is capable of containing 100 kg of xenon gas at 20 atm pressure; we estimate the background budget and analyze the most prominent problematic events via theoretical calculation. Gamma rays emitted from nuclei of 214Bi and 208Tl present in the outer-shell titanium housing of the TPC are an example of such events for which we calculate probabilities of occurrences. We also study the effect of alpha-neutron (α-n)-induced neutrons and calculate their rate. Alpha particles which are created by the decay of naturally occurring uranium and thorium present in most materials, can react with the nucleus of low Z elements, prompting the release of neutrons and leading to thermal neutron capture. Our calculations suggest that the typical polytetrafluoroethylene (PTFE) inner coating of the chamber would constitute the primary material for neutron production, specifically; we find that the fluorine component of Teflon is much more likely to undergo an (α-n) reaction. From known contamination, we calculate an alpha production rate to be 5.5 × 107 alpha/year for the highest-purity titanium vessel with a Teflon lining. Lastly, using measurements of neutron flux from alpha bombardment, we estimate the expected neutron flux from the materials of the proposed toy TPC and identify all gamma rays (prompt or delayed, of energies comparable to the Qβ β -value) originating from thermal neutron capture with all stable elemental isotopes present in the TPC. We show that to limit the most probable reactions to a rate of one event per year or less, the neutron flux would have to be reduced to (3-6) × 10-10 cm-2ṡs-1. The predictions of our crude theoretical calculation are in good agreement with full simulation of TPC radiation background by existing experimental collaboration using xenon for 0ν β β experiment.

Alpha Decay Potential Barriers and Half-Lives and Analytical Formula Predictions for Superheavy Nuclei

NASA Astrophysics Data System (ADS)

Royer, Guy; Zhang, Hongfei

The α decay potential barriers are determined in the cluster-like shape path within a generalized liquid drop model including the proximity effects between the α particle and the daughter nucleus and adjusted to reproduce the experimental Qα. The α emission half-lives are determined within the WKB penetration probability. Calculations using previously proposed formulae depending only on the mass and charge of the alpha emitter and Qα are also compared with new experimental alpha-decay half-lives. The agreement allows to provide predictions for the α decay half-lives of other still unknown superheavy nuclei using the Qα determined from the 2003 atomic mass evaluation of Audi, Wapstra and Thibault.

Derivation of Soil Screening Guidelines for Gross Alpha/Beta Radioactivity for United States Air Force Deployment Sites

DTIC Science & Technology

2007-04-19

These levels are provided to assist in making decisions in case of a large accident. Assessment can be made based on what health effects can be...a beta particle to become polonium -214 (99.98% of decays), or it can emit an alpha particle to become thallium- 210 (0.02% of decays). Bismuth-214...lead- 210 , and polonium - 210 . A decay of bismuth-214 will eventually yield 5 alpha particles and 4 beta particles. Four radionuclides that occur in

Manifestation of the structure of heavy nuclei in their alpha decays

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

Adamian, G. G., E-mail: adamian@theor.jinr.ru; Antonenko, N. V.; Bezbakh, A. N.

2016-11-15

Low-lying one- and two-quasiparticle states of heavy nuclei are predicted. Alpha-decay chains, including those that proceed through isomeric states, are examined on the basis of the predicted properties of superheavy nuclei.

Hypernuclear Weak Decays

NASA Astrophysics Data System (ADS)

Itonaga, K.; Motoba, T.

The recent theoretical studies of Lambda-hypernuclear weak decaysof the nonmesonic and pi-mesonic ones are developed with the aim to disclose the link between the experimental decay observables and the underlying basic weak decay interactions and the weak decay mechanisms. The expressions of the nonmesonic decay rates Gamma_{nm} and the decay asymmetry parameter alpha_1 of protons from the polarized hypernuclei are presented in the shell model framework. We then introduce the meson theoretical Lambda N -> NN interactions which include the one-meson exchanges, the correlated-2pi exchanges, and the chiral-pair-meson exchanges. The features of meson exchange potentials and their roles on the nonmesonic decays are discussed. With the adoption of the pi + 2pi/rho + 2pi/sigma + omega + K + rhopi/a_1 + sigmapi/a_1 exchange potentials, we have carried out the systematic calculations of the nonmesonic decay observables for light-to-heavy hypernuclei. The present model can account for the available experimental data of the decay rates, Gamma_n/Gamma_p ratios, and the intrinsic asymmetry parameters alpha_Lambda (alpha_Lambda is related to alpha_1) of emitted protons well and consistently within the error bars. The hypernuclear lifetimes are evaluated by converting the total weak decay rates Gamma_{tot} = Gamma_pi + Gamma_{nm} to tau, which exhibit saturation property for the hypernuclear mass A ≥ 30 and agree grossly well with experimental data for the mass range from light to heavy hypernuclei except for the very light ones. Future extensions of the model and the remaining problems are also mentioned. The pi-mesonic weak processes are briefly surveyed, and the calculations and predictions are compared and confirmed by the recent high precision FINUDA pi-mesonic decay data. This shows that the theoretical basis seems to be firmly grounded.

Expected accuracy in a measurement of the CKM angle alpha using a Dalitz plot analysis of B0 ---> rho pi decays in the BTeV project

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

Shestermanov, K.E.; Vasiliev, A.N; /Serpukhov, IHEP

2005-12-01

A precise measurement of the angle {alpha} in the CKM triangle is very important for a complete test of Standard Model. A theoretically clean method to extract {alpha} is provided by B{sup 0} {yields} {rho}{pi} decays. Monte Carlo simulations to obtain the BTeV reconstruction efficiency and to estimate the signal to background ratio for these decays were performed. Finally the time-dependent Dalitz plot analysis, using the isospin amplitude formalism for tre and penguin contributions, was carried out. It was shown that in one year of data taking BTeV could achieve an accuracy on {alpha} better than 5{sup o}.

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+.

Synthesis of rutherfordium isotopes in the 238U(26Mg, xn)264-xRf reaction and study of their decay properties

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

Gates, Jacklyn M; Gates, J.M.; Garcia, M.A.

2008-01-15

Isotopes of rutherfordium (258-261Rf) were produced in irradiations of 238U targets with 26Mg beams. Excitation functions were measured for the 4n, 5n and 6n exit channels. Production of 261Rf in the 3n exit channel with a cross section of 28+92-26 pb was observed. Alpha decay of 258Rf was observed for the first time with an alpha-particle energy of 9.05+-0.03 MeV and an alpha/total decay branching ratio of 0.31+-0.11. In 259Rf, the electron capture/total decay branching ratio was measured to be 0.15+-0.04. The measured half-lives for 258Rf, 259Rf and 260Rf were 14.7+1.2-1.0 ms, 2.5+0.4-0.3 s and 22.2+3.0-2.4 ms, respectively, in agreementmore » with literature data. The systematics of the alpha decay Q values and of the partial spontaneous fission half-lives were evaluated for even-even nuclides in the region of the N = 152, Z = 100 deformed shell. The influence of the N = 152 shell on the alpha decay Q values for rutherfordium was observed to be similar to that of the lighter elements (96<_ Z<_ 102). However, the N = 152 shell does not stabilize the rutherfordium isotopes against spontaneous fission, as it does in the lighter elements (96<_ Z<_102).« less

Alpha-decay-induced fracturing in zircon - The transition from the crystalline to the metamict state

NASA Technical Reports Server (NTRS)

Chakoumakos, Bryan C.; Murakami, Takashi; Lumpkin, Gregory R.; Ewing, Rodney C.

1987-01-01

Zonation due to alpha-decay damage in a natural single crystal of zircon from Sri Lanka is discussed. The zones vary in thickness on a scale from one to hundreds of microns. The uranium and thorium concentrations vary from zone to zone such that the alpha decay dose is between 0.2 x 10 to the 16th and 0.8 x 10 to the 16th alpha-events per milligram. The transition from the crystalline to the aperiodic metamict state occurs over this dose range. At doses greater than 0.8 x 10 to the 16th alpha events/mg there is no evidence for long-range order. This type of damage will accumulate in actinide-bearing, ceramic nuclear waste forms. The systematic pattern of fractures would occur in crystalline phases that are zoned with respect to actinide radionuclides.

Reducing DRIFT backgrounds with a submicron aluminized-mylar cathode

NASA Astrophysics Data System (ADS)

Battat, J. B. R.; Daw, E.; Dorofeev, A.; Ezeribe, A. C.; Fox, J. R.; Gauvreau, J.-L.; Gold, M.; Harmon, L.; Harton, J.; Lafler, R.; Landers, J.; Lauer, R. J.; Lee, E. R.; Loomba, D.; Lumnah, A.; Matthews, J.; Miller, E. H.; Mouton, F.; Murphy, A. St. J.; Paling, S. M.; Phan, N.; Sadler, S. W.; Scarff, A.; Schuckman, F. G.; Snowden-Ifft, D.; Spooner, N. J. C.; Walker, D.

2015-09-01

Background events in the DRIFT-IId dark matter detector, mimicking potential WIMP signals, are predominantly caused by alpha decays on the central cathode in which the alpha particle is completely or partially absorbed by the cathode material. We installed a 0.9 μm 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 the ratio of background events to alpha decays. Two independent methods of measuring the absolute alpha decay rate are used to ensure an accurate result, and agree to within 10%. Using alpha range spectroscopy, we measure the radiologically cleanest cathode version to have a contamination of 3.3±0.1 ppt 234U and 73±2 ppb 238U. This cathode reduces the probability of producing an RPR from an alpha decay by a factor of 70±20 compared to the original stainless steel wire cathode. First results are presented from a texturized version of the cathode, intended to be even more transparent to alpha particles. These efforts, along with other background reduction measures, have resulted in a drop in the observed background rate from 500/day to 1/day. With the recent implementation of full-volume fiducialization, these remaining background events are identified, allowing for background-free operation.

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.

The BetaCage, an ultra-sensitive screener for surface contamination

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

Bunker, R.; Bowles, M. A.; Schnee, R. W.

Material screening for identifying low-energy electron emitters and alpha-decaying isotopes is now a prerequisite for rare-event searches (e.g., dark-matter direct detection and neutrinoless double-beta decay) for which surface radiocon-tamination has become an increasingly important background. The BetaCage, a gaseous neon time-projection chamber, is a proposed ultra-sensitive (and nondestructive) screener for alpha-and beta-emitting surface contaminants to which existing screening facilities are insufficiently sensitive. Sensitivity goals are 0.1 betas keV{sup −1} m{sup −2} day{sup −1} and 0.1 alphas m{sup −2} day{sup −1}, with the former limited by Compton scattering of photons in the screening samples and (thanks to tracking) the latter expectedmore » to be signal-limited; radioassays and simulations indicate backgrounds from detector materials and radon daughters should be subdominant. We report on details of the background simulations and detector design that provide the discrimination, shielding, and radiopurity necessary to reach our sensitivity goals for a chamber with a 95 × 95 cm{sup 2} sample area positioned below a 40 cm drift region and monitored by crisscrossed anode and cathode planes consisting of 151 wires each.« less

A method of discriminating transuranic radionuclides from radon progeny using low-resolution alpha spectroscopy and curve-fitting techniques.

PubMed

Konzen, Kevin; Brey, Richard

2012-05-01

²²²Rn (radon) and ²²⁰Rn (thoron) progeny are known to interfere with determining the presence of long-lived transuranic radionuclides, such as plutonium and americium, and require from several hours up to several days for conclusive results. Methods are proposed that should expedite the analysis of air samples for determining the amount of transuranic radionuclides present using low-resolution alpha spectroscopy systems available from typical alpha continuous air monitors (CAMs) with multi-channel analyzer (MCA) capabilities. An alpha spectra simulation program was developed in Microsoft Excel visual basic that employed the use of Monte Carlo numerical methods and serial-decay differential equations that resembled actual spectra. Transuranic radionuclides were able to be quantified with statistical certainty by applying peak fitting equations using the method of least squares. Initial favorable results were achieved when samples containing radon progeny were decayed 15 to 30 min, and samples containing both radon and thoron progeny were decayed at least 60 min. The effort indicates that timely decisions can be made when determining transuranic activity using available alpha CAMs with alpha spectroscopy capabilities for counting retrospective air samples if accompanied by analyses that consider the characteristics of serial decay.

Alpha spectroscopy by the Φ25 mm×0.1 mm YAlO3:Ce scintillation detector under atmospheric conditions

NASA Astrophysics Data System (ADS)

Kvasnicka, Jiri; Urban, Tomas; Tous, Jan; Smejkal, Jan; Blazek, Karel; Nikl, Martin

2017-06-01

The YAlO3:Ce scintillation crystal has excellent mechanical properties and is not affected if used in chemically aggressive environments. The detector with the diameter of Φ25.4 mm and thickness of 0.1 mm was coupled with the PMT, associated electronics and the MCA in order to study its alpha spectroscopy properties. The measured alpha spectra of the surface calibration sources of 241Am and 230Th were compared with results of a Monte Carlo simulation. The experiment and the simulation were carried out for three distances between the detector and the surface alpha source in order to assess the effect of the distance on the detected energy of alpha radiation. Finally, the detector was used for the monitoring of radon (222Rn) decay products (radon daughters) in the air. It was concluded that the detector is suitable for the in-situ alpha spectroscopy monitoring under ambient atmospheric conditions. Nevertheless, in order to identify radionuclides and their activity from the measured alpha spectra a computer code would need to be developed.

Event counting alpha detector

DOEpatents

Bolton, Richard D.; MacArthur, Duncan W.

1996-01-01

An electrostatic detector for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure.

Event counting alpha detector

DOEpatents

Bolton, R.D.; MacArthur, D.W.

1996-08-27

An electrostatic detector is disclosed for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure. 6 figs.

Decay properties of {sup 265}Sg(Z=106) and {sup 266}Sg(Z=106)

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

Tuerler, A.; Dressler, R.; Eichler, B.

1998-04-01

The presently known most neutron-rich isotopes of element 106 (seaborgium, Sg), {sup 265}Sg and {sup 266}Sg, were produced in the fusion reaction {sup 22}Ne+{sup 248}Cm at beam energies of 121 and 123 MeV. Using the On-Line Gas chemistry Apparatus OLGA, a continuous separation of Sg was achieved within a few seconds. Final products were assayed by {alpha}-particle and spontaneous fission (SF) spectrometry. {sup 265}Sg and {sup 266}Sg were identified by observing time correlated {alpha}-{alpha}-({alpha}) and {alpha}-SF decay chains. A total of 13 correlated decay chains of {sup 265}Sg (with an estimated number of 2.8 random correlations) and 3 decay chainsmore » of {sup 266}Sg (0.6 random correlations) were identified. Deduced decay properties were T{sub 1/2}=7.4{sub {minus}2.7}{sup +3.3} s (68{percent} c.i.) and E{sub {alpha}}=8.69 MeV (8{percent}), 8.76 MeV (23{percent}), 8.84 MeV (46{percent}), and 8.94 MeV (23{percent}) for {sup 265}Sg; and T{sub 1/2}=21{sub {minus}12}{sup +20} s (68{percent} c.i.) and E{sub {alpha}}=8.52 MeV (33{percent}) and 8.77 MeV (66{percent}) for {sup 266}Sg. The resolution of the detectors was between 50{endash}100 keV (full width at half maximum). Upper limits for SF of {le}35{percent} and {le}82{percent} were established for {sup 265}Sg and {sup 266}Sg, respectively. The upper limits for SF are given with a 16{percent} error probability. Using the lower error limits of the half-lives of {sup 265}Sg and {sup 266}Sg, the resulting lower limits for the partial SF half-lives are T{sub 1/2}{sup SF}({sup 265}Sg){ge}13 s and T{sub 1/2}{sup SF}({sup 266}Sg){ge}11 s. Correspondingly, the partial {alpha}-decay half-lives are between T{sub 1/2}{sup {alpha}}({sup 265}Sg)=4.7{endash}16.5 s (68{percent} c.i.) and T{sub 1/2}{sup {alpha}}({sup 266}Sg)=9{endash}228 s (68{percent} c.i.), using the upper and lower error limits of the half-lives of {sup 265}Sg and {sup 266}Sg. The lower limit on the partial SF half-life of {sup 266}Sg is in good agreement with theoretical predictions. Production cross sections of about 240 pb and 25 pb for the {alpha}-decay branch in {sup 265}Sg and {sup 266}Sg were estimated, respectively. {copyright} {ital 1998} {ital The American Physical Society}« less

Bile alcohol metabolism in man. Conversion of 5beta-cholestane-3alpha, 7alpha,12alpha, 25-tetrol to cholic acid.

PubMed Central

Salen, G; Shefer, S; Setoguchi, T; Mosbach, E H

1975-01-01

To study the role of C25-HYDROXY BILE ALCOHOLS AS PRECURSORS OF CHOlic acid, [G-3-H]5beta-cholestane-3alpha,7alpha12alpha,25-tetrol was administered intravenously to two subjects with cerebrotendinous xanthomatosis (CTX) and two normal individuals. One day after pulse labeling, radioactivity was present in the cholic acid isolated from the bile and feces of the subjects with CTX and the bile of the normal individuals. In the two normal subjects, the sp act decay curves of [G-3-H]-cholic acid were exponential, and no traces of [G-3-H]-5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol were detected. In contrast, appreciable quantities of labeled 5beta-cholestane-3alpha,-7aopha,12alpha,25-tetrol were present in the bile and feces of the CTX subjects. The sp act vs. time curves of fecal [G-3-H]5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol and [G-3-H]-cholic acid showed a precursor-product relationship. Although these results suggest that 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol may be a precursor of cholic acid in man, the possibility that C26-hydroxy intermediates represent the normal pathway can not be excluded. PMID:1141434

223Ra-dichloride spectrometric characterization: Searching for the presence of long-lived isotopes with radiological protection implications.

PubMed

Sánchez-Jiménez, J; López-Montes, A; Núñez-Martínez, L; Villa-Abaunza, A; Fraile, L M; Sánchez-Tembleque, V; Udías, J M

2017-03-01

223 Ra-dichloride was approved with the commercial name of Xofigo in 2014 for treatment of metastatic castration-resistant prostate cancer. 223 Ra is obtained by neutron irradiation of 226 Ra yielding 227 Ac, which decays to 227 Th and 223 Fr, both decaying to 223 Ra. Since 223 Ra is predominantly (95.3%) an alpha emitter with a 11.42days long half-life, the radiopharmaceutical, its remnants, the patient, and waste material can be managed and disposed with low radiation protection requirements. 227 Ac is a long-lived (T 1/2 =21.77years) beta emitter that demands strong radiation protection measures. In particular waste disposal has to follow the International Atomic Energy Agency (IAEA) and European Commission (EC) regulations. Since 227 Ac is involved in the production of 223 Ra, an impurity analysis of each batch is required after production. Due to time restrictions, the manufacturer's detection limit (<0.001%) exceeds the one required to assure that 227 Ac concentrations are below direct disposal levels. To improve the detection limit, long-term accurate spectroscopy is required. Alpha and gamma spectroscopy measurements were carried out at the Complutense University Nuclear Physics Laboratory. After twelve months follow up of a sample, 227 Ac concentration was found to be smaller than 10 -9 . This allows for direct waste disposal and no additional radiation protection restrictions than those required for 223 Ra. The presence of contamination by other radioisotopes was also ruled out by this experiment. Specifically 226 Ra, involved in 223 Ra production as the original parent and with a very long-lived (T 1/2 =1577years) alpha emitter, was also below the experimental detection limit. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

The luminescence characteristics of CsI(Na) crystal under α and X/γ excitation

NASA Astrophysics Data System (ADS)

Liu, Jinliang; Liu, Fang; Ouyang, Xiaoping; Liu, Bin; Chen, Liang; Ruan, Jinlu; Zhang, Zhongbing; Liu, Jun

2013-01-01

In this paper, we study the effective decay time characteristic of CsI(Na) crystal under 239Pu alpha particle and 137Cs gamma-ray excitation using a single photon counting decay time measurement system. The measurement system employs a silicon optical fiber to couple and transit single photon. The slow decay time component of CsI(Na) crystal is 460-550 ns. We observe a 15 ns fast decay component under alpha particle excitation. In addition, we find that the primary stage of the falling edge in the decay time curve is non-exponential and drops rapidly when CsI(Na) crystal is excited by 239Pu alpha particles. Since the high density of self-trapped-excitons (STEs) is produced in alpha particle excitation process, we propose that the fast falling edge is corresponding to the quenching process of STEs which transit with non-radiation in the case of high excitation density. To prove this proposal, we excited the CsI(Na) crystal with sub-nanosecond intensive pulsed X-ray radiation. Our X-ray impinging results show that the fast falling edge also exists under low energy (average 100 keV) bremsstrahlung X-ray excitation.

Update and evaluation of decay data for spent nuclear fuel analyses

NASA Astrophysics Data System (ADS)

Simeonov, Teodosi; Wemple, Charles

2017-09-01

Studsvik's approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL) and processed (ESTAR) sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources). Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

Removal of Long-Lived Radon Daughters by Electropolishing Thin Layers of Stainless Steel

NASA Astrophysics Data System (ADS)

White, James; Schnee, Richard; Bunker, Raymond; Bowles, Michael; Cushman, Priscilla; Epland, Matthew; Pepin, Mark; Guiseppe, Vince

2012-10-01

Long-lived alpha and beta emitters in the Radon decay chain on detector surfaces may be limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay. To screen detector surfaces for this radioactive contamination, a low-radiation, multi-wire proportional chamber (the BetaCage) is under construction. Removal of Pb-210 implanted on its 25-micron stainless steel wires without causing significant variation in the diameter of the wires is critical to the BetaCage's ultimate sensitivity. An apparatus to perform electropolishing trials to remove roughly a micron of material has been assembled. These trials have shown promising results. Stainless steel square samples implanted with Pb-210 have shown counts with a reduction factor greater than 10 after electropolishing according to gamma assay. Furthermore, alpha counting has produced similar results, with a reduction factor greater than 100. Lastly, the diameters of wires after electropolishing have remained sufficiently uniform, with reduction in thickness consistent with expectations.

Alpha-decay chains of superheavy nuclei 292-296118

NASA Astrophysics Data System (ADS)

Singh, U. K.; Kumawat, M.; Saxena, G.; Kaushik, M.; Jain, S. K.

2018-05-01

We have employed relativistic mean-field plus BCS (RMF+BCS) approach for the study of even-even superheavy nuclei with Z = 118 which is the last and recent observed element in the periodic chart so far. Our study includes binding energies, Qα values, alpha-decay half-lives and spontaneous decay half-lives along with comparison of available experimental data and the results of FRDM calculations. We find an excellent match with the only known decay chain of 294118 for Z = 118 so far and predict decay chain of 292118 and 296118 in consistency with known experimental decay chains and FRDM results. These results may provide a very helpful insight to conduct experiments for realizing the presence of nuclei with Z = 118.

Orthopositronium Lifetime: Analytic Results in O({alpha}) and O({alpha}{sup 3}ln{alpha})

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

Kniehl, Bernd A.; Kotikov, Anatoly V.; Veretin, Oleg L.

2008-11-07

We present the O({alpha}) and O({alpha}{sup 3}ln{alpha}) corrections to the total decay width of orthopositronium in closed analytic form, in terms of basic irrational numbers, which can be evaluated numerically to arbitrary precision.

Cherenkov light identification in TeO2 crystals with Si low-temperature detectors

NASA Astrophysics Data System (ADS)

Gironi, L.; Biassoni, M.; Brofferio, C.; Capelli, S.; Carniti, P.; Cassina, L.; Clemenza, M.; Cremonesi, O.; Faverzani, M.; Ferri, E.; Giachero, A.; Gotti, C.; Maino, M.; Margesin, B.; Nucciotti, A.; Pavan, M.; Pessina, G.; Pozzi, S.; Previtali, E.; Puiu, A.; Sisti, M.; Terranova, F.

2017-09-01

Low temperature thermal detectors with particle identification capabilities are among the best detectors for next generation experiments for the search of neutrinoless double beta decay. Thermal detectors allow to reach excellent energy resolution and to optimize the detection efficiency, while the possibility to identify the interacting particle allows to greatly reduce the background. Tellurium dioxide is one of the favourite compounds since it has long demonstrated the first two features and could reach the third through Cherenkov emission tagging [1]. A new generation of cryogenic light detectors are however required to detect the few Cherenkov photons emitted by electrons of few MeV energy. Preliminary measurements with new Si light detectors demonstrated a clear event-by-event discrimination between alpha and beta/gamma interactions at the 130Te neutrinoless double beta decay Q-value (2528 keV).

Theoretical prediction of probable isotopes of superheavy nuclei of Z = 122

NASA Astrophysics Data System (ADS)

Manjunatha, H. C.

2016-11-01

We have studied the α-decay half-life and spontaneous fission half-lives of isotopes of superheavy element Z = 122 in the range 275 ≤ A ≥ 326. A comparison of calculated alpha half-lives with the literature [D. N. Poenaru, R. A. Gherghescu and W. Greiner, Phys. Rev. C 83 (2011) 014601, D. N. Poenaru, R. A. Gherghescu and W. Greiner, Phys. Rev. C 85 (2012) 034615] and the analytical formulas of Royer [G. Royer, J. Phys. G; Nucl. Part. Phys. 26 (2000) 1149] shows good agreement with each other. To identify the mode of decay of these isotopes, the spontaneous-fission half-lives were also evaluated using the semiempirical relation given by [C. Xu, Z. Ren and Y. Guo, Phys. Rev. C 78 (2008) 044329]. A comparative study on the competition of alpha decay versus spontaneous fission of superheavy nuclei (SHN) reveals that around eight isotopes (307-314122) survive fission and have alpha decay channel as the prominent mode of decay and hold the possibility to be synthesized in the laboratory. The alpha decay half-lives and spontaneous fission half-lives of SHN with Z = 122, A = 299-306, with Z = 120, A = 294-300, and with Z = 119, A = 292-297 are also studied. The present study will be useful in the synthesis of superheavy elements Z > 118 by using the actinide based reactions with stable projectiles heavier than 48Ca.

Calculated half-lives and kinetic energies for spontaneous emission of heavy ions from nuclei

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

Poenaru, D.N.; Greiner, W.; Depta, K.

The most probable decays by spontaneous emission of heavy ions are listed for nuclides with Z = 47--106 and total half-lives>1 ..mu..sec. Partial half-lives, branching ratios relative to ..cap alpha.. decay, kinetic energies, and Q values are estimated by using the analytical superasymmetric fission model, a semiempirical formula for those ..cap alpha..-decay lifetimes which have not been measured, and the new Wapstra--Audi mass tables. Numerous ''stable'' nuclides with Z>40 are found to be metastable with respect to the new decay modes. The current experimental status is briefly reviewed.

Improved measurement of the form factors in the decay lambda+c-->lambda + nue.

PubMed

Hinson, J W; Huang, G S; Lee, J; Miller, D H; Pavlunin, V; Rangarajan, R; Sanghi, B; Shibata, E I; Shipsey, I P J; Cronin-Hennessy, D; Park, C S; Park, W; Thayer, J B; Thorndike, E H; Coan, T E; Gao, Y S; Liu, F; Stroynowski, R; Artuso, M; Boulahouache, C; Blusk, S; Dambasuren, E; Dorjkhaidav, O; Mountain, R; Muramatsu, H; Nandakumar, R; Skwarnicki, T; Stone, S; Wang, J C; Csorna, S E; Danko, I; Bonvicini, G; Cinabro, D; Dubrovin, M; McGee, S; Bornheim, A; Lipeles, E; Pappas, S P; Shapiro, A; Sun, W M; Weinstein, A J; Briere, R A; Chen, G P; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Adam, N E; Alexander, J P; Berkelman, K; Boisvert, V; Cassel, D G; Duboscq, J E; Ecklund, K M; Ehrlich, R; Galik, R S; Gibbons, L; Gittelman, B; Gray, S W; Hartill, D L; Heltsley, B K; Hsu, L; Jones, C D; Kandaswamy, J; Kreinick, D L; Magerkurth, A; Mahlke-Krüger, H; Meyer, T O; Mistry, N B; Patterson, J R; Peterson, D; Pivarski, J; Richichi, S J; Riley, D; Sadoff, A J; Schwarthoff, H; Shepherd, M R; Thayer, J G; Urner, D; Wilksen, T; Warburton, A; Weinberger, M; Athar, S B; Avery, P; Breva-Newell, L; Potlia, V; Stoeck, H; Yelton, J; Benslama, K; Cawlfield, C; Eisenstein, B I; Gollin, G D; Karliner, I; Lowrey, N; Plager, C; Sedlack, C; Selen, M; Thaler, J J; Williams, J; Edwards, K W; Besson, D; Anderson, S; Frolov, V V; Gong, D T; Kubota, Y; Li, S Z; Poling, R; Smith, A; Stepaniak, C J; Urheim, J; Metreveli, Z; Seth, K K; Tomaradze, A; Zweber, P; Ahmed, S; Alam, M S; Ernst, J; Jian, L; Saleem, M; Wappler, F; Arms, K; Eckhart, E; Gan, K K; Gwon, C; Honscheid, K; Kagan, H; Kass, R; Pedlar, T K; von Toerne, E; Severini, H; Skubic, P; Dytman, S A; Mueller, J A; Nam, S; Savinov, V

2005-05-20

Using the CLEO detector at the Cornell Electron Storage Ring, we have studied the distribution of kinematic variables in the decay lambda(+)(c)lambda--> e(+)nu(e). By performing a four-dimensional maximum likelihood fit, we determine the form factor ratio, R= f(2)/f(1) = -0.31 +/- 0.05(stat) +/- 0.04(syst), the pole mass, M(pole) = [2.21 +/- 0.08(stat) +/- 0.14(syst)] GeV/c(2), and the decay asymmetry parameter of the lambda(+)(c), alpha (lambda(c)) = -0.86 +/-0.03(stat) +/- 0.02(syst), for q(2) = 0.67 (GeV/c(2))(2). We compare the angular distributions of the lambda(+)(c) and lambda(-)(c) and find no evidence for CP violation: A(lambda(c)) = (alpha(lambda(c)) + alpha (lambda(c)))/(alpha(lambda(c))-alpha(lambda(c))) = 0.00 +/- 0.03(stat) +/- 0.01(syst) +/- 0.02, where the third error is from the uncertainty in the world average of the CP-violating parameter, A(lambda), for ppi(-).

Acetyl-L-carnitine supplementation to old rats partially reverts the age-related mitochondrial decay of soleus muscle by activating peroxisome proliferator-activated receptor gamma coactivator-1alpha-dependent mitochondrial biogenesis.

PubMed

Pesce, Vito; Fracasso, Flavio; Cassano, Pierluigi; Lezza, Angela Maria Serena; Cantatore, Palmiro; Gadaleta, Maria Nicola

2010-01-01

The age-related decay of mitochondrial function is a major contributor to the aging process. We tested the effects of 2-month-daily acetyl-L-carnitine (ALCAR) supplementation on mitochondrial biogenesis in the soleus muscle of aged rats. This muscle is heavily dependent on oxidative metabolism. Mitochondrial (mt) DNA content, citrate synthase activity, transcript levels of some nuclear- and mitochondrial-coded genes (cytochrome c oxidase subunit IV [COX-IV], 16S rRNA, COX-I) and of some factors involved in the mitochondrial biogenesis signaling pathway (peroxisome proliferator-activated receptor gamma [PPARgamma] coactivator-1alpha [PGC-1alpha], mitochondrial transcription factor A mitochondrial [TFAM], mitochondrial transcription factor 2B [TFB2]), as well as the protein content of PGC-1alpha were determined. The results suggest that the ALCAR treatment in old rats activates PGC-1alpha-dependent mitochondrial biogenesis, thus partially reverting the age-related mitochondrial decay.

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.

Apparatus and method for the simultaneous detection of neutrons and ionizing electromagnetic radiation

DOEpatents

Bell, Zane W.

2000-01-01

A sensor for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising: a sensor for the detection of gamma radiation, the sensor defining a sensing head; the sensor further defining an output end in communication with the sensing head; and an exterior neutron-sensitive material configured to form around the sensing head; wherein the neutron-sensitive material, subsequent to the capture of the neutron, fissions into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the first excited state decaying via the emission of a single gamma ray at 478 keV which can in turn be detected by the sensing head; and wherein the sensing head can also detect the ionizing electromagnetic radiation from an incident radiation field without significant interference from the neutron-sensitive material. A method for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising the steps of: providing a gamma ray sensitive detector comprising a sensing head and an output end; conforming an exterior neutron-sensitive material configured to form around the sensing head of the detector; capturing neutrons by the sensing head causing the neutron-sensitive material to fission into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the state decaying via the emission of a single gamma ray at 478 keV; sensing gamma rays entering the detector through the neutron-sensitive material; and producing an output through a readout device coupled to the output end; wherein the detector provides an output which is proportional to the energy of the absorbed ionizing electromagnetic radiation.

Detection of radon emission at the edges of lunar maria with the Apollo alpha-particle spectrometer

NASA Technical Reports Server (NTRS)

Gorenstein, P.; Golub, L.; Bjorkholm, P.

1974-01-01

The distribution of radioactive polonium-210, a decay product of radon-222, shows enhanced concentrations at the edges of lunar maria. Enhancements are seen at the edges of Mare Fecunditatis, Mare Crisium, Mare Smythii, Mare Tranquillitatis, Mare Nubium, Mare Cognitum, and Oceanus Procellarum. The observation is indicative of the transient emission of radon gas from the perimeters of lunar maria.

Detection of radon emission at the edges of lunar maria with the apollo alpha-particle spectrometer

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

Gorenstein, P.; Golub, L.; Bjorkholm, P.

1974-02-01

The distribution of radioactive /sup 210/Po, a decay product of /sup 222/ Rn, shows enhanced concentrations at the edges of lunar maria. Enhancements are seen at the edges of Mare Fecunditatis, Mare Crisium, Mare Smythii, Mare Tranquillitatis, Mare Nubium, Mare Cognitum, and Oceanus Procellarum. The observation is indicative of the transient emission of radon gas from the perimeters of lunar maria. (auth)

Detection of Alpha Particles and Low Energy Gamma Rays by Thermo-Bonded Micromegas in Xenon Gas

NASA Astrophysics Data System (ADS)

Wei, Yuehuan; Guan, Liang; Zhang, Zhiyong; Lin, Qing; Wang, Xiaolian; Ni, Kaixuan; Zhao, Tianchi

2013-08-01

Micromegas is a type of micro-pattern gaseous detector currently under R&D for applications in rare event search experiments. Here we report the performance of a Micromegas structure constructed with a micromesh thermo-bonded to a readout plane, motivated by its potential application in two-phase xenon detectors for dark matter and neutrinoless double beta decay experiments. The study is carried out in pure xenon at room temperature. Measurements with alpha particles from the Americium-241 source showed that gas gains larger than 200 can be obtained at xenon pressure up to 3 atm. Gamma rays down to 8 keV were observed with such a device.

Visualization of Radioisotope Detectability Over Time.

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

Huynh, Brady

A radioactive isotope is an atom that has an unstable nucleus. The isotope can undergo radioactive decay, the process in which excessive nuclear energy is emitted from the nucleus in many different forms, such as gamma radiation, alpha particles, or beta particles. The important thing to note is that these emissions act as a signature for the isotope. Each radioisotope has a particular emission spectrum, emitting radiation at different energies and at different rates.

Temperature dependence of alpha-induced scintillation in the 1,1,4,4-tetraphenyl-1,3-butadiene wavelength shifter

NASA Astrophysics Data System (ADS)

Veloce, L. M.; Kuźniak, M.; Di Stefano, P. C. F.; Noble, A. J.; Boulay, M. G.; Nadeau, P.; Pollmann, T.; Clark, M.; Piquemal, M.; Schreiner, K.

2016-06-01

Liquid noble based particle detectors often use the organic wavelength shifter 1,1,4,4-tetraphenyl-1,3-butadiene (TPB) which shifts UV scintillation light to the visible regime, facilitating its detection, but which also can scintillate on its own. Dark matter searches based on this type of detector commonly rely on pulse-shape discrimination (PSD) for background mitigation. Alpha-induced scintillation therefore represents a possible background source in dark matter searches. The timing characteristics of this scintillation determine whether this background can be mitigated through PSD. We have therefore characterized the pulse shape and light yield of alpha induced TPB scintillation at temperatures ranging from 300 K down to 4 K, with special attention given to liquid noble gas temperatures. We find that the pulse shapes and light yield depend strongly on temperature. In addition, the significant contribution of long time constants above ~50 K provides an avenue for discrimination between alpha decay events in TPB and nuclear-recoil events in noble liquid detectors.

Low-energy neutron detector based upon lithium lanthanide borate scintillators

DOEpatents

Czirr, John B.

1998-01-01

An apparatus for detecting neutrons includes a cerium activated scintillation crystal containing .sup.10 B, with the scintillation crystal emitting light in response to .alpha. particles emitted from the .sup.10 B(n,.alpha.)Li* reaction. The apparatus also includes a gamma scintillator positioned adjacent the crystal and which generates light in response to gamma rays emitted from the decay of Li*. The apparatus further includes a first and a second light-to-electronic signal converter each positioned to respectively receive light from the crystal and the gamma scintillator, and each respectively outputting first and second electronic signals representative of .alpha. particles from the .sup.10 B(n,.alpha.)Li* reaction and gamma rays from the .sup.10 B(n,.alpha.)Li* reaction. The apparatus includes a coincidence circuit connected to receive the first and second signals and which generates a coincidence signal when the first and second signals coincide. The apparatus also includes a data analyzer for receiving an additional signal from at least one of the first and second converters, and for operating in response to the coincidence signal.

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

Improved Measurement of the Cabibbo-Kobayashi-Maskawa Angle {alpha} Using B{sup 0}(B){yields}{rho}{sup +}{rho}{sup -} Decays

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

Aubert, B.; Barate, R.; Boutigny, D.

2005-07-22

We present results from an analysis of B{sup 0}(B{sup 0}){yields}{rho}{sup +}{rho}{sup -} using 232x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We measure the longitudinal polarization fraction f{sub L}=0.978{+-}0.014(stat)(+0.021/-0.029)(syst) and the CP-violating parameters S{sub L}=-0.33{+-}0.24(stat)(+0.08/-0.14)(syst) and C{sub L}=-0.03{+-}0.18(stat){+-}0.09(syst). Using an isospin analysis of B{yields}{rho}{rho} decays, we determine the unitarity triangle parameter {alpha}. The solution compatible with the standard model is {alpha}=(100{+-}13) deg.

Revisiting alpha decay-based near-light-speed particle propulsion.

PubMed

Zhang, Wenwu; Liu, Zhen; Yang, Yang; Du, Shiyu

2016-08-01

Interplanet and interstellar travels require long-term propulsion of spacecrafts, whereas the conventional schemes of propulsion are limited by the velocity of the ejected mass. In this study, alpha particles released by nuclear decay are considered as a potential solution for long-time acceleration. The principle of near-light-speed particle propulsion (NcPP) was elucidated and the stopping and range of ions in matter (SRIM) was used to predict theoretical accelerations. The results show that NcPP by means of alpha decay is feasible for long-term spacecraft propulsion and posture adjustment in space. A practical NcPP sail can achieve a speed >150km/s and reach the brink of the solar system faster than a mass equivalent solar sail. Finally, to significantly improve the NcPP sail, the hypothesis of stimulated acceleration of nuclear decay (SAND) was proposed, which may shorten the travel time to Mars to within 20 days. Copyright © 2016 Elsevier Ltd. All rights reserved.

Spectroscopic and Magnetic Investigations of Rhenium(i)chlorine(carbon MONOXIDE)(3)(ALPHA, - Complexes and Group (1B, 8B) Bimetallic Complexes.

NASA Astrophysics Data System (ADS)

Striplin, Durwin Ray

Complexes with the generic formula, Re(I)Cl(CO) _3(alpha,alpha-diimine), where alpha,alpha-diimine = 2,2^'-bipyridine, 1,10 -phenanthroline, or methyl-substituted analogs, were subjected to detailed optical investigations in the 77-4 K range, both in rigid glasses and in PMMA plastics. Excitation spectra, absorption spectra, and decay kinetics of the phosphorescing manifolds were complemented by detailed measurements of polarization ratios to arrive at a coherent picture of the emitting manifolds. Symmetry assignments and energy orderings of the ^3MLCT (metal-to-ligand charge transfer) spin sublevels were made. Analogous assignments for the ^3MLCT spin -sublevels of Ru(alpha, alpha -diimine)_3^{2+} and Os(alpha,alpha-diimine) _{3}^{2+} ions are implied by this analysis. Increases in luminescence decay rates and emission intensities with increasing external magnetic field strength were observed at 4 K. The decay rates were found to be non-quadratic with respect to magnetic field strength. A simple parametric model that includes spin-orbit coupling and a magnetic field perturbation was developed to describe the MLCT excited states. The energies, symmetry assignments, and magnetic field mixing of the ^3MLCT states were rationalized by the model. Fluorescence, phosphorescence, and excitation spectra were measured on a series of mu -bridged bis(diphenylphosphinomethane) homo- and heterobimetallic compounds of Rh(I), Ir(I), Pt(II), and Au(I). These results were augmented with polarization ratios obtained at 77 K and detailed studies of the temperature dependence of the phosphorescence in the 77-4 K range. The triplet manifold is split by spin-orbit coupling into a forbidden state lying lowest in energy followed by a quasi-degenerate pair lying a few wavenumbers higher that decays two orders of magnitude faster. A quadratic dependence of the decay rate on magnetic field strength was recorded at 4 K for ail complexes. The results are consistent with a rm d_{sigma*}to p_sigma orbital promotion, and the direction of charge-transfer for heterobimetallic complexes was unambiguously assigned. Electronic structural models based on D_{rm 4h}, D_{rm 2h}, and C _{rm 2v} micro-symmetries about the axial chromophore were employed to make explicit symmetry assignments of the excited states.

Unitary scintillation detector and system

DOEpatents

McElhaney, Stephanie A.; Chiles, Marion M.

1994-01-01

The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations.

Unitary scintillation detector and system

DOEpatents

McElhaney, S.A.; Chiles, M.M.

1994-05-31

The invention is a unitary alpha, beta, and gamma scintillation detector and system for sensing the presence of alpha, beta, and gamma radiations selectively or simultaneously. The scintillators are mounted in a light-tight housing provided with an entrance window for admitting alpha, beta, and gamma radiation and excluding ambient light from the housing. Light pulses from each scintillator have different decay constants that are converted by a photosensitive device into corresponding differently shaped electrical pulses. A pulse discrimination system identifies the electrical pulses by their respective pulse shapes which are determined by decay time. The identified electrical pulses are counted in separate channel analyzers to indicate the respective levels of sensed alpha, beta, and gamma radiations. 10 figs.

The generalized liquid drop model alpha-decay formula: Predictability analysis and superheavy element alpha half-lives

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

Dasgupta-Schubert, N.; Reyes, M.A.

2007-11-15

The predictive accuracy of the generalized liquid drop model (GLDM) formula for alpha-decay half-lives has been investigated in a detailed manner and a variant of the formula with improved coefficients is proposed. The method employs the experimental alpha half-lives of the well-known alpha standards to obtain the coefficients of the analytical formula using the experimental Q{sub {alpha}} values (the DSR-E formula), as well as the finite range droplet model (FRDM) derived Q{sub {alpha}} values (the FRDM-FRDM formula). The predictive accuracy of these formulae was checked against the experimental alpha half-lives of an independent set of nuclei (TEST) that span approximatelymore » the same Z, A region as the standards and possess reliable alpha spectroscopic data, and were found to yield good results for the DSR-E formula but not for the FRDM-FRDM formula. The two formulae were used to obtain the alpha half-lives of superheavy elements (SHE) and heavy nuclides where the relative accuracy was found to be markedly improved for the FRDM-FRDM formula, which corroborates the appropriateness of the FRDM masses and the GLDM prescription for high Z, A nuclides. Further improvement resulted, especially for the FRDM-FRDM formula, after a simple linear optimization over the calculated and experimental half-lives of TEST was used to re-calculate the half-lives of the SHE and heavy nuclides. The advantage of this optimization was that it required no re-calculation of the coefficients of the basic DSR-E or FRDM-FRDM formulae. The half-lives for 324 medium-mass to superheavy alpha decaying nuclides, calculated using these formulae and the comparison with experimental half-lives, are presented.« less

Rotational modulation and flares on RS CVn and BY DRA systems. VIII - Simultaneous EXOSAT and H-alpha observations of a flare on the dMe star GL 644 AB (Wolf 630) on 24/25 August 1985

NASA Astrophysics Data System (ADS)

Doyle, J. G.; Butler, C. J.; Callanan, P. J.; Tagliaferri, G.; de La Reza, R.; White, N. E.; Torres, C. A.; Quast, G.

1988-02-01

A large flare was detected simultaneously in X-rays and H-alpha on the visual binary Gl 644 AB at about 00:15 UT on August 25, 1985. The flare was detected with both the low (0.05-2 keV) and medium energy (2-7 keV) experiments onboard Exosat, with the flare rise time being similar in both the low and medium energy ranges, although in the low energy the peak occurred about 30 s later. This was followed a few minutes later by a second burst. The flare decay time lasted about 10 minutes longer in the low energy band than in the medium energy. The integrated flare energy detected was 11.9 x 10 to the 32nd and 4.15 x 10 to the 32nd erg respectively in the low and medium energy X-rays and 7 x 10 to the 31st erg in H-alpha. This gives an H-alpha flux of approximately 4 percent of the total X-ray flux detected from the flare or 6 percent of the low X-ray flare energy, similar to that observed in a compact solar flare. Based on the observed cooling time, the flare was estimated to have 2-3 loops of height about 10 to the 9th cm and electron density of about 10 to the 12th/cu cm.

Surface alpha backgrounds from plate-out of radon progeny

NASA Astrophysics Data System (ADS)

Perumpilly, Gopakumar; Guiseppe, Vincente

2012-03-01

Low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly Rn-222) and its subsequent daughters present in an experiment are potential backgrounds, more troublesome is the deposition of radon daughters on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by daughters supported by the long half life (22 y) of Pb-210 on sensitive locations of a detector. We have developed a model of the radon progeny implantation using Geant4 simulations based on the low energy nuclear recoil process. We explore the alpha decays from implanted progeny on a Ge crystal as potential backgrounds for a neutrinoless double-beta decay experiment. Results of the simulations validated with alpha spectrum measurement of plate-out samples will be presented.

Influence of deformed surface diffuseness on alpha decay half-lives of actinides and lanthanides

NASA Astrophysics Data System (ADS)

Dahmardeh, S.; Alavi, S. A.; Dehghani, V.

2017-07-01

By using semiclassical WKB method and taking into account the Bohr-Sommerfeld quantization condition, the alpha decay half-lives of some deformed lanthanide (with 151 ≤ A ≤ 160 and 66 ≤ Z ≤ 73) and rare-earth nuclei (with 217 ≤ A ≤ 261 and 92 ≤ Z ≤ 104) have been calculated. The effective potential has been considered as sum of deformed Woods-Saxon nuclear potential, deformed Coulomb potential, and centrifugal potential. The influence of deformed surface diffuseness on the potential barrier, transmission coefficient at each angle, assault frequency, and alpha decay half-lives has been investigated. Good agreement between calculated half-lives with deformed surface diffuseness and experiment is observed. Relative differences between calculated half-lives with deformed surface diffuseness and with constant surface diffuseness were significant.

Radon-related Backgrounds in the LUX Dark Matter Search

NASA Astrophysics Data System (ADS)

Bradley, A.; Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Bernard, E.; Bernstein, A.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Coffey, T.; Currie, A.; de Viveiros, L.; Dobi, A.; Dobson, J.; Druszkiewicz, E.; Edwards, B.; Faham, C. H.; Fiorucci, S.; Flores, C.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C.; Hertel, S. A.; Horn, M.; Huang, D. Q.; Ihm, M.; Jacobsen, R. G.; Kazkaz, K.; Knoche, R.; Larsen, N. A.; Lee, C.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Mannino, R.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H.; Neves, F.; Ott, R. A.; Pangilinan, M.; Parker, P. D.; Pease, E. K.; Pech, K.; Phelps, P.; Reichhart, L.; Shutt, T.; Silva, C.; Solovov, V. N.; Sorensen, P.; O'Sullivan, K.; Sumner, T. J.; Szydagis, M.; Taylor, D.; Tennyson, B.; Tiedt, D. R.; Tripathi, M.; Uvarov, S.; Verbus, J. R.; Walsh, N.; Webb, R.; White, J. T.; Witherell, M. S.; Wolfs, F. L. H.; Woods, M.; Zhang, C.

The LUX detector is currently in operation at the Davis Campus at the 4850' level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily tagged and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.

Spectral and Temporal Properties of the Alpha and Beta Subunits and (alpha Beta) Monomer Isolated from Nostoc SP. Using Picosecond Laser Spectroscopy.

NASA Astrophysics Data System (ADS)

Dagen, Aaron J.

1985-12-01

The fluorescence decay profiles, relative quantum yield and transmission of the (alpha), (beta) and ((alpha)(beta)) complexes from phycoerythrin isolated from the photosynthetic antenna system of Nostoc sp. and measured by single picosecond laser spectroscopic techniques is studied. The fluorescence decay profiles of all three complexes are found to be intensity independent for the intensity range investigated ((TURN)4 x 10('13) to (TURN)4 x 10('15) photons-cm('-2) per pulse). The apparent decrease in the relative quantum yield of all three complexes as intensity increases is offset by a corresponding increase in the relative transmission. This evidence, along with the intensity independent fluorescence kinetics, suggests that exciton annihilation is absent in these complexes. The decay profiles are fit to models assuming energy transfer amongst fluorescing chromophores. The intraprotein transfer rate is found to be 100 ps in the (alpha) subunit, 666 ps in the (beta) subunit. Constraining these rates to be identical in the monomer results in explaining the monomer kinetics by an increase in the nonradiative rate of the f(,(beta)) chromophore, an apparent result of aggregation effects.

Spectral and temporal properties of the alpha and beta subunits and (alpha beta) monomer isolated from Nostoc sp. using picosecond laser spectroscopy

NASA Astrophysics Data System (ADS)

Dagen, A. J.

1985-12-01

The fluorescence decay profiles, relative quantum yield and transmission of the alpha, beta and (alpha beta) complexes from phycoerythrin isolated from the photosynthetic antenna system of Nostoc sp. and measured by single picosecond laser spectroscopic techniques is studied. The fluorescence decay profiles of all three complexes are found to be intensity independent for the intensity range investigated (approx. 4x10 to the 13th power to 4x10 to the 15th power photons/sq cm per pulse). The apparent decrease in the relative quantum yield of all three complexes as intensity increases is offset by a corresponding increase in the relative transmission. This evidence, along with the intensity independent fluorescence kinetics, suggests that exciton annihilation is absent in these complexes. The decay profiles are fit to models assuming energy transfer amongst fluorescing chromophores. The intraprotein transfer rate is found to be 100 ps in the alpha subunit, 666 ps in the beta subunit. Constraining these rates to be identical in the monomer results in explaining the monomer kinetics by an increase in the nonradiative rate of the f beta chromophore, an apparent result of aggregation effects.

From Beamline to Scanner with 225Ac

NASA Astrophysics Data System (ADS)

Robertson, Andrew K. H.; Ramogida, Caterina F.; Kunz, Peter; Rodriguez-Rodriguez, Cristina; Schaffer, Paul; Sossi, Vesna

2016-09-01

Due to the high linear energy transfer and short range of alpha-radiation, targeted radiation therapy using alpha-emitting pharmaceuticals that successfully target small disease clusters will kill target cells with limited harm to healthy tissue, potentially treating the most aggressive forms of cancer. As the parent of a decay chain with four alpha- and two beta-decays, 225Ac is a promising candidate for such a treatment. However, this requires retention of the entire decay chain at the target site, preventing the creation of freely circulating alpha-emitters that reduce therapeutic effect and increase toxicity to non-target tissues. Two major challenges to 225Ac pharmaceutical development exist: insufficient global supply, and the difficulty of preventing toxicity by retaining the entire decay chain at the target site. While TRIUMF works towards large-scale (C i amounts) production of 225Ac, we already use our Isotope Separation On-Line facility to provide small (< 1 mCi) quantities for in-house chemistry and imaging research that aims to improve and assess 225Ac radiopharmaceutical targeting. This presentation provides an overview of this research program and the journey of 225Ac from the beamline to the scanner. This research is funded by the Natural Sciences and Engineering Research Council of Canada.

Novel measurement method of heat and light detection for neutrinoless double beta decay

NASA Astrophysics Data System (ADS)

Kim, G. B.; Choi, J. H.; Jo, H. S.; Kang, C. S.; Kim, H. L.; Kim, I.; Kim, S. R.; Kim, Y. H.; Lee, C.; Lee, H. J.; Lee, M. K.; Li, J.; Oh, S. Y.; So, J. H.

2017-05-01

We developed a cryogenic phonon-scintillation detector to search for 0νββ decay of 100Mo. The detector module, a proto-type setup of the AMoRE experiment, has a scintillating 40Ca100MoO4 absorber composed of 100Mo-enriched and 48Ca-depleted elements. This new detection method employs metallic magnetic calorimeters (MMCs) as the sensor technology for simultaneous detection of heat and light signals. It is designed to have high energy and timing resolutions to increase sensitivity to probe the rare event. The detector, which is composed of a 200 g 40Ca100MoO4 crystal and phonon/photon sensors, showed an energy resolution of 8.7 keV FWHM at 2.6 MeV, with a weak temperature dependence in the range of 10-40 mK. Using rise-time and mean-time parameters and light/heat ratios, the proposed method showed a strong capability of rejecting alpha-induced events from electron events with as good as 20σ separation. Moreover, we discussed how the signal rise-time improves the rejection efficiency for random coincidence signals.

Scalar correlator at [symbol: see text](alpha(s)4), Higgs boson decay into bottom quarks, and bounds on the light-quark masses.

PubMed

Baikov, P A; Chetyrkin, K G; Kühn, J H

2006-01-13

We compute, for the first time, the absorptive part of the massless correlator of two quark scalar currents in five loops. As physical applications, we consider the [symbol: see text](alpha(s)4) corrections to the decay rate of the standard model Higgs boson into quarks, as well as the constraints on the strange quark mass following from QCD sum rules.

Radon-related backgrounds in the LUX dark matter search

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

Bradley, A.; Akerib, D. S.; Araújo, H. M.

The LUX detector is currently in operation at the Davis Campus at the 4850’ level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily taggedmore » and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.« less

Radon-related backgrounds in the LUX dark matter search

DOE PAGES

Bradley, A.; Akerib, D. S.; Araújo, H. M.; ...

2015-01-01

The LUX detector is currently in operation at the Davis Campus at the 4850’ level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily taggedmore » and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.« less

Construction and measurements of a vacuum-swing-adsorption radon-mitigation system

NASA Astrophysics Data System (ADS)

Schnee, R. W.; Bunker, R.; Ghulam, G.; Jardin, D.; Kos, M.; Tenney, A. S.

2013-08-01

Long-lived alpha and beta emitters in the 222Rn decay chain on (and near) detector surfaces may be the limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay, and in screening detectors. In order to reduce backgrounds from radon-daughter plate-out onto the wires of the Beta Cage during its assembly, an ultra-low-radon cleanroom is being commissioned at Syracuse University using a vacuum-swing-adsorption radon-mitigation system. The radon filter shows ˜20× reduction at its output, from 7.47±0.56 to 0.37±0.12 Bq/m3, and the cleanroom radon activity meets project requirements, with a lowest achieved value consistent with that of the filter, and levels consistently < 2 Bq/m3.

Modeling radon daughter deposition rates for low background detectors

NASA Astrophysics Data System (ADS)

Westerdale, S.; Guiseppe, V. E.; Rielage, K.; Elliot, S. R.; Hime, A.

2009-10-01

Detectors such as those looking for dark matter and those working to detect neutrinoless double-beta decay require record low levels of background radiation. One major source of background radiation is from radon daughters that decay from airborne radon. In particular, ^222Rn decay products may be deposited on any detector materials that are exposed to environmental radon. Long-lasting daughters, especially ^210Pb, can pose a long-term background radiation source that can interfere with the detectors' measurements by emitting alpha particles into sensitive parts of the detectors. A better understanding of this radon daughter deposition will allow for preventative actions to be taken to minimize the amount of noise from this source. A test stand has therefore been set up to study the impact of various environmental factors on the rate of radon daughter deposition so that a model can be constructed. Results from the test stand and a model of radon daughter deposition will be presented.

Probable alpha and 14C cluster emission from hyper Ac nuclei

NASA Astrophysics Data System (ADS)

Santhosh, K. P.

2013-10-01

A systematic study on the probability for the emission of 4He and 14C cluster from hyper {Λ/207-234}Ac and non-strange normal 207-234Ac nuclei are performed for the first time using our fission model, the Coulomb and proximity potential model (CPPM). The predicted half lives show that hyper {Λ/207-234}Ac nuclei are unstable against 4He emission and 14C emission from hyper {Λ/217-228}Ac are favorable for measurement. Our study also show that hyper {Λ/207-234}Ac are stable against hyper {Λ/4}He and {Λ/14}C emission. The role of neutron shell closure ( N = 126) in hyper {Λ/214}Fr daughter and role of proton/neutron shell closure ( Z ≈ 82, N = 126) in hyper {Λ/210}Bi daughter are also revealed. As hyper-nuclei decays to normal nuclei by mesonic/non-mesonic decay and since most of the predicted half lives for 4He and 14C emission from normal Ac nuclei are favourable for measurement, we presume that alpha and 14C cluster emission from hyper Ac nuclei can be detected in laboratory in a cascade (two-step) process.

The Discovery of Artificial Radioactivity

NASA Astrophysics Data System (ADS)

Guerra, Francesco; Leone, Matteo; Robotti, Nadia

2012-03-01

We reconstruct Frédéric Joliot and Irène Curie's discovery of artificial radioactivity in January 1934 based in part on documents preserved in the Joliot-Curie Archives in Paris, France. We argue that their discovery followed from the convergence of two parallel lines of research, on the neutron and on the positron, that were focused on a well-defined experimental problem, the nuclear transmutation of aluminum and other light elements. We suggest that a key role was played by a suggestion that Francis Perrin made at the seventh Solvay Conference at the end of October 1933, that the alpha-particle bombardment of aluminum produces an intermediate unstable isotope of phosphorus, which then decays by positron emission. We also suggest that a further idea that Perrin published in December 1933, and the pioneering theory of beta decay that Enrico Fermi also first published in December 1933, established a new theoretical framework that stimulated Joliot to resume the researches that he and Curie had interrupted after the Solvay Conference, now for the first time using a Geiger-Müller counter to detect the positrons emitted when he bombarded aluminum with polonium alpha particles.

Optimization of the Timepix chip to measurement of radon, thoron and their progenies.

PubMed

Janik, Miroslaw; Ploc, Ondrej; Fiederle, Michael; Procz, Simon; Kavasi, Norbert

2016-01-01

Radon and thoron as well as their short-lived progenies are decay products of the radium and thorium series decays. They are the most important radionuclide elements with respect to public exposure. To utilize the semiconductor pixel radiation Timepix chip for the measurement of active and real-time alpha particles from radon, thoron and their progenies, it is necessary to check the registration and visualization of the chip. An energy check for radon, thoron and their progenies, as well as for (241)Am and(210)Po sources, was performed using the radon and thoron chambers at NIRS (National Institute of Radiological Sciences). The check found an energy resolution of 200 keV with a 14% efficiency as well as a linear dependency between the channel number (cluster volume) and the energy. The coefficient of determination r(2) of 0.99 for the range of 5 to 9 MeV was calculated. In addition, an offset for specific Timepix configurations between pre-calibration for low energy from 6 to 60 keV, and the actual calibration for alpha particles with energies from 4000 to 9000 keV, was detected. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

A novel method for rapid in vitro radiobioassay

NASA Astrophysics Data System (ADS)

Crawford, Evan Bogert

Rapid and accurate analysis of internal human exposure to radionuclides is essential to the effective triage and treatment of citizens who have possibly been exposed to radioactive materials in the environment. The two most likely scenarios in which a large number of citizens would be exposed are the detonation of a radiation dispersal device (RDD, "dirty bomb") or the accidental release of an isotope from an industrial source such as a radioisotopic thermal generator (RTG). In the event of the release and dispersion of radioactive materials into the environment in a large city, the entire population of the city -- including all commuting workers and tourists -- would have to be rapidly tested, both to satisfy the psychological needs of the citizens who were exposed to the mental trauma of a possible radiation dose, and to satisfy the immediate medical needs of those who received the highest doses and greatest levels of internal contamination -- those who would best benefit from rapid, intensive medical care. In this research a prototype rapid screening method to screen urine samples for the presence of up to five isotopes, both individually and in a mixture, has been developed. The isotopes used to develop this method are Co-60, Sr-90, Cs-137, Pu-238, and Am-241. This method avoids time-intensive chemical separations via the preparation and counting of a single sample on multiple detectors, and analyzing the spectra for isotope-specific markers. A rapid liquid-liquid separation using an organic extractive scintillator can be used to help quantify the activity of the alpha-emitting isotopes. The method provides quantifiable results in less than five minutes for the activity of beta/gamma-emitting isotopes when present in the sample at the intervention level as defined by the Centers for Disease Control and Prevention (CDC), and quantifiable results for the activity levels of alpha-emitting isotopes present at their respective intervention levels in approximately 30 minutes of sample preparation and counting time. Radiation detector spectra -- e.g. those from high-purity germanium (HPGe) gamma detectors and liquid scintillation detectors -- which contain decay signals from multiple isotopes often have overlapping signals: the counts from one isotope's decay can appear in energy channels associated with another isotope's decay, complicating the calculation of each isotope's activity. The uncertainties associated with analyzing these spectra have been traced in order to determine the effects of one isotope's count rate on the sensitivity and uncertainty associated with each other isotope. The method that was developed takes advantage of activated carbon filtration to eliminate quenching effects and to make the liquid scintillation spectra from different urine samples comparable. The method uses pulse-shape analysis to reduce the interference from beta emitters in the liquid scintillation spectrum and improve the minimum detectable activity (MDA) and minimum quantifiable activity (MQA) for alpha emitters. The method uses an HPGe detector to quantify the activity of gamma emitters, and subtract their isotopes' contributions to the liquid scintillation spectra via a calibration factor, such that the pure beta and pure alpha emitters can be identified and quantified from the resulting liquid scintillation spectra. Finally, the method optionally uses extractive scintillators to rapidly separate the alpha emitters from the beta emitters when the activity from the beta emitters is too great to detect or quantify the activity from the alpha emitters without such a separation. The method is able to detect and quantify all five isotopes, with uncertainties and biases usually in the 10-40% range, depending upon the isotopic mixtures and the activity ratios between each of the isotopes.

Background Characterization for Thermal Ion Release Experiments with 224Ra

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

Kwong, H.; /Stanford U., Phys. Dept.; Rowson, P.

The Enriched Xenon Observatory for neutrinoless double beta decay uses {sup 136}Ba identification as a means for verifying the decay's occurrence in {sup 136}Xe. A current challenge is the release of Ba ions from the Ba extraction probe, and one possible solution is to heat the probe to high temperatures to release the ions. The investigation of this method requires a characterization of the alpha decay background in our test apparatus, which uses a {sup 228}Th source that produces {sup 224}Ra daughters, the ionization energies of which are similar to those of Ba. For this purpose, we ran a backgroundmore » count with our apparatus maintained at a vacuum, and then three counts with the apparatus filled with Xe gas. We were able to match up our alpha spectrum in vacuum with the known decay scheme of {sup 228}Th, while the spectrum in xenon gas had too many unresolved ambiguities for an accurate characterization. We also found that the alpha decays occurred at a near-zero rate both in vacuum and in xenon gas, which indicates that the rate was determined by {sup 228}Th decays. With these background measurements, we can in the future make a more accurate measurement of the temperature dependency of the ratio of ions to neutral atoms released from the hot surface of the probe, which may lead to a successful method of Ba ion release.« less

Radiation and Thermal Ageing of Nuclear Waste Glass

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

Weber, William J

2014-01-01

The radioactive decay of fission products and actinides incorporated into nuclear waste glass leads to self-heating and self-radiation effects that may affect the stability, structure and performance of the glass in a closed system. Short-lived fission products cause significant self-heating for the first 600 years. Alpha decay of the actinides leads to self-radiation damage that can be significant after a few hundred years, and over the long time periods of geologic disposal, the accumulation of helium and radiation damage from alpha decay may lead to swelling, microstructural evolution and changes in mechanical properties. Four decades of research on the behaviormore » of nuclear waste glass are reviewed.« less

Comparison of Cf-252 thin-film sources prepared by evaporation or self-transfer

DOE PAGES

Algutifan, Noor J.; Sherman, Steven R.; Alexander, Charles W.

2014-11-29

Californium-252 (Z = 98) is valued as a potent neutron source due to its spontaneous fission decay path. Thin film sources containing Cf-252 were prepared by two techniques: evaporation and self-transfer. The sources were analyzed by alpha and gamma spectroscopy. Results indicate that self-transfer sources exhibit less alpha energy straggling and energy loss than evaporative sources. Fission fragments may also self-transfer, and sources made by self-transfer may need some decay time to reach radioactive equilibrium.

Nuclear Data Sheets page at the NNDC

Science.gov Websites

Data Sheets is a journal primarily devoted to the publication of evaluated nuclear structure and decay ; neutron, proton, alpha, cluster and cluster emission; fission. Nuclear structure and decay data are basis. The ENSDF database is the source for the nuclear structure and decay articles, which deal with a

Cancellation exponent and multifractal structure in two-dimensional magnetohydrodynamics: direct numerical simulations and Lagrangian averaged modeling.

PubMed

Graham, Jonathan Pietarila; Mininni, Pablo D; Pouquet, Annick

2005-10-01

We present direct numerical simulations and Lagrangian averaged (also known as alpha model) simulations of forced and free decaying magnetohydrodynamic turbulence in two dimensions. The statistics of sign cancellations of the current at small scales is studied using both the cancellation exponent and the fractal dimension of the structures. The alpha model is found to have the same scaling behavior between positive and negative contributions as the direct numerical simulations. The alpha model is also able to reproduce the time evolution of these quantities in free decaying turbulence. At large Reynolds numbers, an independence of the cancellation exponent with the Reynolds numbers is observed.

Precise Determination of the Intensity of 226Ra Alpha Decay to the 186 keV Excited State

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

S.P. LaMont; R.J. Gehrke; S.E. Glover

There is a significant discrepancy in the reported values for the emission probability of the 186 keV gamma-ray resulting from the alpha decay of 226 Ra to 186 keV excited state of 222 Rn. Published values fall in the range of 3.28 to 3.59 gamma-rays per 100 alpha-decays. An interesting observation is that the lower value, 3.28, is based on measuring the 186 keV gamma-ray intensity relative to the 226 Ra alpha-branch to the 186 keV level. The higher values, which are close to 3.59, are based on measuring the gamma-ray intensity from mass standards of 226 Ra that aremore » traceable to the mass standards prepared by HÓNIGSCHMID in the early 1930''s. This discrepancy was resolved in this work by carefully measuring the 226 Ra alpha-branch intensities, then applying the theoretical E2 multipolarity internal conversion coefficient of 0.692±0.007 to calculate the 186 keV gamma-ray emission probability. The measured value for the alpha branch to the 186 keV excited state was (6.16±0.03)%, which gives a 186 keV gamma-ray emission probability of (3.64±0.04)%. This value is in excellent agreement with the most recently reported 186 keV gamma-ray emission probabilities determined using 226 Ra mass standards.« less

An unattended device for high-voltage sampling and passive measurement of thoron decay products.

PubMed

Gierl, Stefanie; Meisenberg, Oliver; Haninger, Thomas; Wielunski, Marek; Tschiersch, Jochen

2014-02-01

An integrating measurement device for the concentration of airborne thoron decay products was designed and calibrated. It is suitable for unattended use over up to several months also in inhabited dwellings. The device consists of a hemispheric capacitor with a wire mesh as the outer electrode on ground potential and the sampling substrates as the inner electrode on +7.0 kV. Negatively charged and neutral thoron decay products are accelerated to and deposited on the sampling substrates. As sampling substrates, CR39 solid-state nuclear track detectors are used in order to record the alpha decay of the sampled decay products. Nuclide discrimination is achieved by covering the detectors with aluminum foil of different thickness, which are penetrated only by alpha particles with sufficient energy. Devices of this type were calibrated against working level monitors in a thoron experimental house. The sensitivity was measured as 9.2 tracks per Bq/m(3) × d of thoron decay products. The devices were used over 8 weeks in several houses built of earthen material in southern Germany, where equilibrium equivalent concentrations of 1.4-9.9 Bq/m(3) of thoron decay products were measured.

Effect of low electric fields on alpha scintillation light yield in liquid argon

NASA Astrophysics Data System (ADS)

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Asner, D. M.; Back, H. O.; Baldin, B.; Biery, K.; Bocci, V.; Bonfini, G.; Bonivento, W.; Bossa, M.; Bottino, B.; Brigatti, A.; Brodsky, J.; Budano, F.; Bussino, S.; Cadeddu, M.; Cadoni, M.; Calaprice, F.; Canci, N.; Candela, A.; Caravati, M.; Cariello, M.; Carlini, M.; Catalanotti, S.; Cavalcante, P.; Chepurnov, A.; Cicalò, C.; Cocco, A. G.; Covone, G.; D'Angelo, D.; D'Incecco, M.; Davini, S.; De Cecco, S.; De Deo, M.; De Vincenzi, M.; Derbin, A.; Devoto, A.; Di Eusanio, F.; Di Pietro, G.; Dionisi, C.; Edkins, E.; Empl, A.; Fan, A.; Fiorillo, G.; Fomenko, K.; Forster, G.; Franco, D.; Gabriele, F.; Galbiati, C.; Giagu, S.; Giganti, C.; Giovanetti, G. K.; Goretti, A. M.; Granato, F.; Gromov, M.; Guan, M.; Guardincerri, Y.; Hackett, B. R.; Herner, K.; Hughes, D.; Humble, P.; Hungerford, E. V.; Ianni, A.; James, I.; Johnson, T. N.; Jollet, C.; Keeter, K.; Kendziora, C. L.; Koh, G.; Korablev, D.; Korga, G.; Kubankin, A.; Li, X.; Lissia, M.; Loer, B.; Lombardi, P.; Longo, G.; Ma, Y.; Machulin, I. N.; Mandarano, A.; Mari, S. M.; Maricic, J.; Marini, L.; Martoff, C. J.; Meregaglia, A.; Meyers, P. D.; Milincic, R.; Miller, J. D.; Montanari, D.; Monte, A.; Mount, B. J.; Muratova, V. N.; Musico, P.; Napolitano, J.; Navrer Agasson, A.; Odrowski, S.; Oleinik, A.; Orsini, M.; Ortica, F.; Pagani, L.; Pallavicini, M.; Pantic, E.; Parmeggiano, S.; Pelczar, K.; Pelliccia, N.; Pocar, A.; Pordes, S.; Pugachev, D. A.; Qian, H.; Randle, K.; Ranucci, G.; Razeti, M.; Razeto, A.; Reinhold, B.; Renshaw, A. L.; Rescigno, M.; Riffard, Q.; Romani, A.; Rossi, B.; Rossi, N.; Rountree, D.; Sablone, D.; Saggese, P.; Sands, W.; Savarese, C.; Schlitzer, B.; Segreto, E.; Semenov, D. A.; Shields, E.; Singh, P. N.; Skorokhvatov, M. D.; Smirnov, O.; Sotnikov, A.; Stanford, C.; Suvorov, Y.; Tartaglia, R.; Tatarowicz, J.; Testera, G.; Tonazzo, A.; Trinchese, P.; Unzhakov, E. V.; Verducci, M.; Vishneva, A.; Vogelaar, B.; Wada, M.; Walker, S.; Wang, H.; Wang, Y.; Watson, A. W.; Westerdale, S.; Wilhelmi, J.; Wojcik, M. M.; Xiang, X.; Xiao, X.; Xu, J.; Yang, C.; Zhong, W.; Zhu, C.; Zuzel, G.

2017-01-01

Measurements were made of scintillation light yield of alpha particles from the 222Rn decay chain within the DarkSide-50 liquid argon time projection chamber. The light yield was found to increase as the applied electric field increased, with alphas in a 200 V/cm electric field exhibiting a ~2% increase in light yield compared to alphas in no field.

Construction and measurements of a vacuum-swing-adsorption radon-mitigation system

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

Schnee, R. W.; Bunker, R.; Ghulam, G.

Long-lived alpha and beta emitters in the {sup 222}Rn decay chain on (and near) detector surfaces may be the limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay, and in screening detectors. In order to reduce backgrounds from radon-daughter plate-out onto the wires of the Beta Cage during its assembly, an ultra-low-radon cleanroom is being commissioned at Syracuse University using a vacuum-swing-adsorption radon-mitigation system. The radon filter shows ∼20× reduction at its output, from 7.47±0.56 to 0.37±0.12 Bq/m{sup 3}, and the cleanroom radon activity meets project requirements, with a lowest achieved value consistent withmore » that of the filter, and levels consistently < 2 Bq/m{sup 3}.« less

Measurement of Radon-Induced Backgrounds in the NEXT Double Beta Decay Experiment

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

Novella, P.; et al.

The measurement of the internal 222Rn activity in the NEXT-White detector during the so-called Run-II period with 136Xe-depleted xenon is discussed in detail, together with its implications for double beta decay searches in NEXT. The activity is measured through the alpha production rate induced in the fiducial volume by 222Rn and its alpha-emitting progeny. The specific activity is measured to bemore » $$(37.5\\pm 2.3~\\mathrm{(stat.)}\\pm 5.9~\\mathrm{(syst.)})$$~mBq/m$^3$. Radon-induced electrons have also been characterized from the decay of the 214Bi daughter ions plating out on the cathode of the time projection chamber. From our studies, we conclude that radon-induced backgrounds are sufficiently low to enable a successful NEXT-100 physics program, as the projected rate contribution should not exceed 0.2~counts/yr in the neutrinoless double beta decay sample.« less

Remote micro-encapsulation of curium-gold cermets

NASA Astrophysics Data System (ADS)

Coops, M. S.; Voegele, A. L.; Hayes, W. N.; Sisson, D. H.

1982-09-01

A technique has been developed to produce miniature, high-density capsules of curium-244 oxide contained in three concentric jackets of metallic gold or silver. The final capsules are right circular cylinders, 6.350 mm diameter by (3.18±0.05) mm long, with a minimum density of 11.0 g/cm 3. Each level of containment was soldered or brazed closed, with the outer surface free of detectable alpha contamination. Fabrication was performed in three separate small cells operated by standard master-slave manipulators. Production capsules have been stored for up to five years without indication of dimensional growth or leakage of radioactive contents. The dimensional stability of the capsules is attributed to the microporous structure of the plated-gold structure which permits helium gas resulting from alpha decay to diffuse through the capsule wall while retaining all radioactive materials.

Localized defects in radiation-damaged zircon

PubMed

Rios; Malcherek; Salje; Domeneghetti

2000-12-01

The crystal structure of a radiation-damaged natural zircon, ZrSiO(4) (alpha-decay radiation dose is ca 1.8 x 10(18) alpha-decay events g(-1)), has been determined. The anisotropic unit-cell swelling observed in the early stages of the amorphization process (0.17% along the a axis and 0.62% along the c axis compared with the undamaged material) is a consequence of the anisotropy of the expansion of ZrO(8) polyhedra. Larger anisotropic displacement parameters were found for Zr and O atoms, indicating that the distortion produced by alpha particle-induced localized defects mainly affects the ZrO(8) unit. The overall shape of SiO(4) tetrahedra remains essentially undistorted, while Si-O bonds are found to lengthen by 0.43%.

Decay properties of charm and beauty open flavour mesons

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

Kumar Rai, Ajay; Vinodkumar, P. C.

The masses of S and P states, pseudoscalar and vector decay constants, leptonic, semileptonic decay widths of charm (D) and beauty (B) open flavour mesons have been computed in the framework of Coulomb and power potential of the form V(r) = -({alpha}{sub c}/r)+Ar{sup v}. The results are compared with other theoretical as well as experimental results.

Effect of low electric fields on alpha scintillation light yield in liquid argon

DOE PAGES

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; ...

2017-01-24

Measurements were made of scintillation light yield of alpha particles from themore » $$^{222}$$Rn decay chain within the DarkSide-50 liquid argon time projection chamber. Furthermore, the light yield was found to increase as the applied electric field increased, with alphas in a 200 V/cm electric field exhibiting a 2% increase in light yield compared to alphas in no field.« less

Systematic study of α-decay half-lives using Royer and related formula

NASA Astrophysics Data System (ADS)

Akrawy, Dashty T.; Hassanabadi, H.; Hosseini, S. S.; Santhosh, K. P.

2018-03-01

The alpha decay half-lives of 356 isotopes were studied using the Royer and related Formula and are compared with experimental data. The study shows that the predicted half-lives match well with experimental data over a wide range for each (Z , N) parity of the parent nuclei. We have calculated the standard deviation of log10 ⁡Tα (s), for each formula and our study indicate that, for alpha decay studies, generally, analytical ℓ-dependent formula proposed by Royer, with σRB = 0.4373, is the best model followed by the formula proposed by Denisov and Khudenko (DK), σDK = 0.4743 for all 356 nuclei. We hope the present study is a clear indicator of the predictive power of Royer and related formula.

Experimental aspects of the adiabatic approach in estimating the effect of electron screening on alpha decay

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

Karpeshin, F. F., E-mail: fkarpeshin@gmail.com; Trzhaskovskaya, M. B.

2015-12-15

Special features of the effect of the electron shell on alpha decay that have important experimental implications are studied within the adiabatic approach. The magnitude of the effect is about several tenths of a percent or smaller, depending on the transition energy and on the atomic number. A dominant role of inner shells is shown: more than 80% of the effect is saturated by 1s electrons. This circumstance plays a crucial role for experiments, making it possible to measure this small effect by a difference method in the same storage rings via a comparison of, for example, decay probabilities inmore » bare nuclei and heliumlike ions. The reasons behind the relative success and the applicability limits of the frozen-shell model, which has been used to calculate the effect in question for more than half a century, are analyzed. An interesting experiment aimed at studying charged alpha-particle states is proposed. This experiment will furnish unique information for testing our ideas of the interplay of nonadiabatic and adiabatic processes.« less

The reliability and validity of the RAPIDD scale: readiness assessment of parents concerning infant dental decay.

PubMed

Weinstein, P; Riedy, C A

2001-01-01

This study assessed the instrument, Readiness Assessment of Parents concerning Infant Dental Decay (RAPIDD), as a measure of parental readiness to change children's dental behaviors. The 38-item instrument based on four constructs (Openness to Health Information, Valuing Dental Health, Convenience/Difficulty, Child Permissiveness) was administered to a random sample of parents of 6-to-36 month old children on Saipan, Commonwealth of the Northern Mariana Islands, USA. Alpha values for each construct's internal consistency ranged from 0.51 to 0.75. Correlations were found with feeding (e.g., Convenience/Difficulty and receiving bottle (r = .24, p < 0.01)) and oral hygiene (e.g., Valuing Dental Health and tooth-cleaning (r = .27, p < 0.01)). Parental responses were used to categorize respondents into precontemplators (16 percent), contemplators (77 percent), and actions (6.7 percent). This categorization was associated with the number of decalcified and decayed surfaces (alpha 2 = 34.8, p = 0.04; alpha 2 = 65.7, p < 0.01). This suggests that parental readiness is associated with infant dental health and that most parents would be willing to contemplate prevention.

Radiation from plutonium 238 used in space applications

NASA Technical Reports Server (NTRS)

Keenan, T. K.; Vallee, R. E.; Powers, J. A.

1972-01-01

The principal mode of the nuclear decay of plutonium 238 is by alpha particle emission at a rate of 17 curies per gram. Gamma radiation also present in nuclear fuels arises primarily from the nuclear de-excitation of daughter nuclei as a result of the alpha decay of plutonium 238 and reactor-produced impurities. Plutonium 238 has a spontaneous fission half life of 4.8 x 10 to the 10th power years. Neutrons associated with this spontaneous fission are emitted at a rate of 28,000 neutrons per second per gram. Since the space fuel form of plutonium 238 is the oxide pressed into a cermet with molybdenum, a contribution to the neutron emission rate arises from (alpha, n) reactions with 0-17 and 0-18 which occur in natural oxygen.

Assault frequency and preformation probability of the {alpha} emission process

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

Zhang, H. F.; Royer, G.; Li, J. Q.

2011-08-15

A study of the assault frequency and preformation factor of the {alpha}-decay description is performed from the experimental {alpha}-decay constant and the penetration probabilities calculated from the generalized liquid-drop model (GLDM) potential barriers. To determine the assault frequency a quantum-mechanical method using a harmonic oscillator is introduced and leads to values of around 10{sup 21} s{sup -1}, similar to the ones calculated within the classical method. The preformation probability is around 10{sup -1}-10{sup -2}. The results for even-even Po isotopes are discussed for illustration. While the assault frequency presents only a shallow minimum in the vicinity of the magic neutronmore » number 126, the preformation factor and mainly the penetrability probability diminish strongly around N=126.« less

Monte Carlo simulation of semiconductor detector response to (222)Rn and (220)Rn environments.

PubMed

Irlinger, J; Trinkl, S; Wielunksi, M; Tschiersch, J; Rühm, W

2016-07-01

A new electronic radon/thoron monitor employing semiconductor detectors based on a passive diffusion chamber design has been recently developed at the Helmholtz Zentrum München (HMGU). This device allows for acquisition of alpha particle energy spectra, in order to distinguish alpha particles originating from radon and radon progeny decays, as well as those originating from thoron and its progeny decays. A Monte-Carlo application is described which uses the Geant4 toolkit to simulate these alpha particle spectra. Reasonable agreement between measured and simulated spectra were obtained for both (220)Rn and (222)Rn, in the energy range between 1 and 10 MeV. Measured calibration factors could be reproduced by the simulation, given the uncertainties involved in the measurement and simulation. The simulated alpha particle spectra can now be used to interpret spectra measured in mixed radon/thoron atmospheres. The results agreed well with measurements performed in both radon and thoron gas environments. It is concluded that the developed simulation allows for an accurate prediction of calibration factors and alpha particle energy spectra. Copyright © 2016 Elsevier Ltd. All rights reserved.

PGC-1{alpha} accelerates cytosolic Ca{sup 2+} clearance without disturbing Ca{sup 2+} homeostasis in cardiac myocytes

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

Chen, Min, E-mail: chenminyx@gmail.com; Yunnan Centers for Diseases Prevention and Control, Kunming 650022; Wang, Yanru

2010-06-11

Energy metabolism and Ca{sup 2+} handling serve critical roles in cardiac physiology and pathophysiology. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1{alpha}) is a multi-functional coactivator that is involved in the regulation of cardiac mitochondrial functional capacity and cellular energy metabolism. However, the regulation of PGC-1{alpha} in cardiac Ca{sup 2+} signaling has not been fully elucidated. To address this issue, we combined confocal line-scan imaging with off-line imaging processing to characterize calcium signaling in cultured adult rat ventricular myocytes expressing PGC-1{alpha} via adenoviral transduction. Our data shows that overexpressing PGC-1{alpha} improved myocyte contractility without increasing the amplitude of Ca{sup 2+}more » transients, suggesting that myofilament sensitivity to Ca{sup 2+} increased. Interestingly, the decay kinetics of global Ca{sup 2+} transients and Ca{sup 2+} waves accelerated in PGC-1{alpha}-expressing cells, but the decay rate of caffeine-elicited Ca{sup 2+} transients showed no significant change. This suggests that sarcoplasmic reticulum (SR) Ca{sup 2+}-ATPase (SERCA2a), but not Na{sup +}/Ca{sup 2+} exchange (NCX) contribute to PGC-1{alpha}-induced cytosolic Ca{sup 2+} clearance. Furthermore, PGC-1{alpha} induced the expression of SERCA2a in cultured cardiac myocytes. Importantly, overexpressing PGC-1{alpha} did not disturb cardiac Ca{sup 2+} homeostasis, because SR Ca{sup 2+} load and the propensity for Ca{sup 2+} waves remained unchanged. These data suggest that PGC-1{alpha} can ameliorate cardiac Ca{sup 2+} cycling and improve cardiac work output in response to physiological stress. Unraveling the PGC-1{alpha}-calcium handing pathway sheds new light on the role of PGC-1{alpha} in the therapy of cardiac diseases.« less

Radon as a Tracer for Lunar Volatiles

NASA Technical Reports Server (NTRS)

Friesen, Larry Jay

1992-01-01

Radon and its decay product polonium can be used as tracers to search for lunar volatiles. One effective technique to look for them would be by using alpha-particle spectrometers from lunar orbit. Alpha spectrometers were flown in the Apollo Service Modules during the Apollo 15 and 16 missions, and did observe Rn-222 and its decay product Po-210 on the lunar surface from orbit. This demonstrates that radon and polonium can be observed from orbit; what must next be shown is that such observations can reveal something about the locations of volatiles on the Moon.

The half-life of 218Po.

PubMed

Martz, D E; Harris, R T; Langner, G H

1989-07-01

Direct observation of the 218Po alpha-peak decay with a microcomputer-controlled alpha-spectrometer yielded a mean half-life value of 3.040 +/- 0.008 min, where the error quoted represents twice the standard deviation of the means from 38 separate decay measurements. The 1912 and 1924 218Po half-life measurements, which provided the 3.05-min value listed in nuclear tables for the past 60 y, are critically reviewed. Two more recent experiments, which yielded longer values of 3.11 min (Van Hise et al. 1982) and 3.093 min (Potapov and Soloshenkov 1986), are also discussed.

Self-absorption Effects on Alpha-Induced Atmospheric Nitrogen Fluorescence Yield

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

Bachelor, Paula P.; Jordan, David V.; Harper, Warren W.

2009-12-01

Nitrogen fluorescence induced by alpha, beta and gamma radiation can be used to detect the presence of radioactive contamination in the environment. Successful measurement of fluorescence yield involves a number of factors, including: known fluorescence signal rate during the measurement; the effective alpha spectrum of the radioactive sources used in the measurement; optical attenuation length of the fluorescence signal in air during the measurement; the absolute throughput of the instrumentation; calibration of the instrumentation; and radiation transport modeling of the "effective" array exposure rate given the spectrum of the alpha particles. Field testing of optical instrumentation was conducted to measuremore » the nitrogen fluorescence yield from the alpha radiation generated from americium-241 (241Am) decay. The 241Am test sources were prepared by direct evaporation of ~1 mCi in nitric acid solution, and some solids were visible on the surface of the sources. A laboratory study was conducted with lower activities of 241Am to determine whether the presence of solids on the surface of the sources prepared both by direct evaporation and by electrodeposition onto stainless steel disks produced sufficient self-absorption to cause a decrease in expected fluorescence. Alpha spectroscopy was used to determine the apparent activity of the sources versus the known activity deposited on the surface. Results from the self-absorption laboratory studies were used to correct the activity values in the model and calculate the nitrogen fluorescence generated by the 241Am during the field experiments.« less

Cluster-model calculations of exotic decays from heavy nuclei

NASA Astrophysics Data System (ADS)

Buck, B.; Merchant, A. C.

1989-05-01

A cluster model employing a local, effective cluster-core potential is used to investigate exotic decay from heavy nuclei as a quantum tunneling phenomenon within a semiclassical approximation. Excellent agreement with all reported experimental measurements of the decay widths for 14C and 24Ne emission is obtained. As an added bonus, the width for alpha particle emission from 212Po is also calculated in good agreement with experiment.

Measurement of (222)Rn by absorption in plastic scintillators and alpha/beta pulse shape discrimination.

PubMed

Mitev, Krasimir K

2016-04-01

This work demonstrates that common plastic scintillators like BC-400, EJ-200 and SCSF-81 absorb radon and their scintillation pulse decay times are different for alpha- and beta-particles. This allows the application of pulse shape analysis for separation of the pulses of alpha- and beta-particles emitted by the absorbed radon and its progeny. It is shown that after pulse shape discrimination of beta-particles' pulses, the energy resolution of BC-400 and EJ-200 alpha spectra is sufficient to separate the peaks of (222)Rn, (218)Po and (214)Po and allows (222)Rn measurements that are unaffected by the presence of thoron ((220)Rn) in the environment. The alpha energy resolution of SCSF-81 in the experiments degrades due to imperfect collection of the light emitted inside the scintillating fibers. The experiments with plastic scintillation microspheres (PSM) confirm previous findings of other researchers that PSM have alpha-/beta-discrimination properties and show suitability for radon measurements. The diffusion length of radon in BC-400 and EJ-200 is determined. The pilot experiments show that the plastic scintillators are suitable for radon-in-soil-gas measurements. Overall, the results of this work suggest that it is possible to develop a new type of radon measurement instruments which employ absorption in plastic scintillators, pulse-shape discrimination and analysis of the alpha spectra. Such instruments can be very compact and can perform continuous, real-time radon measurements and thoron detection. They can find applications in various fields from radiation protection to earth sciences. Copyright © 2016 Elsevier Ltd. All rights reserved.

Suppression of alpha-induced lateral surface events in the COBRA experiment using CdZnTe detectors with an instrumented guard-ring electrode

NASA Astrophysics Data System (ADS)

Arling, J.-H.; Gerhardt, M.; Gößling, C.; Gehre, D.; Klingenberg, R.; Kröninger, K.; Nitsch, C.; Quante, T.; Rohatsch, K.; Tebrügge, J.; Temminghoff, R.; Theinert, R.; Zatschler, S.; Zuber, K.

2017-11-01

The COBRA collaboration searches for neutrinoless double beta-decay (0νββ-decay) using CdZnTe semiconductor detectors with a coplanar-grid readout and a surrounding guard-ring structure. The operation of the COBRA demonstrator at the Gran Sasso underground laboratory (LNGS) indicates that alpha-induced lateral surface events are the dominant source of background events. By instrumenting the guard-ring electrode it is possible to suppress this type of background. In laboratory measurements this method achieved a suppression factor of alpha-induced lateral surface events of 5300+2660-1380, while retaining (85.3 ±0.1%) of gamma events occurring in the entire detector volume. This suppression is superior to the pulse-shape analysis methods used so far in COBRA by three orders of magnitude.

Ca2+ permeability through rat cloned alpha9-containing nicotinic acetylcholine receptors.

PubMed

Fucile, Sergio; Sucapane, Antonietta; Eusebi, Fabrizio

2006-04-01

We investigated the functional properties of rat alpha9 and alpha9alpha10 nicotinic acetylcholine receptors (nAChRs) expressed by transient transfection in the rat GH4C1 cell line, using both Ca(2+) imaging and whole-cell recording. Acute applications of ACh generated short-delay fast-rising and quick-decaying Ca(2+) transients, suppressed in Ca(2+)-free medium and invariably accompanied by the activation of whole-cell inward currents. The mean amplitude of ACh-induced currents was as small as -16 pA in alpha9 subunit cDNA-transfected GH4C1 cells (alpha9-GH4C1), while they were much larger (range: -150 to -300 pA) in alpha9alpha10 subunit cDNAs-transfected GH4C1 cells (alpha9alpha10-GH4C1). Currents were not activated by nicotine, were blocked by methyllycaconitine and were ACh concentration-dependent. Because the Ca(2+) permeability of alpha9-containing nAChRs has been estimated in immortalized cochlear UB/OC-2 mouse cells, we also characterized the ACh-induced responses in these cells. Unlike alpha9- and alpha9alpha10-GH4C1 cells, UB/OC-2 cells responded to ACh with both long-delay methyllycaconitine-insensitive whole-cell currents and long-lasting Ca(2+) transients, the latter being detected in the absence of Ca(2+) in the extracellular medium and being suppressed by the Ca(2+)-ATPase inhibitor thapsigargin, known to deplete IP(3)-sensitive stores. These results indicated the involvement of muscarinic nAChRs and the lack of functional ACh-gated receptor channels in UB/OC-2 cells. Thus, we measured the fractional Ca(2+) current (P(f), i.e. the percentage of total current carried by Ca(2+) ions) in alpha9alpha10-GH4C1, obtaining a P(f) value of 22 +/- 4%; this is the largest value estimated to date for a ligand-gated receptor channel. The physiological role played by Ca(2+) entry through alpha9-containing nAChRs gated by ACh is discussed.

Radiation-stability of smectite.

PubMed

Sorieul, Stéphanie; Allard, Thierry; Wang, Lumin M; Grambin-Lapeyre, Caroline; Lian, Jie; Calas, Georges; Ewings, Rodney C

2008-11-15

The safety assessment of geological repositories for high-level nuclear waste and spent nuclear fuel requires an understanding of the response of materials to high temperatures and intense radiation fields. Clays, such as smectite, have been proposed as backfill material around waste packages, but their response to intense radiation from short-lived fission products and alpha decay of sorbed actinides remains poorly understood. Cumulative doses may amorphize clays and may alter their properties of sorption, swelling, or water retention. We describe the amorphization of smectites induced by electron and heavy ion irradiations to simulate ionizing radiation and alpha recoil nuclei, respectively. A new "bell-shaped" evolution of the amorphization dose with temperature has been determined. The maximum dose for amorphization occurs at about 300-400 degrees C, showing that temperature-induced dehydroxylation enhances amorphization. The exact shape of the bell-shaped curves depends on the interlayer cation. At ambient temperature, ionizing radiation and alpha-decay events do not show the same efficiency. The former results in amorphization at doses between 10(10)-10(11) Gy which are greater than the total radiation dose expected for radioactive waste over 10(6) years. In contrast, alpha-decay events amorphize clays at doses as low as 0.13-0.16 displacements per atom, i.e. doses consistent with nuclear waste accumulated over approximately 1000 yrs. However, the limited penetration of alpha particles and recoil nuclei, in the 100 nm - 20 microm range, will minimize damage. Clays will not be amorphized unless the waste package is breached and released actinides are heavily sorbed onto the clay overpack.

On the decay of outbursts in dwarf novae nad X-ray novae

NASA Technical Reports Server (NTRS)

Cannizzo, John K.

1994-01-01

We perform computations using a time-dependent model for the accretion disk limit-cycle mechanism to examine the decay of the optical light following the peak of a dwarf nova outburst. We present the results of a parameter study of the physical input variables which affect the decay rate. In the model, the decay is brought about by a cooling transition front which begins at large radii in the disk and moves inward. The nature of the decay is strongly influenced by the radial dependence of the accretion disk viscosity parameter alpha. To obtain exponential decays for typical dwarf nova parameters, we require alpha proportional to r(exp epsilon(sub 0)), where epsilon(sub 0) approximately = 0.3-0.4. The exact value of epsilon(sub 0) which produces exponential decays depends on factors such as the mass of the accreting star and the inner radius of the accretion disk. Therefore, the observed ubiquity of exponential decays in two different types of systems (dwarf novae and X-ray novae) leads us to believe that alpha is an unnatural scaling for the viscosity. The physics of the cooling transition front must be self-regulating in that the timescale (-parital derivative of lnSigma(r)/partial derivative +)(exp -1) (where Sigma is the surface density) for mass extraction across the front remains constant. This may be consistent with a scaling alpha proportional to (h/r)(exp n), where h is the local disk semi-thickness and n approximately 1-2. As regards the speed of the cooling front, we find v(sub F)(r) proportional to r(exp p), where p approximately 3 at large radii, with an abrupt transition to p approximately 0 at some smaller radius. The r(exp 3) dependence is much steeper than has been found by previous workers and appears to result from the strong variation of specific heat within the cooling front when the front resides at a large radius in the disk. The outflow of disk material across the cooling front causes a significant departure of dln T(sub dff0/dln r from the standard value of -0.75 (expected from steady state accretion) within about 0.2 dex in radius of the break associated with the cooling front -- T(sub eff) aproximately 10(exp 3.9) K (r/10(exp 10 cm)) (exp -0.1). These effects should be observable with eclipse mapping. Finally, it appears that the relatively slow decay rate for the optical flux in the 1975 outburst of A0620-00 can be accounted for if the primary is a approximately 10 Solar mass black hole.

ATOMIC PHYSICS, AN AUTOINSTRUCTIONAL PROGRAM, VOLUME 3, SUPPLEMENT.

ERIC Educational Resources Information Center

DETERLINE, WILLIAM A.; KLAUS, DAVID J.

THE AUTOINSTRUCTIONAL MATERIALS IN THIS TEXT WERE PREPARED FOR USE IN AN EXPERIMENTAL STUDY, OFFERING SELF-TUTORING MATERIAL FOR LEARNING ATOMIC PHYSICS. THE TOPICS COVERED ARE (1) NUCLEAR BINDING ENERGY, (2) DISCOVERY OF RADIOACTIVITY, (3) RADIOACTIVE RADIATIONS, (4) ALPHA AND BETA DECAY, (5) BETA DECAY REACTIONS, (6) RADIOACTIVE DATING AND…

Surface Alpha Interactions in P-Type Point-Contact HPGe Detectors: Maximizing Sensitivity of 76Ge Neutrinoless Double-Beta Decay Searches

NASA Astrophysics Data System (ADS)

Gruszko, Julieta

Though the existence of neutrino oscillations proves that neutrinos must have non-zero mass, Beyond-the-Standard-Model physics is needed to explain the origins of that mass. One intriguing possibility is that neutrinos are Majorana particles, i.e., they are their own anti-particles. Such a mechanism could naturally explain the observed smallness of the neutrino masses, and would have consequences that go far beyond neutrino physics, with implications for Grand Unification and leptogenesis. If neutrinos are Majorana particles, they could undergo neutrinoless double-beta decay (0nBB), a hypothesized rare decay in which two antineutrinos annihilate one another. This process, if it exists, would be exceedingly rare, with a half-life over 1E25 years. Therefore, searching for it requires experiments with extremely low background rates. One promising technique in the search for 0nBB is the use of P-type point-contact (P-PC) high-purity Germanium (HPGe) detectors enriched in 76Ge, operated in large low-background arrays. This approach is used, with some key differences, by the MAJORANA and GERDA Collaborations. A problematic background in such large granular detector arrays is posed by alpha particles incident on the surfaces of the detectors, often caused by 222Rn contamination of parts or of the detectors themselves. In the MAJORANA DEMONSTRATOR, events have been observed that are consistent with energy-degraded alphas originating near the passivated surface of the detectors, leading to a potential background contribution in the region-of-interest for neutrinoless double-beta decay. However, it is also observed that when energy deposition occurs very close to the passivated surface, high charge trapping occurs along with subsequent slow charge re-release. This leads to both a reduced prompt signal and a measurable change in slope of the tail of a recorded pulse. Here we discuss the characteristics of these events and the development of a filter that can identify the occurrence of this delayed charge recovery (DCR) effect, allowing for the efficient rejection of passivated surface alpha events in analysis. Using a dedicated test-stand called the TUM Upside-down BEGe (TUBE) scanner, we have characterized the response of a P-PC detector like those used in the DEMONSTRATOR to alphas incident on the sensitive surfaces, developing a model for the radial dependence of the energy loss to charge trapping and determining the dominant mechanism behind the delayed charge effect. We have also used these measurements to demonstrate the complementarity of the DCR analysis with the drift-time analysis that is used to identify alpha background candidate events in the GERDA detectors. Using these two methods, we demonstrate the ability to effectively reject all alpha events (to within statistical uncertainty) with only 0.2% bulk event sacrifice. Applying the DCR analysis to the events observed in the MAJORANA DEMONSTRATOR, we find that it reduces the backgrounds in the 0nBB region-of-interest by a factor of 29, increasing the expected experimental sensitivity by a factor of 3 over the lifetime of the DEMONSTRATOR. The results of the dedicated measurements in the TUBE scanner can be used to build a background model for alpha decays in the DEMONSTRATOR; here, we examine two simplified geometric models for the alpha source distribution and find that the observed spectral shape is consistent with alpha events originating in the plastics of the detector units.

Coherent fragmentation of 12C nuclei of momentum 4.5 GeV/ c per nucleon through the 8Beg.s.+4He channel in a nuclear photoemulsion containing lead nuclei

NASA Astrophysics Data System (ADS)

Belaga, V. V.; Gerasimov, S. G.; Dronov, V. A.; Peresadko, N. G.; Pisetskaya, A. V.; Rusakova, V. V.; Fetisov, V. N.; Kharlamov, S. P.; Shesterkina, L. N.

2017-07-01

A two-particle channel in which an unbound nucleus of 8Be in the ground state (8Beg.s.) was one of the fragments was selected among events where 12C nuclei of momentum 4.5 GeV/c per nucleon undergo coherent dissociation into three alpha particles. The events in question were detected in a track nuclear photoemulsion containing lead nuclei, which was irradiated at the synchrophasotron of the Laboratory of High Energies at the Joint Institute for Nuclear Research (JINR, Dubna). The average transverse momentum of alpha particles produced upon the decay of 8Beg.s. nuclei was 87±6 MeV/ c, while that for "single" alpha (αs) particles was 123±15 MeV/ c. The average value of the transverse-momentum transfer in the reaction being considered, Pt(12C), was 223 ± 20 MeV/ c. The average value of the cross section for this channel involving Ag and Br target nuclei was 13 ± 4 mb, while the cross section for the reaction on the Pb nucleus was 40 ± 15 mb. The Coulomb dissociation contribution evaluated on the basis of the number of events where the momentum P t(12C) did not exceed 0.1 GeV/c saturated about 20%. In nine events, the measured total transverse energy of the fragments in the reference frame comoving with the decaying carbon nucleus did not exceed 0.45 MeV, which did not contradict the excitation of the participant 12C nucleus to the level at 7.65 MeV. The average value of the transverse momentum in those events was 234 ± 25 MeV/ c.

Scintillation decay time and pulse shape discrimination in oxygenated and deoxygenated solutions of linear alkylbenzene for the SNO+ experiment

NASA Astrophysics Data System (ADS)

O'Keeffe, H. M.; O'Sullivan, E.; Chen, M. C.

2011-06-01

The SNO+ liquid scintillator experiment is under construction in the SNOLAB facility in Canada. The success of this experiment relies upon accurate characterization of the liquid scintillator, linear alkylbenzene (LAB). In this paper, scintillation decay times for alpha and electron excitations in LAB with 2 g/L PPO are presented for both oxygenated and deoxygenated solutions. While deoxygenation is expected to improve pulse shape discrimination in liquid scintillators, it is not commonly demonstrated in the literature. This paper shows that for linear alkylbenzene, deoxygenation improves discrimination between electron and alpha excitations in the scintillator.

Radionuclides in ground water of the Carson River Basin, western Nevada and eastern California, U.S.A.

USGS Publications Warehouse

Thomas, J.M.; Welch, A.H.; Lico, M.S.; Hughes, J.L.; Whitney, R.

1993-01-01

Ground water is the main source of domestic and public supply in the Carson River Basin. Ground water originates as precipitation primarily in the Sierra Nevada in the western part of Carson and Eagle Valleys, and flows down gradient in the direction of the Carson River through Dayton and Churchill Valleys to a terminal sink in the Carson Desert. Because radionuclides dissolved in ground water can pose a threat to human health, the distribution and sources of several naturally occurring radionuclides that contribute to gross-alpha and gross-beta activities in the study area were investigated. Generally, alpha and beta activities and U concentration increase from the up-gradient to down-gradient hydrographic areas of the Carson River Basin, whereas 222Rn concentration decreases. Both 226Ra and 228Ra concentrations are similar throughout the study area. Alpha and beta activities and U concentration commonly exceed 100 pCi/l in the Carson Desert at the distal end of the flow system. Radon-222 commonly exceeds 2,000 pCi/l in the western part of Carson and Eagle Valleys adjacent to the Sierra Nevada. Radium-226 and 228Ra concentrations are <5 pCi/l. Four ground water samples were analyzed for 210Po and one sample contained a high concentration of 21 pCi/l. Seven samples were analyzed for 210Pb; six contained <3 pCi/l and one contained 12 pCi/l. Thorium-230 was detected at concentrations of 0.15 and 0.20 pCi/l in two of four samples. Alpha-emitting radionuclides in the ground water originated from the dissolution of U-rich granitic rocks in the Sierra Nevada by CO2, oxygenated water. Dissolution of primary minerals, mainly titanite (sphene) in the granitic rocks, releases U to the water. Dissolved U is probably removed from the water by adsorption on Fe- and Mn-oxide coatings on fracture surfaces and fine-grained sediment, by adsorption on organic matter, and by coprecipitation with Fe and Mn oxides. These coated sediments are transported throughout the basin by fluvial processes. Thus, U is transported as dissolved and adsorbed species. A rise in the water table in the Carson Desert because of irrigation has resulted in the oxidation of U-rich organic matter and dissolution of U-bearing coatings on sediments, producing unusually high U concentration in the ground water. Alpha activity in the ground water is almost entirely from the decay of U dissolved in the water. Beta activity in ground water samples is primarily from the decay of 40K dissolved in the water and ingrowth of 238U progeny in the sample before analysis. Approximately one-half of the measured beta activity may not be present in ground water in the aquifer, but instead is produced in the sample after collection and before analysis. Potassium-40 is primarily from the dissolution of K-containing minerals, probably K-feldspar and biotite. Radon-222 is primarily from the decay of 226Ra in the aquifer materials. Radium in the ground water is thought to be mainly from alpha recoil associated with the decay of Th in the aquifer material. Some Ra may be from dissolution (or desorption) or Ra-rich coatings on sediments. ?? 1993.

Automatic measurements and computations for radiochemical analyses

USGS Publications Warehouse

Rosholt, J.N.; Dooley, J.R.

1960-01-01

In natural radioactive sources the most important radioactive daughter products useful for geochemical studies are protactinium-231, the alpha-emitting thorium isotopes, and the radium isotopes. To resolve the abundances of these thorium and radium isotopes by their characteristic decay and growth patterns, a large number of repeated alpha activity measurements on the two chemically separated elements were made over extended periods of time. Alpha scintillation counting with automatic measurements and sample changing is used to obtain the basic count data. Generation of the required theoretical decay and growth functions, varying with time, and the least squares solution of the overdetermined simultaneous count rate equations are done with a digital computer. Examples of the complex count rate equations which may be solved and results of a natural sample containing four ??-emitting isotopes of thorium are illustrated. These methods facilitate the determination of the radioactive sources on the large scale required for many geochemical investigations.

Measurement of the angular distribution of the electron from W {r_arrow} e = {nu} decay, in p pbar at {radical}s = 1.8 TeV, as function of P{sub T}{sup W}

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

NONE

1996-06-01

The goal of this work is to study the behavior of the angular distribution of the electron from the decay of the W boson in a specific rest frame of the W, the Collins-Soper frame. More specifically, the parameter {alpha}{sub 2} from the expression d{sigma}/d(P{sub T}{sup W}){sup 2} d cos {theta}* = k(1 + {alpha}{sub 2} cos {theta}* + {alpha}{sup 2}(cos {theta}*){sup 2}), corresponding to the distribution of cos {theta}* in the Collins-Soper frame, was measured. The experimental value of {alpha}P{sub 2} was compared with the predictions made by E. Mirkes [11] who included the radiative QCD perturbations in themore » weak-interaction B{sub boson} {r_arrow} lepton + lepton. This experimental value was extracted for the first time using knowledge about how the radiative QCD perturbations will modify the predictions given by the Electro-Weak process only.« less

Alpha-emitting isotopes and chromium in a coastal California aquifer

USGS Publications Warehouse

Densmore, Jill N.; Izbicki, John A.; Murtaugh, Joseph M.; Swarzenski, Peter W.; Bullen, Thomas D.

2014-01-01

The unadjusted 72-h gross alpha activities in water from two wells completed in marine and alluvial deposits in a coastal southern California aquifer 40 km north of San Diego were 15 and 25 picoCuries per liter (pCi/L). Although activities were below the Maximum Contaminant Level (MCL) of 15 pCi/L, when adjusted for uranium activity; there is concern that new wells in the area may exceed MCLs, or that future regulations may limit water use from the wells. Coupled well-bore flow and depth-dependent water-quality data collected from the wells in 2011 (with analyses for isotopes within the uranium, actinium, and thorium decay-chains) show gross alpha activity in marine deposits is associated with decay of naturally-occurring 238U and its daughter 234U. Radon activities in marine deposits were as high as 2230 pCi/L. In contrast, gross alpha activities in overlying alluvium within the Piedra de Lumbre watershed, eroded from the nearby San Onofre Hills, were associated with decay of 232Th, including its daughter 224Ra. Radon activities in alluvium from Piedra de Lumbre of 450 pCi/L were lower than in marine deposits. Chromium VI concentrations in marine deposits were less than the California MCL of 10 μg/L (effective July 1, 2014) but δ53Cr compositions were near zero and within reported ranges for anthropogenic chromium. Alluvial deposits from the nearby Las Flores watershed, which drains a larger area having diverse geology, has low alpha activities and chromium as a result of geologic and geochemical conditions and may be more promising for future water-supply development.

Treatment of solid tumors by interstitial release of recoiling short-lived alpha emitters

NASA Astrophysics Data System (ADS)

Arazi, L.; Cooks, T.; Schmidt, M.; Keisari, Y.; Kelson, I.

2007-08-01

A new method utilizing alpha particles to treat solid tumors is presented. Tumors are treated with interstitial radioactive sources which continually release short-lived alpha emitting atoms from their surface. The atoms disperse inside the tumor, delivering a high dose through their alpha decays. We implement this scheme using thin wire sources impregnated with 224Ra, which release by recoil 220Rn, 216Po and 212Pb atoms. This work aims to demonstrate the feasibility of our method by measuring the activity patterns of the released radionuclides in experimental tumors. Sources carrying 224Ra activities in the range 10-130 kBq were used in experiments on murine squamous cell carcinoma tumors. These included gamma spectroscopy of the dissected tumors and major organs, Fuji-plate autoradiography of histological tumor sections and tissue damage detection by Hematoxylin-Eosin staining. The measurements focused on 212Pb and 212Bi. The 220Rn/216Po distribution was treated theoretically using a simple diffusion model. A simplified scheme was used to convert measured 212Pb activities to absorbed dose estimates. Both physical and histological measurements confirmed the formation of a 5-7 mm diameter necrotic region receiving a therapeutic alpha-particle dose around the source. The necrotic regions shape closely corresponded to the measured activity patterns. 212Pb was found to leave the tumor through the blood at a rate which decreased with tumor mass. Our results suggest that the proposed method, termed DART (diffusing alpha-emitters radiation therapy), may potentially be useful for the treatment of human patients.

Evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angle {alpha}

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

Aubert, B.; Bona, M.; Boutigny, D.

2007-03-16

We search for the decays B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0}, B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980), and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) in a sample of about 384x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at Stanford Linear Accelerator Center. We find evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} with 3.5{sigma} significance and measure the branching fraction B=(1.07{+-}0.33{+-}0.19)x10{sup -6} and longitudinal polarization fraction f{sub L}=0.87{+-}0.13{+-}0.04, where the first uncertainty is statistical, and the second is systematic. The uncertainty on the Cabibbo-Kobayashi-Maskawa quark-mixing matrix unitarity angle {alpha} due to penguin contributions in B{yields}{rho}{rho} decays is 18 deg.more » at the 1{sigma} level. We also set upper limits on the B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980) and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) decay rates.« less

The portable device for continual measurement of radon progenies on filter using the detector Timepix.

PubMed

Bulanek, Boris; Hulka, Jiri; Jilek, Karel; Stekl, Ivan

2015-06-01

In this article, a portable device was presented for continual measuring of equilibrium equivalent concentration (EEC) of (222)Rn based on the Timepix detector with 300-µm-thick active layer. In order to have a portable device, a filtration head was developed for collecting short-lived radon progenies attached on aerosols. The short-lived progenies are estimated from analysing alphas from decay of (218,214)Po from Millipore filter after termination of filtration. Comparison with beta measurement was done as well. The dependence of EEC on an air flow and filtration time was studied. The low-level detection limit for EEC was estimated from the last 10 min of 3-h decay measurement and was found in the range of 40-70 Bq m(-3). EEC was measured in National Radiation Protection Institute radon chamber, and results were compared with the commercial detector Fritra4. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Removal of long-lived 222Rn daughters by electropolishing thin layers of stainless steel

NASA Astrophysics Data System (ADS)

Schnee, R. W.; Bowles, M. A.; Bunker, R.; McCabe, K.; White, J.; Cushman, P.; Pepin, M.; Guiseppe, V. E.

2013-08-01

Long-lived alpha and beta emitters in the 222Rn decay chain on detector surfaces may be the limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay. Removal of tens of microns of material via electropolishing has been shown to be effective at removing radon daughters implanted into material surfaces. Some applications, however, require the removal of uniform and significantly smaller thicknesses. Here, we demonstrate that electropolishing < 1 μm from stainless-steel plates reduces the contamination efficiently, by a factor > 100. Examination of electropolished wires with a scanning electron microscope confirms that the thickness removed is reproducible and reasonably uniform. Together, these tests demonstrate the effectiveness of removal of radon daughters for a proposed low-radiation, multi-wire proportional chamber (the BetaCage), without compromising the screener's energy resolution. More generally, electropolishing thin layers of stainless steel may effectively remove radon daughters without compromising precision-machined parts.

Removal of long-lived {sup 222}Rn daughters by electropolishing thin layers of stainless steel

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

Schnee, R. W.; Bowles, M. A.; Bunker, R.

Long-lived alpha and beta emitters in the {sup 222}Rn decay chain on detector surfaces may be the limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay. Removal of tens of microns of material via electropolishing has been shown to be effective at removing radon daughters implanted into material surfaces. Some applications, however, require the removal of uniform and significantly smaller thicknesses. Here, we demonstrate that electropolishing < 1 μm from stainless-steel plates reduces the contamination efficiently, by a factor > 100. Examination of electropolished wires with a scanning electron microscope confirms that the thicknessmore » removed is reproducible and reasonably uniform. Together, these tests demonstrate the effectiveness of removal of radon daughters for a proposed low-radiation, multi-wire proportional chamber (the BetaCage), without compromising the screener’s energy resolution. More generally, electropolishing thin layers of stainless steel may effectively remove radon daughters without compromising precision-machined parts.« less

Corticosteroids reduce IL-6 in ASM cells via up-regulation of MKP-1.

PubMed

Quante, Timo; Ng, Yee Ching; Ramsay, Emma E; Henness, Sheridan; Allen, Jodi C; Parmentier, Johannes; Ge, Qi; Ammit, Alaina J

2008-08-01

The mechanisms by which corticosteroids reduce airway inflammation are not completely understood. Traditionally, corticosteroids were thought to inhibit cytokines exclusively at the transcriptional level. Our recent evidence, obtained in airway smooth muscle (ASM), no longer supports this view. We have found that corticosteroids do not act at the transcriptional level to reduce TNF-alpha-induced IL-6 gene expression. Rather, corticosteroids inhibit TNF-alpha-induced IL-6 secretion by reducing the stability of the IL-6 mRNA transcript. TNF-alpha-induced IL-6 mRNA decays at a significantly faster rate in ASM cells pretreated with the corticosteroid dexamethasone (t(1/2) = 2.4 h), compared to vehicle (t(1/2) = 9.0 h; P < 0.05) (results are expressed as decay constants [k] [mean +/- SEM] and half-life [h]). Interestingly, the underlying mechanism of inhibition by corticosteroids is via the up-regulation of an endogenous mitogen-activated protein kinase (MAPK) inhibitor, MAPK phosphatase-1 (MKP-1). Corticosteroids rapidly up-regulate MKP-1 in a time-dependent manner (44.6 +/- 10.5-fold increase after 24 h treatment with dexamethasone; P < 0.05), and MKP-1 up-regulation was temporally related to the inhibition of TNF-alpha-induced p38 MAPK phosphorylation. Moreover, TNF-alpha acts via a p38 MAPK-dependent pathway to stabilize the IL-6 mRNA transcript (TNF-alpha, t(1/2) = 9.6 h; SB203580 + TNF-alpha, t(1/2) = 1.5 h), exogenous expression of MKP-1 significantly inhibits TNF-alpha-induced IL-6 secretion and MKP-1 siRNA reverses the inhibition of TNF-alpha-induced IL-6 secretion by dexamethasone. Taken together, these results suggest that corticosteroid-induced MKP-1 contributes to the repression of IL-6 secretion in ASM cells.

Four methods for determining the composition of trace radioactive surface contamination of low-radioactivity metal

NASA Astrophysics Data System (ADS)

O'Keeffe, H. M.; Burritt, T. H.; Cleveland, B. T.; Doucas, G.; Gagnon, N.; Jelley, N. A.; Kraus, C.; Lawson, I. T.; Majerus, S.; McGee, S. R.; Myers, A. W.; Poon, A. W. P.; Rielage, K.; Robertson, R. G. H.; Rosten, R. C.; Stonehill, L. C.; VanDevender, B. A.; Van Wechel, T. D.

2011-12-01

Four methods for determining the composition of low-level uranium- and thorium-chain surface contamination are presented. One method is the observation of Cherenkov light production in water. In two additional methods a position-sensitive proportional counter surrounding the surface is used to make both a measurement of the energy spectrum of alpha particle emissions and also coincidence measurements to derive the thorium-chain content based on the presence of short-lived isotopes in that decay chain. The fourth method is a radiochemical technique in which the surface is eluted with a weak acid, the eluate is concentrated, added to liquid scintillator and assayed by recording beta-alpha coincidences. These methods were used to characterize two 'hotspots' on the outer surface of one of the 3He proportional counters in the Neutral Current Detection array of the Sudbury Neutrino Observatory experiment. The methods have similar sensitivities, of order tens of ng, to both thorium- and uranium-chain contamination.

Realizing the potential of the Actinium-225 radionuclide generator in targeted alpha-particle therapy applications

PubMed Central

Miederer, Matthias; Scheinberg, David A.; McDevitt, Michael R.

2013-01-01

Alpha particle-emitting isotopes have been proposed as novel cytotoxic agents for augmenting targeted therapy. Properties of alpha particle radiation such as their limited range in tissue of a few cell diameters and their high linear energy transfer leading to dense radiation damage along each alpha track are promising in the treatment of cancer, especially when single cells or clusters of tumor cells are targeted. Actinium-225 (225Ac) is an alpha particle-emitting radionuclide that generates 4 net alpha particle isotopes in a short decay chain to stable 209Bi, and as such can be described as an alpha particle nanogenerator. This article reviews the literature pertaining to the research, development, and utilization of targeted 225Ac to potently and specifically affect cancer. PMID:18514364

Autoregressive processes with exponentially decaying probability distribution functions: applications to daily variations of a stock market index.

PubMed

Porto, Markus; Roman, H Eduardo

2002-04-01

We consider autoregressive conditional heteroskedasticity (ARCH) processes in which the variance sigma(2)(y) depends linearly on the absolute value of the random variable y as sigma(2)(y) = a+b absolute value of y. While for the standard model, where sigma(2)(y) = a + b y(2), the corresponding probability distribution function (PDF) P(y) decays as a power law for absolute value of y-->infinity, in the linear case it decays exponentially as P(y) approximately exp(-alpha absolute value of y), with alpha = 2/b. We extend these results to the more general case sigma(2)(y) = a+b absolute value of y(q), with 0 < q < 2. We find stretched exponential decay for 1 < q < 2 and stretched Gaussian behavior for 0 < q < 1. As an application, we consider the case q=1 as our starting scheme for modeling the PDF of daily (logarithmic) variations in the Dow Jones stock market index. When the history of the ARCH process is taken into account, the resulting PDF becomes a stretched exponential even for q = 1, with a stretched exponent beta = 2/3, in a much better agreement with the empirical data.

Actinium-225 in targeted alpha-particle therapeutic applications

PubMed Central

Scheinberg, David A.; McDevit, Michael R.

2017-01-01

Alpha particle-emitting isotopes are being investigated in radioimmunotherapeutic applications because of their unparalleled cytotoxicity when targeted to cancer and their relative lack of toxicity towards untargeted normal tissue. Actinium-225 has been developed into potent targeting drug constructs and is in clinical use against acute myelogenous leukemia. The key properties of the alpha particles generated by 225Ac are the following: i) limited range in tissue of a few cell diameters; ii) high linear energy transfer leading to dense radiation damage along each alpha track; iii) a 10 day half-life; and iv) four net alpha particles emitted per decay. Targeting 225Ac-drug constructs have potential in the treatment of cancer. PMID:22202153

Simultaneous determination of gross alpha, gross beta and ²²⁶Ra in natural water by liquid scintillation counting.

PubMed

Fons, J; Zapata-García, D; Tent, J; Llauradó, M

2013-11-01

The determination of gross alpha, gross beta and (226)Ra activity in natural waters is useful in a wide range of environmental studies. Furthermore, gross alpha and gross beta parameters are included in international legislation on the quality of drinking water [Council Directive 98/83/EC]. In this work, a low-background liquid scintillation counter (Wallac, Quantulus 1220) was used to simultaneously determine gross alpha, gross beta and (226)Ra activity in natural water samples. Sample preparation involved evaporation to remove (222)Rn and its short-lived decay daughters. The evaporation process concentrated the sample ten-fold. Afterwards, a sample aliquot of 8 mL was mixed with 12 mL of Ultima Gold AB scintillation cocktail in low-diffusion vials. In this study, a theoretical mathematical model based on secular equilibrium conditions between (226)Ra and its short-lived decay daughters is presented. The proposed model makes it possible to determine (226)Ra activity from two measurements. These measurements also allow determining gross alpha and gross beta simultaneously. To validate the proposed model, spiked samples with different activity levels for each parameter were analysed. Additionally, to evaluate the model's applicability in natural water, eight natural water samples from different parts of Spain were analysed. The eight natural water samples were also characterised by alpha spectrometry for the naturally occurring isotopes of uranium ((234)U, (235)U and (238)U), radium ((224)Ra and (226)Ra), (210)Po and (232)Th. The results for gross alpha and (226)Ra activity were compared with alpha spectrometry characterization, and an acceptable concordance was obtained. Copyright © 2013 Elsevier Ltd. All rights reserved.

Measured 19F(α,n) with VANDLE for Nuclear Safeguards

NASA Astrophysics Data System (ADS)

Peters, William; Clement, R. C. C.; Smith, M. S.; Pain, S.; Febbraro, M.; Pittman, S.; Thomspon, S.; Grinder, M.; Cizewski, J. A.; Reingold, C.; Manning, B.; Burcher, S.; Bardayan, D. W.; Tan, W.-P.; Stech, E.; Smith, M. K.; Avetisyan, R.; Gyurjinyan, A.; Lowe, M.; Ilyushkin, S.; Grzywacz, R.; Madurga, M.; Paulauskas, S. V.; Taylor, S. Z.; Smith, K.

2015-10-01

One of the most promising non-destructive assay (NDA) methods to monitor UF6 canisters consists of measuring gross neutron rates induced by uranium-decay alpha particles reacting with the fluorine and emitting a neutron. This method currently lacks reliable nuclear data on the 19F(α,n) reaction cross section to determine an accurate neutron yield rate for a given sample of UF6. We have measured the cross section and coincident neutron spectrum for the alpha-decay energy range using the VANDLE system. This experiment had two parts: first at Notre Dame with a LaF3 target and and a pulsed alpha-particle beam, and second at ORNL with a windowless He-gas target and a 19F beam. The motivation for this measurement and cross section results will be presented. This work is funded in part by the DOE Office of Science, the National Nuclear Security Administration SSAA and the Office of Defense Nuclear Nonproliferation R&D, and the NSF.

Evolution of spent nuclear fuel in dry storage conditions for millennia and beyond

NASA Astrophysics Data System (ADS)

Wiss, Thierry; Hiernaut, Jean-Pol; Roudil, Danièle; Colle, Jean-Yves; Maugeri, Emilio; Talip, Zeynep; Janssen, Arne; Rondinella, Vincenzo; Konings, Rudy J. M.; Matzke, Hans-Joachim; Weber, William J.

2014-08-01

Significant amounts of spent uranium dioxide nuclear fuel are accumulating worldwide from decades of commercial nuclear power production. While such spent fuel is intended to be reprocessed or disposed in geologic repositories, out-of-reactor radiation damage from alpha decay can be detrimental to its structural stability. Here we report on an experimental study in which radiation damage in plutonium dioxide, uranium dioxide samples doped with short-lived alpha-emitters and urano-thorianite minerals have been characterized by XRD, transmission electron microscopy, thermal desorption spectrometry and hardness measurements to assess the long-term stability of spent nuclear fuel to substantial alpha-decay doses. Defect accumulation is predicted to result in swelling of the atomic structure and decrease in fracture toughness; whereas, the accumulation of helium will produce bubbles that result in much larger gaseous-induced swelling that substantially increases the stresses in the constrained spent fuel. Based on these results, the radiation-ageing of highly-aged spent nuclear fuel over more than 10,000 years is predicted.

Continued X-ray Monitoring of Magnetar Candidate SWIFT J1822.3-1606

NASA Astrophysics Data System (ADS)

Scholz, P.; Livingstone, M. A.; Kaspi, V. M.

2011-08-01

We report on Swift/XRT and RXTE/PCA observations of the new 8.4-s Galactic magnetar candidate SWIFT J1822.3-1606, also referred to as SGR J1822.3-1606 (ATELs #3488, #3489, #3490, #3493, #3495, #3496, #3501, #3503, #3543). The persistent X-ray flux from the source continues to fade in ongoing XRT monitoring observations. For data in the MJD range 55757 to 55781, the best-fit power-law index, alpha, for the decay of the absorbed 1-10 keV flux is -0.47 ± 0.02, assuming a decay of functional form F(t) = F0 + F0*(t-T)^alpha, where T is the epoch of the Swift/BAT trigger (ATEL #3488).

Fluorescence Quenching of Alpha-Fetoprotein by Gold Nanoparticles: Effect of Dielectric Shell on Non-Radiative Decay

NASA Astrophysics Data System (ADS)

Zhu, Jian; Li, Jian-Jun; Wang, A.-Qing; Chen, Yu; Zhao, Jun-Wu

2010-09-01

Fluorescence quenching spectrometry was applied to study the interactions between gold colloidal nanoparticles and alpha-fetoprotein (AFP). Experimental results show that the gold nanoparticles can quench the fluorescence emission of adsorbed AFP effectively. Furthermore, the intensity of fluorescence emission peak decreases monotonously with the increasing gold nanoparticles content. A mechanism based on surface plasmon resonance-induced non-radiative decay was investigated to illuminate the effect of a dielectric shell on the fluorescence quenching ability of gold nanoparticles. The calculation results show that the increasing dielectric shell thickness may improve the monochromaticity of fluorescence quenching. However, high energy transfer efficiency can be obtained within a wide wavelength band by coating a thinner dielectric shell.

Delayed charge recovery discrimination of passivated surface alpha events in P-type point-contact detectors

NASA Astrophysics Data System (ADS)

Gruszko, J.; Majorana Collaboration

2017-09-01

The Majorana Demonstrator searches for neutrinoless double-beta decay of 76Ge using arrays of high-purity germanium detectors. If observed, this process would demonstrate that lepton number is not a conserved quantity in nature, with implications for grand-unification and for explaining the predominance of matter over antimatter in the universe. A problematic background in such large granular detector arrays is posed by alpha particles. In the Majorana Demonstrator, events have been observed that are consistent with energy-degraded alphas originating on the passivated surface, leading to a potential background contribution in the region-of-interest for neutrinoless double-beta decay. However, it is also observed that when energy deposition occurs very close to the passivated surface, charges drift through the bulk onto that surface, and then drift along it with greatly reduced mobility. This leads to both a reduced prompt signal and a measurable change in slope of the tail of a recorded pulse. In this contribution we discuss the characteristics of these events and the development of a filter that can identify the occurrence of this delayed charge recovery, allowing for the efficient rejection of passivated surface alpha events in analysis.

Understanding Temporal and Spatial Variability of the Lunar Helium Atmosphere Using Simultaneous Observations from LRO, LADEE, and ARTEMIS

NASA Technical Reports Server (NTRS)

Hurley, Dana M.; Cook, Jason C.; Benna, Mehdi; Halekas, Jasper S.; Feldman, Paul D.; Retherford, Kurt D.; Hodges, R. Richard; Grava, Cesare; Mahaffy, Paul; Gladstone, G. Randall;

Understanding temporal and spatial variability of the lunar helium atmosphere using simultaneous observations from LRO, LADEE, and ARTEMIS

NASA Astrophysics Data System (ADS)

Hurley, Dana M.; Cook, Jason C.; Benna, Mehdi; Halekas, Jasper S.; Feldman, Paul D.; Retherford, Kurt D.; Hodges, R. Richard; Grava, Cesare; Mahaffy, Paul; Gladstone, G. Randall; Greathouse, Thomas; Kaufmann, David E.; Elphic, Richard C.; Stern, S. Alan

2016-07-01

Simultaneous measurements of helium in the exosphere of the Moon are made from the Lunar Reconnaissance Orbiter (LRO) Lyman Alpha Mapping Project (LAMP) and the Lunar Atmosphere and Dust Environment Explorer (LADEE) Neutral Mass Spectrometer (NMS) through the entire 5-month span of the LADEE mission. In addition, the ARTEMIS mission monitored the solar wind alpha particle flux to the Moon. Modeling the lunar helium exosphere, we relate the LAMP polar observations to the LADEE equatorial observations. Further, using the ARTEMIS alpha flux in the Monte Carlo model reproduces the temporal variations in helium density. Comparing the LAMP data to the LADEE data shows excellent agreement. Comparing those with the ARTEMIS data reveals that the solar wind alpha flux is the primary driver to variability in the helium exosphere throughout the LADEE mission. Using a decay time for exospheric helium of 5 days, we determine that the solar wind contributes 64 ± 5% of the helium to the lunar exosphere. The remaining 36 ± 5% is presumed to come from outgassing of radiogenic helium from the interior of the Moon. Furthermore, the model reproduces the measurements if 63 ± 6% of the incident alpha particles are converted to thermalized helium atoms through the interaction between the alphas and the lunar surface. However, these values are dependent on both inferred source rates from LAMP and LADEE observations and on the assumed time constant of the exospheric decay rate.

Background canceling surface alpha detector

DOEpatents

MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

1996-06-11

A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

Background canceling surface alpha detector

DOEpatents

MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

1996-01-01

A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone.

Intercomparison of retrospective radon detectors.

PubMed Central

Field, R W; Steck, D J; Parkhurst, M A; Mahaffey, J A; Alavanja, M C

1999-01-01

We performed both a laboratory and a field intercomparison of two novel glass-based retrospective radon detectors previously used in major radon case-control studies performed in Missouri and Iowa. The new detectors estimate retrospective residential radon exposure from the accumulation of a long-lived radon decay product, (210)Pb, in glass. The detectors use track registration material in direct contact with glass surfaces to measure the alpha-emission of a (210)Pb-decay product, (210)Po. The detector's track density generation rate (tracks per square centimeter per hour) is proportional to the surface alpha-activity. In the absence of other strong sources of alpha-emission in the glass, the implanted surface alpha-activity should be proportional to the accumulated (210)Po, and hence to the cumulative radon gas exposure. The goals of the intercomparison were to a) perform collocated measurements using two different glass-based retrospective radon detectors in a controlled laboratory environment to compare their relative response to implanted polonium in the absence of environmental variation, b) perform collocated measurements using two different retrospective radon progeny detectors in a variety of residential settings to compare their detection of glass-implanted polonium activities, and c) examine the correlation between track density rates and contemporary radon gas concentrations. The laboratory results suggested that the materials and methods used by the studies produced similar track densities in detectors exposed to the same implanted (210)Po activity. The field phase of the intercomparison found excellent agreement between the track density rates for the two types of retrospective detectors. The correlation between the track density rates and direct contemporary radon concentration measurements was relatively high, considering that no adjustments were performed to account for either the residential depositional environment or glass surface type. Preliminary comparisons of the models used to translate track rate densities to average long-term radon concentrations differ between the two studies. Further calibration of the retrospective detectors' models for interpretation of track rate density may allow the pooling of studies that use glass-based retrospective radon detectors to determine historic residential radon exposures. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:10545336

Intercomparison of retrospective radon detectors.

PubMed

Field, R W; Steck, D J; Parkhurst, M A; Mahaffey, J A; Alavanja, M C

1999-11-01

We performed both a laboratory and a field intercomparison of two novel glass-based retrospective radon detectors previously used in major radon case-control studies performed in Missouri and Iowa. The new detectors estimate retrospective residential radon exposure from the accumulation of a long-lived radon decay product, (210)Pb, in glass. The detectors use track registration material in direct contact with glass surfaces to measure the alpha-emission of a (210)Pb-decay product, (210)Po. The detector's track density generation rate (tracks per square centimeter per hour) is proportional to the surface alpha-activity. In the absence of other strong sources of alpha-emission in the glass, the implanted surface alpha-activity should be proportional to the accumulated (210)Po, and hence to the cumulative radon gas exposure. The goals of the intercomparison were to a) perform collocated measurements using two different glass-based retrospective radon detectors in a controlled laboratory environment to compare their relative response to implanted polonium in the absence of environmental variation, b) perform collocated measurements using two different retrospective radon progeny detectors in a variety of residential settings to compare their detection of glass-implanted polonium activities, and c) examine the correlation between track density rates and contemporary radon gas concentrations. The laboratory results suggested that the materials and methods used by the studies produced similar track densities in detectors exposed to the same implanted (210)Po activity. The field phase of the intercomparison found excellent agreement between the track density rates for the two types of retrospective detectors. The correlation between the track density rates and direct contemporary radon concentration measurements was relatively high, considering that no adjustments were performed to account for either the residential depositional environment or glass surface type. Preliminary comparisons of the models used to translate track rate densities to average long-term radon concentrations differ between the two studies. Further calibration of the retrospective detectors' models for interpretation of track rate density may allow the pooling of studies that use glass-based retrospective radon detectors to determine historic residential radon exposures.

Addendum to Radiative corrections to the Dalitz plot of semileptonic decays of neutral baryons with light or charm quarks''

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

Martinez, A.; Tun, D.M.; Garcia, A.

1994-08-01

We show that the radiative corrections containing terms up to order [alpha][ital q]/[pi][ital M][sub 1] for unpolarized semileptonic decays of baryons with positron emission can be obtained by simply reversing the sign of the axial-vector form factors in the corresponding final expressions of such decays with electron emission. This rule is valid regardless of the final kinematical variables chosen and of the particular Lorentz frame in which the final results are required.

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

Nuclear Data Sheets for A = 230

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

Browne, E.; Tuli, J.K.

The evaluators present in this publication spectroscopic data and level schemes from radioactive decay and nuclear reactions for all isobars with mass number A=230. This evaluation includes the first experimental evidence of {sup 230}Am, produced through the {sup 197}Au({sup 40}Ar,3n){sup 234}Bk ({alpha} decay to {sup 230}Am) reaction, E({sup 40}Ar)=188.4 MeV (2003MoZX).

Radiation Protection. Measurement of radioactivity in the environment - Air- radon 222. A proposed ISO standard.

NASA Astrophysics Data System (ADS)

Gillmore, G.; Woods, M.

2009-04-01

Radon isotopes (222, 220, 219) are radioactive gases produced by the disintegration of radium isotopes 226, 224 and 223, which are decay products of uranium238, thorium232 and uranium235 respectively. All are found in the earth's crust. Solid elements, also radioactive, are produced by radon disintegration. Radon is classed as a rare gas in the periodic table of elements, along with helium, argon, neon, krypton and xenon. When disintegrating, radon emits alpha particles and generates solid decay products, which are also radioactive (polonium, bismuth, lead etc.). The potential danger of radon lies in its solid decay products rather than the gas itself. Whether or not they are attached aerosols, radon decay products can be inhaled and deposited in the bronchopulmonary tree to varying depths according to their size. Radon today is considered to be the main source of human exposure to natural radiation. At the international level, radon accounts for 52% of global average exposure to natural radiation. Isotope 222 (48%) is far more significant than isotope 220 (4%), whilst isotope 219 is considered as negligible. Exposure to radon varies considerably from one region to another, depending on factors such as weather conditions, and underlying geology. Activity concentration can therefore vary by a factor of 10 or even a 100 from one period of time to the next and from one area to another. There are many ways of measuring the radon 222 activity concentration and the potential alpha energy concentration of its short-lived decay products. Measuring techniques fall into three categories: - spot measurement methods; continuous measurement; integrated measurement. The proposed ISO (International Organisation for Standardisation) document suggests guidelines for measuring radon222 activity concentration and the potential alpha energy concentration of its short-lived decay products in a free (environment) and confined (buildings) atmosphere. The target date for availability of this work item is 2011. The ISO document here highlighted is a working draft. ISO is a worldwide federation of national standards bodies. Keywords: radon; international standards; measurement techniques.

Fluorescence lifetimes of anthracycline drugs in phospholipid bilayers determined by frequency-domain fluorometry

NASA Astrophysics Data System (ADS)

Burke, Thomas G.; Malak, Henryk M.; Doroshow, James H.

1990-05-01

Time-resolved fluorescence intensity decay data from anthracycline anticancer drugs present in model membranes were obtained using a gigahertz frequency-domain fluorometer [Lakowicz et al. (1986) Rev. Sci. Instrum. 57, 2499-2506]. Exciting light of 290 nm, modulated at multiple frequencies from 8 MHz to 400 MHz, was used to study the interactions of Adriamycin, daunomycin and related antibiotics with small unilamellar vesicles composed of dimyristoylphosphatidylcholine (DMPC) at 28°C. Fluorescence decay data for drug molecules free in solution as well as bound to membranes were best fit by exponentials requiring two terms rather than by single exponential decays. For example, one-component analysis of the decay data for Adriamycin free in phosphate buffered saline (PBS) solution resulted in a reduced x2 value of 140 ((tau) = 0.88 ns), while a two-component fit resulted in a substantially smaller reduced x2 value of 2.6 ((tau)1 = 1.13 ns, (alpha)1 = 0.60, (tau)2 = 0.30 ns). Upon association with membranes, each of the anthracyclines studied displayed a larger r1 value while the r2 value remained the same or increased (for example, DMPC-bound Adriamycin showed r1 = 1.68 ns , a1 = 0 . 64 , r2 = 0 . 33 ns) . Analyses of the fluorescence emission decays of anthracyclines were also made assuming each decay is composed of a single Lorentzian distribution of lifetimes. Data taken on Adriamycin in PBS, when fit using one continuous component, displayed (tau), (alpha), w, and reduced x2 values of 0.68 ns, 1, 0.60 ns, and 9.1, respectively. The distribution became quite broad upon drug association with membrane (DMPCbound Adriamycin: (tau) = 0.75 ns, (alpha) = 1, w = 2.24 ns, x2 = 13). For each anthracycline studied, continuous component fits showed significant broadening in the distributions upon drug association with membrane. Relatively large shifts in lifetime values were observed for the carminomycin and 4-demethoxydaunomycin analogues upon binding model lipid membranes, making these agents good candidates to employ in future studies on anthracycline interactions with more environmentally-complex biological membranes.

Dosimetry of radium-223 and progeny

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

Fisher, D.R.; Sgouros, G.

Radium-223 is a short-lived (11.4 d) alpha emitter with potential applications in radioimmunotherapy of cancer. Radium-223 can be complexed and linked to protein delivery molecules for specific tumor-cell targeting. It decays through a cascade of short-lived alpha- and beta-emitting daughters with emission of about 28 MeV of energy through complete decay. The first three alpha particles are essentially instantaneous. Photons associated with Ra-223 and progeny provide the means for tumor and normal-organ imaging and dosimetry. Two beta particles provide additional therapeutic value. Radium-223 may be produced economically and in sufficient amounts for widescale application. Many aspects of the chemistry ofmore » carrier-free isotope preparation, complexation, and linkage to the antibody have been developed and are being tested. The radiation dosimetry of a Ra-223-labeled antibody shows favorable tumor to normal tissue dose ratios for therapy. The 11.4-d half-life of Ra-223 allows sufficient time for immunoconjugate preparation, administration, and tumor localization by carrier antibodies before significant radiological decay takes place. If 0.01 percent of a 37 MBq (1 mCi) injection deposits in a one gram tumor mass, and if the activity is retained with a typical effective half-time (75 h), the absorbed dose will be 163 mGy MBq{sup {minus}1} (600 rad mCi{sup {minus}1}) administered. 49 refs., 5 figs., 2 tabs.« less

Design and performance of an ionisation chamber for the measurement of low alpha-activities

NASA Astrophysics Data System (ADS)

Hartmann, A.; Hutsch, J.; Krüger, F.; Sobiella, M.; Wilsenach, H.; Zuber, K.

2016-04-01

A new ionisation chamber for alpha-spectroscopy has been built from radio-pure materials for the purpose of investigating long lived alpha-decays. The measurement makes use of pulse shape analysis to discriminate between signal and background events. The design and performance of the chamber is described in this paper. A background rate of (10.9 ± 0.6) counts per day in the energy region of 1-9 MeV was achieved with a run period of 30.8 days. The background is dominantly produced by radon daughters.

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...

Nucleogenic production of Ne isotopes in Earth's crust and upper mantle induced by alpha particles from the decay of U and Th

NASA Astrophysics Data System (ADS)

Leya, Ingo; Wieler, Rainer

1999-07-01

The production of nucleogenic Ne in terrestrial crust and upper mantle by alpha particles from the decay of U and Th was calculated. The calculations are based on stopping powers for the chemical compounds and thin-target cross sections. This approach is more rigorous than earlier studies using thick-target yields for pure elements, since our results are independent of limiting assumptions about stopping-power ratios. Alpha induced reactions account for >99% of the Ne production in the crust and for most of the 20,21Ne in the upper mantle. On the other hand, our 22Ne value for the upper mantle is a lower limit because the reaction 25Mg(n,α)22Ne is significant in mantle material. Production rates calculated here for hypothetical crustal and upper mantle material with average major element composition and homogeneously distributed F, U, and Th are up to 100 times higher than data presented by Kyser and Rison [1982] but agree within error limits with the results by Yatsevich and Honda [1997]. Production of nucleogenic Ne in "mean" crust and mantle is also given as a function of the weight fractions of O and F. The alpha dose is calculated by radiogenic 4He as well as by the more retentive fissiogenic 136Xe. U and Th is concentrated in certain accessory minerals. Since the ranges of alpha particles from the three decay chains are comparable to mineral dimensions, most nucleogenic Ne is produced in U- and Th-rich minerals. Therefore nucleogenic Ne production in such accessories was also calculated. The calculated correlation between nucleogenic 21Ne and radiogenic 4He agrees well with experimental data for Earth's crust and accessories. Also, the calculated 22Ne/4He ratios as function of the F concentration and the dependence of 21Ne/22Ne from O/F for zircon and apatite agree with measurements.

A search for a new gauge boson A'

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

Jensen, Eric L.

2013-08-01

In the Standard Model, gauge bosons mediate the strong, weak, and electromagnetic forces. New forces could have escaped detection only if their mediators are either heavier than order(TeV) or weakly coupled to charged matter. New vector bosons with small coupling {alpha}' arise naturally from a small kinetic mixing with the photon and have received considerable attention as an explanation of various dark matter related anomalies. Such particles can be produced in electron-nucleus fixed-target scattering and then decay to e +e -+ pairs. New light vector bosons and their associated forces are a common feature of Standard Model extensions, but existingmore » constraints are remarkably sparse. The APEX experiment will search for a new vector boson A' with coupling α'/α fs > 6 × 10 -8 to electrons in the mass range 65MeV < mass A' < 550MeV. The experiment will study e +e - production off an electron beam incident on a high-Z target in Hall A at Jefferson Lab. The e - and e + will be detected in the High Resolution Spectrometers (HRSs). The invariant mass spectrum of the e +e - pairs will be scanned for a narrow resonance corresponding to the mass of the A'. A test run for the APEX experiment was held in the summer of 2010. Using the test run data, an A' search was performed in the mass range 175-250 MeV. The search found no evidence for an A' → e +e -reaction, and set an upper limit of {alpha}'/{alpha}{sub fs} ~ 10 -6.« less

Concept design of a time-of-flight spectrometer for the measurement of the energy of alpha particles.

PubMed

García-Toraño, E

2018-04-01

The knowledge of the energies of the alpha particles emitted in the radioactive decay of a nuclide is a key factor in the construction of its decay scheme. Virtually all existing data are based on a few absolute measurements made by magnetic spectrometry (MS), to which most other MS measurements are traced. An alternative solution would be the use of time-of-flight detectors. This paper discusses the main aspects to be considered in the design of such detectors, and the performances that could be reasonably expected. Based on the concepts discussed here, it is estimated that an energy resolution about 2.5keV may be attainable with a good quality source. Copyright © 2017 Elsevier Ltd. All rights reserved.

Slopes of $pi$-meson spectra in the K $Yields$ 3$pi$ decays (in Russian)

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

Kapustnikov, A.A.

1973-12-01

The strong violation ( approximates 35%) of the rule DELTA T = 1/2 on the Dalitz piot for the K yields 3 pi decays is considered in the framework of the nonlinear realization of the chiral SU(2) x SU(2) symmetry. The Lagrangian without derivatives obtained previously is used to describe the contact weak K pi interaction. It is postulated that the enhancement of effects related to the electromagnetic mass differences of pi and K mesons in the K yields 3 pi amplitudes is due to the PCAC modification: partial delta A = constant pi (1 - 2 alpha lambda /supmore » 2/ KK). At alpha = 0.8 the predictions of the model are shown to coincide with the experiment. (auth)« less

GABAergic miniature postsynaptic currents in septal neurons show differential allosteric sensitivity after binge-like ethanol exposure.

PubMed

DuBois, Dustin W; Trzeciakowski, Jerome P; Parrish, Alan R; Frye, Gerald D

2006-05-17

Binge-like ethanol treatment of septal neurons blunts GABAAR-mediated miniature postsynaptic currents (mPSCs), suggesting it arrests synaptic development. Ethanol may disrupt postsynaptic maturation by blunting feedback signaling through immature GABAARs. Here, the impact of ethanol on the sensitivity of mPSCs to zolpidem, zinc and 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha-OH-DHP) was tested. The decay phase of mPSCs showed concentration-dependent potentiation by zolpidem (0.03-100 microM), which was substantially blunted after ethanol exposure. Since zolpidem potentiation exhibited a substantial age-dependent increase in untreated neurons, this finding supported the idea that ethanol arrests synaptic development. GABAAR alpha1 subunit protein also increased with age in untreated neurons, paralleling enhanced sensitivity to zolpidem. Surprisingly, alpha1 levels were not reduced by binge ethanol even though mPSCs were relatively zolpidem-insensitive. Zinc (3-30 microM) decreased mPSC parameters in a concentration- and age-related manner with older untreated cells showing less inhibition. However, there was no increase in mPSC zinc sensitivity after binge ethanol as would be expected if a general arrest of synaptic maturation had occurred. 3alpha-OH-DHP (3-1000 nM) induced concentration-dependent potentiation of mPSC decay. Although potentiation was age-independent, binge ethanol treatment exaggerated sensitivity to this neurosteroid. Finally, chronic picrotoxin pretreatment (100 microM) intended to mimic GABAAR inhibition from ethanol pretreatment did not significantly change mPSC modulation by zolpidem, zinc or 3alpha-OH-DHP. These results suggest that binge ethanol treatment selectively arrests a subset of processes important for maturation of postsynaptic GABAA Rs. However, it is unlikely that ethanol causes a broad arrest of postsynaptic development through a direct inhibition of GABAAR signaling.

Effects of etching time on alpha tracks in solid state nuclear track detectors.

PubMed

Gillmore, Gavin; Wertheim, David; Crust, Simon

2017-01-01

Solid State Nuclear Track Detectors (SSNTDs) are used extensively for monitoring alpha particle radiation, neutron flux and cosmic ray radiation. Radon gas inhalation is regarded as being a significant contributory factor to lung cancer deaths in the UK each year. Gas concentrations are often monitored using CR39 based SSNTDs as the natural decay of radon results in alpha particles which form tracks in these detectors. Such tracks are normally etched for about 4h to enable microscopic analysis. This study examined the effect of etching time on the appearance of alpha tracks in SSNTDs by collecting 2D and 3D image datasets using laser confocal microscope imaging techniques. Etching times of 2 to 4h were compared and marked differences were noted in resultant track area. The median equivalent diameters of tracks were 20.2, 30.2 and 38.9μm for etching at 2, 3 and 4h respectively. Our results indicate that modern microscope imaging can detect and image the smaller size tracks seen for example at 3h etching time. Shorter etching times may give rise to fewer coalescing tracks although there is a balance to consider as smaller track sizes may be more difficult to image. Thus etching for periods of less than 4h clearly merits further investigation as this approach has the potential to improve accuracy in assessing the number of tracks. Copyright © 2016 Elsevier B.V. All rights reserved.

First Results of Using a UVTron Flame Sensor to Detect Alpha-Induced Air Fluorescence in the UVC Wavelength Range.

PubMed

Crompton, Anita J; Gamage, Kelum A A; Bell, Steven; Wilson, Andrew P; Jenkins, Alex; Trivedi, Divyesh

2017-11-29

In this work, a robust stand-off alpha detection method using the secondary effects of alpha radiation has been sought. Alpha particles ionise the surrounding atmosphere as they travel. Fluorescence photons produced as a consequence of this can be used to detect the source of the alpha emissions. This paper details experiments carried out to detect this fluorescence, with the focus on photons in the ultraviolet C (UVC) wavelength range (180-280 nm). A detector, UVTron R9533 (Hamamatsu, 325-6, Sunayama-cho, Naka-ku, Hamamatsu City, Shizuoka Pref., 430-8587, Japan), designed to detect the UVC emissions from flames for fire alarm purposes, was tested in various gas atmospheres with a 210 Po alpha source to determine if this could provide an avenue for stand-off alpha detection. The results of the experiments show that this detector is capable of detecting alpha-induced air fluorescence in normal indoor lighting conditions, as the interference from daylight and artificial lighting is less influential on this detection system which operates below the UVA and UVB wavelength ranges (280-315 nm and 315-380 nm respectively). Assuming a standard 1 r 2 drop off in signal, the limit of detection in this configuration can be calculated to be approximately 240 mm, well beyond the range of alpha-particles in air, which indicates that this approach could have potential for stand-off alpha detection. The gas atmospheres tested produced an increase in the detector count, with xenon having the greatest effect with a measured 52% increase in the detector response in comparison to the detector response in an air atmosphere. This type of alpha detection system could be operated at a distance, where it would potentially provide a more cost effective, safer, and faster solution in comparison with traditional alpha detection methods to detect and characterise alpha contamination in nuclear decommissioning and security applications.

First Results of Using a UVTron Flame Sensor to Detect Alpha-Induced Air Fluorescence in the UVC Wavelength Range

PubMed Central

Crompton, Anita J.; Wilson, Andrew P.; Jenkins, Alex; Trivedi, Divyesh

2017-01-01

In this work, a robust stand-off alpha detection method using the secondary effects of alpha radiation has been sought. Alpha particles ionise the surrounding atmosphere as they travel. Fluorescence photons produced as a consequence of this can be used to detect the source of the alpha emissions. This paper details experiments carried out to detect this fluorescence, with the focus on photons in the ultraviolet C (UVC) wavelength range (180–280 nm). A detector, UVTron R9533 (Hamamatsu, 325-6, Sunayama-cho, Naka-ku, Hamamatsu City, Shizuoka Pref., 430-8587, Japan), designed to detect the UVC emissions from flames for fire alarm purposes, was tested in various gas atmospheres with a 210Po alpha source to determine if this could provide an avenue for stand-off alpha detection. The results of the experiments show that this detector is capable of detecting alpha-induced air fluorescence in normal indoor lighting conditions, as the interference from daylight and artificial lighting is less influential on this detection system which operates below the UVA and UVB wavelength ranges (280–315 nm and 315–380 nm respectively). Assuming a standard 1r2 drop off in signal, the limit of detection in this configuration can be calculated to be approximately 240 mm, well beyond the range of alpha-particles in air, which indicates that this approach could have potential for stand-off alpha detection. The gas atmospheres tested produced an increase in the detector count, with xenon having the greatest effect with a measured 52% increase in the detector response in comparison to the detector response in an air atmosphere. This type of alpha detection system could be operated at a distance, where it would potentially provide a more cost effective, safer, and faster solution in comparison with traditional alpha detection methods to detect and characterise alpha contamination in nuclear decommissioning and security applications. PMID:29186051

Two-loop virtual top-quark effect on Higgs-boson decay to bottom quarks.

PubMed

Butenschön, Mathias; Fugel, Frank; Kniehl, Bernd A

2007-02-16

In most of the mass range encompassed by the limits from the direct search and the electroweak precision tests, the Higgs boson of the standard model preferably decays to bottom quarks. We present, in analytic form, the dominant two-loop electroweak correction, of O(GF2mt4), to the partial width of this decay. It amplifies the familiar enhancement due to the O(GFmt2) one-loop correction by about +16% and thus more than compensates the screening by about -8% through strong-interaction effects of order O(alphasGFmt2).

Isoporphyrin intermediate in heme oxygenase catalysis. Oxidation of alpha-meso-phenylheme.

PubMed

Evans, John P; Niemevz, Fernando; Buldain, Graciela; de Montellano, Paul Ortiz

2008-07-11

Human heme oxygenase-1 (hHO-1) catalyzes the O2- and NADPH-dependent oxidation of heme to biliverdin, CO, and free iron. The first step involves regiospecific insertion of an oxygen atom at the alpha-meso carbon by a ferric hydroperoxide and is predicted to proceed via an isoporphyrin pi-cation intermediate. Here we report spectroscopic detection of a transient intermediate during oxidation by hHO-1 of alpha-meso-phenylheme-IX, alpha-meso-(p-methylphenyl)-mesoheme-III, and alpha-meso-(p-trifluoromethylphenyl)-mesoheme-III. In agreement with previous experiments (Wang, J., Niemevz, F., Lad, L., Huang, L., Alvarez, D. E., Buldain, G., Poulos, T. L., and Ortiz de Montellano, P. R. (2004) J. Biol. Chem. 279, 42593-42604), only the alpha-biliverdin isomer is produced with concomitant formation of the corresponding benzoic acid. The transient intermediate observed in the NADPH-P450 reductase-catalyzed reaction accumulated when the reaction was supported by H2O2 and exhibited the absorption maxima at 435 and 930 nm characteristic of an isoporphyrin. Product analysis by reversed phase high performance liquid chromatography and liquid chromatography electrospray ionization mass spectrometry of the product generated with H2O2 identified it as an isoporphyrin that, on quenching, decayed to benzoylbiliverdin. In the presence of H218O2, one labeled oxygen atom was incorporated into these products. The hHO-1-isoporphyrin complexes were found to have half-lives of 1.7 and 2.4 h for the p-trifluoromethyl- and p-methyl-substituted phenylhemes, respectively. The addition of NADPH-P450 reductase to the H2O2-generated hHO-1-isoporphyrin complex produced alpha-biliverdin, confirming its role as a reaction intermediate. Identification of an isoporphyrin intermediate in the catalytic sequence of hHO-1, the first such intermediate observed in hemoprotein catalysis, completes our understanding of the critical first step of heme oxidation.

Stellar neutron sources and s-process in massive stars

NASA Astrophysics Data System (ADS)

Talwar, Rashi

The s-process or the slow neutron capture process is a nucleosynthesis process taking place at relatively low neutron densities in stars. It runs along the valley of beta stability since the neutron capture rate is much slower compared to the beta decay rate. The s-process occurs mainly during core helium burning and shell carbon burning phase in massive stars and during thermally pulsing helium burning phase in asymptotic giant-branch stars. The potential stellar neutron source for the s-process is associated with alpha-capture reactions on light nuclei. The capture-reaction rates provide the reaction flow for the build-up of22Ne neutron source during the heliumburning phase in these stars. The low energy 26Mg resonances at stellar energies below 800 keV are predicted to have a critical influence on the alpha-capture rates on 22Ne. Some of these resonances may also correspond to pronounced alpha cluster structure near the alpha-threshold. However, these resonances have remained elusive during direct alpha capture measurements owing to the high Coulomb barrier and background from cosmic rays and beam induced reactions. Hence, in the present work, alpha-inelastic scattering and alpha- transfer measurements have been performed to probe the level structure of 26Mg nucleus in order to determine the 22Ne+alpha-capture rates. Both experiments have been performed using the high-resolution Grand Raiden Spectrometer at the Research Center for Nuclear Physics (RCNP), Osaka, Japan. For the alpha-inelastic scattering measurement, a self-supporting solid 26Mg target was used and for the alpha-transfer study via the (6Li,d) reaction, 22Ne gas enclosed in a gas cell with Aramid windows was used. The reaction products were momentum analysed by the spectrometer and detected at the focal plane equipped with two multi-wire drift chambers and two plastic-scintillation detectors. The focal plane detection system provided information on the position, the angle, the time of flight and the energy of the particles enabling the reconstruction of the kinematics at the target. The focal plane energy calibration allowed for the study of 26 Mg levels from Ex = 7.69 - 12.06 MeV in the (alpha; alpha0) measurement and Ex = 7.36 - 11.32 MeV in the (6Li,d) measurement. Six levels (Ex = 10717 (9) keV , 10822 (10) keV, 10951 (21) keV, 11085 (8) keV, 11167 (8) keV and 11317 (18) keV) were observed above the alpha-threshold in the region of interest (10.61 - 11.32 MeV). The Ex = 10717 keV had a negligible contribution to the alpha-capture rates. The Ex = 10951, 11167 and 11317 keV exhibited pronounced alpha-cluster structure and hence, dominated the alpha-capture rates. The Ex = 11167 keV had the most appreciable impact on the (alpha; gamma ) rate increasing it by 2 orders of magnitude above Longland et al. [58] and Bisterzo et al. [8] rates and by a factor of 3 above NACRE [2] rate. Hence, the recommended 22Ne(alpha,n) + 22Ne(alpha; ) rates, from the present work, strongly favour the reduction of s-process over-abundances associated with massive stars as well as AGB stars of intermediate initial mass. Also, the uncertainty range corresponding to the present rates suggest the need for a more refined measurement of the associated resonance parameters.

Nuclear diagnostic for fast alpha particles

DOEpatents

Grisham, Larry R.; Post Jr., Douglass E.; Dawson, John M.

1986-06-03

Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

Nuclear diagnostic for fast alpha particles

DOEpatents

Grisham, Larry R.; Post, Jr., Douglass E.; Dawson, John M.

1986-01-01

Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

15O(alpha,gamma)19Ne breakout reaction and impact on X-ray bursts.

PubMed

Tan, W P; Fisker, J L; Görres, J; Couder, M; Wiescher, M

2007-06-15

The breakout reaction 15O(alpha,gamma)19Ne, which regulates the flow between the hot CNO cycle and the rp process, is critical for the explanation of the burst amplitude and periodicity of x-ray bursters. We report on the first successful measurement of the critical alpha-decay branching ratios of relevant states in 19Ne populated via 19F(3He,t)19Ne. Based on the experimental results and our previous lifetime measurements of these states, we derive the first experimental rate of 15O(alpha,gamma)19Ne. The impact of our experimental results on the burst pattern and periodicity for a range of accretion rates is analyzed.

As-Built design specification for PARPLT. [program to produce scatter plots of crop greenness profile parameters

NASA Technical Reports Server (NTRS)

Tompkins, M. A.; Cheng, D. E. (Principal Investigator)

1981-01-01

The design and implementation of the PARPLT program are described. The program produces scatter plots of the greenness profile derived parameters alpha, beta, and t sub o computed by the CLASFYG program (alpha being the approximate greenness rise time; beta, the greenness decay time; and t sub o, the spectral crop emergence date). Statistical information concerning the parameters is also computed.

Standoff alpha radiation detection for hot cell imaging and crime scene investigation

NASA Astrophysics Data System (ADS)

Kerst, Thomas; Sand, Johan; Ihantola, Sakari; Peräjärvi, Kari; Nicholl, Adrian; Hrnecek, Erich; Toivonen, Harri; Toivonen, Juha

2018-02-01

This paper presents the remote detection of alpha contamination in a nuclear facility. Alpha-active material in a shielded nuclear radiation containment chamber has been localized by optical means. Furthermore, sources of radiation danger have been identified in a staged crime scene setting. For this purpose, an electron-multiplying charge-coupled device camera was used to capture photons generated by alpha-induced air scintillation (radioluminescence). The detected radioluminescence was superimposed with a regular photograph to reveal the origin of the light and thereby the alpha radioactive material. The experimental results show that standoff detection of alpha contamination is a viable tool in radiation threat detection. Furthermore, the radioluminescence spectrum in the air is spectrally analyzed. Possibilities of camera-based alpha threat detection under various background lighting conditions are discussed.

Standoff alpha radiation detection for hot cell imaging and crime scene investigation

NASA Astrophysics Data System (ADS)

Kerst, Thomas; Sand, Johan; Ihantola, Sakari; Peräjärvi, Kari; Nicholl, Adrian; Hrnecek, Erich; Toivonen, Harri; Toivonen, Juha

2018-06-01

This paper presents the remote detection of alpha contamination in a nuclear facility. Alpha-active material in a shielded nuclear radiation containment chamber has been localized by optical means. Furthermore, sources of radiation danger have been identified in a staged crime scene setting. For this purpose, an electron-multiplying charge-coupled device camera was used to capture photons generated by alpha-induced air scintillation (radioluminescence). The detected radioluminescence was superimposed with a regular photograph to reveal the origin of the light and thereby the alpha radioactive material. The experimental results show that standoff detection of alpha contamination is a viable tool in radiation threat detection. Furthermore, the radioluminescence spectrum in the air is spectrally analyzed. Possibilities of camera-based alpha threat detection under various background lighting conditions are discussed.

Preliminary Therapy Evaluation of 225Ac-DOTA-c(RGDyK) Demonstrates that Cerenkov Radiation Derived from 225Ac Daughter Decay Can Be Detected by Optical Imaging for In Vivo Tumor Visualization

PubMed Central

Pandya, Darpan N.; Hantgan, Roy; Budzevich, Mikalai M.; Kock, Nancy D.; Morse, David L.; Batista, Izadora; Mintz, Akiva; Li, King C.; Wadas, Thaddeus J.

2016-01-01

The theranostic potential of 225Ac-based radiopharmaceuticals continues to increase as researchers seek innovative ways to harness the nuclear decay of this radioisotope for therapeutic and imaging applications. This communication describes the evaluation of 225Ac-DOTA-c(RGDyK) in both biodistribution and Cerenkov luminescence imaging (CLI) studies. Initially, La-DOTA-c(RGDyK) was prepared as a non-radioactive surrogate to evaluate methodologies that would contribute to an optimized radiochemical synthetic strategy and estimate the radioactive conjugate's affinity for αvβ3, using surface plasmon resonance spectroscopy. Surface plasmon resonance spectroscopy studies revealed the IC50 and Ki of La-DOTA-c(RGDyK) to be 33 ± 13 nM and 26 ± 11 nM, respectively, and suggest that the complexation of the La3+ ion to the conjugate did not significantly alter integrin binding. Furthermore, use of this surrogate allowed optimization of radiochemical synthesis strategies to prepare 225Ac-DOTA-c(RGDyK) with high radiochemical purity and specific activity similar to other 225Ac-based radiopharmaceuticals. This radiopharmaceutical was highly stable in vitro. In vivo biodistribution studies confirmed the radiotracer's ability to target αvβ3 integrin with specificity; specificity was detected in tumor-bearing animals using Cerenkov luminescence imaging. Furthermore, tumor growth control was achieved using non-toxic doses of the radiopharmaceutical in U87mg tumor-bearing nude mice. To our knowledge, this is the first report to describe the CLI of αvβ3+ tumors in live animals using the daughter products derived from 225Ac decay in situ. This concept holds promise to further enhance development of targeted alpha particle therapy. PMID:27022417

Preliminary Therapy Evaluation of (225)Ac-DOTA-c(RGDyK) Demonstrates that Cerenkov Radiation Derived from (225)Ac Daughter Decay Can Be Detected by Optical Imaging for In Vivo Tumor Visualization.

PubMed

Pandya, Darpan N; Hantgan, Roy; Budzevich, Mikalai M; Kock, Nancy D; Morse, David L; Batista, Izadora; Mintz, Akiva; Li, King C; Wadas, Thaddeus J

2016-01-01

The theranostic potential of (225)Ac-based radiopharmaceuticals continues to increase as researchers seek innovative ways to harness the nuclear decay of this radioisotope for therapeutic and imaging applications. This communication describes the evaluation of (225)Ac-DOTA-c(RGDyK) in both biodistribution and Cerenkov luminescence imaging (CLI) studies. Initially, La-DOTA-c(RGDyK) was prepared as a non-radioactive surrogate to evaluate methodologies that would contribute to an optimized radiochemical synthetic strategy and estimate the radioactive conjugate's affinity for αvβ3, using surface plasmon resonance spectroscopy. Surface plasmon resonance spectroscopy studies revealed the IC50 and Ki of La-DOTA-c(RGDyK) to be 33 ± 13 nM and 26 ± 11 nM, respectively, and suggest that the complexation of the La(3+) ion to the conjugate did not significantly alter integrin binding. Furthermore, use of this surrogate allowed optimization of radiochemical synthesis strategies to prepare (225)Ac-DOTA-c(RGDyK) with high radiochemical purity and specific activity similar to other (225)Ac-based radiopharmaceuticals. This radiopharmaceutical was highly stable in vitro. In vivo biodistribution studies confirmed the radiotracer's ability to target αvβ3 integrin with specificity; specificity was detected in tumor-bearing animals using Cerenkov luminescence imaging. Furthermore, tumor growth control was achieved using non-toxic doses of the radiopharmaceutical in U87mg tumor-bearing nude mice. To our knowledge, this is the first report to describe the CLI of αvβ3 (+) tumors in live animals using the daughter products derived from (225)Ac decay in situ. This concept holds promise to further enhance development of targeted alpha particle therapy.

Alpha Particle Detection Using Alpha-Induced Air Radioluminescence: A Review and Future Prospects for Preliminary Radiological Characterisation for Nuclear Facilities Decommissioning

PubMed Central

Crompton, Anita J.; Jenkins, Alex

2018-01-01

The United Kingdom (UK) has a significant legacy of nuclear installations to be decommissioned over the next 100 years and a thorough characterisation is required prior to the development of a detailed decommissioning plan. Alpha radiation detection is notoriously time consuming and difficult to carry out due to the short range of alpha particles in air. Long-range detection of alpha particles is therefore highly desirable and this has been attempted through the detection of secondary effects from alpha radiation, most notably the air-radioluminescence caused by ionisation. This paper evaluates alpha induced air radioluminescence detectors developed to date and looks at their potential to develop a stand-off, alpha radiation detector which can be used in the nuclear decommissioning field in daylight conditions to detect alpha contaminated materials. PMID:29597340

Detector Development for the abBA Experiment.

PubMed

Seo, P-N; Bowman, J D; Mitchell, G S; Penttila, S I; Wilburn, W S

2005-01-01

We have developed a new type of field-expansion spectrometer to measure the neutron beta decay correlations (a, b, B, and A). A precision measurement of these correlations places stringent requirements on charged particle detectors. The design employs large area segmented silicon detectors to detect both protons and electrons in coincidence. Other requirements include good energy resolution (< 5 keV), a thin dead layer to allow observation of 30-keV protons, fast timing resolution (~1 ns) to reconstruct electron-backscattering events, and nearly unity efficiency. We report results of testing commercially available surface-barrier silicon detectors for energy resolution and timing performance, and measurement of the dead-layer thickness of ion-implanted silicon detectors with a 3.2 MeV alpha source.

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.

Investigation of the daytime lunar atmosphere for lunar synthesis program

NASA Technical Reports Server (NTRS)

Hodges, R. R., Jr.

1976-01-01

Synthesis studies of the daytime lunar atmoshere were directed toward improved understanding of fundamental lunar atmospheric dynamics and the relationship of the detectable atmosphere to physical processes of the lunar surface and interior. The primary source of data is the Apollo 17 lunar surface mass spectrometer. The Ar40 is radiogenic and its escape rate from the lunar atmosphere requires release of a significant fraction (about 8%) of the argon produced from the decay of K40 within the moon. Furthermore the process of argon release from the solid moon is time varying and related to seismic activity. Most of the helium on the moon is due to release of implanted solar wind alpha particles from the regolith.

Statistical aspects of the 1980 solar flares. 2: Solar cycle activity relationships and additional remarks

NASA Technical Reports Server (NTRS)

Wilson, R. M.

1982-01-01

Based on 1349 hydrogen alpha flares with X-ray counterparts, an investigation into the relationship between the rise time, decay time, duration, latitude, hydrogen alpha importance, and X-ray class with 2800 MHz radio emission (F2800) was accomplished. An important finding is that during 1980 both the number of hydrogen alpha importance class 1 and number of X-ray class M (and M+X) flares appeared to be rather strongly related to F2800, in a positive sense; i.e., number of class 1 and class M events increased as F2800 increased.

Measurement and reduction of low-level radon background in the KATRIN experiment

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

Fränkle, F. M.

The KArlsruhe TRItium Neutrino (KATRIN) experiment is a next generation, model independent, large scale experiment to determine the mass of the electron anti-neutrino by investigating the kinematics of tritium beta decay with a sensitivity of 200 meV/c{sup 2}. The measurement setup consists of a high luminosity windowless gaseous molecular tritium source (WGTS), a differential and cryogenic pumped electron transport and tritium retention section, a tandem spectrometer section (pre-spectrometer and main spectrometer) for energy analysis, followed by a detector system for counting transmitted beta decay electrons. Measurements performed at the KATRIN pre-spectrometer test setup showed that the decay of radon (Rn)more » atoms in the volume of the KATRIN spectrometers is a major background source. Rn atoms from low-level radon emanation of materials inside the vacuum region of the KATRIN spectrometers are able to penetrate deep into the magnetic flux tube so that the alpha decay of Rn contributes to the background. Of particular importance are electrons emitted in processes accompanying the Rn alpha decay, such as shake-off, internal conversion of excited levels in the Rn daughter atoms and Auger electrons. Lowenergy electrons (< 100 eV) directly contribute to the background in the signal region. High-energy electrons can be stored magnetically inside the volume of the spectrometer and are able to create thousands of secondary electrons via subsequent ionization processes with residual gas molecules. In order to reduce the Rn induced background different active and passive counter measures were developed and tested. This proceeding will give an overview on Rn sources within the KATRIN spectrometer, describes how Rn decays inside the spectrometer produce background events at the detector and presents different counter measures to reduce the Rn induced background.« less

Measurement and reduction of low-level radon background in the KATRIN experiment

NASA Astrophysics Data System (ADS)

Fränkle, F. M.

2013-08-01

The KArlsruhe TRItium Neutrino (KATRIN) experiment is a next generation, model independent, large scale experiment to determine the mass of the electron anti-neutrino by investigating the kinematics of tritium beta decay with a sensitivity of 200 meV/c2. The measurement setup consists of a high luminosity windowless gaseous molecular tritium source (WGTS), a differential and cryogenic pumped electron transport and tritium retention section, a tandem spectrometer section (pre-spectrometer and main spectrometer) for energy analysis, followed by a detector system for counting transmitted beta decay electrons. Measurements performed at the KATRIN pre-spectrometer test setup showed that the decay of radon (Rn) atoms in the volume of the KATRIN spectrometers is a major background source. Rn atoms from low-level radon emanation of materials inside the vacuum region of the KATRIN spectrometers are able to penetrate deep into the magnetic flux tube so that the alpha decay of Rn contributes to the background. Of particular importance are electrons emitted in processes accompanying the Rn alpha decay, such as shake-off, internal conversion of excited levels in the Rn daughter atoms and Auger electrons. Lowenergy electrons (< 100 eV) directly contribute to the background in the signal region. High-energy electrons can be stored magnetically inside the volume of the spectrometer and are able to create thousands of secondary electrons via subsequent ionization processes with residual gas molecules. In order to reduce the Rn induced background different active and passive counter measures were developed and tested. This proceeding will give an overview on Rn sources within the KATRIN spectrometer, describes how Rn decays inside the spectrometer produce background events at the detector and presents different counter measures to reduce the Rn induced background.

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

A binding energy study of the Atomic Mass Evaluation 2012 and an updated beta-decay study of neutron-rich 74Cu

NASA Astrophysics Data System (ADS)

Tracy, James L., Jr.

A study of ground state binding energy values listed in the Atomic Mass Evaluation 2012 (AME2012) using an interpretive approach, as opposed to the exploratory methods of previous models, is presented. This model is based on a postulate requiring all protons to pair with available neutrons to form bound alpha clusters as the ground state for an N = Z core upon which excess neutrons are added. For each core, the trend of the binding energy as a function of excess neutrons in the isotopic chain can be fit with a three-term quadratic function. The quadratic parameter reveals a smooth decaying exponential function. By re-envisioning the determination of mass excess, the constant-term fit parameters, representing N = Z nuclei, reveal a near-symmetry around Z = 50. The linear fit parameters exhibit trends which are linear functions of core size. A neutron drip-line prediction is compared against current models. By considering the possibility of an alpha-cluster core, a new ground-state structure grouping scheme is presented; nucleon-nucleon pairing is shown to have a greater role in level filling. This model, referred to as the Alpha-Deuteron-Neutron Model, yields promising first results when considering root-mean-square variances from the AME2012. The beta-decay of the neutron-rich isotope 74Cu has been studied using three high-purity Germanium clover detectors at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. A high-resolution mass separator greatly improved the purity of the 74Cu beam by removing isobaric contaminants, thus allowing decay through its isobar chain to the stable 74Ge at the center of the LeRIBSS detector array without any decay chain member dominating. Using coincidence gating techniques, 121 gamma-rays associated with 74Cu were isolated from the collective singles spectrum. Eighty-seven of these were placed in an expanded level scheme, and updated beta-feeding level intensities and log( ft) values are presented based on multiple newly-placed excited states up to 6.8 MeV. The progression of simulated Total Absorption gamma-ray Spectroscopy (TAGS) based on known levels and beta feeding values from previous measurements to this evaluation are presented and demonstrate the need for a TAGS measurement of this isotope to gain a more complete understanding of its decay scheme.

Nuclear Data Sheets for A = 168

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

Baglin, Coral M.

2010-07-15

Nuclear structure data pertaining to all nuclei with mass A=168 (Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt) have been evaluated and incorporated into the ENSDF data file. This evaluation supersedes the previous publication (V.S. Shirley, Nuclear Data Sheets 71, 261 (1994) (literature cutoff date July 1993)) and subsequent ENSDF file revisions for Tb and Dy (C. Baglin, literature cutoff date of 15 June 1999) and Hf (B. Singh, literature cutoff date of 30 April 2001), and includes literature available by 15 June 2010. Since the above evaluations, the first excited states in {supmore » 168}Pt have been identified (1998Ki20, 2009Go16) and {alpha} decay from {sup 172}Hg has been observed (2009Sa27, 2004Ke06, 1999Se14). New levels in {sup 168}Dy have been excited using the {sup 170}Er({sup 82}Se,{sup 84}Kr{gamma}) reaction (2010So03). (HI,xn{gamma}) studies have significantly expanded our knowledge of level structure in {sup 168}Lu (1999Ka17, 2002Ha33), {sup 168}Ta (2008QiZZ), {sup 168}Yb (1995Fi01), {sup 168}Tm (2007CaZW), {sup 168}Hf (2009Ya21), {sup 168}Os (2001Jo11, 2009Od02) and, for {sup 168}Tm, important information has come also from (d,2n{gamma}) and ({alpha},n{gamma}) reactions (1995Si20). Revised decay schemes are available following new studies of {sup 168}Hf {epsilon} decay (6.7 min) (1997Ba26), {sup 168}Lu {epsilon} decay (1999Ba65), {sup 168}Ta {epsilon} decay (2007Mc08) and {sup 172}Au {alpha} decay (2009Ha42). Significant new information for {sup 168}Er is available from (p,t) (2006Bu09), (d,p) and (t,d) (1996Ma50), ({gamma},{gamma}') (1996Ma18), (136Xe, X{gamma}) (2010Dr02), ({sup 238}U,{sup 238}U{sup '{gamma}}) (2003Wu07) and (n,n{sup '{gamma}}) (1998Be20, 1998Be62) reactions, and the availability of {gamma}{gamma} coin data (1994Ju02, 1996Gi09) for the (n,{gamma}) E=thermal reaction has resulted in some significant level scheme revisions.« less

Development of an Ultra-Pure, Carrier-Free 209Po Solution Standard

PubMed Central

Collé, R.; Fitzgerald, R. P.; Laureano-Perez, L.

2015-01-01

Ultra-pure, carrier-free 209Po solution standards have been prepared and standardized for their massic alpha-particle emission rate. The standards, which will be disseminated by the National Institute of Standards and Technology (NIST) as Standard Reference Material SRM 4326a, have a mean mass of (5.169 ± 0.003) g of a solution of polonium in nominal 2.0 mol▪L−1 HCl (having a solution density of (1.032 ± 0.002) g▪ mL−1 at 20 °C) that are contained in 5 mL, flame-sealed, borosilicate glass ampoules. They are certified to contain a 209Po massic alpha-particle emission rate of (39.01 ± 0.18) s−1▪g−1 as of a reference time of 1200 EST, 01 December 2013. This new standard series replaces SRM 4326 that was issued by NIST in 1994. The standardization was based on 4πα liquid scintillation (LS) spectrometry with two different LS counting systems and under wide variations in measurement and counting source conditions. The methodology for the standardization, with corrections for detection of the low-energy conversion electrons from the delayed 2 keV isomeric state in 205Pb and for the radiations accompanying the small 0.45 % electron-capture branch to 209Bi, involves a unique spectral analysis procedure that is specific for the case of 209Po decay. The entire measurement protocol is similar, but revised and improved from that used for SRM 4326. Spectroscopic impurity analyses revealed that no photon-emitting or alpha-emitting radionuclidic impurities were detected. The most common impurity associated with 209Po is 208Po and the activity ratio of 208Po/209Po was < 10−7. PMID:26958444

Some properties of human neuronal alpha 7 nicotinic acetylcholine receptors fused to the green fluorescent protein.

PubMed

Palma, Eleonora; Mileo, Anna M; Martinez-Torres, Ataulfo; Eusebi, Fabrizio; Miledi, Ricardo

2002-03-19

The functional properties and cellular localization of the human neuronal alpha7 nicotinic acetylcholine (AcCho) receptor (alpha7 AcChoR) and its L248T mutated (mut) form were investigated by expressing them alone or as gene fusions with the enhanced version of the green fluorescent protein (GFP). Xenopus oocytes injected with wild-type (wt), mutalpha7, or the chimeric subunit cDNAs expressed receptors that gated membrane currents when exposed to AcCho. As already known, AcCho currents generated by wtalpha7 receptors decay much faster than those elicited by the mutalpha7 receptors. Unexpectedly, the fusion of GFP to the wt and mutated alpha7 receptors led to opposite results: the AcCho-current decay of the wt receptors became slower, whereas that of the mutated receptors was accelerated. Furthermore, repetitive applications of AcCho led to a considerable "run-down" of the AcCho currents generated by mutalpha7-GFP receptors, whereas those of the wtalpha7-GFP receptors remained stable or increased in amplitude. The AcCho-current run-down of mutalpha7-GFP oocytes was accompanied by a marked decrease of alpha-bungarotoxin binding activity. Fluorescence, caused by the chimeric receptors expressed, was seen over the whole oocyte surface but was more intense and abundant in the animal hemisphere, whereas it was much weaker in the vegetal hemisphere. We conclude that fusion of GFP to wtalpha7 and mutalpha7 receptors provides powerful tools to study the distribution and function of alpha7 receptors. We also conclude that fused genes do not necessarily recapitulate all of the properties of the original receptors. This fact must be borne close in mind whenever reporter genes are attached to proteins.

The stability properties of cylindrical force-free fields - Effect of an external potential field

NASA Technical Reports Server (NTRS)

Chiuderi, C.; Einaudi, G.; Ma, S. S.; Van Hoven, G.

1980-01-01

A large-scale potential field with an embedded smaller-scale force-free structure gradient x B equals alpha B is studied in cylindrical geometry. Cases in which alpha goes continuously from a constant value alpha 0 on the axis to zero at large r are considered. Such a choice of alpha (r) produces fields which are realistic (few field reversals) but not completely stable. The MHD-unstable wavenumber regime is found. Since the considered equilibrium field exhibits a certain amount of magnetic shear, resistive instabilities can arise. The growth rates of the tearing mode in the limited MHD-stable region of k space are calculated, showing time-scales much shorter than the resistive decay time.

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.

Re/Os constraint on the time variability of the fine-structure constant.

PubMed

Fujii, Yasunori; Iwamoto, Akira

2003-12-31

We argue that the accuracy by which the isochron parameters of the decay 187Re-->187Os are determined by dating iron meteorites may constrain the possible time dependence of the decay rate and hence of the fine-structure constant alpha, not directly but only in a model-dependent manner. From this point of view, some of the attempts to analyze the Oklo constraint and the results of the quasistellar-object absorption lines are reexamined.

Limits on uranium and thorium bulk content in GERDA Phase I detectors

NASA Astrophysics Data System (ADS)

Collaboration, Gerda; Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; 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 Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakemüller, 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.; 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.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stepaniuk, M.; 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.

2017-05-01

Internal contaminations of 238U, 235U and 232Th in the bulk of high purity germanium detectors are potential backgrounds for experiments searching for neutrinoless double beta decay of 76Ge. The data from GERDA Phase I have been analyzed for alpha events from the decay chain of these contaminations by looking for full decay chains and for time correlations between successive decays in the same detector. No candidate events for a full chain have been found. Upper limits on the activities in the range of a few nBq/kg for 226Ra, 227Ac and 228Th, the long-lived daughter nuclides of 238U, 235U and 232Th, respectively, have been derived. With these upper limits a background index in the energy region of interest from 226Ra and 228Th contamination is estimated which satisfies the prerequisites of a future ton scale germanium double beta decay experiment.

Data Validation Package, June 2016 Groundwater Sampling at the Hallam, Nebraska, Decommissioned Reactor Site, August 2016

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

Surovchak, Scott; Miller, Michele

The 2008 Long-Term Surveillance Plan [LTSP] for the Decommissioned Hallam Nuclear Power Facility, Hallam, Nebraska (http://www.lm.doe.gov/Hallam/Documents.aspx) requires groundwater monitoring once every 2 years. Seventeen monitoring wells at the Hallam site were sampled during this event as specified in the plan. Planned monitoring locations are shown in Attachment 1, Sampling and Analysis Work Order. Water levels were measured at all sampled wells and at two additional wells (6A and 6B) prior to the start of sampling. Additionally, water levels of each sampled well were measured at the beginning of sampling. See Attachment 2, Trip Report, for additional details. Sampling and analysismore » were conducted as specified in Sampling and Analysis Plan for U.S. Department of Energy Office of Legacy Management Sites (LMS/PRO/S04351, continually updated, http://energy.gov/lm/downloads/sampling-and-analysis-plan-us-department- energy-office-legacy-management-sites). Gross alpha and gross beta are the only parameters that were detected at statistically significant concentrations. Time/concentration graphs of the gross alpha and gross beta data are included in Attachment 3, Data Presentation. The gross alpha and gross beta activity concentrations observed are consistent with values previously observed and are attributed to naturally occurring radionuclides (e.g., uranium and uranium decay chain products) in the groundwater.« less

Alpha decay hindrance factors and reflection asymmetry in nuclei

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

Sheline, R.K.; Bossinga, B.B.

1991-07-01

All available hindrance factors of alpha transitions to low-lying negative-parity states in doubly even nuclei, to odd-{ital A} parity doublets and to doubly odd parity doublet bands, are used to study the systematics of reflection asymmetry in the {ital A}{similar to}218--230 region. Special attention is given to the polarization effect of the odd particle in increasing reflection asymmetry and therefore decreasing hindrance factors to the opposite parity states of octupole bands.

Studies on the reduction of radon plate-out

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

Bruemmer, M.; Nakib, M.; Calkins, R.

The decay of common radioactive gases, such as radon, produces stable isotopes by a sequence of daughter particles with varied half-lives. These daughter particles are a significant source of gamma, neutron, and alpha (α) particle backgrounds that can mimic desired signals in dark matter and neutrinoless double beta decay experiments. In the LUMINA Laboratory at Southern Methodist University (SMU), studies of radon plate-out onto copper samples are conducted using one of XIA’s first five UltraLo 1800 alpha counters. We present results from investigations into various mitigation approaches. A custom-built copper holder (in either plastic or metal) has been designed andmore » produced to maximize the copper’s exposure to {sup 220}Rn. The {sup 220}Rn source is a collection of camping lantern mantles. We present the current status of control and experimental methods for addressing radon exposure levels.« less

Detection of alpha radiation in a beta radiation field

DOEpatents

Mohagheghi, Amir H.; Reese, Robert P.

2001-01-01

An apparatus and method for detecting alpha particles in the presence of high activities of beta particles utilizing an alpha spectrometer. The apparatus of the present invention utilizes a magnetic field applied around the sample in an alpha spectrometer to deflect the beta particles from the sample prior to reaching the detector, thus permitting detection of low concentrations of alpha particles. In the method of the invention, the strength of magnetic field required to adequately deflect the beta particles and permit alpha particle detection is given by an algorithm that controls the field strength as a function of sample beta energy and the distance of the sample to the detector.

Detection of active decay at groundline in utility poles

Treesearch

Alex L. Shigo; Walter C. Shortle; Julian Ochrymowych

1977-01-01

Active wood decay at groundline in in-service utility poles can be detected by a skilled inspector using: 1. A knowledge of basic patterns of decay. 2. Recognition of obvious signs of decay. 3. Proper interpretation of information obtained from a pulsed-current meter-Shigometer®-used with various probes and probing techniques.

Measuring the radon concentration in air meting van de radonconcentratie in lucht

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

Aten, J.B.T.; Bierhuizen, H.W.J.; Vanhoek, L.P.

1975-01-01

A simple transportable apparatus for measurement of the radon concentration in the air of a workshop was developed. An air sample is sucked through a filter and the decay curve of the alpha activity is measured. The counting speed 40 min after sampling gives an indication of the radon activity. The apparatus was calibrated by analyzing an analogous decay curve obtained with a big filter and a big air sample, the activity being measured with an anti-coincidence counter. (GRA)

Applications of a global nuclear-structure model to studies of the heaviest elements

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

Moeller, P.; Nix, J.R.

1993-10-01

We present some new results on heavy-element nuclear-structure properties calculated on the basis of the finite-range droplet model and folded-Yukawa single-particle potential. Specifically, we discuss calculations of nuclear ground-state masses and microscopic corrections, {alpha}-decay properties, {beta}-decay properties, fission potential-energy surfaces, and spontaneous-fission half-lives. These results, obtained in a global nuclear-structure approach, are particularly reliable for describing the stability properties of the heaviest elements.

Effective inertial coefficient for the dinuclear regime of the exotic decay of nuclei

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

Duarte, S.B.; Goncalves, M.G.

Geometric and incompressibility constraint relations are used explicitly in reducing the number of collective variables of the dinuclear phase of the fissioning system to calculate the barrier penetrability factor. Consistently, we define an effective inertial coefficient for the relative motion of the fissioning system. With this inertial coefficient, half-lives of the exotic and alpha decays are successfully reproduced for all available experimental data, using only one well-controlled nuclear parameter, the nuclear radius constant. {copyright} {ital 1996 The American Physical Society.}

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 ...

The jump-off velocity of an impulsively loaded spherical shell

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

Chabaud, Brandon M.; Brock, Jerry S.

2012-04-13

We consider a constant temperature spherical shell of isotropic, homogeneous, linearly elastic material with density {rho} and Lame coefficients {lambda} and {mu}. The inner and outer radii of the shell are r{sub i} and r{sub o}, respectively. We assume that the inside of the shell is a void. On the outside of the shell, we apply a uniform, time-varying pressure p(t). We also assume that the shell is initially at rest. We want to compute the jump-off time and velocity of the pressure wave, which are the first time after t = 0 at which the pressure wave from themore » outer surface reaches the inner surface. This analysis computes the jump-off velocity and time for both compressible and incompressible materials. This differs substantially from [3], where only incompressible materials are considered. We will consider the behavior of an impulsively loaded, exponentially decaying pressure wave p(t) = P{sub 0{sup e}}{sup -{alpha}t}, where {alpha} {ge} 0. We notice that a constant pressure wave P(t) = P{sub 0} is a special case ({alpha} = 0) of a decaying pressure wave. Both of these boundary conditions are considered in [3].« less

Detection and Assessment of Wood Decay in Glulam Beams Using a Decay Rate Approach: A Review

Treesearch

C. Adam Senalik

2013-01-01

A glulam beam is subjected to X-ray computer tomography and acousto-ultrasonic measurements to detect and assess wood decay. A glulam beam without visible indications of wood decay was taken from field use. A modified impulse-echo technique is employed as an inspection method requiring access to only one side of the beam. It is observed that decay-rate analysis of the...

Swelling induced by alpha decay in monazite and zirconolite ceramics: A XRD and TEM comparative study

NASA Astrophysics Data System (ADS)

Deschanels, X.; Seydoux-Guillaume, A. M.; Magnin, V.; Mesbah, A.; Tribet, M.; Moloney, M. P.; Serruys, Y.; Peuget, S.

2014-05-01

Zirconolite and monazite matrices are potential ceramics for the containment of actinides (Np, Cm, Am, Pu) which are produced over the reprocessing of spent nuclear fuel. Actinides decay mainly through the emission of alpha particles, which in turn causes most ceramics to undergo structural and textural changes (amorphization and/or swelling). In order to study the effects of alpha decays on the above mentioned ceramics two parallel approaches were set up. The first involved the use of an external irradiation source, Au, which allowed the deposited recoil energy to be simulated. The second was based on short-lived actinide doping with 238Pu, (i.e. an internal source), via the incorporation of plutonium oxide into both the monazite and zirconolite structures during synthesis. In both types of irradiation experiments, the zirconolite samples became amorphous at room temperature with damage close to 0.3 dpa; corresponding to a critical dose of 4 × 1018 α g-1 (i.e. ∼1.3 × 1021 keV cm-3). Both zirconolite samples also showed the same degree of macroscopic swelling at saturation (∼6%), with ballistic processes being the predominant damaging effect. In the case of the monazite however, the macroscopic swelling and amorphization were dependent on the nature of the irradiation. Externally, (Au), irradiated samples became amorphous while also demonstrating a saturation swelling of up to 8%. In contrast to this, the swelling of the 238Pu doped samples was much smaller at ∼1%. Also, unlike the externally (Au) irradiated monazite these 238Pu doped samples remained crystalline up to 7.5 × 1018 α g-1 (0.8 dpa). XRD, TEM and swelling measurements were used to fully characterize and interpret this behavior. The low swelling and the conservation of the crystalline state of 238Pu doped monazite samples indicates that alpha annealing took place within this material.

Stochastic gravitational wave background from light cosmic strings

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

DePies, Matthew R.; Hogan, Craig J.

2007-06-15

Spectra of the stochastic gravitational wave backgrounds from cosmic strings are calculated and compared with present and future experimental limits. Motivated by theoretical expectations of light cosmic strings in superstring cosmology, improvements in experimental sensitivity, and recent demonstrations of large, stable loop formation from a primordial network, this study explores a new range of string parameters with masses lighter than previously investigated. A standard 'one-scale' model for string loop formation is assumed. Background spectra are calculated numerically for dimensionless string tensions G{mu}/c{sup 2} between 10{sup -7} and 10{sup -18}, and initial loop sizes as a fraction of the Hubble radiusmore » {alpha} from 0.1 to 10{sup -6}. The spectra show a low frequency power-law tail, a broad spectral peak due to loops decaying at the present epoch (including frequencies higher than their fundamental mode, and radiation associated with cusps), and a flat (constant energy density) spectrum at high frequencies due to radiation from loops that decayed during the radiation-dominated era. The string spectrum is distinctive and unlike any other known source. The peak of the spectrum for light strings appears at high frequencies, significantly affecting predicted signals. The spectra of the cosmic string backgrounds are compared with current millisecond pulsar limits and Laser Interferometer Space Antenna (LISA) sensitivity curves. For models with large stable loops ({alpha}=0.1), current pulsar-timing limits exclude G{mu}/c{sup 2}>10{sup -9}, a much tighter limit on string tension than achievable with other techniques, and within the range of current models based on brane inflation. LISA may detect a background from strings as light as G{mu}/c{sup 2}{approx_equal}10{sup -16}, corresponding to field theory strings formed at roughly 10{sup 11} GeV.« less

Periodic Table of Elements: Los Alamos National Laboratory

Science.gov Websites

during the formation of the Earth (4.5 billion years old) has long since decayed away by now. However ) neutrons. Neptunium-237 is irradiated with neutrons to create 238Pu, an alpha emitter for radioisotope

Detection and identification of plasma progesterone metabolites in the female Florida manatee (Trichechus manatus latirostris) using GC/MS/MS.

PubMed

Tripp, K M; Dubois, M; Delahaut, P; Verstegen, J P

2009-08-01

Florida manatees (Trichechus manatus latirostris) have relatively low peripheral concentrations of progesterone (P4). The objective of this study was to determine if these relatively low P4 concentrations are associated with a high ratio of progestin metabolites and to document metabolite concentrations from individual blood samples obtained from manatees during diestrus or pregnancy. Metabolites known to exist in elephants-terrestrial manatee relatives-were targeted. These included 5alpha-reduced progestins (5alpha-pregnane-3,20-dione [5alpha-DHP] and 3alpha-hydroxy-5alpha-pregnan-20-one [5alpha-P3-OH]) and 17alpha-hydroxyprogesterone (17alpha-OHP), which occurs in Asian elephants. An additional, inactive metabolite, 20alpha-hydroxyprogesterone (20alpha-OHP), indicative of P4 overproduction, was also targeted. Progesterone itself was the predominant progestin detected in pregnant and nonpregnant manatee plasma (n = 10) using gas chromatography-mass spectrometry with tandem quadrupole detectors (GC/MS/MS). Progesterone concentrations in pregnant females varied from early (moderate to high) through mid and late (low) pregnancy. Progesterone concentrations ranged from low to high in nonpregnant, nonlactating females. The most commonly detected metabolite was 5alpha-P3-OH (n = 7), which occurred in pregnant (lower limit of detection [LLOD] to high) and nonpregnant (trace to high) females. The 5alpha-DHP metabolite was also detected in pregnant (LLOD to moderate) and nonpregnant (low) females. The 17alpha-OHP metabolite was not detected in any tested female. The 20alpha-OHP metabolite was detected in one nonpregnant, nonlactating, captive female (LLOD). Metabolites were most prevalent during early pregnancy, concurrent with maximum P4 concentrations. Based on their concentrations in peripheral circulation, we inferred that these metabolites may have, opposite to elephants, a limited physiologic role during luteal, pregnant, and nonpregnant phases in the manatee.

As-built design specification for PARHIS

NASA Technical Reports Server (NTRS)

Tompkins, M. A. (Principal Investigator)

1981-01-01

The program is part of the CLASFYG package. It produces histograms of the greeness profile derived parameters alpha, beta, t sub o, and chi squared, which are computed by the CLASFYG program. Alpha is the approximate greeness rise time, beta is the approximate greeness decay time, t sub o is the spectral crop emergence date, and chi squared per degree of freedom is the goodness of fit of the actual data to the computed greeness profile. The program also produces statistical information concerning the parameters.

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.

Rapid detection of α-thalassaemia variants using droplet digital PCR.

PubMed

Lee, T-Y; Lai, M-I; Ramachandran, V; Tan, J A M A; Teh, L-K; Othman, R; Hussein, N H; George, E

2016-08-01

Alpha thalassaemia is a highly prevalent disease globally and is a well-known public health problem in Malaysia. The deletional forms of the mutation are the most common forms found in alpha thalassaemia. The three most common deletional alpha thalassaemia found in this region include --(SEA) deletion, -α(3.7) rightward and -α(4.2) leftward deletions. The prevalence rate of triplication alpha cases such as ααα(anti3.7) and ααα(anti4.2) is not known in Malaysia although it plays a role in exacerbating the clinical phenotypes in beta thalassaemia carriers. Recently, there have been more reported cases of rare alpha thalassaemia mutations due to the advancement of molecular techniques involved in thalassaemia detections. Therefore, it is essential to develop a new method which allows the detection of different alpha thalassaemia mutations including the rare ones simultaneously and accurately. The purpose of this study was to design an assay for the detection of triplications, common and rare deletional alpha thalassaemia using droplet digital PCR (ddPCR). This is a quantitative detection method to measure the changes of copy number which can detect deletions, duplications and triplications of the alpha globin gene simultaneously. In conclusion, ddPCR is an alternative method for rapid detection of alpha thalassaemia variants in Malaysia. © 2016 John Wiley & Sons Ltd.

The effect of alpha-tocopherol on the oxidation and free radical decay in irradiated UHMWPE.

PubMed

Oral, Ebru; Rowell, Shannon L; Muratoglu, Orhun K

2006-11-01

We developed a radiation cross-linked ultra-high molecular weight polyethylene (UHMWPE) stabilized with alpha-tocopherol (Vitamin E) as a bearing material in total joint replacements. The stabilizing effect of alpha-tocopherol on free radical reactions in UHMWPE is not well understood. We investigated the effect of alpha-tocopherol on the oxidation and transformation of residual free radicals during real-time aging of alpha-tocopherol-doped, irradiated UHMWPE (alphaTPE) and irradiated UHMWPE (control). Samples were aged at 22 degrees C (room temperature) in air, at 40 degrees C in air and at 40 degrees C in water for 7 months. During the first month, alphaTPE showed some oxidation at the surface, which stayed constant thereafter. Control exhibited substantial oxidation in the subsurface region, which increased with time. The alkyl/allyl free radicals transformed to oxygen centered ones in both materials; this transformation occurred faster in alpha-TPE. In summary, the real-time oxidation behavior of alpha-TPE was consistent with that observed using accelerated aging methods. This new UHMWPE is oxidation resistant and is expected to maintain its properties in the long term.

Alpha particle spectrometry using superconducting microcalorimeters

NASA Astrophysics Data System (ADS)

Horansky, Robert; Ullom, Joel; Beall, James; Hilton, Gene; Stiehl, Gregory; Irwin, Kent; Plionis, Alexander; Lamont, Stephen; Rudy, Clifford; Rabin, Michael

2009-03-01

Alpha spectrometry is the preferred technique for analyzing trace samples of radioactive material because the alpha particle flux can be significantly higher than the gamma-ray flux from nuclear materials of interest. Traditionally, alpha spectrometry is performed with Si detectors whose resolution is at best 8 keV FWHM. Here, we describe the design and operation of a microcalorimeter alpha detector with an energy resolution of 1.06 keV FWHM at 5 MeV. We demonstrate the ability of the microcalorimeter to clearly resolve the alpha particles from Pu-239 and Pu-240, whose ratio differentiates reactor-grade Pu from weapons-grade. We also show the first direct observation of the decay of Po-209 to the ground state of Pb-205 which has traditionally been obscured by a much stronger alpha line 2 keV away. Finally, the 1.06 keV resolution observed for alpha particles is far worse than the 0.12 keV resolution predicted from thermal fluctuations and measurement of gamma-rays. The cause of the resolution degradation may be ion damage in the tin. Hence, alpha particle microcalorimeters may provide a novel tool for studying ion damage and lattice displacement energies in bulk materials.

Growth rates of new parametric instabilities occurring in a plasma with streaming He(2+)

NASA Technical Reports Server (NTRS)

Jayanti, V.; Hollweg, Joseph V.

1994-01-01

We consider parametic instabilities of a circularly polarized pump Alfven wave, which propagates parallel to the ambient magnetic field; the daughter waves are also parallel-propagating. We follow Hollweg et al. (1993) and consider several new instabilites that owe their existence to the presence of streaming alpha particles. One of the new instabilites is similar to the famililar decay instability, but the daughter waves are a forward going alpha sound wave and a backward going Alfven wave. The growth rate of this instability is usually small if the alpha abundance is small. The other three new instabilities occur at high frequencies and small wavelengths. We find that the new instability which involves the proton cyclotron wave and alpha sound (i.e., the +f, - alpha) instability, which involves both the proton and alpha cycltron resonances, but if the pump wave must have low frequency and large amplitude. These instabilities may be a means of heating and accelerating alpha particles in the solar wind, but this claim is unproven until a fully kinetic study is carried out.

Automatically processed alpha-track radon monitor

DOEpatents

Langner, Jr., G. Harold

1993-01-01

An automatically processed alpha-track radon monitor is provided which includes a housing having an aperture allowing radon entry, and a filter that excludes the entry of radon daughters into the housing. A flexible track registration material is located within the housing that records alpha-particle emissions from the decay of radon and radon daughters inside the housing. The flexible track registration material is capable of being spliced such that the registration material from a plurality of monitors can be spliced into a single strip to facilitate automatic processing of the registration material from the plurality of monitors. A process for the automatic counting of radon registered by a radon monitor is also provided.

Automatically processed alpha-track radon monitor

DOEpatents

Langner, G.H. Jr.

1993-01-12

An automatically processed alpha-track radon monitor is provided which includes a housing having an aperture allowing radon entry, and a filter that excludes the entry of radon daughters into the housing. A flexible track registration material is located within the housing that records alpha-particle emissions from the decay of radon and radon daughters inside the housing. The flexible track registration material is capable of being spliced such that the registration material from a plurality of monitors can be spliced into a single strip to facilitate automatic processing of the registration material from the plurality of monitors. A process for the automatic counting of radon registered by a radon monitor is also provided.

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.

A kinematically complete, interdisciplinary, and co-institutional measurement of the 19F(α,n) cross section for nuclear safeguards science

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

Peters, W. A.; Smith, M. S.; Pittman, S.

2016-05-01

Alpha particles emitted from the decay of uranium in a UF 6 matrix can interact with fluorine and generate neutrons via the 19F(α,n) 22Na reaction. These neutrons can be used to determine the uranium content in a UF 6 storage cylinder. The accuracy of this self-interrogating, non-destructive assay (NDA) technique is, however, limited by the uncertainty of the 19F(α,n) 22Na cross section. We have performed complementary measurements of the 19F(α,n) 22Na reaction with both 4He and 19F beams to improve the precision of the 19F(α,n) 22Na cross section over the alpha energy range that encompasses common actinide alpha decay neededmore » for NDA studies. We have determined an absolute cross section for the 19F(α,n) 22Na reaction to an average precision of 7.6% over the alpha energy range of 3.9 – 6.7 MeV. We utilized this cross section in a simulation of a 100 g spherical UF 6 assembly and obtained a change in neutron emission rate values of approximately 10-12%, and a significant (factor of 3.6) decrease in the neutron emission rate uncertainty (from 50-51% to 13-14%), compared to simulations using the old cross section. Our new absolute cross section enables improved interpretations of NDAs of containers of arbitrary size and configuration.« less

Preliminary Work Toward a Transuranic Activity Estimation Method for Rapid Discrimination of Anthropogenic from Transuranic Activity in Alpha Air Samples

DOE PAGES

Cope, S. Joseph; Hayes, Robert B.

2018-03-01

Radon ( 222Rn) and thoron ( 220Rn) progeny (primarily bismuth and polonium) are known interferents when rapid evaluation of transuranic content on air filters is of interest. These complexities stem from the overlapping energies of the progeny alpha particles onto the transuranic region of interest (3–5.5 MeV) where naturally-occurring alpha emitters can overwhelm the spectra. Due to the immediacy of the alpha counting methods employed, coupled with the half-life of thoron progeny dominated by 212Pb (t 1/2=10.6 h), a conservative transuranic activity estimate with rigorous uncertainty is being sought. A successful transuranic activity estimation method will incorporate any thoron progenymore » present on the filter providing 95% confidence decision levels in which a filter may be evaluated for emergency response applications. Twenty-three pairs of samples of various duration having no transuranic content were taken over a 2-mo period. The resulting filters were counted in a time series before non-linear least squares decay curve fitting was applied to the decay profile. For the samples considered, a transuranic activity estima-tor decision level was determined at 0.2 Bq for the given geographic location and months analyzed. In conclusion, validation of this method for other seasonal and geographic regions could provide enhanced emergency response capability when the presence of transuranic activity is suspected.« less

Preliminary Work Toward a Transuranic Activity Estimation Method for Rapid Discrimination of Anthropogenic from Transuranic Activity in Alpha Air Samples

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

Cope, S. Joseph; Hayes, Robert B.

Radon ( 222Rn) and thoron ( 220Rn) progeny (primarily bismuth and polonium) are known interferents when rapid evaluation of transuranic content on air filters is of interest. These complexities stem from the overlapping energies of the progeny alpha particles onto the transuranic region of interest (3–5.5 MeV) where naturally-occurring alpha emitters can overwhelm the spectra. Due to the immediacy of the alpha counting methods employed, coupled with the half-life of thoron progeny dominated by 212Pb (t 1/2=10.6 h), a conservative transuranic activity estimate with rigorous uncertainty is being sought. A successful transuranic activity estimation method will incorporate any thoron progenymore » present on the filter providing 95% confidence decision levels in which a filter may be evaluated for emergency response applications. Twenty-three pairs of samples of various duration having no transuranic content were taken over a 2-mo period. The resulting filters were counted in a time series before non-linear least squares decay curve fitting was applied to the decay profile. For the samples considered, a transuranic activity estima-tor decision level was determined at 0.2 Bq for the given geographic location and months analyzed. In conclusion, validation of this method for other seasonal and geographic regions could provide enhanced emergency response capability when the presence of transuranic activity is suspected.« less

Alpha-ray detection with a MgB 2 transition edge sensor

NASA Astrophysics Data System (ADS)

Okayasu, S.; Katagiri, M.; Hojou, K.; Morii, Y.; Miki, S.; Shimakage, H.; Wang, Z.; Ishida, T.

2008-09-01

We have been investigating for neutron detection with the MgB 2 transition edge sensor (TES). For the purpose, we have been developing a low noise measurement system for the detection. To confirm the performance of the detecting sensor, alpha ray detection from an americium-241 ( 241Am) alpha-ray source was achieved. A short microfabricated sample with 10 μm length and 1 μm width is used to improve the S/N ratio. The detection is achieved under a constant current condition in the range between 1 and 6 μA bias current, and the resistivity changes at the sample due to the alpha ray irradiation is detected just on the transition edge.

On the claim of modulations in radon decay and their association with solar rotation

NASA Astrophysics Data System (ADS)

Pommé, S.; Lutter, G.; Marouli, M.; Kossert, K.; Nähle, O.

2018-01-01

Claims were made by Sturrock et al. that radioactive decay can be induced by interaction of the nucleus with solar neutrinos and that cyclic modulations in decay rates are indicative of the dynamics of the solar interior. They analysed a series of measurements of gamma radiation associated with the emanation and decay of radon in a sealed container at the Geological Survey of Israel (GSI) laboratory. The integral count rates in the NaI detector showed strong variations in time of year and time of day. From time-series analysis, Sturrock et al. claim the presence of small oscillations at frequencies in a range between 7.4 a-1 and 12.5 a-1, which they speculatively associated with rotational influence on the solar neutrino flux. In this work, it is argued that the GSI radon measurements are unsuited for studying the variability of decay constants, because the data are strongly influenced by environmental conditions, such as solar irradiance and rainfall. At the JRC and PTB, decay rate measurements of the radon decay chain were performed with ionisation chambers, gamma-ray spectrometers and an alpha spectrometer. No deviation from the exponential-decay law was observed. The existence of cyclic variations in the decay constants is refuted, as well as the concept of measuring solar rotation through radioactive decay.

Type I Glanzmann thrombasthenia caused by an apparently silent beta3 mutation that results in aberrant splicing and reduced beta3 mRNA.

PubMed

Xie, Jingli; Pabón, Dina; Jayo, Asier; Butta, Nora; González-Manchón, Consuelo

2005-05-01

We report a novel genetic defect in a patient with type I Glanzmann thrombasthenia. Flow cytometry analysis revealed undetectable levels of platelet glycoproteins alphaIIb and beta3, although residual amounts of both proteins were detectable in immunoblotting analysis. Sequence analysis of reversely transcribed platelet beta3 mRNA showed a 100-base pair deletion in the 3'-boundary of exon 11, that results in a frame shift and appearance of a premature STOP codon. Analysis of the corresponding genomic DNA fragment revealed the presence of a homozygous C1815T transition in exon 11. The mutation does not change the amino acid residue but it creates an ectopic consensus splice donor site that is used preferentially, causing splicing out of part of exon 11. The parents of the proband, heterozygous for this mutation, were asymptomatic and had reduced platelet content of alphaIIbbeta3. PCR-based relative quantification of beta3 mRNA failed to detect the mutant transcript in the parents and showed a marked reduction in the patient. The results suggest that the thrombasthenic phenotype is, mainly, the result of the reduced availability of beta3-mRNA, most probably due to activation of the nonsense-mediated mRNA decay mechanism. They also show the convenience of analyzing both genomic DNA and mRNA, in order to ascertain the functional consequences of single nucleotide substitutions.

Fluorescence-Assisted Gamma Spectrometry for Surface Contamination Analysis

NASA Astrophysics Data System (ADS)

Ihantola, Sakari; Sand, Johan; Perajarvi, Kari; Toivonen, Juha; Toivonen, Harri

2013-02-01

A fluorescence-based alpha-gamma coincidence spectrometry approach has been developed for the analysis of alpha-emitting radionuclides. The thermalization of alpha particles in air produces UV light, which in turn can be detected over long distances. The simultaneous detection of UV and gamma photons allows detailed gamma analyses of a single spot of interest even in highly active surroundings. Alpha particles can also be detected indirectly from samples inside sealed plastic bags, which minimizes the risk of cross-contamination. The position-sensitive alpha-UV-gamma coincidence technique reveals the presence of alpha emitters and identifies the nuclides ten times faster than conventional gamma spectrometry.

Progress of the Study of Neutron Interactions with 7Be

NASA Astrophysics Data System (ADS)

Kading, Emily E.; Gai, Moshe; Seiffert, Christoph; Stora, Thierry; Halfon, Shlomi; Paul, Michael; US-Israel-Switzerland Collaboration

2014-09-01

Big Bang Nucleosynthesis (BBN) is today a parameter-free theory. It correctly predicts the abundance relative to hydrogen, of primordial deuterium, helium, and helion but over predicts the relative abundance of primordial 7Li which is primarily (95%) the byproduct of the decay of 7Be. This has been dubbed as the primordial 7Li problem. We are proposing to study the interaction of neutrons with 7Be in order to understand the direct destruction of the primordial 7Be. The experiment being proposed will be performed at the SARAF facility in Israel using the LiLiT neutron generator and an implanted 7Be target produced at ISOLDE from a 7Be sample produced at the PSI. An implantation set up was constructed and tested at ISOLDE using 35 keV 10B. The implanted 10B targets were tested using the intense CERN Pu-Be source. For the first generation measurement of the 7Be(n, α) reaction we plan to use CR-39 plastic track detectors to detect the emanating alpha-particles (and protons). Such detectors were tested in our lab using alpha-source and we are developing the use of these detectors for our measurement. Future experiments will utilize a split gas ionization chamber and silicon detectors. We will review the progress of this research project. Big Bang Nucleosynthesis (BBN) is today a parameter-free theory. It correctly predicts the abundance relative to hydrogen, of primordial deuterium, helium, and helion but over predicts the relative abundance of primordial 7Li which is primarily (95%) the byproduct of the decay of 7Be. This has been dubbed as the primordial 7Li problem. We are proposing to study the interaction of neutrons with 7Be in order to understand the direct destruction of the primordial 7Be. The experiment being proposed will be performed at the SARAF facility in Israel using the LiLiT neutron generator and an implanted 7Be target produced at ISOLDE from a 7Be sample produced at the PSI. An implantation set up was constructed and tested at ISOLDE using 35 keV 10B. The implanted 10B targets were tested using the intense CERN Pu-Be source. For the first generation measurement of the 7Be(n, α) reaction we plan to use CR-39 plastic track detectors to detect the emanating alpha-particles (and protons). Such detectors were tested in our lab using alpha-source and we are developing the use of these detectors for our measurement. Future experiments will utilize a split gas ionization chamber and silicon detectors. We will review the progress of this research project. Supported in part by the USDOE Grant Number DE-FG02-94ER40870 and the US-Israel Binational Science Foundation Grant Number 2012098.

The cancellation of magnetic flux. II - In a decaying active region. [of sun

NASA Technical Reports Server (NTRS)

Martin, S. F.; Livi, S. H. B.; Wang, J.

1985-01-01

H-alpha filtergrams and videomagnetograms are used to study an active region during its period of decay on August 3-8, 1984; the decay had been initiated by a fragmentation process in which very small knots of magnetic flux separated from larger concentration of flux. The disappearance of magnetic flux was always observed when the small fragments of flux encountered other small fragments or concentrations of flux of opposite polarity. Such 'cancellations' are shared by both polarities of magnetic field, and it is deduced that the disappearance of flux occurred either at or within 5 arcsec of the apparent dividing line between the opposite polarities. All of the 22 flares observed during the decay of this region were initiated around sites where magnetic flux was cancelling or was deduced to be cancelling during the flares. It is hypothesized that cancellation was one of the necessary conditions for flaring in this active region.

Uranium series dating of Allan Hills ice

NASA Technical Reports Server (NTRS)

Fireman, E. L.

1986-01-01

Uranium-238 decay series nuclides dissolved in Antarctic ice samples were measured in areas of both high and low concentrations of volcanic glass shards. Ice from the Allan Hills site (high shard content) had high Ra-226, Th-230 and U-234 activities but similarly low U-238 activities in comparison with Antarctic ice samples without shards. The Ra-226, Th-230 and U-234 excesses were found to be proportional to the shard content, while the U-238 decay series results were consistent with the assumption that alpha decay products recoiled into the ice from the shards. Through this method of uranium series dating, it was learned that the Allen Hills Cul de Sac ice is approximately 325,000 years old.

Influence of proton-skin thickness on the {{\\alpha }} decays of heavy nuclei

NASA Astrophysics Data System (ADS)

Seif, W. M.; Abdurrahman, A.

2018-01-01

We investigate the effect of proton-skin thickness on the α decay process. We consider 188 neutron-deficient nuclei belonging to the isotopic chains from Te (Z = 52) to Pb (Z = 82). The calculations of the half-life are carried out in the framework of the preformed cluster model, with the Wentzel-Kramers-Brillouin penetration probability and assault frequency. It is shown that the proton-skin thickness ({\\varDelta }{{p}}) of the daughter nucleus gives rise to a total α- daughter nucleus interaction potential of relatively wide deep internal pocket and a thinner Coulomb barrier of less height. This increases the penetration probability but decreases the assault frequency. The overall impact of the proton-skin thickness appears as a decrease in the decay half-life. The proton-skin thickness decreases the stability of the nucleus. The half-lives of the proton-skinned isotopes along the isotopic chain decrease exponentially with increasing the proton-skin thickness, whereas the {Q}α -value increases with {\\varDelta }{{p}}. α-decay manifests itself as the second favorite decay mode of neutron-deficient nuclei, next to the {β }+-decay and before proton-decay. It is indicated as main, competing, and minor decay mode, at 21%, 7%, and 57%, respectively, of the investigated nuclei.

Preliminary Experiments Using a Passive Detector for Measuring Indoor 220Rn Progeny Concentrations with an Aerosol Chamber.

PubMed

Sorimachi, Atsuyuki; Tokonami, Shinji; Kranrod, Chutima; Ishikawa, Tetsuo

2015-06-01

This paper describes preliminary experiments using a passive detector for integrating measurements of indoor thoron (²²⁰Rn) progeny concentrations with an aerosol chamber. A solid state nuclear detector (CR-39) covered with a thin aluminum-vaporized polyethylene plate (Mylar film) was used to detect only alpha particles emitted from ²¹²Po due to ²²⁰Rn progeny deposited on the detector surfaces. The initial experiment showed that Mylar film with area density of more than 5 mg cm⁻² was suitable to cut off completely alpha particles of 7.7 MeV from ²¹⁴Po of ²²²Rn progeny decay. In the experiment using the passive detector, it was observed that the net track density increased linearly with an increase of time-integrating ²²⁰Rn progeny concentration. As a result of dividing deposition rates by atom concentrations, the deposition velocity was given as 0.023 cm s⁻¹ for total ²²⁰Rn progeny. The model estimates of deposition velocities were 0.330 cm s⁻¹ for unattached ²²⁰Rn progeny and 0.0011 cm s⁻¹ for aerosol-attached ²²⁰Rn progeny using Lai-Nazaroff formulae. These deposition velocities were in the same range with the results reported in the literature. It was also found that the exposure experiments showed little influence of vertical profiles and surface orientations of the passive detector in the chamber on the detection responses, which was in good agreement with that in the model estimates. Furthermore, it was inferred that the main uncertainty of the passive detector was inhomogeneous deposition of Rn progeny onto its detection surfaces.

Flowing afterglow studies of the electron recombination of protonated cyanides (RCN)H+ and their proton-bound dimer ions (RCN)2H+ where R is H, CH3, and CH3CH2

NASA Astrophysics Data System (ADS)

McLain, J. L.; Molek, C. D.; , D. Osborne, Jr.; Adams, N. G.

2009-05-01

A study has been made of the electron-ion dissociative recombination of the protonated cyanides (RCNH+, R = H, CH3, C2H5) and their proton-bound dimers (RCN)2H+ at 300 K. This has been accomplished with the flowing afterglow technique using an electrostatic Langmuir probe to determine the electron density decay along the flow tube. For the protonated species, the recombination coefficients, [alpha]e(cm3 s-1), are (3.6 +/- 0.5) × 10-7, (3.4 +/- 0.5) × 10-7, (4.6 +/- 0.7) × 10-7 for R = H, CH3, C2H5, respectively. For the proton-bound dimers, the [alpha]e are substantially greater being (2.4 +/- 0.4) × 10-6, (2.8 +/- 0.4) × 10-6, (2.3 +/- 0.3) × 10-6 for R = H, CH3, C2H5, respectively. Fitting of the electron density decay data to a simple model has shown that the rate coefficients for the three-body association of RCNH+ with RCN are very large being (2.0 +/- 0.5) × 10-26 cm6 s-1. The significance of these data to the Titan ionosphere is discussed.

Using MASHA+TIMEPIX Setup for Registration Beta Decay Isotopes Produced in Heavy Ion Induced Reactions

NASA Astrophysics Data System (ADS)

Rodin, A. M.; Belozerov, A. V.; Chernysheva, E. V.; Dmitriev, S. N.; Gulyaev, A. V.; Gulyaeva, A. V.; Itkis, M. G.; Novoselov, A. S.; Oganessian, Yu. Ts.; Salamatin, V. S.; Stepantsov, S. V.; Vedeneev, V. Yu.; Yukhimchuk, S. A.; Krupa, L.; Granja, C.; Pospisil, S.; Kliman, J.; Motycak, S.; Sivacek, I.

2015-06-01

Radon and mercury isotopes were produced in multi nucleon transfer (48Ca + 232Th) and complete fusion (48Ca + naturalNd) reactions, respectively. The isotopes with given masses were detected using two detectors: a multi-strip detector of the well-type (made in CANBERRA) and a position-sensitive quantum counting hybrid pixel detector of the TIMEPIX type. The isotopes implanted into the detectors then emit alpha- and betaparticles until reaching the long lived isotopes. The position of the isotopes, the tracks, the time and energy of beta-particles were measured and analyzed. A new software for the particle recognition and data analysis of experimental results was developed and used. It was shown that MASHA+ TIMEPIX setup is a powerful instrument for investigation of neutron-rich isotopes far from stability limits.

Functional and genomic analyses of alpha-solenoid proteins.

PubMed

Fournier, David; Palidwor, Gareth A; Shcherbinin, Sergey; Szengel, Angelika; Schaefer, Martin H; Perez-Iratxeta, Carol; Andrade-Navarro, Miguel A

2013-01-01

Alpha-solenoids are flexible protein structural domains formed by ensembles of alpha-helical repeats (Armadillo and HEAT repeats among others). While homology can be used to detect many of these repeats, some alpha-solenoids have very little sequence homology to proteins of known structure and we expect that many remain undetected. We previously developed a method for detection of alpha-helical repeats based on a neural network trained on a dataset of protein structures. Here we improved the detection algorithm and updated the training dataset using recently solved structures of alpha-solenoids. Unexpectedly, we identified occurrences of alpha-solenoids in solved protein structures that escaped attention, for example within the core of the catalytic subunit of PI3KC. Our results expand the current set of known alpha-solenoids. Application of our tool to the protein universe allowed us to detect their significant enrichment in proteins interacting with many proteins, confirming that alpha-solenoids are generally involved in protein-protein interactions. We then studied the taxonomic distribution of alpha-solenoids to discuss an evolutionary scenario for the emergence of this type of domain, speculating that alpha-solenoids have emerged in multiple taxa in independent events by convergent evolution. We observe a higher rate of alpha-solenoids in eukaryotic genomes and in some prokaryotic families, such as Cyanobacteria and Planctomycetes, which could be associated to increased cellular complexity. The method is available at http://cbdm.mdc-berlin.de/~ard2/.

Reduction of Radon Progeny in Indoor Air.

DTIC Science & Technology

1986-03-01

arises from indoor radon is due * 4 to inhalation of the short-lived radon daughters Ra-A, Ra-B, and Ra-C. These decay products are formed from the alpha...concentrations of radon daughters 40 ’ in an air sample from the gross alpha counting of a filter 50 ’ in accordance with the modified Tsivoglou method. 60 ’ 70...8217 The modified Tsivoglou method may be found in " Measurement 80 ’ of Radon Daughters in Air," Health Physics, 23, : pp7S3-789 90 ’ (19𔃼). 95 100 The

Extending lifetimes of lanthanide-based near-infrared emitters (Nd, Yb) in the millisecond range through Cr(III) sensitization in discrete bimetallic edifices.

PubMed

Imbert, Daniel; Cantuel, Martine; Bünzli, Jean-Claude G; Bernardinelli, Gérald; Piguet, Claude

2003-12-24

A [Cr(alpha,alpha'-diimine)3]3+ chromophore is used as a donor for sensitizing NdIII and YbIII near-infrared (NIR) emitters in the heterobimetallic helicates [LnCrIIIL3]6+. The intramolecular CrIII --> LnIII energy transfer process controls the population of the lanthanide-centered emitting levels, thus leading to unprecedented extension of the NIR luminescence decay times in the millisecond range for Nd and Yb ions incorporated in coordination complexes.

Alpha and conversion electron spectroscopy of 238,239Pu and 241Am and alpha-conversion electron coincidence measurements

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

Dion, Michael P.; Miller, Brian W.; Warren, Glen A.

2016-09-01

A technique to determine the isotopics of a mixed actinide sample has been proposed by measuring the coincidence of the alpha particle during radioactive decay with the conversion electron (or Auger) emitted during the relaxation of the daughter isotope. This presents a unique signature to allow the deconvolution of isotopes that possess overlapping alpha particle energy. The work presented here are results of conversion electron spectroscopy of 241Am, 238Pu and 239Pu using a dual-stage peltier-cooled 25 mm2 silicon drift detector. A passivated ion implanted planar silicon detector provided measurements of alpha spectroscopy. The conversion electron spectra were evaluated from 20–55more » keV based on fits to the dominant conversion electron emissions, which allowed the relative conversion electron emission intensities to be determined. These measurements provide crucial singles spectral information to aid in the coincident measurement approach.« less

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.

[Methodological study for detecting gene mutation of family with genotyping of compound heterogenicity of SEA alpha-thalassemia 1 and HbCS].

PubMed

Chen, Jian; Luo, Bi; Qi, Zhu; Huo, Pei-Dan; Zhang, Quan-Sheng; Wang, Hong

2010-06-01

This study was aimed to establish a method of PCR combination with PCR-RFLP for detecting the South-East Asian (SEA) deletion type alpha-thalassemia 1 and non-deletion mutation of Hb Constant Spring (CS), and to investigate the application value of this method. For the members of the families with alpha-thalassemia, SEA deletion mutation was detected by PCR, then the HbCS point mutation was screened by PCR-RFLP. The results indicated that 15 carriers with alpha-thalassemia (--(SEA)/) were found in 19 members from 7 families, and 2 families with genotype of --(SEA)/alpha(CS)alpha were screened out successfully. It is concluded that the PCR combination with PCR-RFLP is a simple, rapid, and reliable method for screening HbH disease with genotype of --(SEA)/alpha(CS)alpha.

Absence of detectable immunoreactive alpha melanocyte stimulating hormone in plasma in various types of Cushing's disease.

PubMed

Croughs, R J; Thijssen, J H; Mol, J A

1991-03-01

We have measured alpha-MSH in plasma of normal subjects and subjects with various diseases of the pituitary-adrenocortical system using a radioimmunoassay with a sensitivity of 1.2 pmol/l. No alpha-MSH could be detected in plasma of normal subjects (n = 6), in plasma of patients with Addison's disease (n = 3), Nelson's syndrome (n = 2), bromocriptine responsive (n = 2) and unresponsive (n = 5) Cushing's disease and in plasma of psychiatric patients on chronic treatment with the dopamine antagonist haloperidol (n = 5). Plasma alpha-MSH remained undetectable in 2 patients with Cushing's disease after iv injection of 60 micrograms/kg haloperidol. In contrast, alpha-MSH was detectable in plasma of normal dogs (n = 2) and dogs with pituitary dependent hyperadrenocorticism (n = 2), whereas the iv injection of halo peridol was associated with a rise of plasma alpha-MSH. Thus we are unable to detect circulating alpha-MSH in man despite the use of a sensitive radioimmunoassay.

Multiple proton decays of 6Be, 8C, 8B(IAS) and excited states in 10C

NASA Astrophysics Data System (ADS)

Sobotka, Lee

2011-10-01

Recent technical advances have allowed for high-order correlation experiments to be done. We have primarily focused on experiments in which the final channels are composed of only alphas and protons. Four cases we have studied are: 6Be, 10C*, 8C, and 8B*(IAS) via 3, 4, 5, and 3-particle correlation measurements, respectively. While the first case had been studied before, our work presents very high statistics in the full Jacobi coordinates (the coordinates needed to describe 3-body decay.) Our study of 10C excited states provides isolatable examples of: correlated 2p decay, from one state, and the decay of another which is unusually highly correlated, a ``ménage a quatre.'' 8C decay presents the only case of sequential 3-body 2p decay steps (i.e. 2p-2p.) The intermediate in this 2-step process is the first example (6Be) mentioned above. Unlike the well-studied second step (6Be decay), the first step in this 2p-2p process provides another example of correlated 2p emission. The decay of 8B(IAS), the isobaric analog of 8C, also decays overwhelmingly by 2p emission, in this case to 6Li(IAS). This IAS-to-IAS 2p decay is one for which decay to the potential 1p intermediates is energetically allowed but isospin forbidden. This represents an expansion, over that originally envisioned by Goldanski, of the conceivable nuclear territory for 2p decay.

WE-FG-BRA-10: Radiodosimetry of a Novel Alpha Particle Therapy Targeted to Uveal Melanoma: Absorbed Dose to Organs in Mice

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

Tichacek, Christopher J.; Tafreshi, Narges K.; Budzevich, Mikalai M.

Purpose: The melanocortin-1 receptor (MC1R) is expressed in 94% of uveal melanomas and is described as an ideal target for this untreatable disease. MC1RL is a high affinity MC1R specific peptidomimetic ligand that can serve as a scaffold for therapeutic conjugates such as alpha particle emitting isotopes. The purpose of this study was to assess normal tissue distribution and risk as a result of using the DOTA chelator conjugated to MC1RL to deliver {sup 225}Ac: MC1RL-DOTA-{sup 225}Ac. Methods: 17 non-tumor bearing BALB/c mice were intravenously injected with the novel MC1RL-DOTA-{sup 225}Ac radiopharmaceutical with an average initial administered activity of 2.5more » µCi. After the injection, three groups of animals (6, 6, and 5 per group) were euthanized at 24, 48, and 96 hour time points. A total of 11 organs of interest were harvested at each time point including kidneys and liver. Since the emitted alpha particles from {sup 225}Ac and its daughter products are not easy to detect directly, the isomeric gamma spectra were measured instead in the tissue samples using a modified Atomlab™ Gamma Counter (Biodex Medical Systems, Inc) and converted using factors for gamma ray abundance per alpha decay. Dosimetry was performed using measured radioactivity distribution in organs and the generalized internal dosimetry schema of MIRD pamphlet #21. Results: Our calculations have shown that the maximum absorbed dose was delivered to the liver with a total of 47 cGy per 96 hour period. The average dose per kidney was calculated to be 21 cGy. Heart, brain, lung, spleen, skin doses ranged from 0.01 to 1 cGy over the same time period. All animals gained weight over the 110 day decay period and no organ damage was observed by pathology. Conclusion: Based on our results, the risk of using the MC1RL-DOTA-{sup 225}Ac compound is relatively small in terms of deterministic radiation effects. Funding Support: NIH/NCI P50CA168536-03 Skin SPORE; NIH/NCI Phase I SBIR Contract #HHSN261201500067C; Imaging and Technology Center of Excellence at Moffitt. Disclosures and Conflict of Interest: Collaboration with Modulation Therapeutics, Inc.(MTI) and has been partially funded by sub-contracts from MTI via collaboration on a NIH/NCI phase I SBIR contract.« less

Modeling of Iron K Lines: Radiative and Auger Decay Data for Fe II-Fe IX

NASA Technical Reports Server (NTRS)

Palmeri, P.; Mendoza, C.; Kallman, T. R.; Bautista, M. A.; Melendez, M.

2003-01-01

A detailed analysis of the radiative and Auger de-excitation channels of K-shell vacancy states in Fe II-Fe IX has been carried out. Level energies, wavelengths, A-values, Auger rates and fluorescence yields have been calculated for the lowest fine-structure levels populated by photoionization of the ground state of the parent ion. Different branching ratios, namely K alpha 2/K alpha 1, K beta/K alpha, KLM/KLL, KMM/KLL, and the total K-shell fluorescence yields, omega(sub k), obtained in the present work have been compared with other theoretical data and solid-state measurements, finding good general agreement with the latter. The Kalpha 2/K alpha l ratio is found to be sensitive to the excitation mechanism. From these comparisons it has been possible to estimate an accuracy of approx.10% for the present transition probabilities.

Polarized Nuclei in a Simple Mirror Fusion Reactor

NASA Technical Reports Server (NTRS)

Noever, David A.

1995-01-01

The possibility of enhancing the ratio of output to input power Q in a simple mirror machine by polarizing Deuterium-Tritium (D- T) nuclei is evaluated. Taking the Livermore mirror reference design mirror ratio of 6.54, the expected sin(sup 2) upsilon angular distribution of fusion decay products reduces immediate losses of alpha particles to the loss cone by 7.6% and alpha-ion scattering losses by approx. 50%. Based on these findings, alpha- particle confinement times for a polarized plasma should therefore be 1.11 times greater than for isotropic nuclei. Coupling this enhanced alpha-particle heating with the expected greater than 50% D- T reaction cross section, a corresponding power ratio for polarized nuclei, Q(sub polarized), is found to be 1.63 times greater than the classical unpolarized value Q(sub classical). The effects of this increase in Q are assessed for the simple mirror.

Radioactive sample effects on EDXRF spectra

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

Worley, Christopher G

2008-01-01

Energy dispersive X-ray fluorescence (EDXRF) is a rapid, straightforward method to determine sample elemental composition. A spectrum can be collected in a few minutes or less, and elemental content can be determined easily if there is adequate energy resolution. Radioactive alpha emitters, however, emit X-rays during the alpha decay process that complicate spectral interpretation. This is particularly noticeable when using a portable instrument where the detector is located in close proximity to the instrument analysis window held against the sample. A portable EDXRF instrument was used to collect spectra from specimens containing plutonium-239 (a moderate alpha emitter) and americium-241 (amore » heavy alpha emitter). These specimens were then analyzed with a wavelength dispersive XRF (WDXRF) instrument to demonstrate the differences to which sample radiation-induced X-ray emission affects the detectors on these two types of XRF instruments.« less

THE PREPARATION, PROPERTIES, AND USES OF AMERICIUM-241, ALPHA-, GAMMA-, AND NEUTRON SOURCES

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

Strain, J.E.; Leddicotte, G.W.

1962-09-01

A study was made of the preparation of alpha, gamma, and neutron sources using the long-lived radioisotope of americium, Am/sup 241/. Americium-241 is an artificiallyproduced radioelement which has a half-life of 462 plus or minus 10 years and decays to Np/sup 237/ by alpha emission followed by low-energy gamma emission. The high specific activity of americium-241 (7.0 x 10/sup 9/ d/m/mg) combined with its reasonably long half-life makes it ideally sulted for the preparation of radioactive sources. The chemical and physical properties of Am/ sup 241/ and the physical manipulations involved in fabricating alpha, gamma, and neutron sources are generallymore » described in this report. Uses for each type of source are discussed and data are presented to indicate the respective properties and usefulness of each source type. (auth)« less

Rejection of Alpha Surface Background in Non-scintillating Bolometric Detectors: The ABSuRD Project

DOE PAGES

Biassoni, M.; Brofferio, C.; Bucci, C.; ...

2016-01-14

Due to their excellent energy resolution values and the vast choice of possible materials, bolometric detectors are currently widely used in the physics of rare events. A limiting aspect for bolometers rises from their inability to discriminate among radiation types or surface from bulk events. It has been demonstrated that the main limitation to sensitivity for purely bolometric detectors is represented by surface alpha contaminations, causing a continuous background that cannot be discriminated. A new scintillation based technique for the rejection of surface alpha background in non- scintillating bolometric experiments is proposed in this work. The idea is to combinemore » a scintillating and a high sensitivity photon detector with a non- scintillating absorber. Finally, we present results showing the possibility to reject events due to alpha decay at or nearby the surface of the crystal.« less

A new method for evaluating radon and thoron alpha-activities per unit volume inside and outside various natural material samples by calculating SSNTD detection efficiencies for the emitted alpha-particles and measuring the resulting track densities.

PubMed

Misdaq, M A; Aitnouh, F; Khajmi, H; Ezzahery, H; Berrazzouk, S

2001-08-01

A Monte Carlo computer code for determining detection efficiencies of the CR-39 and LR-115 II solid-state nuclear track detectors (SSNTD) for alpha-particles emitted by the uranium and thorium series inside different natural material samples was developed. The influence of the alpha-particle initial energy on the SSNTD detection efficiencies was investigated. Radon (222Rn) and thoron (220Rn) alpha-activities per unit volume were evaluated inside and outside the natural material samples by exploiting data obtained for the detection efficiencies of the SSNTD utilized for the emitted alpha-particles, and measuring the resulting track densities. Results obtained were compared to those obtained by other methods. Radon emanation coefficients have been determined for some of the considered material samples.

Experimental nuclear physics

NASA Astrophysics Data System (ADS)

An earlier study of unusual electromagnetic decays in (sup 86)Zr was extended in order to make comparisons with its isotone (sup 84)Sr and with (sup 84)Zr. The K=14 (t(sub 1/2) = 70 ns) high-spin isomer in (sup 176)W was found to have a 13 percent branch directly to the K=O ground-state band, one of the strongest violations of K-selection rules known. A new program to search for a predicted region of oblate deformation involving neutron deficient isotopes in the Rn/Fr/Ra region was begun. In the area of nuclear astrophysics, as part of a study of the onset of the rp-Process, a set of measurements searching for possible new resonances for (sup 14)O+(alpha) and (sup 17)F+p reactions was completed and a coincidence experiment measuring the (sup 19)F ((sup 3)He,t) (sup 19)Ne(alpha) (sup 15)O and (sup 19)F ((sup 3)He,t) (sup 19)Ne(p) (sup 18)F reactions in order to determine the rates of the (sup 18)F(p,(alpha)) (sup 15)O and (sup 18)F(p,(gamma)) (sup 19)Ne reactions was begun. Experimental measurements of (beta)n(alpha) coincidences from the (sup 15)N(d,p) (sup 16)N((beta)- (nu)) (sup 16)O((alpha)) (sup 12)C reaction have also been completed and are currently being analyzed to determine the rate of the (sup 12)C((alpha),(gamma)) reaction. In the APEX collaboration, we have completed the assembly and testing of two position-sensitive Na barrels which surround the axial silicon detector arrays and serve as the e(sup +) triggers by detecting their back-to-back annihilation quanta were completed. The HI@AGS and RHIC collaborations, construction and implementation activities associated with the space-time-tracker detector and in the design of the central detector for the PHENIX experiment were carried out. Operation of the ESTU tandem accelerator has been reliable, delivering beam on target at terminal voltages as high as 19.3 MV and running for as long as 143 days between tank openings. Fabrication and bench testing of a new negative ion source system have been completed.

Functional and Genomic Analyses of Alpha-Solenoid Proteins

PubMed Central

Fournier, David; Palidwor, Gareth A.; Shcherbinin, Sergey; Szengel, Angelika; Schaefer, Martin H.; Perez-Iratxeta, Carol; Andrade-Navarro, Miguel A.

2013-01-01

Alpha-solenoids are flexible protein structural domains formed by ensembles of alpha-helical repeats (Armadillo and HEAT repeats among others). While homology can be used to detect many of these repeats, some alpha-solenoids have very little sequence homology to proteins of known structure and we expect that many remain undetected. We previously developed a method for detection of alpha-helical repeats based on a neural network trained on a dataset of protein structures. Here we improved the detection algorithm and updated the training dataset using recently solved structures of alpha-solenoids. Unexpectedly, we identified occurrences of alpha-solenoids in solved protein structures that escaped attention, for example within the core of the catalytic subunit of PI3KC. Our results expand the current set of known alpha-solenoids. Application of our tool to the protein universe allowed us to detect their significant enrichment in proteins interacting with many proteins, confirming that alpha-solenoids are generally involved in protein-protein interactions. We then studied the taxonomic distribution of alpha-solenoids to discuss an evolutionary scenario for the emergence of this type of domain, speculating that alpha-solenoids have emerged in multiple taxa in independent events by convergent evolution. We observe a higher rate of alpha-solenoids in eukaryotic genomes and in some prokaryotic families, such as Cyanobacteria and Planctomycetes, which could be associated to increased cellular complexity. The method is available at http://cbdm.mdc-berlin.de/~ard2/. PMID:24278209

Characterization of inhibin forms and their measurement by an inhibin alpha-subunit ELISA in serum from postmenopausal women with ovarian cancer.

PubMed

Robertson, D M; Stephenson, T; Pruysers, E; McCloud, P; Tsigos, A; Groome, N; Mamers, P; Burger, H G

2002-02-01

The aim of this study was to characterize the molecular wt forms of inhibins A and B and its free alpha-subunit present in serum from women with ovarian cancer as a basis for developing improved monoclonal antibody-based inhibin assays for monitoring ovarian cancer. Three new inhibin alpha-subunit (alphaC) ELISAs were developed using monoclonal antibodies directed to three nonoverlapping peptide regions of the alphaC region of the inhibin alpha-subunit. To characterize serum inhibin molecular wt forms present in women with ovarian cancer, existing inhibin immunoassays (inhibin A, inhibin B, and pro-alphaC) and the new alphaC ELISAs were applied to sera from women with granulosa cell tumors and mucinous carcinomas previously fractionated using a combined immunoaffinity chromatography, preparative SDS-PAGE, and electroelution procedure. The distribution and molecular size of dimeric inhibins and alpha-subunit detected were consistent with known mol wt forms of inhibins A and B and inhibin alpha-subunit and their precursor forms present in serum and follicular fluid from healthy women. The alphaC ELISAs recognized all known forms of inhibin and the free inhibin alpha-subunit, although differences between alphaC ELISAs were observed in their ability to detect high mol wt forms. To assess which of the alphaC ELISAs was preferred in application to ovarian cancer, the alphaC ELISAs were applied to serum from a range of normal postmenopausal women (n = 61) and postmenopausal women (n = 152) with ovarian (serous, mucinous, endometrioid, clear cell carcinomas, and granulosa cell tumors) and nonovarian (breast and colon) cancers. Despite differences in their ability to detect high mol wt forms of inhibin, the alphaC ELISAs showed similar sensitivity (i.e. proportion of cancer patients correctly detected) and specificity (proportion of controls correctly detected) indexes in the detection of mucinous carcinomas (84% and 95%) and granulosa cell tumors (100% and 95%) compared with earlier inhibin RIA or polyclonal antibody-based immunofluorometric assays. A combination of the alphaC ELISAs with the CA125 assay, an ovarian tumor marker that has a high sensitivity and specificity for other ovarian cancers (serous, clear cell, and endometrioid), resulted in an increase in sensitivity/specificity indexes (95% and 95%) for the all ovarian cancer group. These new monoclonal antibody-based inhibin alphaC ELISAs now provide practical and sensitive assays suitable for evaluation as diagnostic tests for monitoring ovarian cancers.

Nefiracetam facilitates hippocampal neurotransmission by a mechanism independent of the piracetam and aniracetam action.

PubMed

Nomura, T; Nishizaki, T

2000-07-07

Nefiracetam, a nootropic (cognition-enhancing) agent, facilitated neurotransmission in the dentate gyrus of rat hippocampal slices in a dose-dependent manner at concentrations ranged from 1 nM to 1 microM, being evident at 60-min washing-out of the drug. The facilitatory action was blocked by the nicotinic acetylcholine (ACh) receptor antagonists, alpha-bungarotoxin and mecamylamine. A similar facilitation was induced by the other nootropic agents, piracetam and aniracetam, but the facilitation was not inhibited by nicotinic ACh receptor antagonists and it did not occlude the potentiation induced by nefiracetam. In the Xenopus oocyte expression systems, nefiracetam potentiated currents through a variety of neuronal nicotinic ACh receptors (alpha 3beta 2, alpha 3beta 4, alpha 4 beta 2, alpha 4 beta 4, and alpha 7) to a different extent. In contrast, neither piracetam nor aniracetam had any potentiating action on alpha 7 receptor currents. While aniracetam delayed the decay time of currents through the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor, GluR1, -2, -3, expressed in oocytes, nefiracetam or piracetam had no effect on the currents. Nefiracetam, thus, appears to facilitate hippocampal neurotransmission by functionally targeting nicotinic ACh receptors, independently of the action of piracetam and aniracetam.

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

Tritium trick

NASA Technical Reports Server (NTRS)

Green, W. V.; Zukas, E. G.; Eash, D. T.

1971-01-01

Large controlled amounts of helium in uniform concentration in thick samples can be obtained through the radioactive decay of dissolved tritium gas to He3. The term, tritium trick, applies to the case when helium, added by this method, is used to simulate (n,alpha) production of helium in simulated hard flux radiation damage studies.

Estimates of production and structure of nuclei with Z = 119

NASA Astrophysics Data System (ADS)

Adamian, G. G.; Antonenko, N. V.; Lenske, H.

2018-02-01

The comparative analysis of the hot fusion reactions 50Ti +247-249Bk and 51V +246-248Cm for synthesis of element 119 is made with the dinuclear system model and the prediction of nuclear properties of the microscopic-macroscopic approach, where the closed proton shell at Z ≥ 120 is expected. The quasiparticle structures of nuclei in the α-decay chain of 295119 and a possible spread of alpha energies are studied. The calculated values of Qα are compared with available experimental data. The termination of the α-decay chain of 295119 is revealed.

Measurement of the 19F(α,n)22Na Cross Section for Nuclear Safeguards Science

NASA Astrophysics Data System (ADS)

Lowe, Marcus; Smith, M. S.; Pain, S.; Febbraro, M.; Pittman, S.; Chipps, K. A.; Thompson, S. J.; Grinder, M.; Grzywacz, R.; Smith, K.; Thornsberry, C.; Thompson, P.; Peters, W. A.; Waddell, D.; Blanchard, R.; Carls, A.; Shadrick, S.; Engelhardt, A.; Hertz-Kintish, D.; Allen, N.; Sims, H.

2015-10-01

Enriched uranium is commonly stored in fluoride matrices such as UF6. Alpha decays of uranium in UF6 will create neutrons via the 19F(α,n)22Na reaction. An improved cross section for this reaction will enable improved nondestructive assays of uranium content in storage cylinders at material enrichment facilities. To determine this reaction cross section, we have performed experiments using both forward and inverse kinematic techniques at the University of Notre Dame (forward) and Oak Ridge National Laboratory (inverse). Both experiments utilized the Versatile Array of Neutron Detectors at Low Energy (VANDLE) for neutron detection. The ORNL experiment also used a new ionization chamber for 22Na particle identification. Gating on the 22Na nuclei detected drastically reduced the background counts in the neutron time-of-flight spectra. The latest analysis and results will be presented for 19F beam energies ranging from 20-37 MeV. This work is funded in part by the DOE Office of Nuclear Physics, the National Nuclear Security Administration's Office of Defense Nuclear Nonproliferation R&D, and the NSF.

Direct and precise determination of environmental radionuclides in solid materials using a modified Marinelli beaker and a HPGe detector.

PubMed

Seo, B K; Lee, K Y; Yoon, Y Y; Lee, D W

2001-06-01

A simple but precise detection method was studied for the determination of natural radionuclides using a conventional HPGe detector. A new aluminium beaker instead of a plastic Marinelli beaker was constructed and examined to reach radioactive equilibrium conditions between radon and its daughter elements without the escape of gaseous radon. Using this beaker fifteen natural radionuclides from three natural decay series could be determined by direct gamma-ray measurement and sixteen radionuclides could be determined indirectly after radioactive equilibrium had been reached. Analytical results from ground water were compared with those from conventional alpha spectroscopy and the results agreed well within 12% difference. Nitrogen gas purge was used to replace the surrounding air of the detector to obtain a stable background and reducing the interference of radon daughter nuclides in the atmosphere. The use of nitrogen purging and the aluminium Marinelli beaker results in an approximately tenfold increase of sensitivity and a decrease of the detection limit of 226Ra to about 0.74 Bq kg(-1) in soil samples.

Molecular characterization of variant alpha-subunit of electron transfer flavoprotein in three patients with glutaric acidemia type II--and identification of glycine substitution for valine-157 in the sequence of the precursor, producing an unstable mature protein in a patient.

PubMed Central

Indo, Y; Glassberg, R; Yokota, I; Tanaka, K

1991-01-01

In our previous study of eight glutaric acidemia type II (GAII) fibroblast lines by using [35S]methionine labeling and immunoprecipitation, three of them had a defect in the synthesis of the alpha-subunit of electron transfer flavoprotein (alpha-ETF) (Ikeda et al. 1986). In one of them (YH1313) the labeling of the mature alpha-ETF was barely detectable, while that of the precursor (p) was stronger. In another (YH605) no synthesis of immunoreactive p alpha-ETF was detectable. In the third cell line (YH1391) the rate of variant p alpha-ETF synthesis was comparable to normal, but its electrophoretic mobility was slightly faster than normal. In the present study, the northern blot analysis revealed that all three mutant cell lines contained p alpha-ETF mRNA and that their size and amount were comparable to normal. In immunoblot analysis, both alpha- and beta-ETF bands were barely detectable in YH1313 and YH605 but were detectable in YH1391 in amounts comparable to normal. Sequencing of YH1313 p alpha-ETF cDNA via PCR identified a transversion of T-470 to G. We then devised a simple PCR method for the 119-bp section (T-443/G-561) for detecting this mutation. In the upstream primer, A-466 was artificially replaced with C, to introduce a BstNI site into the amplified copies in the presence of G-470 from the variant sequence. The genomic DNA analysis using this method demonstrated that YH1313 was homozygous for T----G-470 transversion. It was not detected either in two other alpha-ETF-deficient GAII or in seven control cell lines. The alpha-ETF cDNA sequence in YH605 was identical to normal. Images Figure 1 Figure 2 Figure 3 Figure 5 PMID:1882842

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.

First detection of winds in red giants by microwave continuum techniques

NASA Technical Reports Server (NTRS)

Drake, S. A.; Linsky, J. L.

1983-01-01

Eight red giants and supergiants have been observed at 4885 MHz (6 cm) with the Very Large Array in an attempt to detect continuum emission. The bright giant Alpha-1 Her (M5 II) was detected at an average flux density of 0.9 + or - 0.13 mJy. Since the likely source of this emission is an ionized, optically thick component of a stellar wind, this detection implies a mass loss rate of 2 x 10 to the -9th solar masses per yr for the ionized gas. The fraction of the outflow in Alpha-1 Her that is ionized (0.002-0.02) seems to be similar to that previously found for Alpha Ori and Alpha Sco A. Alpha Boo (K2 IIIp) and Beta Gem (K0 III) are probable and definite detections, respectively. The derived ionized mass loss rates for these two stars are about 1 x 10 to the -10th solar masses per yr, implying in the case of Alpha Boo that the wind is largely ionized.

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.

Photodiode radiation hardness, lyman-alpha emitting galaxies and photon detection in liquid argon neutrino detectors

NASA Astrophysics Data System (ADS)

Baptista, Brian

2013-12-01

My dissertation is comprised of three projects: 1) studies of Lyman-alpha Emitting galaxies (LAEs), 2) radiation hardness studies of InGaAs photodiodes (PDs), and 3) scintillation photon detection in liquid argon (LAr) neutrino detectors. I began work on the project that has now become WFIRST, developing a science case that would use WFIRST after launch for the observation of LAEs. The radiation hardness of PDs was as an effort to support the WFIRST calibration team. When WFIRST was significantly delayed, I joined an R&D effort that applied my skills to work on photon detection in LAr neutrino detectors. I report results on a broadband selection method developed to detect high equivalent width (EW) LAEs. Using photometry from the CFHT-Legacy Survey Deep 2 and 3 fields, I have spectroscopically confirmed 63 z=2.5-3.5 LAEs using the WIYN/Hydra spectrograph. Using UV continuum-fitting techniques I computed properties such as EWs, internal reddening and star formation rates. 62 of my LAEs show evidence to be normal dust-free LAEs. Second, I present an investigation into the effects of ionizing proton radiation on commercial off-the-shelf InGaAs PDs. I developed a monochromator-based test apparatus that utilized NIST-calibrated reference PDs. I tested the PDs for changes to their dark current, relative responsivity as a function of wavelength, and absolute responsivity. I irradiated the test PDs using 30, 52, and 98 MeV protons at the IU Cyclotron Facility. I found the InGaAs PDs showed increased dark current as the fluence increased with no evidence of broadband response degradation at the fluences expected at an L2 orbit and a 10-year mission lifetime. Finally, I detail my efforts on technology development of both optical detector technologies and waveshifting light guide construction for LAr vacuum UV scintillation light. Cryogenic neutrino detectors use photon detection for both accelerator based science and for SNe neutrino detection and proton decay. I have developed waveshifter doped cast acrylic light guides that convert scintillation light and guide the waveshifted light to SiPMs detectors.

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.

Phenyl-alpha-tert-butyl nitrone reverses mitochondrial decay in acute Chagas' disease.

PubMed

Wen, Jian-Jun; Bhatia, Vandanajay; Popov, Vsevolod L; Garg, Nisha Jain

2006-12-01

In this study, we investigated the mechanism(s) of mitochondrial functional decline in acute Chagas' disease. Our data show a substantial decline in respiratory complex activities (39 to 58%) and ATP (38%) content in Trypanosoma cruzi-infected murine hearts compared with normal controls. These metabolic alterations were associated with an approximately fivefold increase in mitochondrial reactive oxygen species production rate, substantial oxidative insult of mitochondrial membranes and respiratory complex subunits, and >60% inhibition of mtDNA-encoded transcripts for respiratory complex subunits in infected myocardium. The antioxidant phenyl-alpha-tert-butyl nitrone (PBN) arrested the oxidative damage-mediated loss in mitochondrial membrane integrity, preserved redox potential-coupled mitochondrial gene expression, and improved respiratory complex activities (47 to 95% increase) and cardiac ATP level (>or=40% increase) in infected myocardium. Importantly, PBN resulted twofold decline in mitochondrial reactive oxygen species production rate in infected myocardium. Taken together, our data demonstrate the pathological significance of oxidative stress in metabolic decay and energy homeostasis in acute chagasic myocarditis and further suggest that oxidative injuries affecting mitochondrial integrity-dependent expression and activity of the respiratory complexes initiate a feedback cycle of electron transport chain inefficiency, increased reactive oxygen species production, and energy homeostasis in acute chagasic hearts. PBN and other mitochondria-targeted antioxidants may be useful in altering mitochondrial decay and oxidative pathology in Chagas' disease.

Controlling alpha tracks registration in Makrofol DE 1-1 detector

NASA Astrophysics Data System (ADS)

Hassan, N. M.; Hanafy, M. S.; Naguib, A.; El-Saftawy, A. A.

2017-09-01

Makrofol DE 1-1 is a recent type of solid state nuclear track detectors could be used to measure radon concentration in the environment throughout the detection of α-particles emitted from radon decay. Thus, studying the physical parameters that control the formation of alpha tracks is vital for environmental radiation protection. Makrofol DE 1-1 polycarbonate detector was irradiated by α-particles of energies varied from 2 to 5 MeV emitted from the 241Am source of α-particle energy of 5.5 MeV. Then, the detector was etched in an optimum etching solution of mixed ethyl alcohol in KOH aqueous solution of (85% (Vol.) of 6 M KOH + 15% (Vol.) C2H5OH) at 50 °C for 3 h. Afterward, the bulk etch rate, etching sensitivity, and the registration efficiency of the detector, which control the tracks registration, were measured. The bulk etch rate of Makrofol detector was found to be 3.71 ± 0.71 μm h-1. The etching sensitivity and the detector registration efficiency were decreased exponentially with α-particles' energies following Bragg curve. A precise registration of α-particle was presented in this study. Therefore, Makrofol DE 1-1 can be applied as a radiation dosimeter as well as radon and thoron monitors.

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.

Production and Evaluation of 236gNp and Reference Materials for Naturally Occurring Radioactive Materials

NASA Astrophysics Data System (ADS)

Larijani, Cyrus Kouroush

This thesis is based on the development of a radiochemical separation scheme capable of separating both 236gNp and 236Pu from a uranium target of natural isotopic composition ( 1 g uranium) and 200 MBq of fission decay products. The isobaric distribution of fission residues produced following the bombardment of a natural uranium target with a beam of 25 MeV protons has been evaluated. Decay analysis of thirteen isobarically distinct fission residues were carried out using high-resolution gamma-ray spectrometry at the UK National Physical Laboratory. Stoichiometric abundances were calculated via the determination of absolute activity concentrations associated with the longest-lived members of each isobaric chain. This technique was validated by computational modelling of likely sequential decay processes through an isobaric decay chain. The results were largely in agreement with previously published values for neutron bombardments on natural uranium at energies of 14 MeV. Higher relative yields of products with mass numbers A 110-130 were found, consistent with the increasing yield of these radionuclides as the bombarding energy is increased. Using literature values for the production cross-section for fusion of protons with uranium targets, it is estimated that an upper limit of approximately 250 Bq of activity from the 236Np ground state was produced in this experiment. Using a radiochemical separation scheme, Np and Pu fractions were separated from the produced fission decay products, with analyses of the target-based final reaction products made using Inductively Couple Plasma Mass Spectrometry (ICP-MS) and high-resolution alpha and gamma-ray spectrometry. In a separate research theme, reliable measurement of Naturally Occurring Radioactive Materials is of significance in order to comply with environmental regulations and for radiological protection purposes. The thesis describes the standardisation of three reference materials, namely Sand, Tuff and TiO2 which can serve as quality control materials to achieve traceability, method validation and instrument calibration. The sample preparation, material characterization via gamma, alpha and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the assignment of values for both the 4n Thorium and 4n + 2 Uranium decay series are presented.

Hard-sphere-like dynamics in highly concentrated alpha-crystallin suspensions

DOE PAGES

Vodnala, Preeti; Karunaratne, Nuwan; Lurio, Laurence; ...

2018-02-02

The dynamics of concentrated suspensions of the eye-lens protein alpha crystallin have been measured using x-ray photon correlation spectroscopy. Measurements were made at wave vectors corresponding to the first peak in the hard-sphere structure factor and volume fractions close to the critical volume fraction for the glass transition. Langevin dynamics simulations were also performed in parallel to the experiments. The intermediate scattering function f(q,τ) could be fit using a stretched exponential decay for both experiments and numerical simulations. The measured relaxation times show good agreement with simulations for polydisperse hard-sphere colloids.

Hard-sphere-like dynamics in highly concentrated alpha-crystallin suspensions

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

Vodnala, Preeti; Karunaratne, Nuwan; Lurio, Laurence

The dynamics of concentrated suspensions of the eye-lens protein alpha crystallin have been measured using x-ray photon correlation spectroscopy. Measurements were made at wave vectors corresponding to the first peak in the hard-sphere structure factor and volume fractions close to the critical volume fraction for the glass transition. Langevin dynamics simulations were also performed in parallel to the experiments. The intermediate scattering function f(q,τ) could be fit using a stretched exponential decay for both experiments and numerical simulations. The measured relaxation times show good agreement with simulations for polydisperse hard-sphere colloids.

Hard-sphere-like dynamics in highly concentrated alpha-crystallin suspensions

NASA Astrophysics Data System (ADS)

Vodnala, Preeti; Karunaratne, Nuwan; Lurio, Laurence; Thurston, George M.; Vega, Michael; Gaillard, Elizabeth; Narayanan, Suresh; Sandy, Alec; Zhang, Qingteng; Dufresne, Eric M.; Foffi, Giuseppe; Grybos, Pawel; Kmon, Piotr; Maj, Piotr; Szczygiel, Robert

2018-02-01

The dynamics of concentrated suspensions of the eye-lens protein alpha crystallin have been measured using x-ray photon correlation spectroscopy. Measurements were made at wave vectors corresponding to the first peak in the hard-sphere structure factor and volume fractions close to the critical volume fraction for the glass transition. Langevin dynamics simulations were also performed in parallel to the experiments. The intermediate scattering function f (q ,τ ) could be fit using a stretched exponential decay for both experiments and numerical simulations. The measured relaxation times show good agreement with simulations for polydisperse hard-sphere colloids.

A study of energy-energy correlations and measurement of [alpha][sub s] at the Z[sup 0] resonance

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

Not Available

1992-01-01

We present the energy-energy correlation (EEC) distribution and its asymmetry (AEEC) in hadronic decays of [Zeta][sup 0] bosons measured by the SLD at SLAC. The data are found to be in good agreement with the predictions of perturbative QCD and fragmentation Monte Carlo models of hadron production. After correction for hadronization effects the data are compared with [Omicron]([alpha][sub s][sup 2]) perturbative QCD calculations from various authors. Fits to the central region of the EEC yield substantially different values of the QCD scale [lambda][sub [ovr MS

Influence of thermal quenching on the thermostimulated processes in alpha-Al2O3. Role of F and F+ centres.

PubMed

Vincellér, S; Molnár, G; Berkane-Krachai, A; Iacconi, P

2002-01-01

Anion deficient alpha-Al2O3 is highly sensitive to ionising radiations and is widely used as a thermoluminescence and optically stimulated luminescence dosemeter in environmental monitoring. Two types of alpha alumina were studied and it was observed that both were affected by thermal quenching of luminescence. This effect, which manifests itself by the decay of the TL response when the heating rate increases, can be described by the Mott-Seitz theory. It was observed that thermostimulated exoemission response increased when the heating rate increased, whereas thermostimulated conductivity remained constant. However, none of the available theories could explain the dependence of the F- centre emission on the heating rate. A model is proposed to describe simultaneously the various thermally stimulated processes.

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

Biassoni, M.; Brofferio, C.; Bucci, C.

Due to their excellent energy resolution values and the vast choice of possible materials, bolometric detectors are currently widely used in the physics of rare events. A limiting aspect for bolometers rises from their inability to discriminate among radiation types or surface from bulk events. It has been demonstrated that the main limitation to sensitivity for purely bolometric detectors is represented by surface alpha contaminations, causing a continuous background that cannot be discriminated. A new scintillation based technique for the rejection of surface alpha background in non- scintillating bolometric experiments is proposed in this work. The idea is to combinemore » a scintillating and a high sensitivity photon detector with a non- scintillating absorber. Finally, we present results showing the possibility to reject events due to alpha decay at or nearby the surface of the crystal.« less

Alpha decay calculations with a new formula

NASA Astrophysics Data System (ADS)

Akrawy, D. T.; Poenaru, D. N.

2017-10-01

A new semi-empirical formula for calculations of α decay half-lives is presented. It was derived from the Royer relationship by introducing new parameters which are fixed by fit to a set of experimental data. We are using three sets: set A with 130 e-e (even-even), 119 e-o (even-odd), 109 o-e, and 96 o-o, set B with 188 e-e, 147 e-o, 131 o-e and 114 o-o, and set C with 136 e-e, 84 e-o, 76 o-e and 48 o-o alpha emitters. A comparison of results obtained with the new formula (newF) and the following well known relationships: semiempirical relationship based on fission theory (semFIS), analytical superasymmetric fission (ASAF) model and universal formula (UNIV) made in terms of rms standard deviation. We also introduced a weighted mean value of this quantity, allowing us to compare the global properties of a given model. For set B the order of the four models is the following: semFIS, UNIV, newF and ASAF. Nevertheless for even-even alpha emitters, UNIV gives the second best result after semFIS, and for odd-even parents the second is newF. Despite its simplicity in comparison with semFIS, newF, presented in this article, behaves quite well, competing with the other well known relationships.

Biodegradation of lignin by Agaricus Bisporus

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

Vane, C.H.; Abbott, G.D.; Head, I.M.

The lignolytic activity of Agaricus bisporus will be addressed in this paper. Sound and fungally degraded lignins were characterized by Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS), Fourier Transform Infrared Spectroscopy (FnR) and elemental analysis. Fungally degraded lignins displayed increased wt%N, wt%H and wt%O content and decreased wt%C content The FTIR spectrum of decayed lignin showed an increase in the relative intensity of absorption bands assigned to carbonyl and carboxyl functional groups located on the aliphatic side chain and a decrease in absorption bands assigned to aromatic skeletal vibration modes. Semiquantitative Py-GC-MS revealed an 82% decrease in lignin derived pyrolysis products upon biodegradation.more » No significant increase in pyrolysis products with an oxygenated aliphatic side chain were detected in the fungally degraded lignin however shortening of the aliphatic side chain via cleavage at the {alpha}, {beta} and {gamma} positions was observed.« less

Dark Matter Search Results from the PICO -60 C 3F8 Bubble Chamber

NASA Astrophysics Data System (ADS)

Amole, C.; Ardid, M.; Arnquist, I. J.; Asner, D. M.; Baxter, D.; Behnke, E.; Bhattacharjee, P.; Borsodi, H.; Bou-Cabo, M.; Campion, P.; Cao, G.; Chen, C. J.; Chowdhury, U.; Clark, K.; Collar, J. I.; Cooper, P. S.; Crisler, M.; Crowder, G.; Dahl, C. E.; Das, M.; Fallows, S.; Farine, J.; Felis, I.; Filgas, R.; Girard, F.; Giroux, G.; Hall, J.; Harris, O.; Hoppe, E. W.; Jin, M.; Krauss, C. B.; Laurin, M.; Lawson, I.; Leblanc, A.; Levine, I.; Lippincott, W. H.; Mamedov, F.; Maurya, D.; Mitra, P.; Nania, T.; Neilson, R.; Noble, A. J.; Olson, S.; Ortega, A.; Plante, A.; Podviyanuk, R.; Priya, S.; Robinson, A. E.; Roeder, A.; Rucinski, R.; Scallon, O.; Seth, S.; Sonnenschein, A.; Starinski, N.; Štekl, I.; Tardif, F.; Vázquez-Jáuregui, E.; Wells, J.; Wichoski, U.; Yan, Y.; Zacek, V.; Zhang, J.; PICO Collaboration

2017-06-01

New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C3 F8 located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO -60 C 3F8 exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than one event per month. A blind analysis of an efficiency-corrected 1167-kg day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the weakly interacting massive particle (WIMP)-proton spin-dependent cross section at 3.4 ×10-41 cm2 for a 30 -GeV c-2 WIMP, more than 1 order of magnitude improvement from previous PICO results.

A Correlation Between Intrinsic Brightness and Average Decay Rate of Swift UVOT GRB Optical/UV Light Curves

NASA Technical Reports Server (NTRS)

Oates, S. R.; Page, M. J.; De Pasquale, M.; Schady, P.; Breeveld, A. A.; Holland, S. T.; Kuin, N. P. M.; Marshall, F. E.

2012-01-01

We examine a sample of 48 Swift/UVOT long Gamma-ray Burst light curves and find a correlation between the logarithmic luminosity at 200s and average decay rate determined from 200s onwards, with a Spearman rank coefficient of -0.58 at a significance of 99.998% (4.2 sigma ). We discuss the causes of the log L200s - alpha (greater than) 200s correlation, finding it to be an intrinsic property of long GRBs, and not resulting from the selection criteria. We find two ways to produce the correlation. One possibility is that there is some property of the central engine, outflow or external medium that affects the rate of energy release so that the bright afterglows release their energy more quickly and decay faster than the fainter afterglows. Alternatively, the correlation may be produced by variation of the observers viewing angle, with observers at large viewing angles observing fainter and slower decaying light curves.

Alpha decay properties of the semi-magic nucleus 219Np

NASA Astrophysics Data System (ADS)

Yang, H. B.; Ma, L.; Zhang, Z. Y.; Yang, C. L.; Gan, Z. G.; Zhang, M. M.; Huang, M. H.; Yu, L.; Jiang, J.; Tian, Y. L.; Wang, Y. S.; Wang, J. G.; Liu, Z.; Liu, M. L.; Duan, L. M.; Zhou, S. G.; Ren, Z. Z.; Zhou, X. H.; Xu, H. S.; Xiao, G. Q.

2018-02-01

The semi-magic nucleus 219Np was produced in the fusion reaction 187Re(36Ar, 4n)219Np at the gas-filled recoil separator SHANS (Spectrometer for Heavy Atoms and Nuclear Structure). A fast electronics system based on waveform digitizers was used in the data acquisition and the sampled pulses were processed by digital algorithms. The reaction products were identified using spatial and time correlations between the implants and subsequent α decays. According to the observed α-decay chain, an energy of Eα = 9039 (40) keV and a half-life of T1/2 =0.15-0.07 + 0.72 ms were determined for 219Np. The deduced proton binding energy of 219Np fits well into the systematics, which gives another evidence of that there is no sub-shell closure at Z = 92. The influence of the N = 126 shell closure on the stability of Np isotopes is discussed within the framework of α-decay reduced widths.

Evolvement of preformation probability of alpha cluster decay of parent nuclei 84≤Z≤92 having N=126

NASA Astrophysics Data System (ADS)

Kaur, Rupinder; Singh, Bir Bikram; Kaur, Mandeep; Sandhu, B. S.; Kaur, Maninder

2018-05-01

The preformed cluster decay model (PCM) based on collective clusterisation approach of quantum mechanical fragmentation theory (QMFT) has been applied to study the ground state decay of trans-lead parent nuclei 84≤Z≤92 with N=126 emitting α cluster. Within PCM, the α cluster is assumed to be preborn with certain preformation probability P0α before tunneling the potential barrier with penetrability Pα. The nuclear structure information of the emitted α cluster is carried out by P0α . The present work reveals that the relative P0α found to increase as the Z number of parent nuclei moves away from magic proton shell closure i.e. Z=82. It is observed that Pα also increases, consequently, shorter half life T1/2 α of α cluster decay of parent nuclei with increasing Z. The PCM calculated results for the T1/2 α of parent nuclei under study are very well compared with available experimental data.

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

Neutron noise measurements at the Delphi subcritical assembly

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

Szieberth, M.; Klujber, G.; Kloosterman, J. L.

2012-07-01

The paper presents the results and evaluations of a comprehensive set of neutron noise measurements on the Delphi subcritical assembly of the Delft Univ. of Technology. The measurements investigated the effect of different source distributions (inherent spontaneous fission and {sup 252}Cf) and the position of the detectors applied (both radially and vertically). The evaluation of the measured data has been performed by the variance-to-mean ratio (VTMR, Feynman-{alpha}), the autocorrelation (ACF, Rossi-{alpha}) and the cross-correlation (CCF) methods. The values obtained for the prompt decay constant show a strong bias, which depends both on the detector position and on the source distribution.more » This is due to the presence of higher modes in the system. It has been observed that the {alpha} value fitted is higher when the detector is close to the boundary of the core or to the {sup 252}Cf point-source. The higher alpha-modes have also been observed by fitting functions describing two alpha-modes. The successful set of measurement also provides a good basis for further theoretical investigations including the Monte Carlo simulation of the noise measurements and the calculation of the alpha-modes in the Delphi subcritical assembly. (authors)« 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

IL-17A acts via p38 MAPK to increase stability of TNF-alpha-induced IL-8 mRNA in human ASM.

PubMed

Henness, Sheridan; van Thoor, Eveline; Ge, Qi; Armour, Carol L; Hughes, J Margaret; Ammit, Alaina J

2006-06-01

Human airway smooth muscle (ASM) plays an immunomodulatory role in asthma. Recently, IL-17A has become of increasing interest in asthma, being found at elevated levels in asthmatic airways and emerging as playing an important role in airway neutrophilia. IL-17A predominantly exerts its neutrophil orchestrating role indirectly via the induction of cytokines by resident airway structural cells. Here, we perform an in vitro study to show that although IL-17A did not induce secretion of the CXC chemokine IL-8 from ASM cells, IL-17A significantly potentiates TNF-alpha-induced IL-8 protein secretion and gene expression in a concentration- and time-dependent manner (P < 0.05). Levels of IL-8 protein produced after 24 h of incubation with TNF-alpha were enhanced 2.7-fold in the presence of IL-17A, and conditioned media significantly enhanced neutrophil chemotaxis in vitro. As IL-17A had no effect on the activity of NF-kappaB, a key transcriptional regulator of IL-8 gene expression, we then examined whether IL-17A acts at the posttranscriptional level. We found that IL-17A significantly augmented TNF-alpha-induced IL-8 mRNA stability. Interestingly, this enhanced stability occurred via a p38 MAPK-dependent pathway. The decay of IL-8 mRNA transcripts proceeded at a significantly faster rate when cells were pretreated with the p38 MAPK inhibitor SB-203580 (-0.05763 +/- 0.01964, t(1/2) = 12.0 h), compared with vehicle (-0.01030 +/- 0.007963, t(1/2) = 67.3 h) [results are expressed as decay constant (means +/- SE) and half-life (t(1/2) in h): P < 0.05]. Collectively, these results demonstrate that IL-17A amplifies the synthetic function of ASM cells, acting via a p38 MAPK-dependent posttranscriptional pathway to augment TNF-alpha-induced secretion of the potent neutrophil chemoattractant IL-8 from ASM cells.

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.

Detection of Polonium-210 on Spirit Dust Magnets and Implications for the Global Martian Dust Cycle

NASA Astrophysics Data System (ADS)

Wong, R.; Meslin, P.; Sabroux, J.; Madsen, M. B.; Pineau, J.; Richon, P.

2013-12-01

The radioactivity of airborne aerosols, which originates from the attachment of radionuclides produced by radon disintegration, Galactic Cosmic Rays (GCR) or anthropogenic activities, especially fallouts from nuclear weapons testing, can be used to measure the residence time of these aerosols in the atmosphere and their deposition rate. It is also used to characterize soils erosion rates (Matissof et al., 2002) or to investigate the origin of desert rock varnish (Hodge et al., 2005), to name only a few terrestrial applications. A translation of these nuclear methods to the Martian atmosphere, which is characterized by a very active dust cycle, is tempting, and has the potential to offer a unique insight into the present-day recycling of the Martian surface. This approach is made possible by two facts: 1) the presence of radon in the Martian atmosphere, which produces long-lived radioactive decay products, in particular polonium-210, and whose abundance can be indirectly inferred by gamma ray spectrometry from orbit using Mars Odyssey Gamma Ray Spectrometer (GRS) (Meslin et al., 2012); 2) the presence at the surface of Mars of two Alpha Particle X-Ray Spectrometers (APXS), onboard Opportunity and Spirit Mars Exploration Rovers, whose energy range (in the alpha mode) very fortuitously happens to include the energy of alpha particles emitted by the decay of polonium-210. The long half-life of this radionuclide is such that it is almost entirely attached to the particles that have been in suspension in the atmosphere, especially those characterized by a large specific surface area or by a long atmospheric residence time. It can therefore be used as a tracer of the dust cycle. An analysis of the alpha spectra acquired on the dust Capture and Filter magnets of the Spirit rover confirms results obtained by Meslin et al. (2006) that the Martian dust is radioactive w/r to polonium-210, thereby extending Opportunity's result to a global scale. This result enables us to derive an estimate of the effective thickness of the dust reservoir that is involved in the present-day Mars atmospheric cycle. Differences between 210Po activities measured at Gusev and Meridiani Planum could be indicative of different dust transport histories and/or physical properties, possibly related to the differences in brightness/mineralogy/composition already noted on the dust magnets at the two sites (Madsen et al., 2009). The dust coating of rocks, on the other hand, does not show any detectable 210Po signal, which suggests that these dust particles are not as easily mobilized and have not been as much involved in the present-day atmospheric cycle. Finally, a new upper limit of radon near-surface concentration has been derived. Hodge, V. F., et al. (2005), J. Env. Radioactivity, 78, 331-342. Madsen, M.B., et al. (2009), J. Geophys. Res., 114, E06S90. Matissof, G., et al. (2002), Journal Environ. Qual., 31, 54-61. Meslin, P.-Y., et al. (2006), J. Geophys. Res., 111, E09012. Meslin, P.-Y., et al. (2012), 43rd LPSC, abstr. #2852.

Coosa River Storage Annex, Talladega, Alabama. Environmental Investigation Report. Volume 1 of 2

DTIC Science & Technology

1992-09-01

radon and radon daughters using an alpha track detector; and the interior surfaces of six igloos were analyzed for the presence of polychlorinated...ATSDR, 1990]. Radon gas is a health hazard due to its radioactive transformation or decay into radioactive by- products or radon daughters . As radon

A Graphical Examination of Uranium and Plutonium Fissility

ERIC Educational Resources Information Center

Reed, B. Cameron

2008-01-01

The issue of why only particular isotopes of uranium and plutonium are suitable for use in nuclear weapons is analyzed with the aid of graphs and semiquantitative discussions of parameters such as excitation energies, fission barriers, reaction cross-sections, and the role of processes such as [alpha]-decay and spontaneous fission. The goal is to…

a Theoretical and Experimental Investigation of 1/F Noise in the Alpha Decay Rates of AMERICIUM-241.

NASA Astrophysics Data System (ADS)

Pepper, Gary T.

New experimental methods and data analysis techniques were used to investigate the hypothesis of the existence of 1/f noise in a alpha particle emission rates for ^{241}Am. Experimental estimates of the flicker floor were found to be almost two orders of magnitude less than Handel's theoretical prediction and previous measurements. The existence of a flicker floor for ^{57}Co decay, a process for which no charged particles are emitted, indicate that instrumental instability is likely responsible for the values of the flicker floor obtained. The experimental results and the theoretical arguments presented indicate that a re-examination of Handel's theory of 1/f noise is appropriate. Methods of numerical simulation of noise processes with a 1/f^{rm n} power spectral density were developed. These were used to investigate various statistical aspects of 1/f ^{rm n} noise. The probability density function for the Allan variance was investigated in order to establish confidence limits for the observations made. The effect of using grouped (correlated) data, for evaluating the Allan variance, was also investigated.

Single and double grid long-range alpha detectors

DOEpatents

MacArthur, Duncan W.; Allander, Krag S.

1993-01-01

Alpha particle detectors capable of detecting alpha radiation from distant sources. In one embodiment, a voltage is generated in a single electrically conductive grid while a fan draws air containing air molecules ionized by alpha particles through an air passage and across the conductive grid. The current in the conductive grid can be detected and used for measurement or alarm. Another embodiment builds on this concept and provides an additional grid so that air ions of both polarities can be detected. The detector can be used in many applications, such as for pipe or duct, tank, or soil sample monitoring.

Single and double grid long-range alpha detectors

DOEpatents

MacArthur, D.W.; Allander, K.S.

1993-03-16

Alpha particle detectors capable of detecting alpha radiation from distant sources. In one embodiment, a voltage is generated in a single electrically conductive grid while a fan draws air containing air molecules ionized by alpha particles through an air passage and across the conductive grid. The current in the conductive grid can be detected and used for measurement or alarm. Another embodiment builds on this concept and provides an additional grid so that air ions of both polarities can be detected. The detector can be used in many applications, such as for pipe or duct, tank, or soil sample monitoring.

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.

Identification and quantification of metabolites common to 17alpha-methyltestosterone and mestanolone in horse urine.

PubMed

Yamada, Masayuki; Aramaki, Sugako; Okayasu, Toshimasa; Hosoe, Tomoo; Kurosawa, Masahiko; Kijima-Suda, Isao; Saito, Koichi; Nakazawa, Hiroyuki

2007-09-21

Anabolic steroids with the 17alpha-methyl,17beta-hydroxyl group, which were developed as oral formulations for therapeutic purposes, have been abused in the field of human sports. These anabolic steroids are also used to enhance racing performance in racehorses. In humans, structurally related 17alpha-methyltestosterone (MTS) and mestanolone (MSL), which are anabolic steroids with the 17alpha-methyl,17beta-hydroxyl group, have metabolites in common. The purpose of this study was to determine metabolites common to these two steroids in horses, which may serve as readily available screening targets for the doping test of these steroids in racehorses. Urine sample collected after administering MTS and MSL to horses was treated to obtain unconjugated steroid, glucuronide, and sulfate fractions. The fractions were subjected to gas chromatography/mass spectrometry (GC/MS), and 17alpha-methyl-5alpha-androstan-3beta,17beta-diol, 17alpha-hydroxymethyl-5alpha-androstan-3beta,17beta-diol, 17alpha-methyl-5alpha-androstan-3beta,16beta,17beta-triol, and 17alpha-methyl-5alpha-androstan-3beta,16alpha,17beta-triol were detected as the common metabolites by comparison with synthesized reference standards. The urinary concentrations of these metabolites after dosing were determined by GC/MS. 17Alpha-methyl-5alpha-androstan-3beta,16beta,17beta-triol was mainly detected in the sulfate fractions of urine samples after administration. This compound was consistently detected for the longest time in the urine samples after dosing with both steroids. The results suggest that 17alpha-methyl-5alpha-androstan-3beta,16beta,17beta-triol is a very useful screening target for the doping test of MTS and MSL in racehorses.

Immunoreactive transforming growth factor alpha is commonly present in colorectal neoplasia.

PubMed Central

Tanaka, S.; Imanishi, K.; Yoshihara, M.; Haruma, K.; Sumii, K.; Kajiyama, G.; Akamatsu, S.

1991-01-01

Surgical specimens from 19 patients with invasive colorectal cancers and 12 specimens of normal mucosa from the same patients were examined immunohistochemically for the production of the immunoreactive (IR-) transforming growth factor (TGF)-alpha and IR-epidermal growth factor (EGF) with an anti-TGF-alpha monoclonal antibody (MAb) OAL-MTG01 and anti-EGF MAb KEM-10. Immunoreactive TGF-alpha was detected in 16 (84.2%) of 19 colorectal cancers. In contrast, there was no IR-TGF-alpha in the gland cells of normal mucosa. Immunoreactive EGF was detected in 7 (36.8%) of 19 colorectal cancers and 1 (8.3%) of 12 cases of normal mucosa. The production of both IR-TGF-alpha and IR-EGF in colorectal cancer did not differ by histologic type and Dukes' stage. Immunoreactive TGF-alpha was detected at significantly higher incidence than IR-EGF in colorectal cancer. These results indicate that IR-TGF-alpha should prove valuable as a possible tumor marker in colorectal cancers, and it may be very useful in understanding the biology of colorectal cancer. Images Figure 2 Figure 3 Figure 4 Figure 5 PMID:1853928

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...

The Z2/A dependence in heavy-ion fusion for the reactions of chlorine on thulium, lutetium, tantalum and tungsten. Final report

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

DiRienzo, A.C.

1980-06-01

Evaporation residues produced in the reactions 35Cl+169Tm and 37Cl+169Tm, 175Lu, 181Ta and 186W were observed at zero degree utilizing the Mass Inst of Tech.- Brookhaven Nat'l Lab Recoil Mass Spectrometer. The recoiling nuclei were separated from the beam and refocused onto a surface barrier detector by a combination of electrostatic and magnetic fields and magnetic quadrupole lenses. The residual nuclei are alpha radioactive and can thus be identified by a characteristic alpha line observed after the arrival pulse of the evaporation residue. The recoiling nuclei also pass through a gas ionization chamber whereas the decay alpha do not. A separatemore » anti-coincidence spectrum therefore displayed the alphas background free. Trends of evaporation residue cross section were charted versus Z sq (proton no.)/ A(atomic no.) and compared to statistical evaporation codes.« less

Leptonic decay constants for D-mesons from 3-flavour CLS ensembles

NASA Astrophysics Data System (ADS)

Collins, Sara; Eckert, Kevin; Heitger, Jochen; Hofmann, Stefan; Söldner, Wolfgang

2018-03-01

e report on the status of an ongoing effort by the RQCD and ALPHA Collaborations, aimed at determining leptonic decay constants of charmed mesons. Our analysis is based on large-volume ensembles generated within the CLS effort, employing Nf = 2 + 1 non-perturbatively O(a) improved Wilson quarks, tree-level Symanzik-improved gauge action and open boundary conditions. The ensembles cover lattice spac-ings from a ≈ 0.09 fm to a ≈ 0.05 fm, with pion masses varied from 420 to 200 MeV. To extrapolate to the physical masses, we follow both the (2ml + ms) = const. and the ms = const. lines in parameter space.

Superluminal Neutrinos at OPERA Confront Pion Decay Kinematics

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

Cowsik, Ramanath; Nussinov, Shmuel; Schmidt College of Science, Chapman University,Orange California 92866

2011-12-16

Violation of Lorentz invariance (VLI) has been suggested as an explanation of the superluminal velocities of muon neutrinos reported by OPERA. In this Letter, we show that the amount of VLI required to explain this result poses severe difficulties with the kinematics of the pion decay, extending its lifetime and reducing the momentum carried away by the neutrinos. We show that the OPERA experiment limits {alpha}=(v{sub {nu}}-c)/c<4x10{sup -6}. We then take recourse to cosmic-ray data on the spectrum of muons and neutrinos generated in Earth's atmosphere to provide a stronger bound on VLI: (v-c)/c<10{sup -12}.

Long range alpha particle detector

DOEpatents

MacArthur, Duncan W.; Wolf, Michael A.; McAtee, James L.; Unruh, Wesley P.; Cucchiara, Alfred L.; Huchton, Roger L.

1993-01-01

An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

Long range alpha particle detector

DOEpatents

MacArthur, D.W.; Wolf, M.A.; McAtee, J.L.; Unruh, W.P.; Cucchiara, A.L.; Huchton, R.L.

1993-02-02

An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

Expected Backgrounds of the BetaCage, an Ultra-sensitive Screener for Surface Contamination

NASA Astrophysics Data System (ADS)

Wang, Boqian; Bunker, Raymond; Schnee, Richard; Bowles, Michael; Kos, Marek; Ahmed, Zeeshan; Golwala, Sunil; Nelson, Robert; Grant, Darren

2013-04-01

Material screening for low-energy betas and alphas is necessary for rare-event-search experiments, such as dark matter and neutrinoless double-beta decay searches where surface radiocontamination has become a significant background. The BetaCage, a gaseous neon time-projection chamber, has been proposed as a screener for emitters of low-energy betas and alphas to which existing screening facilities are insufficiently sensitive. The expected sensitivity is 0.1 betas / (keV m^2 day) and 0.1 alphas / (m^2 day). Expected backgrounds are dominated by Compton scattering of external photons in the sample to be screened; radioassays and simulations indicate backgrounds from detector materials and radon daughters should be subdominant. We will report on details of the background simulations and the detector design that allows discrimination to reach these sensitivity levels.

Addition products of alpha-tocopherol with lipid-derived free radicals.

PubMed

Yamauchi, Ryo

2007-01-01

The addition products of alpha-tocopherol with lipid-derived free radicals have been reviewed. Free radical scavenging reactions of alpha-tocopherol take place via the alpha-tocopheroxyl radical as an intermediate. If a suitable free radical is present, an addition product can be formed from the coupling of the free radical with the alpha-tocopheroxyl radical. The addition products of alpha-tocopherol with lipid-peroxyl radicals are 8a-(lipid-dioxy)-alpha-tocopherones, which are hydrolyzed to alpha-tocopherylquinone. On the other hand, the carbon-centered radicals of lipids prefer to react with the phenoxyl radical of alpha-tocopherol to form 6-O-lipid-alpha-tocopherol under anaerobic conditions. The addition products of alpha-tocopherol with peroxyl radicals (epoxylinoleoyl-peroxyl radicals) produced from cholesteryl ester and phosphatidylcholine were detected in the peroxidized human plasma using a high-sensitive HPLC procedure with postcolumn reduction and electrochemical detection. Thus, the formation of these addition products provides us with much information on the antioxidant function of vitamin E in biological systems.

Direct CP Violation in Charmless Hadronic B-Meson Decays at the PEP-II Asymmetric B-Meson Factory

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

Telnov, Alexandre Valerievich; /UC, Berkeley

2005-05-06

The study of the quark transition b {yields} s{bar s}s, which is a pure loop-level (''penguin'') process leading to several B-meson-decay final states, most notably {phi}K, is arguably the hottest topic in B-meson physics today. The reason is the sensitivity of the amplitudes and the CP-violating asymmetries in such processes to physics beyond the Standard Model. By performing these measurements, we improve our understanding of the phenomenon of combined-parity (CP) violation, which is believed to be responsible for the dominance of matter over antimatter in our Universe. Here, we present measurements of branching fractions and charge asymmetries in the decaysmore » B{sup +} {yields} {phi}K{sup +} and B{sup 0} {yields} {phi}K{sup 0} in a sample of approximately 89 million B{bar B} pairs collected by the BABAR detector at the PEP-II asymmetric-energy B-meson Factory at SLAC. We determine {Beta}(B{sup +} {yields} {phi}K{sup +}) = (10.0{sub -0.8}{sup +0.9} {+-} 0.5) x 10{sup -6} and {Beta}(B{sup 0} {yields} {phi}K{sup 0}) = (8.4{sub -1.3}{sup +1.5} {+-} 0.5) x 10{sup -6}, where the first error is statistical and the second is systematic. Additionally, we measure the CP-violating charge asymmetry {Alpha}{sub CP}(B{sup {+-}} {yields} {phi}K{sup {+-}}) = 0.04 {+-} 0.09 {+-} 0.01, with a 90% confidence-level interval of [-0.10, 0.18], and set an upper limit on the CKM- and color-suppressed decay B{sup +} {yields} {phi}{pi}{sup +}, {Beta}(B{sup +} {yields} {phi}{pi}{sup +}) < 0.41 x 10{sup -6} (at the 90% confidence level). Our results are consistent with the Standard Model, which predicts {Alpha}{sub CP}(B{sup {+-}} {yields} {phi}K{sup {+-}}) {approx}< 1% and {Beta}(B {yields} {phi}{tau}) << 10{sup -7}. Since many models of physics beyond the Standard Model introduce additional loop diagrams with new heavy particles and new CP-violating phases that would contribute to these decays, potentially making {Alpha}{sub CP} (B{sup {+-}} {yields} {phi}K{sup {+-}}) and {Beta}(B {yields} {phi}{pi}) quite large, our results can be used to substantially constrain the parameter spaces of such models.« less

Results from the Crystal Ball at DORIS II

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

Gaiser, J.E.

1983-10-01

Results are presented from studies of the inclusive photon spectra in hadronic decays of the UPSILON' and UPSILON and the exclusive channel UPSILON' ..-->.. ..gamma gamma..UPSILON ..-->.. ..cap alpha cap alpha..l/sup +/l/sup -/, by the Crystal Ball detector at DORIS II. We measure two signals in the UPSILON' ..-->.. ..gamma.. + anything inclusive channel at E(..gamma..) == 108.3 +- 0.9 +- 3.0 MeV and at E(..gamma..) == 127.5 +- 1.2 +- 4.0 MeV. Branching ratios obtained for these signals are: BR(UPSILON' ..-->.. ..gamma..(108) + anything) == (6.3 +- 1.3 +- 1.4)% BR(UPSILON' ..-->.. ..gamma..(128) + anything) == (6.0 +- 1.3more » +- 1.4)%.« less

Modeling Cell and Tumor-Metastasis Dosimetry with the Particle and Heavy Ion Transport Code System (PHITS) Software for Targeted Alpha-Particle Radionuclide Therapy.

PubMed

Lee, Dongyoul; Li, Mengshi; Bednarz, Bryan; Schultz, Michael K

2018-06-26

The use of targeted radionuclide therapy for cancer is on the rise. While beta-particle-emitting radionuclides have been extensively explored for targeted radionuclide therapy, alpha-particle-emitting radionuclides are emerging as effective alternatives. In this context, fundamental understanding of the interactions and dosimetry of these emitted particles with cells in the tumor microenvironment is critical to ascertaining the potential of alpha-particle-emitting radionuclides. One important parameter that can be used to assess these metrics is the S-value. In this study, we characterized several alpha-particle-emitting radionuclides (and their associated radionuclide progeny) regarding S-values in the cellular and tumor-metastasis environments. The Particle and Heavy Ion Transport code System (PHITS) was used to obtain S-values via Monte Carlo simulation for cell and tumor metastasis resulting from interactions with the alpha-particle-emitting radionuclides, lead-212 ( 212 Pb), actinium-225 ( 225 Ac) and bismuth-213 ( 213 Bi); these values were compared to the beta-particle-emitting radionuclides yttrium-90 ( 90 Y) and lutetium-177 ( 177 Lu) and an Auger-electron-emitting radionuclide indium-111 ( 111 In). The effect of cellular internalization on S-value was explored at increasing degree of internalization for each radionuclide. This aspect of S-value determination was further explored in a cell line-specific fashion for six different cancer cell lines based on the cell dimensions obtained by confocal microscopy. S-values from PHITS were in good agreement with MIRDcell S-values (cellular S-values) and the values found by Hindié et al. (tumor S-values). In the cellular model, 212 Pb and 213 Bi decay series produced S-values that were 50- to 120-fold higher than 177 Lu, while 225 Ac decay series analysis suggested S-values that were 240- to 520-fold higher than 177 Lu. S-values arising with 100% cellular internalization were two- to sixfold higher for the nucleus when compared to 0% internalization. The tumor dosimetry model defines the relative merit of radionuclides and suggests alpha particles may be effective for large tumors as well as small tumor metastases. These results from PHITS modeling substantiate emerging evidence that alpha-particle-emitting radionuclides may be an effective alternative to beta-particle-emitting radionuclides for targeted radionuclide therapy due to preferred dose-deposition profiles in the cellular and tumor metastasis context. These results further suggest that internalization of alpha-particle-emitting radionuclides via radiolabeled ligands may increase the relative biological effectiveness of radiotherapeutics.

Quantitative Analysis of Plutonium Content in Particles Collected from a Certified Reference Material by Total Nuclear Reaction Energy (Q Value) Spectroscopy

NASA Astrophysics Data System (ADS)

Croce, M. P.; Hoover, A. S.; Rabin, M. W.; Bond, E. M.; Wolfsberg, L. E.; Schmidt, D. R.; Ullom, J. N.

2016-08-01

Microcalorimeters with embedded radioisotopes are an emerging category of sensor with advantages over existing methods for isotopic analysis of trace-level nuclear materials. For each nuclear decay, the energy of all decay products captured by the absorber (alpha particles, gamma rays, X-rays, electrons, daughter nuclei, etc.) is measured in one pulse. For alpha-decaying isotopes, this gives a measurement of the total nuclear reaction energy (Q value) and the spectra consist of well-separated, narrow peaks. We have demonstrated a simple mechanical alloying process to create an absorber structure consisting of a gold matrix with small inclusions of a radioactive sample. This absorber structure provides an optimized energy thermalization environment, resulting in high-resolution spectra with minimal tailing. We have applied this process to the analysis of particles collected from the surface of a plutonium metal certified reference material (CRM-126A from New Brunswick Laboratory) and demonstrated isotopic analysis by microcalorimeter Q value spectroscopy. Energy resolution from the Gaussian component of a Bortels function fit was 1.3 keV FWHM at 5244 keV. The collected particles were integrated directly into the detector absorber without any chemical processing. The ^{238}Pu/^{239}Pu and ^{240}Pu/^{239}Pu mass ratios were measured and the results confirmed against the certificate of analysis for the reference material. We also demonstrated inter-element analysis capability by measuring the ^{241}Am/^{239}Pu mass ratio.

Vertical length scale selection for pancake vortices in strongly stratified viscous fluids

NASA Astrophysics Data System (ADS)

Godoy-Diana, Ramiro; Chomaz, Jean-Marc; Billant, Paul

2004-04-01

The evolution of pancake dipoles of different aspect ratio is studied in a stratified tank experiment. Two cases are reported here for values of the dipole initial aspect ratio alpha_0 = L_v/L_h (where L_v and L_h are vertical and horizontal length scales, respectively) of alpha_0 = 0.4 (case I) and alpha_0 = 1.2 (case II). In the first case, the usual decay scenario is observed where the dipole diffuses slowly with a growing thickness and a decaying circulation. In case II, we observed a regime where the thickness of the dipole decreases and the circulation in the horizontal mid-plane of the vortices remains constant. We show that this regime where the vertical length scale decreases can be explained by the shedding of two boundary layers at the top and bottom of the dipole that literally peel off vorticity layers. Horizontal advection and vertical diffusion cooperate in this regime and the decrease towards the viscous vertical length scale delta = L_hRe(-1/2) occurs on a time scale alpha_0 Re(1/2) T_A, T_A being the advection time L_h/U. From a scaling analysis of the equations for a stratified viscous fluid in the Boussinesq approximation, two dominant balances depending on the parameter R = ReF_h(2) are discussed, where F_h = U/NL_h is the horizontal Froude number and Re = UL_h/nu is the Reynolds number, U, N and nu being, respectively, the translation speed of the dipole, the Brunt Väisälä frequency and the kinematic viscosity. When R≫ 1 the vertical length scale is determined by buoyancy effects to be of order L_b = U/N. The experiments presented in this paper pertain to the case of small R, where viscous effects govern the selection of the vertical length scale. We show that if initially L_v ≤ delta, the flow diffuses on the vertical (case I), while if L_v ≫ delta (case II), vertically sheared horizontal advection decreases the vertical length scale down to delta. This viscous regime may explain results from experiments and numerical simulations on the late evolution of stratified flows where the decay is observed to be independent of the buoyancy frequency N.

Uroepithelial cells are part of a mucosal cytokine network.

PubMed Central

Hedges, S; Agace, W; Svensson, M; Sjögren, A C; Ceska, M; Svanborg, C

1994-01-01

This study compared the cytokine production of uroepithelial cell lines in response to gram-negative bacteria and inflammatory cytokines. Human kidney (A498) and bladder (J82) epithelial cell lines were stimulated with either Escherichia coli Hu734, interleukin 1 alpha (IL-1 alpha), or tumor necrosis factor alpha (TNF-alpha). Supernatant samples were removed, and the RNA was extracted from cells at 0, 2, 6, and 24 h. The secreted cytokine levels were determined by bioassay or immunoassay; mRNA was examined by reverse transcription-PCR. The two cell lines secreted IL-6 and IL-8 constitutively. IL-6 and IL-8 mRNA were constitutively produced in both cell lines; IL-1 beta mRNA was detected in J82 cells. IL-1 alpha induced significantly higher levels of IL-6 secretion than did E. coli Hu734 or TNF-alpha. IL-1 alpha and TNF-alpha induced significantly higher levels of IL-8 secretion than did E. coli Hu734. Secreted IL-1 beta was not detected; IL-1 alpha and TNF-alpha were not detected above the levels used for stimulation. IL-1 alpha, IL-1 beta, IL-6, and IL-8 mRNAs were detected in both cell lines after exposure to the stimulants. TNF-alpha mRNA was occasionally detected in the J82 cell line after TNF-alpha stimulation. Cytokine (IL-6 and IL-8) and control (glyceraldehyde 3-phosphate dehydrogenase [G3PDH] and beta-actin) mRNA concentrations were quantitated with internal PCR standards. Cytokine mRNA levels relative to beta-actin mRNA levels were the highest in E. coli-stimulated cells. In comparison, the cytokine mRNA levels relative to G3PDH mRNA levels were the highest in IL-1 alpha-stimulated cells. beta-Actin mRNA levels decreased after bacterial stimulation but not after cytokine stimulation, while G3PDH mRNA levels increased in response to all of the stimulants tested. These results suggested that E. coli Hu734 lowered the beta-actin mRNA levels in uroepithelial cells, thus distorting the IL-6 and IL-8 mRNA levels relative to this control. In summary, E. coli IL-1 alpha and TNF-alpha were found to activate the de novo synthesis and secretion of IL-6 and IL-8 in uroepithelial cells. These results emphasize the role of epithelial cells in cytokine-mediated responses during the early stages of infection. Images PMID:8188354

Different patterns of 5{alpha}-reductase expression, cellular distribution, and testosterone metabolism in human follicular dermal papilla cells

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

Liu, Shicheng; Yamauchi, Hitoshi

Androgens regulate hair growth, and 5{alpha}-reductase (5{alpha}R) plays a pivotal role in the action of androgens on target organs. To clarify the molecular mechanisms responsible for controlling hair growth, the present study presents evidence that the human follicular dermal papilla cells (DPCs) from either beard (bDPCs) or scalp hair (sDPCs) possess endogenous 5{alpha}R activity. Real-time RT-PCR revealed that the highest level of 5{alpha}R1 mRNA was found in bDPCs, followed by sDPCs, and a low but detectable level of 5{alpha}R1 mRNA was observed in fibroblasts. Minimally detectable levels of 5{alpha}R2 mRNA were found in all three cell types. A weak bandmore » at 26 kDa corresponding to the human 5{alpha}R1 protein was detected by Western blot in both DPCs, but not in fibroblasts. Immuonofluorescence analysis confirmed that 5{alpha}R1 was localized to the cytoplasm rather than in the nuclei in both DPCs Furthermore, a 5{alpha}R assay using [{sup 14}C]testosterone labeling in intact cells revealed that testosterone was transformed primarily into androstenedione, and in small amounts, into DHT. Our results demonstrate that the 5{alpha}R activities of either bDPCs or sDPCs are stronger than that of dermal fibroblasts, despite the fact that the major steroidogenic activity is attributed to 17{beta}-HSD rather than 5{alpha}R among the three cell types. The 5{alpha}R1 inhibitor MK386 exhibited a more potent inhibitory effect on 5{alpha}R activity than finasteride (5{alpha}R2 inhibitor) in bDPCs.« less

Automation of Classical QEEG Trending Methods for Early Detection of Delayed Cerebral Ischemia: More Work to Do.

PubMed

Wickering, Ellis; Gaspard, Nicolas; Zafar, Sahar; Moura, Valdery J; Biswal, Siddharth; Bechek, Sophia; OʼConnor, Kathryn; Rosenthal, Eric S; Westover, M Brandon

2016-06-01

The purpose of this study is to evaluate automated implementations of continuous EEG monitoring-based detection of delayed cerebral ischemia based on methods used in classical retrospective studies. We studied 95 patients with either Fisher 3 or Hunt Hess 4 to 5 aneurysmal subarachnoid hemorrhage who were admitted to the Neurosciences ICU and underwent continuous EEG monitoring. We implemented several variations of two classical algorithms for automated detection of delayed cerebral ischemia based on decreases in alpha-delta ratio and relative alpha variability. Of 95 patients, 43 (45%) developed delayed cerebral ischemia. Our automated implementation of the classical alpha-delta ratio-based trending method resulted in a sensitivity and specificity (Se,Sp) of (80,27)%, compared with the values of (100,76)% reported in the classic study using similar methods in a nonautomated fashion. Our automated implementation of the classical relative alpha variability-based trending method yielded (Se,Sp) values of (65,43)%, compared with (100,46)% reported in the classic study using nonautomated analysis. Our findings suggest that improved methods to detect decreases in alpha-delta ratio and relative alpha variability are needed before an automated EEG-based early delayed cerebral ischemia detection system is ready for clinical use.

Conformal Aspects of QCD

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

Brodsky, S

2003-11-19

Theoretical and phenomenological evidence is now accumulating that the QCD coupling becomes constant at small virtuality; i.e., {alpha}{sub s}(Q{sup 2}) develops an infrared fixed point in contradiction to the usual assumption of singular growth in the infrared. For example, the hadronic decays of the {tau} lepton can be used to determine the effective charge {alpha}{sub {tau}}(m{sub {tau}{prime}}{sup 2}) for a hypothetical {tau}-lepton with mass in the range 0 < m{sub {tau}{prime}} < m{sub {tau}}. The {tau} decay data at low mass scales indicates that the effective charge freezes at a value of s = m{sub {tau}{prime}}{sup 2} of order 1more » GeV{sup 2} with a magnitude {alpha}{sub {tau}} {approx} 0.9 {+-} 0.1. The near-constant behavior of effective couplings suggests that QCD can be approximated as a conformal theory even at relatively small momentum transfer and why there are no significant running coupling corrections to quark counting rules for exclusive processes. The AdS/CFT correspondence of large N{sub c} supergravity theory in higher-dimensional anti-de Sitter space with supersymmetric QCD in 4-dimensional space-time also has interesting implications for hadron phenomenology in the conformal limit, including an all-orders demonstration of counting rules for exclusive processes and light-front wavefunctions. The utility of light-front quantization and light-front Fock wavefunctions for analyzing nonperturbative QCD and representing the dynamics of QCD bound states is also discussed.« less

Relating to monitoring ion sources

DOEpatents

Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore; Bounds, John Alan

2002-01-01

The apparatus and method provide techniques for monitoring the position on alpha contamination in or on items or locations. The technique is particularly applicable to pipes, conduits and other locations to which access is difficult. The technique uses indirect monitoring of alpha emissions by detecting ions generated by the alpha emissions. The medium containing the ions is moved in a controlled manner frog in proximity with the item or location to the detecting unit and the signals achieved over time are used to generate alpha source position information.

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.

Modelling control of epidemics spreading by long-range interactions.

PubMed

Dybiec, Bartłomiej; Kleczkowski, Adam; Gilligan, Christopher A

2009-10-06

We have studied the spread of epidemics characterized by a mixture of local and non-local interactions. The infection spreads on a two-dimensional lattice with the fixed nearest neighbour connections. In addition, long-range dynamical links are formed by moving agents (vectors). Vectors perform random walks, with step length distributed according to a thick-tail distribution. Two distributions are considered in this paper, an alpha-stable distribution describing self-similar vector movement, yet characterized by an infinite variance and an exponential power characterized by a large but finite variance. Such long-range interactions are hard to track and make control of epidemics very difficult. We also allowed for cryptic infection, whereby an infected individual on the lattice can be infectious prior to showing any symptoms of infection or disease. To account for such cryptic spread, we considered a control strategy in which not only detected, i.e. symptomatic, individuals but also all individuals within a certain control neighbourhood are treated upon the detection of disease. We show that it is possible to eradicate the disease by using such purely local control measures, even in the presence of long-range jumps. In particular, we show that the success of local control and the choice of the optimal strategy depend in a non-trivial way on the dispersal patterns of the vectors. By characterizing these patterns using the stability index of the alpha-stable distribution to change the power-law behaviour or the exponent characterizing the decay of an exponential power distribution, we show that infection can be successfully contained using relatively small control neighbourhoods for two limiting cases for long-distance dispersal and for vectors that are much more limited in their dispersal range.

An investigation of the effects of wavelength shifter thickness on backgrounds for the DEAP-3600 dark matter direct detection experiment

NASA Astrophysics Data System (ADS)

Cranshaw, Derek

Several lines of astronomical evidence indicate that most of the matter in our universe is made of non-luminous material known as dark matter, the nature of which remains a mystery. DEAP-3600 is a liquid-argon-based scintillation detector located 2 km underground outside Sudbury, Ontario, Canada, purposed towards directly detecting dark matter particles as they pass through the target material. Since the acrylic vessel containing the 3600-kg liquid argon target is not transparent to the 128-nm scintillation light produced during these interactions, a thin layer of 1,1,4,4-tetraphenyl-1,3-butadiene (TPB) was deposited onto the inner surface of the acrylic vessel to shift the wavelength of the scintillation light to the visible range, where is can pass through the transparent acrylic vessel and is more easily detected by the surrounding array of photomultiplier tubes. The dark matter signal in DEAP-3600 is accompanied by a host of other background signals, which must either be suppressed, or identified as background signals and subsequently cut from the analysis. A major anticipated source of background events is alpha decays of radioactive isotopes on the inner surface of the acrylic vessel, near the TPB layer. The potential for these events to generate a background signal depends sensitively on the choice of thickness of the TPB layer. A study of the effects of TPB layer thickness on the background rate of these surface alpha events is presented, and a model for the dominant contributor to these background events is developed to generate estimates of the probability that an event of this type would mimic a dark matter signal. Other effects considered in the choice of TPB layer thickness are presented, and the final decision of a 2.99 +- 0.02 micron TPB layer thickness, along with the TPB deposition campaign, is briefly described.

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.

Methods and Data Used to Investigate Polonium-210 as a Source of Excess Gross-Alpha Radioactivity in Ground Water, Churchill County, Nevada

USGS Publications Warehouse

Seiler, Ralph L.

2007-01-01

Ground water is the major source of drinking water in the Carson River Basin, California and Nevada. Previous studies have shown that uranium and gross-alpha radioactivities in ground water can be greater than U.S. Environmental Protection Agency Maximum Contaminant Levels, particularly in the Carson Desert, Churchill County, Nevada. Studies also have shown that the primary source of the gross-alpha radioactivity and alpha-emitting radionuclides in ground water is the dissolution of uranium-rich granitic rocks and basin-fill sediments that have their origins in the Sierra Nevada. However, ground water sampled from some wells in the Carson Desert had gross-alpha radioactivities greater than could be accounted for by the decay of dissolved uranium. The occurrence of polonium-210 (Po-210) was hypothesized to explain the higher than expected gross-alpha radioactivities. This report documents and describes the study design, field and analytical methods, and data used to determine whether Po-210 is the source of excess gross-alpha radioactivity in ground water underlying the Carson Desert in and around Fallon, Nevada. Specifically, this report presents: 1) gross alpha and uranium radioactivities for 100 wells sampled from June to September 2001; and 2) pH, dissolved oxygen, specific conductance, and Po-210 radioactivity for 25 wells sampled in April and June 2007. Results of quality-control samples for the 2007 dataset are also presented.

Investigation of Deuterium Loaded Materials Subject to X-Ray Exposure

NASA Technical Reports Server (NTRS)

Benyo, Theresa L.; Steinetz, Bruce M.; Hendricks, Robert C.; Martin, Richard E.; Forsley, Lawrence P.; Daniels, Christopher C.; Chait, Arnon; Pines, Vladimir; Pines, Marianna; Penney, Nicholas;

An alpha particle instrument with alpha, proton, and X-ray modes for planetary chemical analyses

NASA Technical Reports Server (NTRS)

Economou, T. E.; Turkevich, A. L.

1976-01-01

The interaction of alpha particles with matter is employed in a compact instrument that could provide rather complete in-situ chemical analyses of surfaces and thin atmospheres of extraterrestrial bodies. The instrument is a miniaturized and improved version of the Surveyor lunar instrument. The backscattering of alpha particles and (alpha, p) reactions provide analytical data on the light elements (carbon-iron). An X-ray mode that detects the photons produced by the alpha sources provides sensitivity and resolution for the chemical elements heavier than about silicon. The X-rays are detected by semiconductor detectors having a resolution between 150 and 250 eV at 5.9 keV. Such an instrument can identify and determine with good accuracy 99 percent of the atoms (except hydrogen) in rocks. For many trace elements, the detecting sensitivity is a few ppm. Auxiliary sources could be used to enhance the sensitivities for elements of special interest. The instrument could probably withstand the acceleration involved in semi-hard landings.

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.

Screening materials with the XIA UltraLo alpha particle counter at Southern Methodist University

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

Nakib, M. Z.; Cooley, J.; Kara, B.

2013-08-08

Southern Methodist University houses one of five existing commercially available UltraLo 1800 production model alpha counters made by XIA LLC. The instrument has an electron drift chamber with a 707 cm{sup 2} or 1800 cm{sup 2} counting region which is determined by selecting the inner electrode size. The SMU team operating this device is part of the SuperCDMS screening working group, and uses the alpha counter to study the background rates from the decay of radon in materials used to construct the SuperCDMS experiment. We have studied four acrylic samples obtained from the MiniCLEAN direct dark matter search with themore » XIA instrument demonstrating its utility in low background experiments by investigating the plate-out of {sup 210}Pb and comparing the effectiveness of cleaning procedures in removing {sup 222}Rn progenies from the samples.« less

Validation of a Pseudo-Sound Theory for the Pressure-Dilatation in DNS of Compressible Turbulence

NASA Technical Reports Server (NTRS)

Ristorcelli, J. R.; Blaisdell, G. A.

1997-01-01

The results of an asymptotic theory for statistical closures for compressible turbulence are explored and validated with the direct numerical simulation of the isotropic decay and the homogeneous shear. An excellent collapse of the data is seen. The slow portion is found to scale, as predicted by the theory, with the quantity M(sub t)(sup 2) and epsilon(sub s). The rapid portion has an unambiguous scaling with alpha(sup 2)M(sub t)(sup s)epsilon(sub s)[P(sub k)/epsilon - l](Sk/epsilon)(sup 2). Implicit in the scaling is a dependence, as has been noted by others, on the gradient Mach number. A new feature of the effects of compressibility, that of the Kolmogorov scaling coefficient, alpha, is discussed. It is suggested that alpha may contain flow specific physics associated with large scales that might provide further insight into the structural effects of compressibility.

Energy of the ground and 2{sup +} excited states of {sub {lambda}}{sub {lambda}}{sup 10}Be: A partial ten-body model

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

Shoeb, Mohammad; Sonika

2009-08-15

The energies of the ground and excited 2{sup +} states of {sub {lambda}}{sub {lambda}}{sup 10}Be have been calculated variationally in the Monte Carlo framework. The hypernucleus is treated as a partial ten-body problem in the {lambda}{lambda}+{alpha}{alpha} model where nucleonic degrees of freedom of {alpha}'s are taken into consideration ignoring the antisymmetrization between two {alpha}'s. The central two-body {lambda}N and {lambda}{lambda} and the three-body dispersive and two-pion exchange {lambda}NN forces, constrained by the {lambda}p scattering data and the observed ground state energies of {sub {lambda}}{sup 5}He and {sub {lambda}}{sub {lambda}}{sup 6}He, are employed. The product-type trial wave function predicts binding energymore » for the ground state considerably less than for the event reported by Danysz et al.; however, it is consistent with the value deduced assuming a {gamma} ray of 3.04 MeV must have escaped undetected in the decay of the product {sub {lambda}}{sup 9}Be* {yields} {sub {lambda}}{sup 9}Be+{gamma} of the emulsion event {sub {lambda}}{sub {lambda}}{sup 10}Be{yields} {pi}{sup -}+p+{sub {lambda}}{sup 9}Be* and for the excited 2{sup +} state closer to the value measured in the Demachi-Yanagi event. The hypernucleus {sub {lambda}}{sub {lambda}}{sup 10}Be has an oblate shape in the excited state. These results are consistent with the earlier four-body {alpha} cluster model approach where {alpha}'s are assumed to be structureless entities.« less

Incidence of premature estrus in lactating dairy cows and conception rates to standing estrus or fixed-time inseminations after synchronization using GnRH and PGF(2alpha).

PubMed

DeJarnette, J M; Salverson, R R; Marshall, C E

2001-07-03

Fixed-time AI (TAI) after GnRH-PGF(2alpha)-GnRH treatment is a method to achieve pregnancies in dairy herds without estrous detection. However, cows that fail to respond to the initial GnRH may have compromised TAI conception rates due to asynchronous ovarian response. This study documented the percentage of GnRH-treated Holstein cows (n=345) in two herds that displayed estrus at an inopportune time for optimum TAI conception rate (< or =48h post-PGF(2alpha); premature estrus (PE)) and compared conception rates of two TAI protocols in cows that did not display PE. At biweekly herd health exams, cows diagnosed as not pregnant to a previous AI and cows >80 days postpartum with no AI were treated with 100 microg GnRH (day -7) and 25mg PGF(2alpha) (day 0). Cows detected in PE by twice-daily visual observation from day -7 to day 2 were bred by AI 8-12h later. Cows not detected in PE were randomly assigned by parity, body condition score, and postpartum interval to receive either: (1) 100microg GnRH at 48h after PGF(2alpha) and TAI 16 to 18h later (Ovsynch); or (2) TAI at 72h post-PGF(2alpha) and a concurrent 100 microg GnRH injection to those cows not detected in estrus between 48 and 72h post-PGF(2alpha) (modified Ovsynch (MOV)). All hormone injections were im. Twenty percent (68/345) of the cows were detected in estrus before 48 after PGF(2alpha), of which 5% (17/345) were detected in estrus before PGF(2alpha) (< or =day 0). Herd influenced the percentage of cows in the PE group (herd A versus herd B; 25% versus 14%; P<0.05). Conception rates were not affected by treatment (PE versus Ovsynch versus MOV; 32% (21/65) versus 30% (37/125) versus 32% (47/145); P>0.10). However, within MOV-treated cows, conception rates were greater (P<0.05) in cows detected in estrus (46% (23/50)) compared with cows not detected in estrus (25% (24/95)). In conclusion, 20% of GnRH-treated cows displayed PE and necessitates estrous detection during this period if maximal pregnancy rates are to be achieved. Although additional estrous detection is required compared to Ovsynch, reduced cow handling and hormone usage, efficient use of expensive semen through greater conception rates in cows detected in estrus, and comparable TAI conception rates, suggests the MOV protocol may be a cost effective alternative to Ovsynch in many dairy herd reproductive management programs.

Detecting decay in wood components

Treesearch

R.J. Ross; X. Wang; B.K. Brashaw

2005-01-01

This chapter presents a summary of the Wood and Timber Condition Assessment Manual. It focuses on current inspection techniques for decay detection and provides guidelines on the use of various non-destructive evaluation (NDE) methods in locating and defining areas of deterioration in timber bridge components and other civil structures.

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...

New Fragment Separation Technology for Superheavy Element Research

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

Shaughnessy, D A; Moody, K J; Henderson, R A

2008-01-28

This project consisted of three major research areas: (1) development of a solid Pu ceramic target for the MASHA separator, (2) chemical separation of nuclear decay products, and (3) production of new isotopes and elements through nuclear reactions. There have been 16 publications as a result of this project, and this collection of papers summarizes our accomplishments in each of the three areas of research listed above. The MASHA (Mass Analyzer for Super-Heavy Atoms) separator is being constructed at the U400 Cyclotron at the Flerov Laboratory of Nuclear Reactions in Dubna, Russia. The purpose of the separator is to physicallymore » separate the products from nuclear reactions based on their isotopic masses rather than their decay characteristics. The separator was designed to have a separation between isotopic masses of {+-}0.25 amu, which would enable the mass of element 114 isotopes to be measured with outstanding resolution, thereby confirming their discovery. In order to increase the production rate of element 114 nuclides produced via the {sup 244}Pu+{sup 48}Ca reaction, a new target technology was required. Instead of a traditional thin actinide target, the MASHA separator required a thick, ceramic-based Pu target that was thick enough to increase element 114 production while still being porous enough to allow reaction products to migrate out of the target and travel through the separator to the detector array located at the back end. In collaboration with UNLV, we began work on development of the Pu target for MASHA. Using waste-form synthesis technology, we began by creating zirconia-based matrices that would form a ceramic with plutonium oxide. We used samarium oxide as a surrogate for Pu and created ceramics that had varying amounts of the starting materials in order to establish trends in material density and porosity. The results from this work are described in more detail in Refs. [1,4,10]. Unfortunately, work on MASHA was delayed in Russia because it was found that the efficiency of transporting products from the target chamber to the detector array was much too low for applications in heavy element experiments where production rates are on the order of one atom per day or less. Work continues on the MASHA separator, and once the efficiency has been improved, we plan to continue our work on the Pu target for future element 114 experiments. Due to the delays of the MASHA separator, work on establishing the identity of heavy element species produced through nuclear reactions focused instead on chemical separations. In particular, element 115 decays through a series of alpha decays, terminating with an element 105 isotope with a long half-life ({approx} 1 day). By chemically separating the element 105 daughter and observing its subsequent fission decay, the identity of the original parent nucleus can be established through the genetic correlation of the initial series of alpha decays. Chemical separations of element 105 were developed in Switzerland, Russia, and at LLNL. Over the course of two experiments, reaction products from the {sup 243}Am+{sup 48}Ca reaction were collected in a copper block and subsequently processed for chemical separation of the Group Five elements [8,9,13,15]. The Group Five elements were initially separated from the Group Four species, and then the samples were sub-divided into tantalum and niobium fractions. All of the fission events were observed in the tantalum fractions, which implied that element 105 behaved more like tantalum under the chemical conditions of these experiments. These experiments were very successful, and not only demonstrated that chemical separation could be performed on single atoms of interest, but also lent proof to the identity of the parent nucleus as element 115. Subsequent analysis of the alpha spectra taken during the experiment further prove that the fission events observed during the two experiments came from element 105 as the decay daughter of element 115 and could not attributed to interference from other background species [16]. The final aspect of this project was the production of new isotopes and elements. All of the experiments were performed in Dubna at the U400 Cyclotron and the results are described in more detail in Refs. [2,3,5-8,11,12,14]. The first experiments were designed to establish the decay properties of isotopes of elements 112, 114, and 116 [5]. Because these isotopic signatures were established through these initial experiments, the discovery of element 118 [11] was possible, since the 118 nuclides decayed into these previously studied isotopes. This was the first successful report of the discovery of element 118, which was reported by the media to a large extent. The last experiment that was performed for this project was the production and detection of a new isotope of element 113 [14].« less

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...

Noncompetitive Homogeneous Detection of Small Molecules Using Synthetic Nanopeptamer-Based Luminescent Oxygen Channeling.

PubMed

Lassabe, Gabriel; Kramer, Karl; Hammock, Bruce D; González-Sapienza, Gualberto; González-Techera, Andrés

2018-05-15

Our group has previously developed immunoassays for noncompetitive detection of small molecules based on the use of phage borne anti-immunocomplex peptides. Recently, we substituted the phage particles by biotinylated synthetic anti-immunocomplex peptides complexed with streptavidin and named these constructs nanopeptamers. In this work, we report the results of combining AlphaLisa, a commercial luminescent oxygen channeling bead system, with nanopeptamers for the development of a noncompetitive homogeneous assay for the detection of small molecules. The signal generation of AlphaLisa assays relies on acceptor-donor bead proximity induced by the presence of the analyte (a macromolecule) simultaneously bound by antibodies immobilized on the surface of these beads. In the developed assay, termed as nanoAlphaLisa, bead proximity is sustained by the presence of a small model molecule (atrazine, MW = 215) using an antiatrazine antibody captured on the acceptor bead and an atrazine nanopeptamer on the donor bead. Atrazine is one of the most used pesticides worldwide, and its monitoring in water has relevant human health implications. NanoAlphaLisa allowed the homogeneous detection of atrazine down to 0.3 ng/mL in undiluted water samples in 1 h, which is 10-fold below the accepted limit in drinking water. NanoAlphaLisa has the intrinsic advantages for automation and high-throughput, simple, and fast homogeneous detection of target analytes that AlphaLisa assay provides.

Feasibility Study and System Architecture of Radioisotope Thermoelectric Generation Power Systems for USMC Forward Operating Bases

DTIC Science & Technology

2013-06-01

isotopes decay primarily through alpha particle emission, a small critical mass will cause sustained nuclear chain reaction, emitting gamma neutron...viii 1. Strontium-90 (Example) ....................................................................33 a. Pure Radioisotope Mass to Produce 300W...Power .................33 b. Compound Mass to Produce 300W Power .............................33 c. Estimated cost to Produce 300W power at BOL

Decay channels of Al L sub 2,3 excitons and the absence of O K excitons in. alpha. -Al sub 2 O sub 3

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

O'Brien, W.L.; Jia, J.; Dong, Q.

1991-12-15

The Al {ital L}{sub 2,3} and O {ital K} thresholds for single-crystal {alpha}-Al{sub 2}O{sub 3} have been studied by photoemission. Energy-distribution curves, constant-initial-state (CIS), and constant-final-state (CFS) spectra are reported and compared to the absorption spectrum reported previously. An exciton appears as a doublet at threshold in the Al {ital L}{sub 2,3} CFS, CIS, and absorption spectra. The details of the Al {ital L}{sub 2,3} CFS spectrum and absorption spectrum are similar, while the exciton is the only feature present in the CIS spectrum. Comparisons of the various Al {ital L}{sub 2,3} spectra allow the probabilities of different exciton decaymore » channels to be determined. The probability for nonradiative direct recombination of the exciton is found to be (8{plus minus}1)% and the probability for Auger decay of the exciton is found to be (72{plus minus}20)%. Comparisons of the O {ital K} CIS and CFS spectra suggest that no O {ital K} exciton is formed.« less

Far-Infrared Hydrogen Lasers in the Peculiar Star MWC 349A

NASA Technical Reports Server (NTRS)

Strelnitski, Vladimir; Haas, Michael R.; Smith, Howard A.; Erickson, Edwin F.; Colgan, Sean W. J.; Hollenbach, David J.

1996-01-01

Far-infrared hydrogen recombination lines H15(alpha)(169.4 micrometers), H12(alpha)(88.8 micrometers), and H10(alpha)(52.5 micrometers) were detected in the peculiar luminous star MWC 349A from the Kuiper Airborne Observatory. Here it is shown that at least H15(alpha) is strongly amplified, with the probable amplification factor being greater than or about equal to 10(exp 3) and a brightness temperature that is greater than or about equal to 10(exp 7) kelvin. The other two lines also show signs of amplification, although to a lesser degree. Beyond H10(alpha) the amplification apparently vanishes. The newly detected amplified lines fall into the laser wavelength domain. These lasers, as well as the previously detected hydrogen masers may originate in the photoionized circumstellar disk of MWC 349A and constrain the disk's physics and structure.

Pulse-shape discrimination of surface events in CdZnTe detectors for the COBRA experiment

NASA Astrophysics Data System (ADS)

Fritts, M.; Tebrügge, J.; Durst, J.; Ebert, J.; Gößling, C.; Göpfert, T.; Gehre, D.; Hagner, C.; Heidrich, N.; Homann, M.; Köttig, T.; Neddermann, T.; Oldorf, C.; Quante, T.; Rajek, S.; Reinecke, O.; Schulz, O.; Timm, J.; Wonsak, B.; Zuber, K.

2014-06-01

Events near the cathode and anode surfaces of a coplanar grid CdZnTe detector are identifiable by means of the interaction depth information encoded in the signal amplitudes. However, the amplitudes cannot be used to identify events near the lateral surfaces. In this paper a method is described to identify lateral surface events by means of their pulse shapes. Such identification allows for discrimination of surface alpha particle interactions from more penetrating forms of radiation, which is particularly important for rare event searches. The effectiveness of the presented technique in suppressing backgrounds due to alpha contamination in the search for neutrinoless double beta decay with the COBRA experiment is demonstrated.

Alternating current long range alpha particle detector

DOEpatents

MacArthur, Duncan W.; McAtee, James L.

1993-01-01

An alpha particle detector, utilizing alternating currents, whcih is capable of detecting alpha particles from distinct sources. The use of alternating currents allows use of simpler ac circuits which, in turn, are not susceptible to dc error components. It also allows the benefit of gas gain, if desired. In the invention, a voltage source creates an electric field between two conductive grids, and between the grids and a conductive enclosure. Air containing air ions created by collision with alpha particles is drawn into the enclosure and detected. In some embodiments, the air flow into the enclosure is interrupted, creating an alternating flow of ions. In another embodiment, a modulated voltage is applied to the grid, also modulating the detection of ions.

Alternating current long range alpha particle detector

DOEpatents

MacArthur, D.W.; McAtee, J.L.

1993-02-16

An alpha particle detector, utilizing alternating currents, which is capable of detecting alpha particles from distinct sources. The use of alternating currents allows use of simpler ac circuits which, in turn, are not susceptible to dc error components. It also allows the benefit of gas gain, if desired. In the invention, a voltage source creates an electric field between two conductive grids, and between the grids and a conductive enclosure. Air containing air ions created by collision with alpha particles is drawn into the enclosure and detected. In some embodiments, the air flow into the enclosure is interrupted, creating an alternating flow of ions. In another embodiment, a modulated voltage is applied to the grid, also modulating the detection of ions.

An astrophysical engine that stores gravitational work as nuclear Coulomb energy

NASA Astrophysics Data System (ADS)

Clayton, Donald

2014-03-01

I describe supernovae gravity machines that store large internal nuclear Coulomb energy, 0.80Z2A- 1 / 3MeV per nucleus. Excess of it is returned later by electron capture and positron emission. Decay energy manifests as (1) observable gamma-ray lines (2) light curves of supernovae (3) chemical energy of free carbon dissociated from CO molecules (4) huge abundances of radiogenic daughters. I illustrate by rapid silicon burning, a natural epoch in SN II. Gravitational work produces the high temperatures that photoeject nucleons and alpha particles from heavy nuclei. These are retained by other nuclei to balance photoejection rates (quasiequilibrium). The abundance distribution adjusts slowly as remaining abundance of Z = N 28Si decomposes, so p, n, α recaptures hug the Z = N line. This occurs in milliseconds, too rapidly for weak decay to alter bulk Z/N ratio. The figure displays those quasiequilibrium abundances color-coded to their decays. Z = N = 2k nuclei having k < 11 are stable, whereas k > 10 are radioactive owing to excess Coulomb energy. Weak decays radiate that excess energy weeks later to fuel the four macroscopic energetic phenomena cited. How startling to think of the Coulomb nuclear force as storing cosmic energy and its weak decay releasing macroscopic activation to SNII.

Time variations of magnetospheric intensities of outer zone protons, alpha particles and ions (Z greater than or equal to 2). Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Randall, B. A.

1973-01-01

A comprehensive study of the temporal behavior of trapped protons, alpha particles and ions (Z 2) in outer zone of the earth's magnetosphere has been made. These observations were made by the Injun V satellite during the first 21 months of operation, August 1968 to May 1970. Rapid increases in the observed number of particles followed by slower exponential decay characterize the data. Comparisons are made with the temporal behavior of interplanetary particles of the same energy observed by Explorer 35. Increases in the trapped fluxes generally correspond to enhanced interplanetary activity. The energy spectra of protons and alpha particles at L = 3 have similar shapes when compared on an energy per charge basis while the respective polar cap spectra have similar shape on an energy per nucleon basis. Apparent inward trans-L motion of energetic protons is observed. These particles are diffused inward by a process involving fluctuating electric fields. The loss of trapped low altitude protons, alpha particles and ions (Z 2) is controlled by coulombic energy loss in the atmosphere.

Boron modulates extracellular matrix and TNF alpha synthesis in human fibroblasts.

PubMed

Benderdour, M; Hess, K; Dzondo-Gadet, M; Nabet, P; Belleville, F; Dousset, B

1998-05-29

Boric acid was not mitogenic for human fibroblasts and it did not change cell viability until 0.5% (w/v). Boric acid treatment affected the metabolism of human dermal fibroblasts in culture, decreasing the synthesis of extracellular matrix macromolecules such as proteoglycans, collagen, and total proteins. It also increased the release of these molecules into the culture medium. The principal proteins secreted into the medium after boric acid treatment had molecular masses of 90, 70, 58, 49, and 43 kDa and faint bands were detected by electrophoresis between 14 and 30 kDa. hsp 70 and TNF alpha were detected among the secreted proteins by immunoblotting, and the amount of TNF alpha released was quantified by radioimmunoassay. Total mRNA levels were higher after boric acid treatment and peaked after 6 h of treatment. TNF alpha mRNA was undetectable in unstimulated fibroblasts and two TNF alpha mRNA bands were detected after stimulation: immature mRNA (4.8 kb) and mature TNF alpha mRNA (1.9 kb). Thus, the effects of boric acid observed in wound repair in vivo may be due to TNF alpha synthesis and secretion.

QUASARS PROBING QUASARS. IV. JOINT CONSTRAINTS ON THE CIRCUMGALACTIC MEDIUM FROM ABSORPTION AND EMISSION

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

Hennawi, Joseph F.; Prochaska, J. Xavier, E-mail: xavier@ucolick.org

2013-03-20

We have constructed a sample of 29 close projected quasar pairs where the background quasar spectrum reveals absorption from optically thick H I gas associated with the foreground quasar. These unique sightlines allow us to study the quasar circumgalactic medium (CGM) in absorption and emission simultaneously, because the background quasar pinpoints large concentrations of gas where Ly{alpha} emission, resulting from quasar-powered fluorescence, resonant Ly{alpha} scattering, and/or cooling radiation, is expected. A sensitive search (1{sigma} surface-brightness limits of SB{sub Ly{alpha}}{approx_equal}3 Multiplication-Sign 10{sup -18} erg s{sup -1} cm{sup -2} arcsec{sup -2}) for diffuse Ly{alpha} emission in the environments of the foreground (predominantlymore » radio-quiet) quasars is conducted using Gemini/GMOS and Keck/LRIS slit spectroscopy. We fail to detect large-scale {approx}100 kpc Ly{alpha} emission, either at the location of the optically thick absorbers or in the foreground quasar halos, in all cases except a single system. We interpret these non-detections as evidence that the gas detected in absorption is shadowed from the quasar UV radiation due to obscuration effects, which are frequently invoked in unified models of active galactic nuclei. Small-scale R {approx}< 50 kpc extended Ly{alpha} nebulosities are detected in 34% of our sample, which are likely the high-redshift analogs of the extended emission-line regions (EELRs) commonly observed around low-redshift (z < 0.5) quasars. This may be fluorescent recombination radiation from a population of very dense clouds with a low covering fraction illuminated by the quasar. We also detect a compact high rest-frame equivalent width (W{sub Ly{alpha}} > 50 A) Ly{alpha}-emitter with luminosity L{sub Ly{alpha}} = 2.1 {+-} 0.32 Multiplication-Sign 10{sup 41} erg s{sup -1} at small impact parameter R = 134 kpc from one foreground quasar, and argue that it is more likely to result from quasar-powered fluorescence, than simply be a star-forming galaxy clustered around the quasar. Our observations imply that much deeper integrations with upcoming integral-field spectrometers such as MUSE and KCWI will be able to routinely detect a diffuse Ly{alpha} glow around bright quasars on scales R {approx} 100 kpc and thus directly image the CGM.« less

Barium Tagging n Solid Xenon for nEXO Neutrinoless Double Beta Decay

NASA Astrophysics Data System (ADS)

Walton, Tim; Chambers, Chris; Craycraft, Adam; Fairbank, William; nEXO Collaboration

2015-04-01

nEXO is a next-generation experiment designed to search for neutrinoless double beta decay of the isotope Xe136 in a liquid xenon time projection chamber. Positive observation of this decay would determine the nature of the neutrino to be a Majorana particle. Since the daughter of this decay is barium (Ba136), detecting the presence of Ba136 at a decay site (called ``barium tagging'') would provide strong rejection of backgrounds in the search for this decay. This would involve detecting a single barium ion from within a macroscopic volume of liquid xenon. This technique may be available for a second phase of the nEXO detector and sensitivity beyond the inverted hierarchy to neutrino oscillations. Several methods of barium tagging are being explored by the nEXO collaboration, but here we present a method of trapping the barium ion/atom (it may neutralize) in solid xenon (SXe) at the end of a cold probe, and then detecting the ion/atom by its fluorescence in the SXe. Our group at CSU has been studying the fluorescence of Ba in SXe by laser excitation, in order to ultimately detect a single Ba +/Ba in a SXe sample. We present studies of fluorescence signals, as well as recent results on imaging small numbers of Ba atoms in SXe, in a focused laser region. This work is supported by grants from the National Science Foundation and the Department of Energy.

SU-C-9A-04: Alternative Analytic Solution to the Paralyzable Detector Model to Calculate Deadtime and Deadtime Loss

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

Siman, W; Kappadath, S

2014-06-01

Purpose: Some common methods to solve for deadtime are (1) dual-source method, which assumes two equal activities; (2) model fitting, which requires multiple acquisitions as source decays; and (3) lossless model, which assumes no deadtime loss at low count rates. We propose a new analytic alternative solution to calculate deadtime for paralyzable gamma camera. Methods: Deadtime T can be calculated analytically from two distinct observed count rates M1 and M2 when the ratio of the true count rates alpha=N2/N1 is known. Alpha can be measured as a ratio of two measured activities using dose calibrators or via radioactive decay. Knowledgemore » of alpha creates a system with 2 equations and 2 unknowns, i.e., T and N1. To verify the validity of the proposed method, projections of a non-uniform phantom (4GBq 99mTc) were acquired in using Siemens SymbiaS multiple times over 48 hours. Each projection has >100kcts. The deadtime for each projection was calculated by fitting the data to a paralyzable model and also by using the proposed 2-acquisition method. The two estimates of deadtime were compared using the Bland-Altmann method. In addition, the dependency of uncertainty in T on uncertainty in alpha was investigated for several imaging conditions. Results: The results strongly suggest that the 2-acquisition method is equivalent to the fitting method. The Bland-Altman analysis yielded mean difference in deadtime estimate of ∼0.076us (95%CI: -0.049us, 0.103us) between the 2-acquisition and model fitting methods. The 95% limits of agreement were calculated to be -0.104 to 0.256us. The uncertainty in deadtime calculated using the proposed method is highly dependent on the uncertainty in the ratio alpha. Conclusion: The 2-acquisition method was found to be equivalent to the parameter fitting method. The proposed method offers a simpler and more practical way to analytically solve for a paralyzable detector deadtime, especially during physics testing.« less

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. D.; Segura Delgado, M. A.; Courbon, B.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Sculac, T.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Ferencek, D.; Kadija, K.; Mesic, B.; Starodumov, A.; Susa, T.; Ather, M. W.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Finger, M.; Finger, M.; Carrera Jarrin, E.; Abdelalim, A. A.; Assran, Y.; Elgammal, S.; Bhowmik, S.; Dewanjee, R. K.; Kadastik, M.; Perrini, L.; Raidal, M.; Veelken, C.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Faure, J. L.; Ferri, F.; Ganjour, S.; Ghosh, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Leloup, C.; Locci, E.; Machet, M.; Malcles, J.; Negro, G.; Rander, J.; Rosowsky, A.; Sahin, M. Ö.; Titov, M.; Abdulsalam, A.; Amendola, C.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Charlot, C.; Granier de Cassagnac, R.; Jo, M.; Kucher, I.; Lisniak, S.; Lobanov, A.; Martin Blanco, J.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Stahl Leiton, A. G.; Yilmaz, Y.; Zabi, A.; Zghiche, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. 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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. P.; Tosi, N.; Albergo, S.; Costa, S.; Di Mattia, A.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Chatterjee, K.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Latino, G.; Lenzi, P.; Meschini, M.; Paoletti, S.; Russo, L.; Sguazzoni, G.; Strom, D.; Viliani, L.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Primavera, F.; Calvelli, V.; Ferro, F.; Ravera, F.; Robutti, E.; Tosi, S.; Benaglia, A.; Beschi, A.; Brianza, L.; Brivio, F.; Ciriolo, V.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Ghezzi, A.; Govoni, P.; Malberti, M.; Malvezzi, S.; Manzoni, R. A.; Menasce, D.; Moroni, L.; Paganoni, M.; Pauwels, K.; Pedrini, D.; Pigazzini, S.; Ragazzi, S.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; Di Guida, S.; Fabozzi, F.; Fienga, F.; Iorio, A. O. M.; Khan, W. 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. 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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. 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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

Silencing alpha-fetoprotein inhibits VEGF and MMP-2/9 production in human hepatocellular carcinoma cell.

PubMed

Meng, Wenbo; Li, Xun; Bai, Zhongtian; Li, Yan; Yuan, Jinqiu; Liu, Tao; Yan, Jun; Zhou, Wence; Zhu, Kexiang; Zhang, Hui; Li, Yumin

2014-01-01

Alpha-fetoprotein not only serves as a diagnostic marker for liver cancer, but also posses a variety of biological functions. However, the role of Alpha-fetoprotein on tumor angiogenesis and cell invasion remains incompletely understood. In this study, we aimed to evaluate if Alpha-fetoprotein can regulate the major angiogenic factors and matrix metalloproteinases in human liver cancer cells. Alpha-fetoprotein silencing was achieved by Stealth RNAi. Expression of Alpha-fetoprotein was examined by a full-automatic electrochemistry luminescence immunity analyzer. Expression of VEGF, VEGFR-2, MMP-9, and MMP-2 was examined by Western blot and immunocytochemistry. Apoptosis was detected by TUNEL assay. Angiogenesis was detected by in vitro angiogenesis assay kit. Silencing of Alpha-fetoprotein led to an increased apoptosis, which was associated with a decreased expression of vascular endothelial growth factor, vascular endothelial growth factor receptor 2, matrix metalloproteinases-2/9. These results suggest that Alpha-fetoprotein may play a regulatory role on angiogenesis and cell invasion during liver cancer development.

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.

Dark Matter Search Results from the PICO-60 C$$_3$$F$$_8$$ Bubble Chamber

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

Amole, C.; et al.

2017-02-24

New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of Cmore » $$_3$$F$$_8$$ located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60 C$$_3$$F$$_8$$ exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than 1 event per month. A blind analysis of an efficiency-corrected 1167-kg-day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the WIMP-proton spin-dependent cross section at 3.4 $$\\times$$ 10$$^{-41}$$ cm$^2$ for a 30-GeV$$\\thinspace$$c$$^{-2}$$ WIMP, more than one order of magnitude improvement from previous PICO results.« less

Modern Measurements of Uranium Decay Rates

NASA Astrophysics Data System (ADS)

Parsons-Moss, T.; Faye, S. A.; Williams, R. W.; Wang, T. F.; Renne, P. R.; Mundil, R.; Harrison, M.; Bandong, B. B.; Moody, K.; Knight, K. B.

2015-12-01

It has been widely recognized that accurate and precise decay constants (λ) are critical to geochronology as highlighted by the EARTHTIME initiative, particularly the calibration benchmarks λ235U and λ238U. [1] Alpha counting experiments in 1971[2] measured λ235U and λ238U with ~0.1% precision, but have never been independently validated. We are embarking on new direct measurements of λ235U, λ238U, λ234Th, and λ234U using independent approaches for each nuclide. For the measurement of λ235U, highly enriched 235U samples will be chemically purified and analyzed for U concentration and isotopic composition by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Thin films will be electrodeposited from these solutions and the α activity will be measured in an α-γ coincidence counting apparatus, which allows reduced uncertainty in counting efficiency while achieving adequate counting statistics. For λ238U measurement we will measure ingrowth of 234Th in chemically purified, isotopically enriched 238U solutions, by quantitatively separating the Th and allowing complete decay to 234U. All of the measurements will be done using MC-ICP-MS aiming at 0.05% precision. This approach is expected to result in values of λ238U with less than 0.1% uncertainty, if combined with improved λ234Th measements. These will be achieved using direct decay measurements with an E-ΔE charged particle telescope in coincidence with a gamma detector. This system allows measurement of 234Th β-decay and simultaneous detection and identification of α particles emitted by the 234U daughter, thus observing λ234U at the same time. The high-precision λ234U obtained by the direct activity measurements can independently verify the commonly used values obtained by indirect methods.[3] An overarching goal of the project is to ensure the quality of results including metrological traceability in order to facilitate implementation across diverse disciplines. [1] T.M. Harrison et al., (2015) It's About Time:Opportunities and Challenges for U.S. Geological Survey. Institute of Geophysics and Planetary Physics Publication 6539, University of California, Los Angeles [2] A. H. Jaffey et al., Physical Review C, 4, 5, (1971), 1889-1906 [3] H. Cheng et al., Chemical Geology, 169, (2000), 17-33

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...

A consumer`s guide to lattice QCD results

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

DeGrand, T.

1994-12-01

The author presents an overview of recent lattice QCD results on hadron spectroscopy and matrix elements. Case studies include light quark spectroscopy, the determination of {alpha}{sub s} from heavy quark spectroscopy, the D-meson decay constant, a calculation of the Isgur-Wise function, and some examples of the (lack of) effect of sea quarks on matrix elements. The review is intended for the nonexpert.

Expression of the transforming growth factor alpha protooncogene in differentiating human promyelocytic leukemia (HL-60) cells.

PubMed

Walz, T M; Malm, C; Wasteson, A

1993-01-01

The process of myeloid differentiation in human promyelocytic leukemia cells (HL-60) is accompanied by the coordinate expression of numerous protooncogenes. To investigate the expression of transforming growth factor alpha (TGF-alpha) in myeloid differentiation, HL-60 cells were induced to differentiate into granulocytes with 1.25% dimethyl sulfoxide, 0.2 microM all-trans retinoic acid, or 500 microM N6,O2-dibutyryladenosine-3'5'-cyclic monophosphate or differentiated along the monocyte/macrophage pathway with 0.1 microM phorbol-12-myristate-13-acetate. Using Northern blot analyses, TGF-alpha transcripts were detected within 24 h of treatment in cells differentiating toward granulocytes; maximal levels of gene expression were reached after 3 days or later and remained essentially constant throughout the observation period. These cells released TGF-alpha protein, as demonstrated by analysis of the incubation medium. In contrast, no TGF-alpha RNA or protein was detectable in HL-60 cell cultures when induced with phorbol-12-myristate-13-acetate. Epidermal growth factor receptor transcripts could not be detected either in undifferentiated or in differentiated HL-60 cells; therefore it appears as if an autocrine loop involving TGF-alpha in HL-60 cells is unlikely. In conclusion, the results demonstrate, for the first time, the expression of TGF-alpha in human granulocyte precursor cells. Our findings may indicate novel regulatory pathways in hematopoiesis.

Method for radioactivity monitoring

DOEpatents

Umbarger, C. John; Cowder, Leo R.

1976-10-26

The disclosure relates to a method for analyzing uranium and/or thorium contents of liquid effluents preferably utilizing a sample containing counting chamber. Basically, 185.7-keV gamma rays following .sup.235 U alpha decay to .sup.231 Th which indicate .sup.235 U content and a 63-keV gamma ray doublet found in the nucleus of .sup.234 Pa, a granddaughter of .sup.238 U, are monitored and the ratio thereof taken to derive uranium content and isotopic enrichment .sup.235 U/.sup.235 U + .sup.238 U) in the liquid effluent. Thorium content is determined by monitoring the intensity of 238-keV gamma rays from the nucleus of .sup.212 Bi in the decay chain of .sup.232 Th.

Numerical Simulations of Homogeneous Turbulence Using Lagrangian-Averaged Navier-Stokes Equations

NASA Technical Reports Server (NTRS)

Mohseni, Kamran; Shkoller, Steve; Kosovic, Branko; Marsden, Jerrold E.; Carati, Daniele; Wray, Alan; Rogallo, Robert

2000-01-01

The Lagrangian-averaged Navier-Stokes (LANS) equations are numerically evaluated as a turbulence closure. They are derived from a novel Lagrangian averaging procedure on the space of all volume-preserving maps and can be viewed as a numerical algorithm which removes the energy content from the small scales (smaller than some a priori fixed spatial scale alpha) using a dispersive rather than dissipative mechanism, thus maintaining the crucial features of the large scale flow. We examine the modeling capabilities of the LANS equations for decaying homogeneous turbulence, ascertain their ability to track the energy spectrum of fully resolved direct numerical simulations (DNS), compare the relative energy decay rates, and compare LANS with well-accepted large eddy simulation (LES) models.

Chinks in Solar Dynamo Theory: Turbulent Diffusion, Dynamo Waves and Magnetic Helicity

NASA Technical Reports Server (NTRS)

DeLuca, E. E.; Hurlburt, N.

1998-01-01

In this first year of our investigation we explored the role of compressibility and stratification in the dissipation of magnetic fields. The predictions of Mean Field Electrodynamics have been questioned because of the strong feedback of small scale magnetic structure on the velocity fields. In 2-D, this nonlinear feedback results in a lengthening of the turbulent decay time. In 3-D alpha-quenching is predicted. Previous studies assumed a homogeneous fluid. This first year we present recent results from 2-D compressible MHD decay simulations in a highly stratified atmosphere that more closely resembles to solar convection zone. We have applied for NCCS T3E time to assist in the performance of our 3-D calculations.

Gold coated lanthanide phosphate nanoparticles for targeted alpha generator radiotherapy.

PubMed

McLaughlin, Mark F; Woodward, Jonathan; Boll, Rose A; Wall, Jonathan S; Rondinone, Adam J; Kennel, Stephen J; Mirzadeh, Saed; Robertson, J David

2013-01-01

Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo α-generator targeted radiotherapies can deliver multiple α particles to a receptor site dramatically amplifying the radiation dose delivered to the target. The major challenge with α-generator radiotherapies is that traditional chelating moieties are unable to sequester the radioactive daughters in the bioconjugate which is critical to minimize toxicity to healthy, non-target tissue. The recoil energy of the (225)Ac daughters following α decay will sever any metal-ligand bond used to form the bioconjugate. This work demonstrates that an engineered multilayered nanoparticle-antibody conjugate can deliver multiple α radiations and contain the decay daughters of (225)Ac while targeting biologically relevant receptors in a female BALB/c mouse model. These multi-shell nanoparticles combine the radiation resistance of lanthanide phosphate to contain (225)Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established gold chemistry for attachment of targeting moieties.

Investigating 3-body Decays of Cluster States with the PAT-TPC

NASA Astrophysics Data System (ADS)

Carpenter, Lisa; Ayyad Limonge, Y.; Bazin, D.; Beceiro-Novo, S.; Bradt, J.; Cortesi, M.; Mittig, W.; Ahn, T.; Kolata, J. J.; Meisel, Z.; Bechetti, F. D.; Fritsch, A.; Howard, A.

2016-03-01

Recent model calculations with most advanced methods for cluster states have shown the need of experimental data to probe the structure of light exotic nuclei, including those with α-clustering, such as 14C. The Prototype Active Target Time Projection Chamber (PAT-TPC) allows us to investigate these types of structures, giving access to the full excitation function with a single beam energy. This type of experiment measures resonances in 14C that can be compared to the models. With an improved Micromegas pad plane with a circular backgammon design we are able to investigate 3-body decays in addition to 2-body scattering. The measurements were carried out by resonant alpha-scattering on 10Be beam delivered by the TwinSol facility at the University of Notre Dame. We also observed the 3-body decay of the Hoyle State in 12C from a 12N or 12B beam with the same device. Preliminary results will be presented. This work is supported by the National Science Foundation.

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...

Time-averaged exposures to 220Rn and 222Rn progeny in Colorado homes.

PubMed

Martz, D E; Falco, R J; Langner, G H

1990-06-01

Week-long time-averaged exposures to naturally occurring 220Rn and 222Rn progeny have been measured at several locations in Colorado by monitoring the alpha activity collected continuously on a fixed-membrane filter. The alpha-energy spectrum associated with the activity collected on the filter was recorded every 15 min using a microcomputer-controlled alpha spectrometer. The alpha counts observed in three energy regions permitted complete separation of the contributions from each decay chain, and calculation of the separate time-averaged potential alpha-energy concentrations in air from 220Rn progeny, PAEC(Tn), and from 222Rn progeny, PAEC(Rn). The time-averaged PAEC(Tn) ranged from 0.3 to 6.9 mWL at 12 indoor locations, and the time-averaged PAEC(Rn) ranged from 1.0 to 59.0 mWL. The ratios of the indoor PAEC(Tn) to indoor PAEC(Rn) ranged from 0.09 to 0.58, with an overall average ratio of 0.32 and a standard deviation of 0.15. The 10 L min-1 flow rate through the filter was selected to approximate the air intake rate of a resting human; the time-averaged PAEC thus represents the progeny concentrations that would have been inhaled by a person breathing the same atmosphere.

A Correlation Between the Intrinsic Brightness and Average Decay Rate of Gamma-Ray Burst X-Ray Afterglow Light Curves

NASA Technical Reports Server (NTRS)

Racusin, J. L.; Oates, S. R.; De Pasquale, M.; Kocevski, D.

2016-01-01

We present a correlation between the average temporal decay (alpha X,avg, greater than 200 s) and early-time luminosity (LX,200 s) of X-ray afterglows of gamma-ray bursts as observed by the Swift X-ray Telescope. Both quantities are measured relative to a rest-frame time of 200 s after the gamma-ray trigger. The luminosity â€" average decay correlation does not depend on specific temporal behavior and contains one scale-independent quantity minimizing the role of selection effects. This is a complementary correlation to that discovered by Oates et al. in the optical light curves observed by the Swift Ultraviolet Optical Telescope. The correlation indicates that, on average, more luminous X-ray afterglows decay faster than less luminous ones, indicating some relative mechanism for energy dissipation. The X-ray and optical correlations are entirely consistent once corrections are applied and contamination is removed. We explore the possible biases introduced by different light-curve morphologies and observational selection effects, and how either geometrical effects or intrinsic properties of the central engine and jet could explain the observed correlation.

Distribution of alpha3, alpha5 and alpha(v) integrin subunits in mature and immature human oocytes.

PubMed

Capmany, G; Mart, M; Santaló, J; Bolton, V N

1998-10-01

The distribution of three integrin subunits, alpha3, alpha5 and alpha(v), in immature and mature human oocytes has been examined using immunofluorescence and confocal microscopy. The results demonstrate that both alpha5 and alpha(v) are present at the germinal vesicle stage, while alpha3 was only detected in oocytes after germinal vesicle breakdown, in metaphase I and II stage oocytes. The cortical concentration of integrin subunits alpha3 and alpha5 is consistent with their localization in the oolemma. In contrast, the homogeneous distribution of alpha(v) throughout the oocyte suggests the existence of cytoplasmic reservoirs of this protein in the oocyte.

[Effect of Yiguan Decoction on differentiation of bone marrow mesenchymal stem cells into hepatocyte-like cells: an experimental research].

PubMed

Ping, Jian; Chen, Hong-Yun; Yang, Zhou; Yang, Cheng; Xu, Lie-Ming

2014-03-01

To observe the effect of Yiguan Decoction (YGD) on differentiation of bone marrow mesenchymal stem cells (BMSCs) into hepatocyte-like cells in vitro. Rat BMSCs were isolated using whole bone marrow adherent method. The properties of BMSCs were identified by analyzing the expression of surface cytokines by flow cytometry. The third passage cells were differentiated into fat cells to identify their features. BMSCs were incubated with hepatocyte growth factor (HGF) plus fibroblast growth factor 4 (FGF4) or YGD containing serum YGD for 21 days. The mRNA expression of alpha-fetoprotein (alphaAFP), albumin (Alb), and hepatocyte nuclear factor 4alpha (HNF4alpha) were detected by real time PCR. Expression of AFP and cytokeratin 18 (CK18) protein was detected by cell immunofluorescence. Glycogen synthesis was observed using periodic acid-Schiff stain (PAS). CK18, Wnt 3alpha, and alphacatenin protein expressions were detected by Western blot. High expression of CD90, CD29, and CD44, and low expression of CD34 and CD11b were observed in BMSCs isolated by whole bone mar- row adherent method, and numerous lipid droplets were observed in BMSCs using oil red O staining. Both YGD containing serum and growth factor stimulated the expression levels of Alb, AFP, HNF4alpha mRNA and CK18 protein. The down-regulated expression of Wnt 3alpha and beta-catenin could be detected at 21 days after induction. The synthesized glycogen granule could be seen. Down-regulated Wnt 3alpha and beta-catenin expression could also be observed. YGD could induce the differentiation of rat BMSCs into hepatocyte-like cells, which was related to down-regulating Wnt/beta-catenin signal pathway.

Evaluation of acoustic tomography for tree decay detection

Treesearch

Shanquing Liang; Xiping Wang; Janice Wiedenbeck; Zhiyong Cai; Feng Fu

2008-01-01

In this study, the acoustic tomography technique was used to detect internal decay in high value black cherry (Prunus seratina) trees. Two-dimensional images of the cross sections of the tree samples were constructed using PiCUS Q70 software. The trees were felled following the field test, and a disc from each testing elevation was subsequently cut...

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...

A one-dimensional free energy surface does not account for two-probe folding kinetics of protein alpha(3)D.

PubMed

Liu, Feng; Dumont, Charles; Zhu, Yongjin; DeGrado, William F; Gai, Feng; Gruebele, Martin

2009-02-14

We present fluorescence-detected measurements of the temperature-jump relaxation kinetics of the designed three-helix bundle protein alpha(3)D taken under solvent conditions identical to previous infrared-detected kinetics. The fluorescence-detected rate is similar to the IR-detected rate only at the lowest temperature where we could measure it (326 K). The fluorescence-detected rate decreases by a factor of 3 over the 326-344 K temperature range, whereas the IR-detected rate remains nearly constant over the same range. To investigate this probe dependence, we tested an extensive set of physically reasonable one-dimensional (1D) free energy surfaces by Langevin dynamics simulation. The simulations included coordinate- and temperature-dependent roughness, diffusion coefficients, and IR/fluorescence spectroscopic signatures. None of these can reproduce the IR and fluorescence data simultaneously, forcing us to the conclusion that a 1D free energy surface cannot accurately describe the folding of alpha(3)D. This supports the hypothesis that alpha(3)D has a multidimensional free energy surface conducive to downhill folding at 326 K, and that it is already an incipient downhill folder with probe-dependent kinetics near its melting point.

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

Prospects for future experiments to search for nucleon decay

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

Ayres, D.S.; Heller, K.; LoSecco, J.

1982-01-01

We review the status of theoretical expectations and experimental searches for nucleon decay, and predict the sensitivities which could be reached by future experiments. For the immediate future, we concur with the conclusions of the 1982 Summer Workshop on Proton Decay Experiments: all detectors now in operation or construction will be relatively insensitive to some potentially important decay modes. Next-generation experiments must therefore be designed to search for these modes, and should be undertaken whether or not present experiments detect nucleon decay in other modes. These future experiments should be designed to push the lifetime limits on all decay modesmore » to the levels at which irreducible cosmic-ray neutrino-induced backgrounds become important. Since the technology for these next-generation experiments is available now, the timetable for starting work on them will be determined by funding constraints and not by the need for extensive development of detectors. Efforts to develop advanced detector techniques should also be pursued, in order to mount more sensitive searches than can be envisioned using current technology, or to provide the most precise measurements possible of the properties of the nucleon decay interaction if it should occur at a detectable rate.« less

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.

High-throughput screening in two dimensions: binding intensity and off-rate on a peptide microarray.

PubMed

Greving, Matthew P; Belcher, Paul E; Cox, Conor D; Daniel, Douglas; Diehnelt, Chris W; Woodbury, Neal W

2010-07-01

We report a high-throughput two-dimensional microarray-based screen, incorporating both target binding intensity and off-rate, which can be used to analyze thousands of compounds in a single binding assay. Relative binding intensities and time-resolved dissociation are measured for labeled tumor necrosis factor alpha (TNF-alpha) bound to a peptide microarray. The time-resolved dissociation is fitted to a one-component exponential decay model, from which relative dissociation rates are determined for all peptides with binding intensities above background. We show that most peptides with the slowest off-rates on the microarray also have the slowest off-rates when measured by surface plasmon resonance (SPR). 2010 Elsevier Inc. All rights reserved.

Study on molecular epidemiology of the alpha-thalassemias in Liuzhou City, Guangxi Autonomous Region, China.

PubMed

Cai, Ren; Liu, Jingzhong; Wang, Lirong; Liang, Xin; Xiao, Bai; Su, Liu; Zhou, Yan; Pan, Lizhen

2004-01-01

Guangxi is one of the provinces of Southern China with the highest incidence of alpha-thalassemia (thal). Liuzhou is the second biggest city in Guangxi. To find out the incidence of the various alpha-thal genotypes, and their distribution in the Liuzhou area, an F820 Blood Cell Analysis System was used to measure the parameters of red blood cells. A SPIFE Rapid Auto-Electrophoresis System was used to analyze the normal and abnormal hemoglobins (Hbs). Multiplex polymerase chain reaction (mPCR) was used to detect the alpha-globin genotypes. Thirty-two (2.05%) out of 7805 young couples undergoing pre-marriage counseling, were diagnosed as having an Hb H (beta4) disease. The study of 1228 cord blood samples revealed 138 newborn children carrying an alpha-thal determinant with nine different genotypes, thus making the total incidence of alpha-thal 11.24%. Among 185 cases of Hb H, 119 (64.1%) were confirmed as being deletional, and 66 cases (35.7%) nondeletional types. The severity of the Hb H diseases could be classified in the following order: alphaCSalpha/--SEA (alphaConstant (Spring)alpha/--Southeast Asia); alpha(-4.2)/--SEA; alpha(-3.7)/--SEA. Ten cases of alpha-thal determinants were found in combination with beta-thal. The mPCR technique can detect all kinds of combinations of the three common large deletions (--SEA, alpha(-4.2) and alpha(-3.7)) accurately and conveniently.

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.

Development of a homogeneous pulse shape discriminating flow-cell radiation detection system

NASA Astrophysics Data System (ADS)

Hastie, K. H.; DeVol, T. A.; Fjeld, R. A.

1999-02-01

A homogeneous flow-cell radiation detection system which utilizes coincidence counting and pulse shape discrimination circuitry was assembled and tested with five commercially available liquid scintillation cocktails. Two of the cocktails, Ultima Flo (Packard) and Mono Flow 5 (National Diagnostics) have low viscosities and are intended for flow applications; and three of the cocktails, Optiphase HiSafe 3 (Wallac), Ultima Gold AB (Packard), and Ready Safe (Beckman), have higher viscosities and are intended for static applications. The low viscosity cocktails were modified with 1-methylnaphthalene to increase their capability for alpha/beta pulse shape discrimination. The sample loading and pulse shape discriminator setting were optimized to give the lowest minimum detectable concentration for alpha radiation in a 30 s count time. Of the higher viscosity cocktails, Optiphase HiSafe 3 had the lowest minimum detectable activities for alpha and beta radiation, 0.2 and 0.4 Bq/ml for 233U and 90Sr/ 90Y, respectively, for a 30 s count time. The sample loading was 70% and the corresponding alpha/beta spillover was 5.5%. Of the low viscosity cocktails, Mono Flow 5 modified with 2.5% (by volume) 1-methylnaphthalene resulted in the lowest minimum detectable activities for alpha and beta radiation; 0.3 and 0.5 Bq/ml for 233U and 90Sr/ 90Y, respectively, for a 30 s count time. The sample loading was 50%, and the corresponding alpha/beta spillover was 16.6%. HiSafe 3 at a 10% sample loading was used to evaluate the system under simulated flow conditions.

Diagnostic performance of tumor markers AFP and PIVKA-II in Chinese hepatocellular carcinoma patients.

PubMed

Huang, Shujing; Jiang, Feifei; Wang, Ying; Yu, Yanhua; Ren, Siqian; Wang, Xiaowei; Yin, Peng; Lou, Jinli

2017-06-01

Alpha-fetoprotein is an effective biomarker as an aid in hepatocellular carcinoma detection in many countries. However, alpha-fetoprotein has its limitations, especially in early hepatocellular carcinoma diagnosis. Protein induced by vitamin K absence or antagonist-II is another biomarker that is used for hepatocellular carcinoma detection. The aim of this study is to compare the diagnostic performance of alpha-fetoprotein and protein induced by vitamin K absence or antagonist-II alone and in combination to explore improving biomarker performance as an aid in early hepatocellular carcinoma detection. In this study a total of 582 serum samples including 132 hepatocellular carcinoma patients, 250 non-hepatocellular carcinoma patients, and 200 healthy volunteers were collected. Alpha-fetoprotein and protein induced by vitamin K absence or antagonist-II levels were measured by both chemiluminescent enzyme immunoassay on LUMIPULSE platform and by chemiluminescent microparticle immunoassay on ARCHITECT platform. Receiver operation characteristic curve analyses were performed for each biomarker and in combination. The results showed that Alpha-fetoprotein and protein induced by vitamin K absence or antagonist-II in combination have shown higher area under the curve compared to alpha-fetoprotein alone for diagnosis in whole patients (0.906 vs 0.870) in hepatocellular carcinoma early-stage patients (0.809 vs 0.77) and in hepatitis B virus-related hepatocellular carcinoma patients (0.851 vs 0.788) with ARCHITECT platform. Protein induced by vitamin K absence or antagonist-II showed higher area under the curve than alpha-fetoprotein for diagnosis of hepatitis B virus-related hepatocellular carcinoma patients (0.901 vs 0.788).We conclude that Combining alpha-fetoprotein and protein induced by vitamin K absence or antagonist-II may improve the diagnostic value for early detection of hepatocellular carcinoma. Protein induced by vitamin K absence or antagonist-II performs better than alpha-fetoprotein in diagnosis of hepatitis B virus-related hepatocellular carcinoma patients.

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.

Spent nuclear fuel/water interface behavior: Alpha dose rate profile determination for model surfaces and microcracks by using Monte-Carlo methods

NASA Astrophysics Data System (ADS)

Tribet, M.; Mougnaud, S.; Jégou, C.

2017-05-01

This work aims to better understand the nature and evolution of energy deposits at the UO2/water reactional interface subjected to alpha irradiation, through an original approach based on Monte-Carlo-type simulations, using the MCNPX code. Such an approach has the advantage of describing the energy deposit profiles on both sides of the interface (UO2 and water). The calculations have been performed on simple geometries, with data from an irradiated UOX fuel (burnup of 47 GWd.tHM-1 and 15 years of alpha decay). The influence of geometric parameters such as the diameter and the calculation steps at the reactional interface are discussed, and the exponential laws to be used in practice are suggested. The case of cracks with various different apertures (from 5 to 35 μm) has also been examined and these calculations have also enabled new information on the mean range of radiolytic species in cracks, and thus on the local chemistry.

Measurement of the {sup 12}C({alpha},{gamma}){sup 16}O reaction at TRIAC

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

Makii, H.; Miyatake, H.; Wakabayashi, Y.

2012-11-12

We have measured the {gamma}-ray angular distribution of the {sup 12}C({alpha},{gamma}){sup 16}O reaction at TRIAC (Tokai Radioactive Ion Accelerator Complex) to accurately determine the E1 and E2 cross sections. In this experiment, we used high efficiency anti-Compton NaI(T1) spectrometers to detect a {gamma}-ray from the reaction with large S/N ratio, intense pulsed {alpha}-beams to discriminate true event from background events due to neutrons from {sup 13}C({alpha},n){sup 16}O reaction with a time-of-flight (TOF) method. We succeeded in removing a background events due to neutrons and clearly detected {gamma}-ray from the {sup 12}C({alpha}{gamma}){sup 16}O reaction with high statistics.

Sediment data for computations of deposition rates in the tidal Potomac system, Maryland and Virginia

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

Glenn, J.L.; Martin, E.A.; Rice, C.A.

1986-01-01

Sixty-two cores ranging in length from 33 to 1,002 cm were collected from the tidal Potomac system and from selected tributaries downstream from the local head-of-tides between June 1978 and July 1981. Segments from selected depths below the sediment surface have been analyzed for a variety of constituents, including lead-210, trace metals, nutrients, and particle size. The core sites were positioned throughout the hydrologic divisions and geomorphic units of the tidal Potomac system and in water depths ranging from 1 to 30 cm. Alpha counting methods were used to determine the polonium-210 radioactivity and secular equilibrium was assumed between lead-210more » and polonium-210. The alpha decay of polonium-210 provides a measure of the lead-210 radioactivity of the lead-210 produced by in-situ decay of radium-226 in the sediment column and the lead-210 from external sources. Only the unsupported lead-210 was used in computations of the deposition rate. The background level of lead-210 in tidal Potomac system sediment cores usually is based on in-situ measurements of total lead-210 at depths below which no unsupported lead-210 is believed to be present, and the lead-210 concentrations are relatively constant. 6 refs., 3 figs., 1 tab.« less

Polonium and lung cancer.

PubMed

Zagà, Vincenzo; Lygidakis, Charilaos; Chaouachi, Kamal; Gattavecchia, Enrico

2011-01-01

The alpha-radioactive polonium 210 (Po-210) is one of the most powerful carcinogenic agents of tobacco smoke and is responsible for the histotype shift of lung cancer from squamous cell type to adenocarcinoma. According to several studies, the principal source of Po-210 is the fertilizers used in tobacco plants, which are rich in polyphosphates containing radio (Ra-226) and its decay products, lead 210 (Pb-210) and Po-210. Tobacco leaves accumulate Pb-210 and Po-210 through their trichomes, and Pb-210 decays into Po-210 over time. With the combustion of the cigarette smoke becomes radioactive and Pb-210 and Po-210 reach the bronchopulmonary apparatus, especially in bifurcations of segmental bronchi. In this place, combined with other agents, it will manifest its carcinogenic activity, especially in patients with compromised mucous-ciliary clearance. Various studies have confirmed that the radiological risk from Po-210 in a smoker of 20 cigarettes per day for a year is equivalent to the one deriving from 300 chest X-rays, with an autonomous oncogenic capability of 4 lung cancers per 10000 smokers. Po-210 can also be found in passive smoke, since part of Po-210 spreads in the surrounding environment during tobacco combustion. Tobacco manufacturers have been aware of the alpha-radioactivity presence in tobacco smoke since the sixties.

Polonium and Lung Cancer

PubMed Central

Zagà, Vincenzo; Lygidakis, Charilaos; Chaouachi, Kamal; Gattavecchia, Enrico

2011-01-01

The alpha-radioactive polonium 210 (Po-210) is one of the most powerful carcinogenic agents of tobacco smoke and is responsible for the histotype shift of lung cancer from squamous cell type to adenocarcinoma. According to several studies, the principal source of Po-210 is the fertilizers used in tobacco plants, which are rich in polyphosphates containing radio (Ra-226) and its decay products, lead 210 (Pb-210) and Po-210. Tobacco leaves accumulate Pb-210 and Po-210 through their trichomes, and Pb-210 decays into Po-210 over time. With the combustion of the cigarette smoke becomes radioactive and Pb-210 and Po-210 reach the bronchopulmonary apparatus, especially in bifurcations of segmental bronchi. In this place, combined with other agents, it will manifest its carcinogenic activity, especially in patients with compromised mucous-ciliary clearance. Various studies have confirmed that the radiological risk from Po-210 in a smoker of 20 cigarettes per day for a year is equivalent to the one deriving from 300 chest X-rays, with an autonomous oncogenic capability of 4 lung cancers per 10000 smokers. Po-210 can also be found in passive smoke, since part of Po-210 spreads in the surrounding environment during tobacco combustion. Tobacco manufacturers have been aware of the alpha-radioactivity presence in tobacco smoke since the sixties. PMID:21772848

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.

Large-amplitude jumps and non-Gaussian dynamics in highly concentrated hard sphere fluids.

PubMed

Saltzman, Erica J; Schweizer, Kenneth S

2008-05-01

Our microscopic stochastic nonlinear Langevin equation theory of activated dynamics has been employed to study the real-space van Hove function of dense hard sphere fluids and suspensions. At very short times, the van Hove function is a narrow Gaussian. At sufficiently high volume fractions, such that the entropic barrier to relaxation is greater than the thermal energy, its functional form evolves with time to include a rapidly decaying component at small displacements and a long-range exponential tail. The "jump" or decay length scale associated with the tail increases with time (or particle root-mean-square displacement) at fixed volume fraction, and with volume fraction at the mean alpha relaxation time. The jump length at the alpha relaxation time is predicted to be proportional to a measure of the decoupling of self-diffusion and structural relaxation. At long times corresponding to mean displacements of order a particle diameter, the volume fraction dependence of the decay length disappears. A good superposition of the exponential tail feature based on the jump length as a scaling variable is predicted at high volume fractions. Overall, the theoretical results are in good accord with recent simulations and experiments. The basic aspects of the theory are also compared with a classic jump model and a dynamically facilitated continuous time random-walk model. Decoupling of the time scales of different parts of the relaxation process predicted by the theory is qualitatively similar to facilitated dynamics models based on the concept of persistence and exchange times if the elementary event is assumed to be associated with transport on a length scale significantly smaller than the particle size.

The Kepler Light Curves of V1504 Cygni and V344 Lyrae: A Study of the Outburst Properties

NASA Technical Reports Server (NTRS)

Cannizzo, John K.; Smale, Alan P.; Still, Martin D.; Wood, Matt A.; Howell, Steve B.

2011-01-01

We examine the Kepler light curves of V1504 Cyg and V344 Lyr, encompassing approximately 460 d at 1 min cadence. During this span each system exhibited approximately 40 outbursts, including four superoutbursts. We find that, in both systems, the normal outbursts lying between two superoutbursts increase in duration by a factor approximately 1.2 - 1.7, and then reset to a small value after the following superoutburst. In V344 Lyr the trend of quiescent intervals between normal outbursts is to increase to a local maximum about half way through the supercycle the interval from one superoutburst to the next - and then to decrease back to a small value by the time of the next superoutburst, whereas for V1504 Cyg the quiescent intervals are relatively constant during the supercycle. Both of these trends are inconsistent with the Osaki's thermal-tidal model, which robustly predicts a secular increase in the quiescent intervals between normal outbursts during a supercycle. Also, most of the normal outbursts have an asymmetric, fast-rise/slower-decline shape, which would be consistent with outbursts triggered at large radii. The exponential rate of decay of the plateau phase of the superoutbursts is 8 d mag(sup -1) for approximately 1504 Cyg and 12 d mag(sup -1) for V344 Lyr. This time scale gives a direct measure of the VISCOUS time scale III the outer accretion disk given the expectation that the entire disk is in the hot, viscous state during superoutburst. The resulting constraint on the Shakura-Sunyaev parameter, alpha(sub hot) approximately equal to 0.1, is consistent with the value inferred from the fast dwarf nova decays. By looking at the slow decay rate for superoutbursts, which occur in systems below the period gap, in combination with the slow decay rate in one long outburst above the period gap (in U Gem), we infer a steep dependence of the decay rate on orbital period for long outbursts. We argue that this relation implies a steep dependence of alpha(sub cold) on orbital period, which may be consistent with recent findings of Patterson, and is consistent with tidal torquing as being the dominant angular momentum transport mechanism in quiescent disks in interacting binary systems.

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

Alpha Background Discrimination in the MAJORANA DEMONSTRATOR

NASA Astrophysics Data System (ADS)

Gruszko, Julieta; Majorana Collaboration

2017-09-01

The Majorana Demonstrator (MJD) searches for neutrinoless double-beta decay of 76Ge using arrays of high-purity germanium detectors. If observed, this process would have implications for grand-unification and the predominance of matter over antimatter in the universe. A problematic background in such large granular detector arrays is posed by alpha particles. In MJD, potential background events that are consistent with energy-degraded alphas originating on the passivated detector surface have been observed. We have studied these events by scanning the passivated surface of a P-type point contact detector like those used in MJD with a collimated alpha source. We observe that surface alpha events exhibit high charge-trapping, with a significant fraction of the trapped charge being re-released slowly. This leads to both a reduced prompt signal and a measurable change in slope of the tail of a recorded pulse. In this contribution we discuss the characteristics of these events and the filter developed to identify the occurrence of this delayed charge recovery, allowing for the efficient rejection of passivated surface alpha events while retaining 99.8% of bulk events. We also discuss the impact of this filter on the sensitivity of MJD. This material is based upon work supported by the U.S. DOE, Office of Science, Office of Nuclear Phys., the Particle Astrophys. and Nuclear Phys. Programs of the NSF, and SURF. Additional support from the NSFGRFP under Grant No. 1256082.

ESR study of electron reactions with esters and triglycerides

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

Sevilla, M.D.; Morehouse, K.M.; Swarts, S.

1981-04-02

Reactions which occurred after electron attachment at 77K to a number of small carboxylic acid esters and triglycerides in an aqueous glass are reported. Most ester anions are found to decay on warming to form alkyl radicals by ..beta.. scission: RC(O/sup -/)OR' ..-->.. RCO/sub 2//sup -/ + R'.. The alkyl radical (R'.) produced by annealing is found to abstract hydrogen from the parent ester at an ..cap alpha..-carbon site, R'.+ R''CH/sub 2/CO/sub 2/R' ..-->.. R''CHCO/sub 2/R', or in the case of ethyl formate from the formate hydrogen, CH/sub 3/CH/sub 2/.+ HCO/sub 2/C/sub 2/H/sub 5/ ..-->.. C/sub 2/H/sub 6/ +.CO/sub 2/C/submore » 2/H/sub 5/. Results found for the methyl formate anion suggest hydrogen abstraction by the anion itself may compete with alkyl radical formation. The anion of the triglyceride triacetin is found to undergo an analogous mechanism to the ester anions producing the propane diol diester radical, .CH/sub 2/CH(Ac)CH/sub 2/(Ac), Ac = acetate. This species subsequently abstracts hydrogen from the parent compound to produce the ..cap alpha..-carbon radical, .CH/sub 2/CO/sub 2/R. Results found after annealing the tripropionin radical anion give evidence for abstraction from the ..cap alpha.. carbon in the propionate side groups producing CH/sub 3/CHCO/sub 2/R. Studies of a ..gamma..-irradiated ester (ethyl myristate) and two triglycerides (tripalmitin and tristearin) yield results which suggest that the mechanism of ester anion decay found in aqueous glasses applies to ..gamma..-irradiated neat long-chain esters and triglycerides. Results found in this work are compared to the results of product analysis.« less

Glutathione regulation of redox-sensitive signals in tumor necrosis factor-{alpha}-induced vascular endothelial dysfunction

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

Tsou, T.-C.; Yeh, S.C.; Tsai, F.-Y.

2007-06-01

We investigated the regulatory role of glutathione in tumor necrosis factor-alpha (TNF-{alpha})-induced vascular endothelial dysfunction as evaluated by using vascular endothelial adhesion molecule expression and monocyte-endothelial monolayer binding. Since TNF-{alpha} induces various biological effects on vascular cells, TNF-{alpha} dosage could be a determinant factor directing vascular cells into different biological fates. Based on the adhesion molecule expression patterns responding to different TNF-{alpha} concentrations, we adopted the lower TNF-{alpha} (0.2 ng/ml) to rule out the possible involvement of other TNF-{alpha}-induced biological effects. Inhibition of glutathione synthesis by L-buthionine-(S,R)-sulfoximine (BSO) resulted in down-regulations of the TNF-{alpha}-induced adhesion molecule expression and monocyte-endothelial monolayermore » binding. BSO attenuated the TNF-{alpha}-induced nuclear factor-kappaB (NF-{kappa}B) activation, however, with no detectable effect on AP-1 and its related mitogen-activated protein kinases (MAPKs). Deletion of an AP-1 binding site in intercellular adhesion molecule-1 (ICAM-1) promoter totally abolished its constitutive promoter activity and its responsiveness to TNF-{alpha}. Inhibition of ERK, JNK, or NF-{kappa}B attenuates TNF-{alpha}-induced ICAM-1 promoter activation and monocyte-endothelial monolayer binding. Our study indicates that TNF-{alpha} induces adhesion molecule expression and monocyte-endothelial monolayer binding mainly via activation of NF-{kappa}B in a glutathione-sensitive manner. We also demonstrated that intracellular glutathione does not modulate the activation of MAPKs and/or their downstream AP-1 induced by lower TNF-{alpha}. Although AP-1 activation by the lower TNF-{alpha} was not detected in our systems, we could not rule out the possible involvement of transiently activated MAPKs/AP-1 in the regulation of TNF-{alpha}-induced adhesion molecule expression.« less

[Prevalence survey and molecular characterization of alpha and beta thalassemia in Liuzhou city of Guangxi].

PubMed

Cai, Ren; Li, Liyan; Liang, Xin; Liu, Zhongying; Su, Liu; Li, Wenjun; Zhu, Qiangui; Mo, Qiuhua; Pan, Lizhen; Ouyang, Hong; Huang, Lihua; Xu, Xiangmin

2002-08-01

To investigate the gene frequencies and mutation patterns of alpha thalassemia (alpha-thal) and beta thalassemia (beta-thal) in Liuzhou city of Guangxi Zhuang Autonomous Region. Cluster sampling was used. A total of 1 028 of umbilical blood samples were collected for a prevalence study of alpha-thal and a total of 1 312 healthy young people when receiving pre-marriage consultation were recruited for a beta-thal prevalence survey. Individuals live in city or town area of Liuzhou. A complete blood count as well as hemoglobin electrophoresis analysis were done in all of samples for phenotyping of alpha and beta-thals. Those with Hb Bart's for alpha-thal indicator and those with both microcytosis (MCV < 85 fl) and elevated levels of Hb A(2) (>/=4.0%) for beta-thal were further studied by DNA analysis. PCR-based methodologies were used to characterize the mutation contributions of alpha and beta-thals. All the subjects were tested for the state of carrying beta-thala alleles for evaluating the situation of the compound heterozygotes of alpha-thal with beta-thal. Of 1 028 random samples of umbilical blood screened, 112 of subjects were defined to be the gene carriers of alpha-thal. The alpha-thal carrier rate was as high as 11.19% including 3 compound heterozygotes. Five well-known types of alpha-thal alleles were detected with gene contributions of 37.4% (--(SEA) deletion), 31.3% (-alpha(3.7) deletion), 17.4% (-alpha(4.2) deletion), 12.1% (alpha(CS)alpha mutation), and 0.9% (alpha(QS)alpha mutation), successively. Of the 1 312 adult specimens studied, 89 with beta-thal including 14 of the compound higher Hb F subjects were detected. All of the 89 phenotypic beta-thal carriers had the mutations in the beta-globin gene, making the overall prevalence 6.78%. The commonly seen three mutations, beta CD41 - 42 (-CTTT) frameshift, beta CD17 (T-A) nonsense mutation and beta-28 (A-G) promoter variation were accounted for 90% of the beta-thal alleles in Liuzhou. Of these beta-thal subjects, 16 (accounting for 18%) were found to be the compound heterozygosity for a beta-thal and an alpha-thal with 9 different types of gene defects with a detection rate 1.22%. Data from ecidation of alpha and beta-thal gene frequencies and mutation spectrum in Liuzhou city was useful for genetic counselling and prenatal diagnosis of this disease.

Cow's milk proteins in human milk.

PubMed

Coscia, A; Orrù, S; Di Nicola, P; Giuliani, F; Rovelli, I; Peila, C; Martano, C; Chiale, F; Bertino, E

2012-01-01

Cow's milk proteins (CMPs) are among the best characterized food allergens. Cow's milk contains more than twenty five different proteins, but only whey proteins alpha-lactalbumin, beta-lactoglobulin, bovine serum albumin (BSA), and lactoferrin, as well as the four caseins, have been identified as allergens. Aim of this study was to investigate by proteomics techniques cow's milk allergens in human colostrum of term and preterm newborns' mothers, not previously detected, in order to understand if such allergens could be cause of sensitization during lactation. Term colostrum samples from 62 healthy mothers and preterm colostrum samples from 11 healthy mothers were collected for this purpose. The most relevant finding was the detection of the intact bovine alpha-S1-casein in both term and preterm colostrum. Using this method, which allows direct proteins identification, beta-lactoglobulin was not detected in any of colostrum samples. According to our results bovine alpha 1 casein that is considered a major cow's milk allergen is readily secreted in human milk: further investigations are needed in order to clarify if alpha-1-casein has a major role in sensitization or tolerance to cow's milk of exclusively breastfed predisposed infants.

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.

Ship Detection in SAR Image Based on the Alpha-stable Distribution

PubMed Central

Wang, Changcheng; Liao, Mingsheng; Li, Xiaofeng

2008-01-01

This paper describes an improved Constant False Alarm Rate (CFAR) ship detection algorithm in spaceborne synthetic aperture radar (SAR) image based on Alpha-stable distribution model. Typically, the CFAR algorithm uses the Gaussian distribution model to describe statistical characteristics of a SAR image background clutter. However, the Gaussian distribution is only valid for multilook SAR images when several radar looks are averaged. As sea clutter in SAR images shows spiky or heavy-tailed characteristics, the Gaussian distribution often fails to describe background sea clutter. In this study, we replace the Gaussian distribution with the Alpha-stable distribution, which is widely used in impulsive or spiky signal processing, to describe the background sea clutter in SAR images. In our proposed algorithm, an initial step for detecting possible ship targets is employed. Then, similar to the typical two-parameter CFAR algorithm, a local process is applied to the pixel identified as possible target. A RADARSAT-1 image is used to validate this Alpha-stable distribution based algorithm. Meanwhile, known ship location data during the time of RADARSAT-1 SAR image acquisition is used to validate ship detection results. Validation results show improvements of the new CFAR algorithm based on the Alpha-stable distribution over the CFAR algorithm based on the Gaussian distribution. PMID:27873794

A defective retroviral vector encoding human interferon-alpha2 can transduce human leukemic cell lines.

PubMed

Austruy, E; Bagnis, C; Carbuccia, N; Maroc, C; Birg, F; Dubreuil, P; Mannoni, P; Chabannon, C

1998-01-01

Using the LXSN backbone, a defective retroviral vector (LISN) was constructed that encodes the human interferon (IFN)-alpha2 (hIFN-alpha2) gene and the neomycin resistance gene; the hIFN-alpha2 gene was cloned from human placental genomic DNA. High titers of the LISN retrovirus were produced by the amphotropic packaging cell line GP+envAM12. LISN is able to infect three human hematopoietic and leukemic cell lines: K562, LAMA-84, and TF-1. G418-resistant cells were detected in a similar proportion after infection with either the LISN retroviral vector or the LnLSN retroviral vector (encoding the nlsLacZ gene instead of hIFN-alpha2), suggesting that hIFN-alpha2 does not inhibit (or only partially inhibits) the production of retroviral particles by the packaging cell line and the infection of human cells. LISN-infected cells express and secrete hIFN-alpha2 as demonstrated by Northern blot analysis of poly(A)+ RNA, detection of the intracellular protein by fluorescence-activated cell sorter analysis, and detection of secreted hIFN-alpha in cell supernatants using an enzyme-linked immunosorbent assay. Retrovirally produced hIFN-alpha2 is biologically active, as demonstrated by the partial inhibition of the growth of K562 and TF-1, the modulation of the expression of cell surface antigens, the induction of the (2'-5') oligoadenylate synthetase, and, for LAMA-84, the down-modulation of the BCR-ABL protein. We conclude that the infection of human leukemic cell lines with a retroviral vector encoding hIFN-alpha2 is feasible and induces the expected biological effects. This experimental model will be useful in investigating the possibility of transducing normal and leukemic cells and hematopoietic progenitors and in determining the consequences of the autocrine production of hIFN-alpha2 on the behavior of these cells.

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

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.

Somato-synaptic variation of GABA(A) receptors in cultured murine cerebellar granule cells: investigation of the role of the alpha6 subunit.

PubMed

Mellor, J R; Wisden, W; Randall, A D

2000-07-10

Electrophysiological investigation of cultured cerebellar murine granule cells revealed differences between the GABA(A) receptors at inhibitory synapses and those on the cell body. Specifically, mIPSCs decayed more rapidly than cell body receptors deactivated, the mean single channel conductance at the synapse (32 pS) was greater than that at cell body (21 pS) and only cell body receptors were sensitive to Zn(2+) (150 microM), which depressed response amplitude by 82+/-5% and almost doubled the rate of channel deactivation. The GABA(A) receptor alpha6 subunit is selectively expressed in cerebellar granule cells. Although concentrated at synapses, it is also found on extrasynaptic membranes. Using a mouse line (Deltaalpha6lacZ) lacking this subunit, we investigated its role in the somato-synaptic differences in GABA(A) receptor function. All differences between cell body and synaptic GABA(A) receptors observed in wild-type (WT) granule cells persisted in Deltaalpha6lacZ cells, thus demonstrating that they are not specifically due to the cellular distribution of the alpha6 subunit. However, mIPSCs from WT and Deltaalpha6lacZ cells differed in both their kinetics (faster decay in WT cells) and underlying single channel conductance (32 pS WT, 25 pS Deltaalpha6lacZ). This provides good evidence for a functional contribution of the alpha6 subunit to postsynaptic GABA(A) receptors in these cells. Despite this, deactivation kinetics of mIPSCs in WT and Deltaalpha6lacZ granule cells exhibited similar benzodiazepene (BDZ) sensitivity. This suggests that the enhanced BDZ-induced ataxia seen in Deltaalpha6lacZ mice may reflect physiological activity at extrasynaptic receptors which, unlike those at synapses, display differential BDZ-sensitivity in WT and Deltaalpha6lacZ granule cells (Jones, A.M., Korpi, E.R., McKernan, R.M., Nusser, Z., Pelz, R., Makela, R., Mellor, J.R., Pollard, S., Bahn, S., Stephenson, F.A., Randall, A.D., Sieghart, W., Somogyi, P., Smith, A.J.H., Wisden, W., 1997. Ligand-gated ion channel partnerships: GABA(A) receptor alpha(6) subunit inactivation inhibits delta subunit expression. Journal of Neuroscience 17, 1350-1362).

Significance of detecting circulating hepatocellular carcinoma cells in peripheral blood of hepatocellular carcinoma patients by nested reverse transcription-polymerase chain reaction and its clinical value: a retrospective study.

PubMed

Liu, Yang; Wang, Yue-ru; Wang, Long; Song, Rui-mei; Zhou, Bo; Song, Zhen-shun

2014-01-01

Circulating hepatocellular carcinoma cells may be detected by reverse transcription-polymerase chain reaction. We investigated the relationship between circulating hepatocellular carcinoma cells and hepatoma patient survival after different managements and survival periods. Peripheral vein blood (5 ml) samples were obtained from 113 patients with hepatocellular carcinoma and from 33 control subjects (9 with liver cirrhosis after hepatitis B, 14 with chronic hepatitis B, 10 healthy individuals) between January 1, 2009, and December 31, 2013. To detect circulating hepatocellular carcinoma cells in peripheral blood, alpha-fetoprotein messenger RNA was amplified from total RNA extracted from whole blood by reverse transcription-polymerase chain reaction. Alpha-fetoprotein messenger RNA was detected in 59 blood samples from the hepatocellular carcinoma patients (59/113, 52.2%). In contrast, there were no clinical control subjects whose samples showed detectable alpha-fetoprotein messenger RNA. The presence of alpha-fetoprotein messenger RNA in blood seemed to be correlated with the stage (by TNM classification) of hepatocellular carcinoma, serum alpha-fetoprotein value, and the presence of intrahepatic metastasis, portal vein thrombosis, tumor diameter and/or distant metastasis. In addition, alpha-fetoprotein messenger RNA was detected in the blood of 25 patients showing distant metastasis at extrahepatic organs (100%), in contrast to 32 of 88 cases without metastasis (36.4%). All the patients with hepatocellular carcinoma were followed. Seventeen patients with resection of a T 2 stage hepatocellular carcinoma had a survival of 3.2 years after surgical management, 38 cases with resection of a T3 stage hepatocellular carcinoma had a 1.3-year survival, and only 37 cases with T4 stage disease after different treatments except surgery survived for 0.6 years (P <0.01). The presence of alpha-fetoprotein messenger RNA in peripheral blood may be an indicator of circulating hepatocellular carcinoma cells, which might predict hematogenous spreading metastasis in patients with hepatocellular carcinoma and may be a poor prognostic factor for hepatocellular carcinoma patients.

The highly obscured nucleus of 3C 219

NASA Technical Reports Server (NTRS)

Fabbiano, G.; Willner, S. P.; Carleton, N. P; Elvis, M.

1986-01-01

The detection of a strong, and possibly broad, Paschen-alpha line from the narrow-line radio galaxy 3C 219 is reported. The detected flux is larger than predicted from the H-alpha line and the case B recombination. This implies the presence of a highly reddened line-emitting region in the nucleus.

Schindler disease: the molecular lesion in the alpha-N-acetylgalactosaminidase gene that causes an infantile neuroaxonal dystrophy.

PubMed Central

Wang, A M; Schindler, D; Desnick, R

1990-01-01

Schindler disease is a recently recognized infantile neuroaxonal dystrophy resulting from the deficient activity of the lysosomal hydrolase, alpha-N-acetylgalctosaminidase (alpha-GalNAc). The recent isolation and expression of the full-length cDNA encoding alpha-GalNAc facilitated the identification of the molecular lesions in the affected brothers from family D, the first cases described with this autosomal recessive disease. Southern and Northern hybridization analyses of DNA and RNA from the affected homozygotes revealed a grossly normal alpha-GalNAc gene structure and normal transcript sizes and amounts. Therefore, the alpha-GalNAc transcript from an affected homozygote was reverse-transcribed, amplified by the polymerase chain reaction (PCR), and sequenced. A single G to A transition at nucleotide 973 was detected in multiple subclones containing the PCR products. This point mutation resulted in a glutamic acid to lysine substitution in residue 325 (E325K) of the alpha-GalNAc polypeptide. The base substitution was confirmed by dot blot hybridization analyses of PCR-amplified genomic DNA from family members with allele-specific oligonucleotides. Furthermore, transient expression of an alpha-GalNAc construct containing the E325K mutation resulted in the expression of an immunoreactive polypeptide which had no detectable alpha-GalNAc activity. Images PMID:2243144

Ghost-Free APT Analysis of Perturbative QCD Observables

NASA Astrophysics Data System (ADS)

Shirkov, Dmitry V.

The review of the essence and of application of recently devised ghost-free Analytic Perturbation Theory (APT) is presented. First, we discuss the main intrinsic problem of perturbative QCD - ghost singularities and with the resume of its resolving within the APT. By examples for diverse energy and momentum transfer values we show the property of better convergence for the APT modified QCD expansion. It is shown that in the APT analysis the three-loop contribution (sim alpha_s^3) is numerically inessential. This gives raise a hope for practical solution of the well-known problem of non-satisfactory convergence of QFT perturbation series due to its asymptotic nature. Our next result is that a usual perturbative analysis of time-like events is not adequate at sleq 2 GeV2. In particular, this relates to tau decay. Then, for the "high" (f=5) region it is shown that the common NLO, NLLA perturbation approximation widely used there (at 10 GeV lesssimsqrt{s}lesssim 170 GeV) yields a systematic theoretic negative error of a couple per cent level for the bar {alpha}_s^2 values. This results in a conclusion that the bar α_s(M^2_Z) value averaged over the f=5 data appreciably differs < bar {alpha}_s(M^2_Z)rangle_{f=5} simeq 0.124 from the currently popular "world average" (=0.118 ).

Palladium alpha-lipoic acid complex formulation enhances activities of Krebs cycle dehydrogenases and respiratory complexes I-IV in the heart of aged rats.

PubMed

Sudheesh, N P; Ajith, T A; Janardhanan, K K; Krishnan, C V

2009-08-01

Age-related decline in the capacity to withstand stress, such as ischemia and reperfusion, results in congestive heart failure. Though the mechanisms underlying cardiac decay are not clear, age dependent somatic damages to mitochondrial DNA (mtDNA), loss of mitochondrial function, and a resultant increase in oxidative stress in heart muscle cells may be responsible for the increased risk for cardiovascular diseases. The effect of a safe nutritional supplement, POLY-MVA, containing the active ingredient palladium alpha-lipoic acid complex, was evaluated on the activities of the Krebs cycle enzymes such as isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase as well as mitochondrial complexes I, II, III, and IV in heart mitochondria of aged male albino rats of Wistar strain. Administration of 0.05 ml/kg of POLY-MVA (which is equivalent to 0.38 mg complexed alpha-lipoic acid/kg, p.o), once daily for 30 days, was significantly (p<0.05) effective to enhance the Krebs cycle dehydrogenases, and mitochondrial electron transport chain complexes. The unique electronic and redox properties of palladium alpha-lipoic acid complex appear to be a key to this physiological effectiveness. The results strongly suggest that this formulation might be effective to protect the aging associated risk of cardiovascular and neurodegenerative diseases.

Gap junctions and memory: an investigation using a single trial discrimination avoidance task for the neonate chick.

PubMed

Verwey, L J; Edwards, T M

2010-02-01

Gap junctions are important to how the brain functions but are relatively under-investigated with respect to their contribution towards behaviour. In the present study a single trial discrimination avoidance task was used to investigate the effect of the gap junction inhibitor 18-alpha-glycyrrhetinic acid (alphaGA) on retention. Past studies within our research group have implied a potential role for gap junctions during the short-term memory (STM) stage which decays by 15 min post-training. A retention function study comparing 10 microM alphaGA and vehicle given immediately post-training demonstrated a significant main effect for drug with retention loss at all times of test (10-180 min post-training). Given that the most common gap junction in the brain is that forming the astrocytic network it is reasonable to conclude that alphaGA was acting upon these. To confirm this finding and interpretation two additional investigations were undertaken using endothelin-1 (ET-1) and ET-1+tolbutamide. Importantly, a retention function study using 10nM ET-1 replicated the retention loss observed for alphaGA. In order to confirm that ET-1 was acting on astrocytic gap junctions the amnestic action of ET-1 was effectively challenged with increasing concentrations of tolbutamide. The present findings suggest that astrocytic gap junctions are important for memory processing. Copyright 2009 Elsevier Inc. All rights reserved.

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.

A hypothetical dusty plasma mechanism of Hessdalen lights

NASA Astrophysics Data System (ADS)

Paiva, G. S.; Taft, C. A.

2010-10-01

Hessdalen lights (HL) are unexplained light balls usually seen in the valley of Hessdalen, Norway. In this work, it is suggested that HL are formed by a cluster of macroscopic Coulomb crystals in a plasma produced by the ionization of air and dust by alpha particles during radon decay in the dusty atmosphere. Several physical properties (oscillation, geometric structure, and light spectrum) observed in HL phenomenon can be explained through the dust plasma model.

Glycosidases in Brachionus plicatilis (Rotifera).

PubMed

Kühle, K; Kleinow, W

1990-01-01

1. Tests for glycosidases were performed in homogenates of Brachionus plicatilis. 2. Hydrolytic activity was detected with the following substrates: (a) with synthetic substrates (NP = 4-nitrophenyl): NP-alpha- and NP-beta-D-glucopyranoside, NP-alpha- and NP-beta-D-galactopyranoside, NP-N-acetyl-beta-D-glucosaminide, NP-N-acetyl-beta-D-galactosaminide, NP-alpha- and NP-beta-D-mannopyranoside and NP-alpha-L-fucopyranoside; (b) with disaccharides: sucrose, maltose, trehalose, isomaltose, cellobiose, gentiobiose and lactose; (c) with polysaccharides: laminarine, carboxymethyl-cellulose, avicel, Micrococcus luteus (for lysozyme) and 4-nitrophenyl-alpha-D-maltoheptaoside (for amylase). 3. The pH dependence of the glycosidase activities was determined. 4. The distribution of enzyme activities within fractions from the homogenate was studied in order to localize them within the cell. 5. Proteins from Brachionus homogenate were separated by SDS-gel electrophoresis and the positions of the following glycosidase activities were detected by assays performed on the gels (estimated molecular weights in parentheses): alpha-glucosidase (250,000); beta-glucosidase (200,000); beta-galactosidase (70,000); N-acetyl-beta-glucosaminidase (60,000).

Dissociation of {sup 10}C nuclei in a track nuclear emulsion at an energy of 1.2 GeV per nucleon

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

Mamatkulov, K. Z.; Kattabekov, R. R.; Alikulov, S. S.

2013-10-15

The charge topology in the fragmentation of {sup 10}C nuclei in a track nuclear emulsion at an energy of 1.2 GeV per nucleon is studied. In the coherent dissociation of {sup 10}C nuclei, about 82% of events are associated with the channel {sup 10}C {yields} 2{alpha}+ 2p. The angular distributions and correlations of product fragments are presented for this channel. It is found that among {sup 10}C {yields} 2{alpha}+ 2p events, about 30% are associated with the process in which dissociation through the ground state of the unstable {sup 9}Be{sub g.s.} nucleus is followed by {sup 8}Be{sub g.s.} + pmore » decays.« less

Radiation effects in accelerator components

NASA Astrophysics Data System (ADS)

Borden, M. J.

1995-05-01

A review of basic radiation effects is presented. The fundamental definitions of radioactivity are given for alpha, beta, positron decay, gamma-ray emission and electron capture. The interaction of neutrons with material is covered including: absorption through radiative capture, neutron-proton interaction, alpha particle emission, neutron-multi-neutron reactions and fission. Basic equations defining inelastic and elastic scattering are presented with examples of neutron energy loss per collision for several elements. Photon interactions are considered for gamma-rays and x-rays. Photoelectric collisions, the Compton effect and pair production are reviewed. Electron-proton interactions are discussed with emphasis placed on defect production. Basic displacement damage mechanisms for photon and particle interaction are presented. Several examples of radiation effects to plastics, electronics and ceramics are presented. Extended references are given for each example.

Nuclear half-lives for {alpha}-radioactivity of elements with 100 {<=} Z {<=} 130

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

Chowdhury, P. Roy; Samanta, C.; Physics Department, Gottwald Science Center, University of Richmond, Richmond, VA 23173

2008-11-15

Theoretical estimates for the half-lives of about 1700 isotopes of heavy elements with 100 {<=} Z {<=} 130 are tabulated using theoretical Q-values. The quantum mechanical tunneling probabilities are calculated within a WKB framework using microscopic nuclear potentials. The microscopic nucleus-nucleus potentials are obtained by folding the densities of interacting nuclei with a density-dependent M3Y effective nucleon-nucleon interaction. The {alpha}-decay half-lives calculated in this formalism using the experimental Q-values were found to be in good agreement over a wide range of experimental data spanning about 20 orders of magnitude. The theoretical Q-values used for the present calculations are extracted frommore » three different mass estimates viz. Myers-Swiatecki, Muntian-Hofmann-Patyk-Sobiczewski, and Koura-Tachibana-Uno-Yamada.« less

Evaluation of IgY capture ELISA for sensitive detection of alpha hemolysin of Staphylococcus aureus without staphylococcal protein A interference.

PubMed

Reddy, Prakash Kudumala; Shekar, Aravind; Kingston, Joseph Jeyabalaji; Sripathy, Murali Harishchandra; Batra, Harshvardhan

2013-05-31

Staphylococcal protein A (Spa) secreted by all Staphylococcus aureus strains is the major hindrance in development of specific immunoassays for detecting S. aureus antigens, because of its characteristic feature of binding to Fc region of most mammalian immunoglobulins and also to Fab region of certain classes of mammalian immunoglobulins. Immunoglobulin Y (IgY) is the avian equivalent of mammalian IgG which does not have any affinity to Spa. In the present study we report that using chicken egg yolk IgY over mammalian IgG as capture antibody prevents both soluble and surface bound protein A from causing false positives quantified by chicken anti-protein A antibodies. This was demonstrated by development of sandwich ELISA for detection of alpha hemolysin toxin from culture supernatants of S. aureus strains with anti alpha hemolysin IgY as capture and rabbit anti alpha hemolysin IgG as revealing antibody. This indirect sandwich ELISA was evaluated onto a large number of S. aureus isolates recovered from clinical sources for alpha hemolysin secretion. Results of sandwich ELISA were compared with PCR and Western blot analysis. The immunoassay is highly specific and has high sensitivity of detecting less than 1 ng/ml. This procedure is highly effective in eliminating Spa interference and can be extended to detection of other important superantigen toxins of S. aureus. Copyright © 2013 Elsevier B.V. All rights reserved.

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.

Aurel Sandulescu—a life dedicated to nuclear physics

NASA Astrophysics Data System (ADS)

Liotta, R. J.

2013-02-01

I was surprised to receive an invitation letter from Andrei Dorobantu, whom I did not know, to give a talk about pairing excitations at the Predeal International School of 1978, which I accepted. This was the first time that I would visit Romania, and I knew very little about the research that was performed in the country. In my talk I was showing the role of the pairing mode in a rather popular theory at that time which was called Nuclear Field Theory. Suddenly I was interrupted in a rather brusque fashion by a man with an acute and loud voice, telling me that it has been shown by somebody that the Nuclear Field Theory does not converge. I was very upset by this interruption, particularly because he was right. I told him this and asked him to wait up at the end of my talk. During the coffee break the man came to me and presented himself. It was the first time I came into contact with the extraordinary person that is Aurel Sandulescu. During the coffee break we spoke about his research, especially in alpha decay. I was interested in this subject because just then I had started to perform calculations in relation to experiments carried out at my Institution in Stockholm, which at that time was called the Research Institute of Physics. We continued with our discussions during the whole duration of the School, often with his wife, Violeta, present. I became amazed by the extensive work he had done since the late 1950s on microscopic treatments of alpha decay. He had studied the decay of both normal and superfluid as well as spherical and deformed nuclei, all within the framework of the shell model or its BCS equivalent. I was very enthusiastic about this, since I was convinced that one should, in principle, be able to describe the decay process by using a shell model representation. I was disappointed to realize that he did not agree with me. I insisted that from a purely theoretical point of view the shell model was, rather more than a model, an excellent representation to describe nuclear processes. However, with the perspective that the passing years provides, I have since had to admit that one needs cluster components in the shell model wave functions in order to properly describe the clustering and subsequent decay. For Aurel, this realization led him to consider the decay as a fission process. It was through this that he found, just by simply looking through the penetrability, that cluster radioactivity is a valid form of decay, as was indeed confirmed experimentally several years afterwards. This new form of radioactive decay has had a profound influence on nuclear physics. It opened the way to the investigation of the structure and exotic forms that superheavy nuclei may acquire, since one expects that heavy clusters are likely to be emitted from these nuclei. The importance of cluster decay, and the theory behind its discovery, is of great relevance even today. This can be attested, for example, by the recent prediction of Poenaru, Gherghescu and Greiner (2011 Phys. Rev. Lett 107 062503) that in some superheavy nuclei this form of decay is dominant even over alpha emission, thus making cluster decay a powerful tool in the detection of superheavy nuclei. The description of cluster decay as a fragmentation process and its relation to heavy and superheavy elements was a natural extension of the research that Aurel Sandulescu was conducting at that time. Just before the cluster decay paper appeared he addressed the important question of the production of superheavy elements. The straightforward method of reaching this is by heavy ions collisions, but the question was: which nuclei should one use as reaction partners? Sandulescu proposed choosing those nuclei that provide a minimum of the potential energy, which was an important step in the synthesis of superheavy nuclei. Another subject which is of great importance in nuclear physics and in which Sandulescu played a crucial role was his prediction of neutronless spontaneous binary and ternary fission. He was so elated and eager about this that he even contributed to the experimental discovery of this rare phenomenon. Since then, there have been many theoretical as well as experimental studies performed in this and similar subjects related to cold fission processes. Particularly relevant in the framework of this conference are his studies on the damping of collective modes in deep inelastic collisions. He treated this difficult subject by extending a formalism derived for open systems to nuclear collective motions. The master equation that he thus obtained describes well the dynamics of degrees of freedom not only in the damping of excited nuclear states, but also particularly in heavy ion collisions and in the decaying of the most collective states in nuclear physics—giant resonances. He has also analyzed the complicated mechanisms that induce the clustering of nucleons, which led to his realization that the cluster structure can be viewed as solitons moving on the nuclear surface. This intense scientific work was followed by other related activities. In Romania he became a full professor in 1970, a corresponding member of the Romanian Academy of Sciences in 1991, an ordinary member in 1992 and Vice President in the period 1994-1998. Most remarkable is that he tried to influence the development of Science in the country by himself becoming a politician. Thus, he was a member of the Romanian Parliament in the period 1996-2000. Outside of Romania he has also undertaken remarkable activities. He has been Invited Scientist and Invited Professor to many institutions around the world. One should mention in particular his position as Vice Director of the Joint Institute of Nuclear Research, Dubna, Russia, in the period 1983-1986. He has proceeded through all these endeavors by attracting many foreign scientists to Romania, including myself. But especially important was his influence upon students, many of whom are today recognized physicists and leaders of Romanian physics. It is in recognition of his contribution to physics, especially nuclear physics, as well as his work for Romanian science that this School is organized in his honour, on the occasion of his 80th birthday. I cannot finish this short account without mentioning the person that accompanied Aurel Sandulescu through all his life, his wife of more than fifty years, Violeta. She also was an exceptional person. In her youth she was a very dedicated sporty girl, very athletic, very courageous, very fair and, above all, very generous. These qualities remained with her throughout her life. With deep sorrow I learnt that she passed away three months ago, still youthful and enthusiastic. R J Liotta

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

Radon and Thoron Measured in Petrol and Gas-oil Exhaust Fumes by Using CR-39 and LR-115 II Nuclear Track Detectors: Radiation Doses to the Respiratory Tract of Mechanic Workers.

PubMed

Misdaq, M A; Chaouqi, A; Ouguidi, J; Touti, R; Mortassim, A

2015-06-01

Mechanic workers are exposed to exhaust fumes when controlling vehicle engines in motion inside repair shops. To assess radiation doses due to radon short-lived progeny from the inhalation of exhaust fumes by mechanic workers, concentrations of these radionuclides were measured in petrol (gasoline) and gas-oil exhaust fumes by evaluating mean critical angles of etching of the CR-39 and LR-115 type II SSNTDs for alpha particles emitted by the radon and thoron decay series. Committed effective doses due to ²¹⁸Po and ²¹⁴Po short-lived radon decay products from the inhalation of petrol and gas-oil exhaust fumes by workers were evaluated. A maximum value of 1.35 mSv y⁻¹ due to radon short-lived decay products from the inhalation of gas-oil exhaust fumes by mechanic workers was found, which is lower than the (3-10 mSv y⁻¹) dose limit interval for workers.

Excretion profile of boldenone in urine of veal calves fed two different milk replacers.

PubMed

Draisci, R; Merlanti, R; Ferretti, G; Fantozzi, L; Ferranti, C; Capolongo, F; Segato, S; Montesissa, C

2007-03-14

The residue profiles of 17alpha-/17beta-boldenone conjugated (17alpha/beta-Bol) and ADD were investigated by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in urine of male veal calves fed two commercial milk replacers, with different content of cholesterol and phytosterols. The urine samples were collected within 4 h after feeding and further from all the animals. Detectable amounts of 17alpha-Bol conjugated were measured in urine collected from all calves, but the concentrations of 17alpha-Bol were higher in urine from calves receiving the milk replacer with the greater amount of phytosterols. During the whole experiment, 17beta-Bol and ADD were never detected in urine samples collected.

State of the art of D&D Instrumentation Technology: Alpha counting in the presence of high background

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

Dickerman, C.E.

1995-08-01

Discrimination of alpha activity in the presence of a high radiation background has been identified as an area of concern to be studied for D&D applications. Upon evaluating the range of alpha detection needs for D&D operations, we have expanded this study to address the operational concern of greatly expediting alpha counting of rough surfaces and rubble. Note that the term, ``rough surfaces`` includes a wide range of practical cases, including contaminated equipment and work surfaces. We have developed provisional applications requirements for instrumentation of this type; and we also have generated the scope of a program of instrument evaluationmore » and testing, with emphasis on practical implementation. In order to obtain the full operational benefit of alpha discrimination in the presence of strong beta-gamma radiation background, the detection system must be capable of some form of remote or semi-remote operation in order to reduce operator exposure. We have identified a highly promising technique, the long-range alpha detector (LRAD), for alpha discrimination in the presence of high radiation background. This technique operates upon the principle of transporting alphaionized air to an ionization detector. A transport time within a few seconds is adequate. Neither the provisional requirements nor the evaluation and testing scope were expressly tailored to force the selection of a LRAD technology, and they could be used as a basis for studies of other promising technologies. However, a technology that remotely detects alpha-ionized air (e. g., LRAD) is a natural fit to the key requirements of rejection of high background at the survey location and operator protection. Also, LRAD appears to be valuable for D&D applications as a means of greatly expediting surface alpha-activity surveys that otherwise would require performing time-consuming scans over surfaces of interest with alpha detector probes, and even more labor-intensive surface wipe surveys.« less

New method for determining temperature and emission measure during solar flares from light curves of soft X-ray line fluxes

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

Bornmann, P.L.

I describe a new property of soft X-ray line fluxes observed during the decay phase of solar flares and a technique for using this property to determine the plasma temperature and emission measure as functions of time. The soft X-ray line fluxes analyzed in this paper were observed during the decay phase of the 1980 November 5 flare by the X-Ray Polychromator (XRP) instrument on board the Solar Maximum Mission (SMM). The resonance, intercombination, and forbidden lines of Ne IX, Mg XI, Si XIII, S XV, Ca XIX, and Fe XXV, as well as the Lyman-..cap alpha.. line of Omore » VIII and the resonance lines of Fe XIX, were observed. The rates at which the observed line fluxes decayed were not constant. For all but the highest temperature lines observed, the rate changed abruptly, causing the fluxes to fall at a more rapid rate later in the flare decay. These changes occurred at earlier times for lines formed at higher temperatures. This behavior is proposed to be due to the decreasing temperature of the flare plasma tracking the rise and subsequent fall of each line emissivity function. This explanation is used to empirically model the observed light curves and to estimate the temperature and the change in emission measure of the plasma as a function of time during the decay phase. Estimates are made of various plasma parameters based on the model results.« less

Penning trap mass spectrometry Q-value determinations for highly forbidden β-decays

NASA Astrophysics Data System (ADS)

Sandler, Rachel; Bollen, Georg; Eibach, Martin; Gamage, Nadeesha; Gulyuz, Kerim; Hamaker, Alec; Izzo, Chris; Kandegedara, Rathnayake; Redshaw, Matt; Ringle, Ryan; Valverde, Adrian; Yandow, Isaac; Low Energy Beam Ion Trap Team

2017-09-01

Over the last several decades, extremely sensitive, ultra-low background beta and gamma detection techniques have been developed. These techniques have enabled the observation of very rare processes, such as highly forbidden beta decays e.g. of 113Cd, 50V and 138La. Half-life measurements of highly forbidden beta decays provide a testing ground for theoretical nuclear models, and the comparison of calculated and measured energy spectra could enable a determination of the values of the weak coupling constants. Precision Q-value measurements also allow for systematic tests of the beta-particle detection techniques. We will present the results and current status of Q value determinations for highly forbidden beta decays. The Q values, the mass difference between parent and daughter nuclides, are measured using the high precision Penning trap mass spectrometer LEBIT at the National Superconducting Cyclotron Laboratory.

Detection and characterization of a new metabolite of 17alpha-methyltestosterone.

PubMed

Pozo, Oscar J; Van Eenoo, Peter; Deventer, Koen; Lootens, Leen; Van Thuyne, Wim; Parr, Maria K; Schänzer, Wilhelm; Sancho, Juan V; Hernández, Felix; Meuleman, Philip; Leroux-Roels, Geert; Delbeke, Frans T

2009-11-01

The misuse of the anabolic steroid methyltestosterone is currently routinely monitored in doping control laboratories by gas chromatography-mass spectrometry (GC-MS) of two of its metabolites: 17alpha-methyl-5beta-androstane-3alpha,17beta-diol and 17alpha-methyl-5alpha-androstane-3alpha,17beta-diol. Because of the absence of any easy ionizable moiety, these metabolites are poorly detectable using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). In this study, the metabolism of methyltestosterone has been reinvestigated by the use of a precursor ion scan method in LC-ESI-MS/MS. Two metabolites have been detected using this method. Both compounds have been confirmed in postadministration urine samples of an urokinase plasminogen activator-severe combined immunodeficiency (uPA-SCID) mouse with humanized liver and were characterized by LC-MS/MS and GC-MS using both quadrupole and time of flight analyzers. From the detailed study of the fragmentation, these metabolites were proposed to be epimethyltestosterone and a dehydrogenated compound. Epimethyltestosterone has previously been described as a minor metabolite, whereas the occurrence of the oxidized metabolite has not been reported. Comparison with the synthesized reference revealed that the structure of the dehydrogenated metabolite is 6-ene-epimethyltestosterone. A selected reaction monitoring method including three transitions for each metabolite has been developed and applied to samples from an excretion study and to samples declared positive after GC-MS analysis. 6-Ene-epimethyltestosterone was found in all samples, showing its applicability in the detection of methyltestosterone misuse.

Method for detecting the presence of prostate cancer

DOEpatents

Karin, Michael; Luo, Jun-Li; Tan, Wei

2010-04-13

The present invention relates to compositions and methods for cancer diagnosis, treatment and drug screening. In particular, the present invention provides compositions and methods for targeting the nuclear translocation of IkB kinase-.alpha. (IKK.alpha.) and the IKK.alpha.-mediated suppression of Maspin expression observed in metastatic prostate cancer cells.

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.

First Results from Faint Infrared Grism Survey (Figs): First Simultaneous Detection of Ly Alpha Emission and Lyman Break From a Galaxy at Z =7.51

NASA Technical Reports Server (NTRS)

Tilvi, V.; Pirzkal, N.; Malhotra, S.; Finkelstein, S. L.; Rhoads, J. E.; Windhorst, R.; Grogin, N. A.; Koekemoer, A.; Zakamska, N. L.; Ryan, R.;

Measurement of radon diffusion in polyethylene based on alpha detection

NASA Astrophysics Data System (ADS)

Rau, Wolfgang

2012-02-01

Radon diffusion in different materials has been measured in the past. Usually the diffusion measurements are based on a direct determination of the amount of radon that diffuses through a thin layer of material. Here we present a method based on the measurement of the radon daughter products which are deposited inside the material. Looking at the decay of 210Po allows us to directly measure the exponential diffusion profile characterized by the diffusion length. In addition we can determine the solubility of radon in PE. We also describe a second method to determine the diffusion constant based on the short-lived radon daughter products 218Po and 214Po, using the identical experimental setup. Measurements for regular polyethylene (PE) and High Molecular Weight Polyethylene (HMWPE) yielded diffusion lengths of (1.3±0.3) mm and (0.8±0.2) mm and solubilities of 0.5±0.1 and 0.7±0.2, respectively, for the first method; the diffusion lengths extracted from the second method are noticeably larger which may be caused by different experimental conditions during diffusion.

Registration of alpha particles in Makrofol-E nuclear track detectors

NASA Astrophysics Data System (ADS)

Rammah, Y. S.; Abdalla, Ayman M.; Ashraf, O.; Ashry, A. H.

2016-06-01

Fast detection of alpha particles in the range from 1 to 5 MeV in Makrofol-E polycarbonate nuclear track detectors (PCTDs) using a new chemical etchant was investigated. 252Cf and 241Am-thin open sources were used for irradiating Makrofol-E detectors with fission fragments and alpha particles in air at normal pressure and temperature (NPT). A chain of experimental work has been carried out using new etchants to register alpha particle in short time in Makrofol-E polycarbonate detectors. The etching efficiency were exhibited a clear dependence on the amount of methanol in the etching solution and etching time. The optimized chemical condition obtained at this stage of development for 200 μm Makrofol-E detectors are (8 ml of 10 N NaOH + 2 ml CH3OH) etching solutions at 60 °C for 3 h. In this study; it is possible to observe energy detection windows for Makrofol-E detectors according to applied etching duration. Makrofol-E introduced the characteristic Bragg peak, which indicates the advantages of this detector as alpha spectrometer. Consequently, the suggested new etchant can be developed for heavy ions detection and monitoring radon levels and its daughters.

Hypoxia preconditioning protection of corneal stromal cells requires HIF1alpha but not VEGF.

PubMed

Xing, Dongmei; Bonanno, Joseph A

2009-05-18

Hypoxia preconditioning protects corneal stromal cells from stress-induced death. This study determined whether the transcription factor HIF-1alpha (Hypoxia Inducible Factor) is responsible and whether this is promulgated by VEGF (Vascular Endothelial Growth Factor). Cultured bovine stromal cells were preconditioned with hypoxia in the presence of cadmium chloride, a chemical inhibitor of HIF-1alpha, and HIF-1alpha siRNA to test if HIF-1alpha activity is needed for hypoxia preconditioning protection from UV-irradiation induced cell death. TUNEL assay was used to detect cell apoptosis after UV-irradiation. RT-PCR and western blot were used to detect the presence of HIF-1alpha and VEGF in transcriptional and translational levels. During hypoxia (0.5% O2), 5 muM cadmium chloride completely inhibited HIF-1alpha expression and reversed the protection by hypoxia preconditioning. HIF-1alpha siRNA (15 nM) reduced HIF-1alpha expression by 90% and produced a complete loss of protection provided by hypoxia preconditioning. Since VEGF is induced by hypoxia, can be HIF-1alpha dependent, and is often protective, we examined the changes in transcription of VEGF and its receptors after 4 h of hypoxia preconditioning. VEGF and its receptors Flt-1 and Flk-1 are up-regulated after hypoxia preconditioning. However, the transcription and translation of VEGF were paradoxically increased by siHIF-1alpha, suggesting that VEGF expression in stromal cells is not down-stream of HIF-1alpha. These findings demonstrate that hypoxia preconditioning protection in corneal stromal cells requires HIF-1alpha, but that VEGF is not a component of the protection.

Nicotinic Receptor Alpha7 Expression during Tooth Morphogenesis Reveals Functional Pleiotropy

PubMed Central

Rogers, Scott W.; Gahring, Lorise C.

2012-01-01

The expression of nicotinic acetylcholine receptor (nAChR) subtype, alpha7, was investigated in the developing teeth of mice that were modified through homologous recombination to express a bi-cistronic IRES-driven tau-enhanced green fluorescent protein (GFP); alpha7GFP) or IRES-Cre (alpha7Cre). The expression of alpha7GFP was detected first in cells of the condensing mesenchyme at embryonic (E) day E13.5 where it intensifies through E14.5. This expression ends abruptly at E15.5, but was again observed in ameloblasts of incisors at E16.5 or molar ameloblasts by E17.5–E18.5. This expression remains detectable until molar enamel deposition is completed or throughout life as in the constantly erupting mouse incisors. The expression of alpha7GFP also identifies all stages of innervation of the tooth organ. Ablation of the alpha7-cell lineage using a conditional alpha7Cre×ROSA26-LoxP(diphtheria toxin A) strategy substantially reduced the mesenchyme and this corresponded with excessive epithelium overgrowth consistent with an instructive role by these cells during ectoderm patterning. However, alpha7knock-out (KO) mice exhibited normal tooth size and shape indicating that under normal conditions alpha7 expression is dispensable to this process. The function of ameloblasts in alpha7KO mice is altered relative to controls. High resolution micro-computed tomography analysis of adult mandibular incisors revealed enamel volume of the alpha7KO was significantly reduced and the organization of enamel rods was altered relative to controls. These results demonstrate distinct and varied spatiotemporal expression of alpha7 during tooth development, and they suggest that dysfunction of this receptor would have diverse impacts upon the adult organ. PMID:22666322

Development and irradiation test of lost alpha detection system for ITER.

PubMed

Nishiura, M; Nagasaka, T; Fujioka, K; Fujimoto, Y; Tanaka, T; Ido, T; Yamamoto, S; Kashiwa, S; Sasao, M

2010-10-01

We developed a lost alpha detection system to use in burning plasma experiments. The scintillators of Ag:ZnS and polycrystalline Ce:YAG were designed for a high-temperature environment, and the optical transmission line was designed to transmit from the scintillator to the port plug. The required optical components of lenses and mirrors were irradiated using the fission reactor with the initial result that there was no clear change after the irradiation with a neutron flux of 9.6×10(17) nm(-2)  s(-1) for 48 h. We propose a diagnostic of alpha particle loss, so-called alpha particle induced gamma ray spectroscopy. The initial laboratory test has been carried out by the use of the Ce doped Lu(2)SiO(5) scintillator detector and an Am-Be source to detect the 4.44 MeV high energy gamma ray due to the (9)Be(α,nγ)(12)C reaction.

Rapid, automated, parallel quantitative immunoassays using highly integrated microfluidics and AlphaLISA

PubMed Central

Tak For Yu, Zeta; Guan, Huijiao; Ki Cheung, Mei; McHugh, Walker M.; Cornell, Timothy T.; Shanley, Thomas P.; Kurabayashi, Katsuo; Fu, Jianping

2015-01-01

Immunoassays represent one of the most popular analytical methods for detection and quantification of biomolecules. However, conventional immunoassays such as ELISA and flow cytometry, even though providing high sensitivity and specificity and multiplexing capability, can be labor-intensive and prone to human error, making them unsuitable for standardized clinical diagnoses. Using a commercialized no-wash, homogeneous immunoassay technology (‘AlphaLISA’) in conjunction with integrated microfluidics, herein we developed a microfluidic immunoassay chip capable of rapid, automated, parallel immunoassays of microliter quantities of samples. Operation of the microfluidic immunoassay chip entailed rapid mixing and conjugation of AlphaLISA components with target analytes before quantitative imaging for analyte detections in up to eight samples simultaneously. Aspects such as fluid handling and operation, surface passivation, imaging uniformity, and detection sensitivity of the microfluidic immunoassay chip using AlphaLISA were investigated. The microfluidic immunoassay chip could detect one target analyte simultaneously for up to eight samples in 45 min with a limit of detection down to 10 pg mL−1. The microfluidic immunoassay chip was further utilized for functional immunophenotyping to examine cytokine secretion from human immune cells stimulated ex vivo. Together, the microfluidic immunoassay chip provides a promising high-throughput, high-content platform for rapid, automated, parallel quantitative immunosensing applications. PMID:26074253

2013 Review of Neutron and Non-Neutron Nuclear Data

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

Holden, N. E.

2014-05-23

The results of a review and evaluation of neutron and non-neutron nuclear data published in the scientific literature over the past three years since the ISRD-14 Symposium has been performed and the highlights are presented. Included in the data review are the status of new chemical elements, new measurements of the isotopic composition for many chemical elements and the resulting change in the atomic weight values. New half-life measurements for both short-lived and longlived nuclides, some alpha decay and double beta decay measurements for quasistable nuclides are discussed. The latest evaluation of atomic masses has been published. Data from newmore » measurements on the very heavy (trans-meitnerium) elements are discussed and tabulated. Data on various recent neutron cross section and resonance integral measurements are discussed and tabulated.« less

Uranium and its decay products in samples contaminated with uranium mine and mill waste

NASA Astrophysics Data System (ADS)

Benedik, L.; Klemencic, H.; Repinc, U.; Vrecek, P.

2003-05-01

The routine determination of the activity concentrations of uranium isotopes (^{238}U, ^{235}U and ^{234}U), thorium isotopes (^{212}Th, ^{230}TI, and ^{228}Th), ^{231}Pa, ^{226}Ra, ^{210}Pb and ^{210}Po in the environment is one of the most important tasks in uranium mining areas. Natural radionuclides contribute negligibly to the extemal radiation dose, but in the case of ingestion or inhalation can represent a very serious hazard. The objective of this study was to determine the activities of uranium and its decay products ^{230}Th, ^{231}Pa, ^{226}Ra, ^{210}Pb and ^{210}Po in sediments and water below sources of contamination (uranium mine, disposal sites and individual inflows) using gamma and alpha spectrometry, beta counting, the liquid scintillation technique and radiochemical neutron activation analysis.

On the Origin of the Saturnian Satellite System: Did Iapetus Form In-Situ?

NASA Technical Reports Server (NTRS)

Mosqueira, I.; Estrada, P. R.

2005-01-01

Current models of planet and satellite formation are marred by our lack of understanding regarding the turbulent state of accretion disks. According to the Rayleigh criterion, Keplerian disks are hydrodynamically stable. Indeed, it has been argued that a carefully designed Taylor Couette experiment shows stability in the case of positive radial gradients in specific angular momentum even for high Reynolds numbers [1], in agreement with numerical simulations which consistently show turbulence decay [2]. Other possible sources of turbulence may fail due to low ionization, may decay as the optical depth decreases due to dust coagulation, may involve unrealistic boundary conditions, or result in limited transport. The difficulty stems not only from the degree of turbulence, but also from the kind of turbulence, and whether it may be characterized by an alpha parameter.

Lifetime measurements of 214Po and 212Po with the CTF liquid scintillator detector at LNGS

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

Bellini, G.; Benziger, J.; Bick, D.

2013-07-01

We have studied the alpha decays of 214Po into 210Pb and of 212Po into 208Pb tagged by the coincidence with the preceding beta decays from 214Bi and 212Bi, respectively. The employed 222Rn, 232Th, and 220Rn sources were sealed inside quartz vials and inserted in the Counting Test Facility at the underground Gran Sasso National Laboratory in Italy. We find that the mean lifetime of 214Po is (236.00 +- 0.42(stat) +- 0.15(syst)) \\mu s and that of 212Po is (425.1 +- 0.9(stat) +- 1.2(syst)) ns. Our results, obtained from data with signal-to-background ratio larger than 1000, reduce the overall uncertainties andmore » are compatible with previous measurements.« less

Monitoring materials

DOEpatents

Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore

2002-01-01

The apparatus and method provide techniques for effectively implementing alpha and/or beta and/or gamma monitoring of items or locations as desired. Indirect alpha monitoring by detecting ions generated by alpha emissions, in conjunction with beta and/or gamma monitoring is provided. The invention additionally provides for screening of items prior to alpha monitoring using beta and/or gamma monitoring, so as to ensure that the alpha monitoring apparatus is not contaminated by proceeding direct to alpha monitoring of a heavily contaminated item or location. The invention provides additional versatility in the emission forms which can be monitored, whilst maintaining accuracy and avoiding inadvertent contamination.

Dark Matter Search Results from the PICO - 60 C 3 F 8 Bubble Chamber

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

Amole, C.; Ardid, M.; Arnquist, I. J.

2017-06-01

New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C 3F 8 located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60C 3F 8 exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than one event per month.

Determination of (241)Pu by the method of disturbed radioactive equilibrium using 2πα-counting and precision gamma-spectrometry.

PubMed

Alekseev, I; Kuzmina, T

2016-04-01

A simple technique is proposed for the determination of the content of (241)Pu, which is based on disturbance of radioactive equilibrium in the genetically related (237)U←(241)Pu→(241)Am decay chain of radionuclides, with the subsequent use of 2πα-counting and precision gamma-spectroscopy for monitoring the process of restoration of that equilibrium. It has been shown that the data on dynamics of accumulation of the daughter (241)Am, which were obtained from the results of measurements of α- and γ-spectra of the samples, correspond to the estimates calculated for the chain of two genetically related radionuclides, the differences in the estimates of (241)Pu radioactivity not exceeding 2%. Combining the different methods of registration (2πα-counting, semiconductor alpha- and gamma-spectrometry) enables the proposed method to be efficiently applied both for calibration of (241)Pu-sources (from several hundreds of kBq and higher) and for radioisotopic analysis of plutonium mixtures. In doing so, there is a deep purification of (241)Pu from its daughter decay products required due to unavailability of commercial detectors that could make it possible, based only on analysis of alpha-spectra, to conduct quantitative analysis of the content of (238)Pu and (241)Am. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modeling of Zircon (ZrSiO{sub 4}) and Zirconia (ZrO{sub 2}) using ADF-GUI Software

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

Lwin, Maung Tin Moe; Amin, Yusoff Mohd; Kassim, Hasan Abu

2010-07-07

Natural zircon (ZrSiO{sub 4}) has very high concentration of Uranium and Thorium of up to 5000 ppm. Radioactive decay process of alpha particles from these impurities affects some changes like several atomic displacements in the crystalline structure of zircon. The amount of track density caused by alpha particles decay process of these radioactive materials in zircon can be decreased with annealing temperatures from 700 deg. C to 980 deg. C. Recently it has been extensively studied as the possible candidate material for immobilization of fission products and actinides. Besides, zirconia (ZrO{sub 2}), product from natural zircon, is widely used inmore » industrial field because it has excellent chemical and mechanical properties at high temperature. Dielectric constant of monoclinic, cubic and tetragonal ZrO{sub 2} can be found in the range of 22, 35 and 50 by computer simulation works. In recent years, atomistic simulations and modeling have been studied, because a lot of computational techniques can offer atomic-level approaching with minimum errors in estimations. One favorite methods is Density Functional Theory (DFT). In this study, ADF-GUI software from DFT will be used to calculate the frequency and absorption Intensity of zircon and zirconia molecules. The data from calculations will be verified with experimental works such as Raman Spectroscopy, AFM and XRD.« less

Molecular and functional analyses of the contractile apparatus in lymphatic muscle

NASA Technical Reports Server (NTRS)

Muthuchamy, Mariappan; Gashev, Anatoliy; Boswell, Niven; Dawson, Nancy; Zawieja, David; Delp, Z. (Principal Investigator)

2003-01-01

Lymphatics are necessary for the generation and regulation of lymph flow. Lymphatics use phasic contractions and extrinsic compressions to generate flow; tonic contractions alter resistance. Lymphatic muscle exhibits important differences from typical vascular smooth muscle. In this study, the thoracic duct exhibited significant functional differences from mesenteric lymphatics. To understand the molecular basis for these differences, we examined the profiles of contractile proteins and their messages in mesenteric lymphatics, thoracic duct, and arterioles. Results demonstrated that mesenteric lymphatics express only SMB smooth muscle myosin heavy chain (SM-MHC), whereas thoracic duct and arterioles expressed both SMA and SMB isoforms. Both SM1 and SM2 isoforms of SM-MHC were detected in arterioles and mesenteric and thoracic lymphatics. In addition, the fetal cardiac/skeletal slow-twitch muscle-specific beta-MHC message was detected only in mesenteric lymphatics. All four actin messages, cardiac alpha-actin, vascular alpha-actin, enteric gamma-actin, and skeletal alpha-actin, were present in both mesenteric lymphatics and arterioles. However, in thoracic duct, predominantly cardiac alpha-actin and vascular alpha-actin were found. Western blot and immunohistochemical analyses corroborated the mRNA studies. However, in arterioles only vascular alpha-actin protein was detected. These data indicate that lymphatics display genotypic and phenotypic characteristics of vascular, cardiac, and visceral myocytes, which are needed to fulfill the unique roles of the lymphatic system.

MAGNETIC ENERGY SPECTRA IN SOLAR ACTIVE REGIONS

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

Abramenko, Valentyna; Yurchyshyn, Vasyl

Line-of-sight magnetograms for 217 active regions (ARs) with different flare rates observed at the solar disk center from 1997 January until 2006 December are utilized to study the turbulence regime and its relationship to flare productivity. Data from the SOHO/MDI instrument recorded in the high-resolution mode and data from the BBSO magnetograph were used. The turbulence regime was probed via magnetic energy spectra and magnetic dissipation spectra. We found steeper energy spectra for ARs with higher flare productivity. We also report that both the power index, {alpha}, of the energy spectrum, E(k) {approx} k{sup -}{alpha}, and the total spectral energy,more » W = {integral}E(k)dk, are comparably correlated with the flare index, A, of an AR. The correlations are found to be stronger than those found between the flare index and the total unsigned flux. The flare index for an AR can be estimated based on measurements of {alpha} and W as A = 10{sup b}({alpha}W){sup c}, with b = -7.92 {+-} 0.58 and c = 1.85 {+-} 0.13. We found that the regime of the fully developed turbulence occurs in decaying ARs and in emerging ARs (at the very early stage of emergence). Well-developed ARs display underdeveloped turbulence with strong magnetic dissipation at all scales.« less

Vlasov Simulations of Multi-ion Plasma Turbulence in the Solar Wind

NASA Astrophysics Data System (ADS)

Perrone, D.; Valentini, F.; Servidio, S.; Dalena, S.; Veltri, P.

2013-01-01

Hybrid Vlasov-Maxwell simulations are employed to investigate the role of kinetic effects in a two-dimensional turbulent multi-ion plasma, composed of protons, alpha particles, and fluid electrons. In the typical conditions of the solar-wind environment, and in situations of decaying turbulence, the numerical results show that the velocity distribution functions of both ion species depart from the typical configuration of thermal equilibrium. These non-Maxwellian features are quantified through the statistical analysis of the temperature anisotropy, for both protons and alpha particles, in the reference frame given by the local magnetic field. Anisotropy is found to be higher in regions of high magnetic stress. Both ion species manifest a preferentially perpendicular heating, although the anisotropy is more pronounced for the alpha particles, according to solar wind observations. The anisotropy of the alpha particle, moreover, is correlated to the proton anisotropy and also depends on the local differential flow between the two species. Evident distortions of the particle distribution functions are present, with the production of bumps along the direction of the local magnetic field. The physical phenomenology recovered in these numerical simulations reproduces very common measurements in the turbulent solar wind, suggesting that the multi-ion Vlasov model constitutes a valid approach to understanding the nature of complex kinetic effects in astrophysical plasmas.

A study of energy-energy correlations and measurement of {alpha}{sub s} at the Z{sup 0} resonance

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

Not Available

1992-12-31

We present the energy-energy correlation (EEC) distribution and its asymmetry (AEEC) in hadronic decays of {Zeta}{sup 0} bosons measured by the SLD at SLAC. The data are found to be in good agreement with the predictions of perturbative QCD and fragmentation Monte Carlo models of hadron production. After correction for hadronization effects the data are compared with {Omicron}({alpha}{sub s}{sup 2}) perturbative QCD calculations from various authors. Fits to the central region of the EEC yield substantially different values of the QCD scale {lambda}{sub {ovr MS}} for each of the QCD calculations. There is also a sizeable dependence of the fittedmore » {lambda}{sub {ovr MS}} value on the QCD renormalization scale factor, f. Our preliminary results are {alpha}{sub s}(M {sub Z}) = 0.121 {plus_minus} 0.002(stat.) {plus_minus} 0.004(exp.sys.) {sub {minus}0.009}{sup +0.016} (theor.) for EEC and {alpha}{sub s}(M{sub Z}) = 0.108 {plus_minus} 0.003(stat.) {plus_minus} 0.005(exp.sys.){sub {minus}0.003}{sup +0.008}(theor.) for AEEC. The largest contribution to the error arises from the theoretical uncertainty in choosing the QCD renormalization scale.« less

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.

Targeted alpha therapy using short-lived alpha-particles and the promise of nanobodies as targeting vehicle

PubMed Central

Dekempeneer, Yana; Keyaerts, Marleen; Krasniqi, Ahmet; Puttemans, Janik; Muyldermans, Serge; Lahoutte, Tony; D’huyvetter, Matthias; Devoogdt, Nick

2016-01-01

ABSTRACT Introduction: The combination of a targeted biomolecule that specifically defines the target and a radionuclide that delivers a cytotoxic payload offers a specific way to destroy cancer cells. Targeted radionuclide therapy (TRNT) aims to deliver cytotoxic radiation to cancer cells and causes minimal toxicity to surrounding healthy tissues. Recent advances using α-particle radiation emphasizes their potential to generate radiation in a highly localized and toxic manner because of their high level of ionization and short range in tissue. Areas covered: We review the importance of targeted alpha therapy (TAT) and focus on nanobodies as potential beneficial vehicles. In recent years, nanobodies have been evaluated intensively as unique antigen-specific vehicles for molecular imaging and TRNT. Expert opinion: We expect that the efficient targeting capacity and fast clearance of nanobodies offer a high potential for TAT. More particularly, we argue that the nanobodies’ pharmacokinetic properties match perfectly with the interesting decay properties of the short-lived α-particle emitting radionuclides Astatine-211 and Bismuth-213 and offer an interesting treatment option particularly for micrometastatic cancer and residual disease. PMID:27145158

Improved version of a binding energy formula for heavy and superheavy nuclei with Z{>=}90 and N{>=}140

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

Dong Tiekuang; Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing 210008; Ren Zhongzhou

2008-06-15

A local formula of binding energy for heavy and superheavy nuclei has very recently been proposed [Dong and Ren, Phys. Rev. C 72, 064331 (2005)]. In this paper, the limit of the predictive ability of this local formula is investigated. It is found that the neutron-proton correlations should be considered when higher precision is required. On the one hand, we introduce a new term |N-Z-50|/A, and on the other hand we consider the different strengths of proton-proton, neutron-neutron, and neutron-proton pairing correlations. For the first time, the standard deviation {radical}({sigma}{sup 2}) of the binding energies for 117 nuclei with Z{>=}90more » and N{>=}140 is reduced to 0.105 MeV. The {alpha} decay energies Q{sub {alpha}} and half-lives T{sub {alpha}} of nuclei with Z=102-118 are reproduced quite well. The proton drip line of superheavy elements from Md (Z=101) to Ds (Z=110) are predicted.« less

Characterization of antibodies that selectively detect alpha-synuclein in pathological inclusions.

PubMed

Waxman, Elisa A; Duda, John E; Giasson, Benoit I

2008-07-01

Sensitive detection of alpha-synuclein (alpha-syn) pathology is important in the diagnosis of disorders like Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy and in providing better insights into the etiology of these diseases. Several monoclonal antibodies that selectively react with aggregated alpha-syn in pathological inclusions and reveal extensive and underappreciated alpha-syn pathology in the brains of diseased patients were previously reported by Duda et al. (Ann Neurol 52:205-210, 2002). We sought to characterize the specificity of some of these antibodies (Syn 505, Syn 506 and Syn 514); using C-terminal and N-terminal truncations of alpha-syn, all three antibodies were determined to require N-terminal epitopes that minimally comprise amino acids 2-4, but possibly extend to amino acid 12 of alpha-syn. The selectivity of these antibodies was further assessed using biochemical analysis of human brains and reactivity to altered recombinant alpha-syn proteins with duplication variants of amino acids 1-12. In addition, by expressing wild-type or a double mutant (E46K/A53T) of alpha-syn in cultured cells and by comparing their immunoreactivities to another antibody (SNL-4), which has a similar primary epitope, it was determined that Syn 505, Syn 506 and Syn 514 recognize conformational variants of alpha-syn that is enhanced by the presence of the double mutations. These studies indicate that antibodies Syn 505, Syn 506 and Syn 514 preferentially recognize N-terminal epitopes in complex conformations, consistent with the dramatic conformational change associated with the polymerization of alpha-synuclein into amyloid fibrils that form pathological inclusions.

Development of an alpha scattering instrument for heavy element detection in surface materials

NASA Technical Reports Server (NTRS)

Turkevich, A. L.; Economou, T.; Blume, E.; Anderson, W.

1974-01-01

The development and characteristics of a portable instrument for detecting and measuring the amounts of lead in painted surfaces are discussed. The instrument is based on the ones used with the alpha scattering experiment on the Surveyor lunar missions. The principles underlying the instrument are described. It is stated that the performance tests of the instrument were satisfactory.

Blood and tissue tocopherol levels in rats following intraperitoneally administered alpha-tocopheryl acetate.

PubMed

McGee, C D; Greenwood, C E; Jeejeebhoy, K N

1990-01-01

The correction or maintenance of blood and tissue alpha-tocopherol (alpha-Toc) levels by intraperitoneally administered all-rac-alpha-tocopheryl acetate (alpha-Tac) was compared with RRR- alpha-tocopherol (alpha-Toc) in vitamin E-depleted and control rats. Rats received 1.3 TE vitamin E daily for 7 days. alpha-Tac was detected in plasma of one-third of alpha-Tac-treated rats 24 hr after the first treatment, although not in subsequent samplings. Both alpha-Tac and alpha-Toc increased tocopherol levels in plasma and liver of E-deprived rats, while little or no change was observed in adipose tissue and brain. Similarly, control rats treated with alpha-Tac or alpha-Toc had significantly greater (p less than 0.05) plasma and liver alpha-Toc levels at day 3 and day 7 than did saline-treated rats. There was no significant difference in adipose alpha-Toc levels among treatment groups of control rats. The results of this study suggest that alpha-Tac is rapidly hydrolyzed to its biologically active alcohol form and results in similar effects to that of intraperitoneally administered alpha-Toc.

Fusion of Scores in a Detection Context Based on Alpha Integration.

PubMed

Soriano, Antonio; Vergara, Luis; Ahmed, Bouziane; Salazar, Addisson

2015-09-01

We present a new method for fusing scores corresponding to different detectors (two-hypotheses case). It is based on alpha integration, which we have adapted to the detection context. Three optimization methods are presented: least mean square error, maximization of the area under the ROC curve, and minimization of the probability of error. Gradient algorithms are proposed for the three methods. Different experiments with simulated and real data are included. Simulated data consider the two-detector case to illustrate the factors influencing alpha integration and demonstrate the improvements obtained by score fusion with respect to individual detector performance. Two real data cases have been considered. In the first, multimodal biometric data have been processed. This case is representative of scenarios in which the probability of detection is to be maximized for a given probability of false alarm. The second case is the automatic analysis of electroencephalogram and electrocardiogram records with the aim of reproducing the medical expert detections of arousal during sleeping. This case is representative of scenarios in which probability of error is to be minimized. The general superior performance of alpha integration verifies the interest of optimizing the fusing parameters.

Analysis of fragrance compounds in blood samples of mice by gas chromatography, mass spectrometry, GC/FTIR and GC/AES after inhalation of sandalwood oil.

PubMed

Jirovetz, L; Buchbauer, G; Jäger, W; Woidich, A; Nikiforov, A

1992-01-01

After inhalation experiments with sandalwood oil and the pure fragrance compounds coumarin and alpha-terpineol, substances were detected and measured in the blood samples of test animals (mice) using gas chromatography/mass spectrometry (GC/MS) (MID) in connection with GC/FTIR (SWC), GC/AES (carbon and oxygen trace) and flame ionization detection/gas chromatography. Using tiglinic acid benzyl ester as the internal standard the following concentrations in serum could be found: alpha-santalol 6.1 ng/mL, beta-santalol 5.3 ng/mL and alpha-santalene 0.5 ng/mL. In separate inhalation experiments with coumarin and with alpha-terpineol the corresponding concentrations were 7.7 ng/mL and 6.9 ng/mL, respectively.

Quantitative measurement of intact alpha-synuclein proteoforms from post-mortem control and Parkinson's disease brain tissue by intact protein mass spectrometry.

PubMed

Kellie, John F; Higgs, Richard E; Ryder, John W; Major, Anthony; Beach, Thomas G; Adler, Charles H; Merchant, Kalpana; Knierman, Michael D

2014-07-23

A robust top down proteomics method is presented for profiling alpha-synuclein species from autopsied human frontal cortex brain tissue from Parkinson's cases and controls. The method was used to test the hypothesis that pathology associated brain tissue will have a different profile of post-translationally modified alpha-synuclein than the control samples. Validation of the sample processing steps, mass spectrometry based measurements, and data processing steps were performed. The intact protein quantitation method features extraction and integration of m/z data from each charge state of a detected alpha-synuclein species and fitting of the data to a simple linear model which accounts for concentration and charge state variability. The quantitation method was validated with serial dilutions of intact protein standards. Using the method on the human brain samples, several previously unreported modifications in alpha-synuclein were identified. Low levels of phosphorylated alpha synuclein were detected in brain tissue fractions enriched for Lewy body pathology and were marginally significant between PD cases and controls (p = 0.03).

Systems and methods for neutron detection using scintillator nano-materials

DOEpatents

Letant, Sonia Edith; Wang, Tzu-Fang

2016-03-08

In one embodiment, a neutron detector includes a three dimensional matrix, having nanocomposite materials and a substantially transparent film material for suspending the nanocomposite materials, a detector coupled to the three dimensional matrix adapted for detecting a change in the nanocomposite materials, and an analyzer coupled to the detector adapted for analyzing the change detected by the detector. In another embodiment, a method for detecting neutrons includes receiving radiation from a source, converting neutrons in the radiation into alpha particles using converter material, converting the alpha particles into photons using quantum dot emitters, detecting the photons, and analyzing the photons to determine neutrons in the radiation.

Development and Testing of a 212Pb/212Bi Peptide for Targeting Metastatic Melanoma

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

Fisher, Darrell R.

2012-10-25

The purpose of this project is to develop a new radiolabeled peptide for imaging and treating metastatic melanoma. The immunoconjugate consists of a receptor-specific peptide that targets melanoma cells. The beta-emitter lead-212 (half-life = 10.4 hours) is linked by coordination chemistry to the peptide. After injection, the peptide targets melanoma receptors on the surfaces of melanoma cells. Lead-212 decays to the alpha-emitter bismuth-212 (half-life = 60 minutes). Alpha-particles that hit melanoma cell nuclei are likely to kill the melanoma cell. For cancer cell imaging, the lead-212 is replaced by lead-203 (half-life = 52 hours). Lead-203 emits 279 keV photons (80.1%more » abundance) that can be imaged and measured for biodistribution analysis, cancer imaging, and quantitative dosimetry.« less

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.

Statistical aspects of solar flares

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

1987-01-01

A survey of the statistical properties of 850 H alpha solar flares during 1975 is presented. Comparison of the results found here with those reported elsewhere for different epochs is accomplished. Distributions of rise time, decay time, and duration are given, as are the mean, mode, median, and 90th percentile values. Proportions by selected groupings are also determined. For flares in general, mean values for rise time, decay time, and duration are 5.2 + or - 0.4 min, and 18.1 + or 1.1 min, respectively. Subflares, accounting for nearly 90 percent of the flares, had mean values lower than those found for flares of H alpha importance greater than 1, and the differences are statistically significant. Likewise, flares of bright and normal relative brightness have mean values of decay time and duration that are significantly longer than those computed for faint flares, and mass-motion related flares are significantly longer than non-mass-motion related flares. Seventy-three percent of the mass-motion related flares are categorized as being a two-ribbon flare and/or being accompanied by a high-speed dark filament. Slow rise time flares (rise time greater than 5 min) have a mean value for duration that is significantly longer than that computed for fast rise time flares, and long-lived duration flares (duration greater than 18 min) have a mean value for rise time that is significantly longer than that computed for short-lived duration flares, suggesting a positive linear relationship between rise time and duration for flares. Monthly occurrence rates for flares in general and by group are found to be linearly related in a positive sense to monthly sunspot number. Statistical testing reveals the association between sunspot number and numbers of flares to be significant at the 95 percent level of confidence, and the t statistic for slope is significant at greater than 99 percent level of confidence. Dependent upon the specific fit, between 58 percent and 94 percent of the variation can be accounted for with the linear fits. A statistically significant Northern Hemisphere flare excess (P less than 1 percent) was found, as was a Western Hemisphere excess (P approx 3 percent). Subflares were more prolific within 45 deg of central meridian (P less than 1 percent), while flares of H alpha importance or = 1 were more prolific near the limbs greater than 45 deg from central meridian; P approx 2 percent). Two-ribbon flares were more frequent within 45 deg of central meridian (P less than 1 percent). Slow rise time flares occurred more frequently in the western hemisphere (P approx 2 percent), as did short-lived duration flares (P approx 9 percent), but fast rise time flares were not preferentially distributed (in terms of east-west or limb-disk). Long-lived duration flares occurred more often within 45 deg 0 central meridian (P approx 7 percent). Mean durations for subflares and flares of H alpha importance or + 1, found within 45 deg of central meridian, are 14 percent and 70 percent, respectively, longer than those found for flares closer to the limb. As compared to flares occurring near cycle maximum, the flares of 1975 (near solar minimum) have mean values of rise time, decay time, and duration that are significantly shorter. A flare near solar maximum, on average, is about 1.6 times longer than one occurring near solar minimum.

Importance of interferon alpha in the resistance of allogeneic C57B1/6 mice to the multiplication of Friend erythroleukemia cells in the liver.

PubMed

Gresser, I; Maury, C; Bandu, M T; Belardelli, F

1990-02-15

Friend erythroleukemia cells (FLC) (H-2d) injected intravenously multiply extensively in the livers of syngeneic DBA/2 mice and not at all in the livers of allogeneic C57B1/6 mice. Our results indicate that interferon alpha (IFN-alpha) is an important factor in the resistance of allogeneic mice to the multiplication of FLC in the liver. (a) After i.v. inoculation of FLC there was an inverse correlation between the presence of IFN-alpha in the serum and the capacity of FLC to multiply in the liver. Thus, all 44 FLC-injected adult C57B1/6 mice had circulating IFN-alpha and FLC did not multiply in the liver of any of the mice. Interferon was not detected in the serum of 83% of 41 FLC-injected DBA/2 mice (and was found only at a low titer in 17% of the mice) and FLC multiplied in the liver of all mice. (b) FLC did multiply in the livers of newborn C57B1/6 mice and in the livers of irradiated adult C57B1/6 mice, and IFN-alpha was not detected in their sera. In contrast, after i.v. inoculation of FLC, IFN-alpha was detected in the sera of 3-week-old and athymic nu/nu adult C57B1/6 mice while FLC failed to multiply in the liver. (c) FLC also induced IFN-alpha in congenic B10.D2 (H-2d) mice and FLC did not multiply in the liver. We suggest that, depending on the site of tumor implantation, different host mechanisms have various degrees of importance in controlling the growth and/or rejection of allogeneic tumor cells, and that IFN-alpha is particularly important when FLC are injected i.v.

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.

Multi-wavelength Radio Continuum Emission Studies of Dust-free Red Giants

NASA Technical Reports Server (NTRS)

O'Gorman, Eamon; Harper, Graham M.; Brown, Alexander; Dranke, Stephen; Richards, Anita M. S.

2013-01-01

Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths, however, and previous observations have provided only a small number of modest signal-to-noise measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (alpha Boo: K2 III) and Aldebaran (alpha Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for alpha Boo. This is the first time single (non-binary) luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of alpha Boo's atmosphere where its wind velocity is approaching (or possibly has reached) its terminal value and the ionization balance is becoming frozen-in. For alpha Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of alpha Boo. Finally, we develop a simple analytical wind model for alpha Boo based on our new long-wavelength flux measurements.

Prototype Demonstration of Gamma- Blind Tensioned Metastable Fluid Neutron/Multiplicity/Alpha Detector – Real Time Methods for Advanced Fuel Cycle Applications

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

McDeavitt, Sean M.

The content of this report summarizes a multi-year effort to develop prototype detection equipment using the Tensioned Metastable Fluid Detector (TMFD) technology developed by Taleyarkhan [1]. The context of this development effort was to create new methods for evaluating and developing advanced methods for safeguarding nuclear materials along with instrumentation in various stages of the fuel cycle, especially in material balance areas (MBAs) and during reprocessing of used nuclear fuel. One of the challenges related to the implementation of any type of MBA and/or reprocessing technology (e.g., PUREX or UREX) is the real-time quantification and control of the transuranic (TRU)more » isotopes as they move through the process. Monitoring of higher actinides from their neutron emission (including multiplicity) and alpha signatures during transit in MBAs and in aqueous separations is a critical research area. By providing on-line real-time materials accountability, diversion of the materials becomes much more difficult. The Tensioned Metastable Fluid Detector (TMFD) is a transformational technology that is uniquely capable of both alpha and neutron spectroscopy while being “blind” to the intense gamma field that typically accompanies used fuel – simultaneously with the ability to provide multiplicity information as well [1-3]. The TMFD technology was proven (lab-scale) as part of a 2008 NERI-C program [1-7]. The bulk of this report describes the advancements and demonstrations made in TMFD technology. One final point to present before turning to the TMFD demonstrations is the context for discussing real-time monitoring of SNM. It is useful to review the spectrum of isotopes generated within nuclear fuel during reactor operations. Used nuclear fuel (UNF) from a light water reactor (LWR) contains fission products as well as TRU elements formed through neutron absorption/decay chains. The majority of the fission products are gamma and beta emitters and they represent the more significant hazards from a radiation protection standpoint. However, alpha and neutron emitting uranium and TRU elements represent the more significant safeguards and security concerns. Table 1.1 presents a representative PWR inventory of the uranium and actinide isotopes present in a used fuel assembly. The uranium and actinide isotopes (chiefly the Pu, Am and Cm elements) are all emitters of alpha particles and some of them release significant quantities of neutrons through spontaneous fissions« less

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.

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.

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. 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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. 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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.