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1

Experimental and simulated efficiency of a HPGe detector with point-like and extended sources  

Microsoft Academic Search

The absolute efficiency of a high purity germanium (HPGe) detector was determined with a point-like calibrated 152Eu source at two distances from the detector and three pure metallic thorium foils of different thicknesses. The experimental values are compared with the ones determined with the simulation codes MCNP4B and GEANT 3.21. A procedure for HPGe absolute efficiency calibration is proposed for

D. Karamanis; V. Lacoste; S. Andriamonje; G. Barreau; M. Petit

2002-01-01

2

Experimental and simulated efficiency of a HPGe detector with point-like and extended sources  

NASA Astrophysics Data System (ADS)

The absolute efficiency of a high purity germanium (HPGe) detector was determined with a point-like calibrated 152Eu source at two distances from the detector and three pure metallic thorium foils of different thicknesses. The experimental values are compared with the ones determined with the simulation codes MCNP4B and GEANT 3.21. A procedure for HPGe absolute efficiency calibration is proposed for ?-ray energies higher than 200 keV.

Karamanis, D.; Lacoste, V.; Andriamonje, S.; Barreau, G.; Petit, M.

2002-07-01

3

New approach for calibration the efficiency of HpGe detectors  

NASA Astrophysics Data System (ADS)

This work evaluates the efficiency calibrating of HpGe detector coupled with Canberra GC3018 with Genie 2000 software and Ortec GEM25-76-XLB-C with Gamma Vision software; available at Neutron activation analysis laboratory in Malaysian Nuclear Agency (NM). The efficiency calibration curve was constructed from measurement of an IAEA, standard gamma-point sources set composed by 214Am, 57Co, 133Ba, 152Eu, 137Cs and 60Co. The efficiency calibrations were performed for three different geometries: 5, 10 and 15 cm distances from the end cap detector. The polynomial parameters functions were simulated through a computer program, MATLAB in order to find an accurate fit to the experimental data points. The efficiency equation was established from the known fitted parameters which allow for the efficiency evaluation at particular energy of interest. The study shows that significant deviations in the efficiency, depending on the source-detector distance and photon energy.

Alnour, I. A.; Wagiran, H.; Ibrahim, N.; Hamzah, S.; Siong, W. B.; Elias, M. S.

2014-02-01

4

Efficiency calibration of x-ray HPGe detectors for photons with energies above the Ge K binding energy  

NASA Astrophysics Data System (ADS)

We report on the efficiency calibration of a HPGe x-ray detector using radioactive sources and an analytical expression taken from the literature, in two different arrangements, with and without a broad-angle collimator. The frontal surface of the Ge crystal was scanned with pencil beams of photons. The Ge dead layer was found to be nonuniform, with central and intermediate regions that have thin (?m range) and thick (mm range) dead layers, respectively, surrounded by an insensitive ring. We discuss how this fact explains the observed efficiency curves and generalize the adopted model. We show that changes in the thickness of the Ge-crystal dead layer affect the efficiency of x-ray detectors, but the use of an appropriate broad-beam external collimator limiting the photon flux to the thin dead layer in the central region leads to the expected efficiency dependence with energy and renders the calibration simpler.

Maidana, Nora L.; Vanin, Vito R.; Jahnke, Viktor; Fernández-Varea, José M.; Martins, Marcos N.; Brualla, Lorenzo

2013-11-01

5

Optimum condition of efficiency functions for HPGe ?-ray detectors in the 121-1408 keV energy range  

NASA Astrophysics Data System (ADS)

The optimum condition of three commonly used functions in the Genie 2000 ? spectra analysis software have been studied in the 121-1408 keV energy range. The three functions are applied for fitting the full-energy peak efficiency of the HPGe gamma-ray detector. A detailed procedure to obtain the optimum condition is described. The HPGe detector is calibrated at 11 cm by three radioactive sources of point form (152Eu, 137Cs, 60Co) providing 11 energy peaks. After data processing, results shows that the three functions used in the Genie 2000 gamma spectra analysis software fit best at orders 3-5. Lastly the standard radioactive source 133Ba is chosen to validate the results. Differences between the standard activity of 133Ba and the result obtained from the fitting functions are below 1.5%. Therefore the optimum orders of the three functions used in the Genie 2000 ? spectra analysis software are 3-5 with the 11 energy peaks.

Chen, Zhi-Lin; Song, Guo-Yang; Mu, Long; Wang, He-Yi; Xing, Shi-Xiong; Guo, Hong-Bo; Liao, Zhen-Xing; Chen, Ping; Hua, Sheng

2010-05-01

6

Efficiency calibration of an HPGe X-ray detector for quantitative PIXE analysis  

NASA Astrophysics Data System (ADS)

Particle Induced X-ray Emission (PIXE) is an analytical technique, which provides reliably and accurately quantitative results without the need of standards when the efficiency of the X-ray detection system is calibrated. The ion beam microprobe of the Ion Beam Modification and Analysis Laboratory at the University of North Texas is equipped with a 100 mm2 high purity germanium X-ray detector (Canberra GUL0110 Ultra-LEGe). In order to calibrate the efficiency of the detector for standard less PIXE analysis we have measured the X-ray yield of a set of commercially available X-ray fluorescence standards. The set contained elements from low atomic number Z = 11 (sodium) to higher atomic numbers to cover the X-ray energy region from 1.25 keV to about 20 keV where the detector is most efficient. The effective charge was obtained from the proton backscattering yield of a calibrated particle detector.

Mulware, Stephen J.; Baxley, Jacob D.; Rout, Bibhudutta; Reinert, Tilo

2014-08-01

7

A study for improving detection efficiency of an HPGe detector based gamma spectrometer using Monte Carlo simulation and genetic algorithms.  

PubMed

This work aims at improving the detection efficiency of an HPGe detector based gamma spectrometer for measurements of environmental radioactivity sample. Application of a simple genetic algorithm and the Monte Carlo simulation computer code MCNP5 allows to search for optimal dimensions of the Marinelli beaker typed source geometry that maximizes the detector efficiency for a fixed configuration of the gamma spectrometer. The interested gamma energies are in the range of 255-1926 keV. Optimization calculation was repeated several times to deduce average dimensions of an optimal Marinelli beaker typed sample with a volume of 450 cm(3). Effects of gamma energy, sample chemical composition and sample density on the optimal dimensions were also investigated. Calculated results showed that the effects were negligible. A validated experiment with arrangements using an optimal beaker and three other ones was carried out to verify calculated results. It is shown that experimental and calculated results of the detector efficiency are in a good agreement. PMID:23037923

Huy, Ngo Quang; Binh, Do Quang; An, Vo Xuan

2012-12-01

8

Gamma-ray imaging with position-sensitive HPGe detectors  

Microsoft Academic Search

Due to advances in manufacturing large and highly segmented HPGe detectors along with the availability of fast and high-precision digital electronics, it is now possible to build efficient and high-resolution Compton cameras. Two-dimensionally segmented semi-conductor detectors along with pulse-shape analysis allow to obtain three-dimensional positions and energies of individual gamma-ray interactions. By employing gamma-ray tracking procedures it is possible to

K. Vetter; M. Burks; L. Mihailescu

2004-01-01

9

Determining HPGe Total Detection Efficiency Using ?–? Coincidence  

SciTech Connect

Abstract Both the peak and total detection efficiencies are generally needed in order to calculate sample activity from a gamma spectroscopic measurement, except in the case of isotope specific calibration. This is particularly true when the sample is in close proximity to the detector and corrections for cascade summing effects are required to avoid significant inaccuracy in the result. These corrections use the total detection efficiency to correct for summing-in and summing-out events, and the extent of the correction depends on both the geometry and the gamma cascade for the isotope in question. Experimentally determining the total efficiency is a labor intensive endeavor requiring multiple measurements with a set of single-gamma-emitting standards. Modeling the total efficiency vs. energy may be less time consuming, but is also likely to produce less confidence in the final result. Pacific Northwest National Laboratory's Radiation Detection and Nuclear Sciences group has constructed a low background 14-crystal HPGe array for sample measurement; in all measurements, samples will be in close proximity to the germanium crystals. This close geometry and the sheer number efficiency calibrations required for the system have led us to investigate methods to simplify the efficiency calibration procedure. One method we are developing uses the Y-Y coincidence plane to isolate Compton scattering event populations, allowing experimental determination of total detection efficiency values from the measurement of a single mixed isotope standard. A description of the analysis and experimental results of this method are presented.

Erikson, Luke E.; Keillor, Martin E.; Aalseth, Craig E.; Hossbach, Todd W.; Mizouni, Leila K.; Stavenger, Timothy J.; McDonald, Benjamin S.; Lepel, Elwood A.; Greenwood, Lawrence R.; Rutherford, Crystal E.

2013-05-01

10

A trapezoid approach for the experimental total-to-peak efficiency curve used in the determination of true coincidence summing correction factors in a HPGe detector  

NASA Astrophysics Data System (ADS)

In this work, a simple method for true coincidence correction is suggested for a voluminous source measured in close detection geometry for a HPGe detector. TrueCoinc program based on Sudár's algorithm was used to determine true coincidence summing correction (TCS) factors by using full energy peak (FEP) efficiency, and total-to-peak (TTP) efficiency curves in which experimental efficiencies are obtained from almost coincident-free radionuclides such as 54Mn, 57Co, 65Zn, 109Cd, 137Cs and 241Am. In order to calculate TTP efficiency curve three different approaches were tested. One of them is new and here called trapezoid approach which was used successfully in determining total count of spectrum for the TTP efficiency curves. According to different TTP determination methods, the changes in true coincidence factors are observed. The FEP efficiency curves are also established for a cylindrical source. Then, TCS factors were determined for the particular peaks of daughters of 226Ra, 238U, and 232Th using the suggested method. Those activities measured from some certified reference materials such as IAEA RGU-1 and RGTh-1 are used to validate the present TCS correction procedure.

?ahiner, Eren; Meriç, Niyazi

2014-03-01

11

Measurement of ?-decay end point energy with planar HPGe detector  

NASA Astrophysics Data System (ADS)

The ?-? coincidence measurement has been performed with a segmented planar Hyper-Pure Germanium (HPGe) detector and a single coaxial HPGe detector to determine the end point energies of nuclear ?-decays. The experimental end point energies have been determined for some of the known ?-decays in Rh106?Pd106. The end point energies corresponding to three weak branches in Rh106?Pd106 decay have been measured for the first time. The ? ray and ? particle responses for the planar HPGe detector were simulated using the Monte Carlo based code GEANT3. The experimentally obtained ? spectra were successfully reproduced with the simulation.

Bhattacharjee, T.; Pandit, Deepak; Das, S. K.; Chowdhury, A.; Das, P.; Banerjee, D.; Saha, A.; Mukhopadhyay, S.; Pal, S.; Banerjee, S. R.

2014-12-01

12

Performance of CdTe, HPGe and NaI(Tl) detectors for radioactivity measurements.  

PubMed

The characteristics and performances of the NIST High-Purity Germanium (HPGe), Sodium Iodide (NaI(Tl)) and Cadmium Telluride (CdTe) gamma-ray detectors were studied. The efficiencies, the minimum detectable activities and the energy resolutions of each were measured and compared. The data were analyzed using different software packages. The measurements were performed in a low background radiation environment using calibrated point sources. The CdTe detector showed a higher energy resolution than the NaI(Tl) detector but a lower efficiency than both the HPGe and NaI(Tl) detectors. This makes it a suitable detector only for relatively high activity measurements restricted to the 35 keV to 200 keV energy range. PMID:14687635

Perez-Andujar, A; Pibida, L

2004-01-01

13

Calculation of Gamma-ray Responses for HPGe Detectors with TRIPOLI-4 Monte Carlo Code  

NASA Astrophysics Data System (ADS)

The gamma-ray response calculation of HPGe (High Purity Germanium) detector is one of the most important topics of the Monte Carlo transport codes for nuclear instrumentation applications. In this study the new options of TRIPOLI-4 Monte Carlo transport code for gamma-ray spectrometry were investigated. Recent improvements include the gamma-rays modeling of the electron-position annihilation, the low energy electron transport modeling, and the low energy characteristic X-ray production. The impact of these improvements on the detector efficiency of the gamma-ray spectrometry calculations was verified. Four models of HPGe detectors and sample sources were studied. The germanium crystal, the dead layer of the crystal, the central hole, the beryllium window, and the metal housing are the essential parts in detector modeling. A point source, a disc source, and a cylindrical extended source containing a liquid radioactive solution were used to study the TRIPOLI-4 calculations for the gamma-ray energy deposition and the gamma-ray self-shielding. The calculations of full-energy-peak and total detector efficiencies for different sample-detector geometries were performed. Using TRIPOLI-4 code, different gamma-ray energies were applied in order to establish the efficiency curves of the HPGe gamma-ray detectors.

Lee, Yi-Kang; Garg, Ruchi

2014-06-01

14

Development of the MCNPX model for the portable HPGe detector  

NASA Astrophysics Data System (ADS)

The portable HPGe coaxial detector Canberra Big MAC is used in LVR-15 research reactor for spectrometric measurement of spent nuclear fuel. The fuel is measured in the dedicated system located in the spent fuel pool situated near the reactor. For the purpose of the spectrometric system calibration, the detector was precisely modeled with the MCNPX code. This model was constructed with the data acquired from the technical specification provided by the manufacturer and from the data obtained by the radiography of the crystal. The detector model was verified on the experimental data measured with available standard radionuclide sources and on-site prepared 110mAg source.

Koleska, Michal; Viererbl, Ladislav; Marek, Milan

2014-11-01

15

Performance of CdTe, HPGe and NaI(Tl) detectors for radioactivity measurements  

Microsoft Academic Search

The characteristics and performances of the NIST High-Purity Germanium (HPGe), Sodium Iodide (NaI(Tl)) and Cadmium Telluride (CdTe) gamma-ray detectors were studied. The efficiencies, the minimum detectable activities and the energy resolutions of each were measured and compared. The data were analyzed using different software packages. The measurements were performed in a low background radiation environment using calibrated point sources. The

A. Perez-Andujar; L. Pibida

2004-01-01

16

Comparison of background in underground HPGe-detectors in different lead shield configurations.  

PubMed

In underground HPGe-detector systems where the cosmic ray induced background is low, it is often difficult to assess the location of background sources. In this study, background counting rates of different HPGe-detectors in different lead shields are reported with the aim of better understanding background sources. To further enhance the understanding of the variations of environmental parameters, the background as a function of time over a long period was also studied. PMID:23602708

Hult, Mikael; Lutter, Guillaume; Yüksel, Ayhan; Marissens, Gerd; Misiaszek, Marcin; Rosengård, Ulf

2013-11-01

17

Application of GEANT4 simulation on calibration of HPGe detectors for cylindrical environmental samples.  

PubMed

The determination of radionuclide activity concentration requires a prior knowledge of the full-energy peak (FEP) efficiency at all photon energies for a given measuring geometry. This problem has been partially solved by using procedures based on Monte Carlo simulations, developed in order to complement the experimental calibration procedures used in gamma-ray measurements of environmental samples. The aim of this article is to apply GEANT4 simulation for calibration of two HPGe detectors, for measurement of liquid and soil-like samples in cylindrical geometry. The efficiencies obtained using a simulation were compared with experimental results, and applied to a realistic measurement. Measurement uncertainties for both simulation and experimental values were estimated in order to see whether the results of the realistic measurement fall within acceptable limits. The trueness of the result was checked using the known activity of the measured samples provided by IAEA. PMID:24894534

Nikolic, J D; Jokovic, D; Todorovic, D; Rajacic, M

2014-06-01

18

Locating a "hot spot" in the lungs when using an array of four HPGe detectors.  

PubMed

Considerable errors in the activity determination in lungs can be induced for the case of a "hot spot". Modern lung counter systems use several HPGe detectors, and the count rate ratios of the detectors can be used to locate the "hot spot" and apply correction algorithms. Some criteria for location determination of a point source in the lungs were investigated, and it is shown that an average error of up to about 10% can be achieved. PMID:15177329

Pelled, O; Tsroya, S; German, U; Haquin, G; Alfassi, Z B

2004-01-01

19

Calculation of HPGe efficiency for environmental samples: comparison of EFFTRAN and GEANT4  

NASA Astrophysics Data System (ADS)

Determination of full energy peak efficiency is one of the most important tasks that have to be performed before gamma spectrometry of environmental samples. Many methods, including measurement of specific reference materials, Monte Carlo simulations, efficiency transfer and semi empirical calculations, were developed in order to complete this task. Monte Carlo simulation, based on GEANT4 simulation package and EFFTRAN efficiency transfer software are applied for the efficiency calibration of three detectors, readily used in the Environment and Radiation Protection Laboratory of Institute for Nuclear Sciences Vinca, for measurement of environmental samples. Efficiencies were calculated for water, soil and aerosol samples. The aim of this paper is to perform efficiency calculations for HPGe detectors using both GEANT4 simulation and EFFTRAN efficiency transfer software and to compare obtained results with the experimental results. This comparison should show how the two methods agree with experimentally obtained efficiencies of our measurement system and in which part of the spectrum do the discrepancies appear. The detailed knowledge of accuracy and precision of both methods should enable us to choose an appropriate method for each situation that is presented in our and other laboratories on a daily basis.

Nikolic, Jelena; Vidmar, Tim; Jokovic, Dejan; Rajacic, Milica; Todorovic, Dragana

2014-11-01

20

Position sensitivity of the first SmartPET HPGe detector  

NASA Astrophysics Data System (ADS)

In this paper we discuss the Smart Positron Emission Tomography (PET) imaging system being developed by the University of Liverpool in conjunction with CCLRC Daresbury Laboratory. We describe the motivation for the development of a semiconductor-based PET system and the advantages it will offer over current tomographs. Details of the detectors and associated electronics are discussed and results of high precision scans are presented. Analysis of this scan data has facilitated full characterization of the detector response function and calibration of the three-dimensional position sensitivity. This work presents the analysis of the depth sensitivity of the detector.

Cooper, R. J.; Turk, G.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Mather, A. R.; Nolan, P. J.; Hall, C. J.; Lazarus, I.; Simpson, J.; Berry, A.; Beveridge, T.; Gillam, J.; Lewis, R. A.

2007-04-01

21

Comparison of the NDA of HEU Oxide between the AWCC and the HPGe Detector  

SciTech Connect

This paper compares the performance of the Active Well Coincidence Counter (AWCC) with the performance of high resolution gamma spectrometry using an HPGe detector to nondestructively assay highly enriched (HEU) oxide. Traditionally the AWCC was considered to be the more appropriate instrument for this measurement. Although the AWCC had a high degree of precision, the HPGe provided the more accurate measurement of this material. The AWCC determines mass of U-235 from the coincident pairs of neutron detections, or doubles rate. The HPGe determines the mass of both U-235 and U238, the enrichment, and the quantity of other radioisotopes. The Tl-208 gamma rays were used to verify the amount of attenuation for the HPGe analysis. Fifty-four cans of enriched U3O8 were shipped to the Y-12 National Security Complex from Los Alamos National Laboratory (LANL) under Scrap Declaration LANL-45. The declared values for net weight, mass of uranium, mass of U-235, and enrichment (percent mass of U-235 to total uranium) are shown in Table A-1. The masses of U-235 range from 104g to 2404g and the enrichment varies from 20% to 98%.

Chiang, L. G.; Oberer, R. B.; Gunn, C. A.; Dukes, E. E.; Akin, J. A.

2009-12-01

22

Triple and quadruple-escape peaks in HPGe detectors: Experimental observation and Monte Carlo simulation  

Microsoft Academic Search

The triple- and quadruple-escape peaks of 6.128 MeV photons from the F(p,alphagamma)19O16 nuclear reaction were observed in an HPGe detector. The experimental peak areas, measured in spectra projected with a restriction function that allows quantitative comparison of data from different multiplicities, are in reasonably good agreement with those predicted by Monte Carlo simulations done with the general-purpose radiation-transport code PENELOPE.

N. L. Maidana; L. Brualla; V. R. Vanin; J. R. B. Oliveira; M. A. Rizzutto; E. Do Nascimento; J. M. Fernández-Varea

2010-01-01

23

Triple and quadruple-escape peaks in HPGe detectors: Experimental observation and Monte Carlo simulation  

Microsoft Academic Search

The triple- and quadruple-escape peaks of 6.128MeV photons from the F(p,??)19O16 nuclear reaction were observed in an HPGe detector. The experimental peak areas, measured in spectra projected with a restriction function that allows quantitative comparison of data from different multiplicities, are in reasonably good agreement with those predicted by Monte Carlo simulations done with the general-purpose radiation-transport code penelope. The

N. L. Maidana; L. Brualla; V. R. Vanin; J. R. B. Oliveira; M. A. Rizzutto; E. do Nascimento; J. M. Fernández-Varea

2010-01-01

24

Triple- and quadruple-escape peaks in HPGe detectors: Experimental observation and Monte Carlo simulation  

NASA Astrophysics Data System (ADS)

The triple- and quadruple-escape peaks of 6.128 MeV photons from the F(p,??)19O16 nuclear reaction were observed in an HPGe detector. The experimental peak areas, measured in spectra projected with a restriction function that allows quantitative comparison of data from different multiplicities, are in reasonably good agreement with those predicted by Monte Carlo simulations done with the general-purpose radiation-transport code PENELOPE. The behaviour of the escape intensities was simulated for some gamma-ray energies and detector dimensions; the results obtained can be extended to other energies using an empirical function and statistical properties related to the phenomenon.

Maidana, N. L.; Brualla, L.; Vanin, V. R.; Oliveira, J. R. B.; Rizzutto, M. A.; do Nascimento, E.; Fernández-Varea, J. M.

2010-04-01

25

Single channel beta-gamma coincidence system for radioxenon measurement using well-type HPGe and plastic scintillator detectors  

NASA Astrophysics Data System (ADS)

In order to improve detection sensitivity for radioxenon isotopes, a new single channel beta-gamma coincidence system has been developed. The system combines a well-type High-purity Germanium (HPGe) detector to measure gamma or X radiation and a plastic scintillator detector to obtain electron radiation. A 133Xe sample has been produced and the radioactive concentration was determined with length-compensated method based on three internal gas proportional counters. The performance of system has been checked by measuring 133Xe sample with and without coincidence. The coincidence detection efficiency of 81 keV gamma-ray from decay of 133Xe was calibrated to be 0.34 (1±2.4%), and the Minimum detectable activity (MDA) of the beta-gamma coincidence system for 133Xe was determined to be 1.8 mBq after one day of measurement.

Xie, Feng; Jiang, Wengang; Li, Xuesong; He, Xiaobing; Zhang, Jiamei; Yu, Gongshuo

2013-11-01

26

Determining the drift time of charge carriers in p-type point-contact HPGe detectors  

NASA Astrophysics Data System (ADS)

An algorithm to determine the drift time of charge carriers in p-type point contact (PPC) high-purity germanium (HPGe) detectors from the signals processed with a charge-sensitive preamplifier is introduced. It is demonstrated that the drift times can be used to estimate the distance of charge depositions from the point contact and to characterize losses due to charge trapping. A correction for charge trapping effects over a wide range of energies is implemented using the measured drift times and is shown to improve the energy resolution by up to 30%.

Martin, R. D.; Amman, M.; Chan, Y. D.; Detwiler, J. A.; Loach, J. C.; Looker, Q.; Luke, P. N.; Poon, A. W. P.; Qian, J.; Vetter, K.; Yaver, H.

2012-06-01

27

Search for double beta decay of $^{136}$Ce and $^{138}$Ce with HPGe gamma detector  

E-print Network

Search for double $\\beta$ decay of $^{136}$Ce and $^{138}$Ce was realized with 732 g of deeply purified cerium oxide sample measured over 1900 h with the help of an ultra-low background HPGe $\\gamma$ detector with a volume of 465 cm$^3$ at the STELLA facility of the Gran Sasso National Laboratories of the INFN (Italy). New improved half-life limits on double beta processes in the cerium isotopes were set at the level of $\\lim T_{1/2}\\sim 10^{17}-10^{18}$~yr; many of them are even two orders of magnitude larger than the best previous results.

P. Belli; R. Bernabei; R. S. Boiko; F. Cappella; R. Cerulli; F. A. Danevich; A. Incicchitti; B. N. Kropivyansky; M. Laubenstein; D. V. Poda; O. G. Polischuk; V. I. Tretyak

2014-09-09

28

Search for double beta decay of $^{136}$Ce and $^{138}$Ce with HPGe gamma detector  

E-print Network

Search for double $\\beta$ decay of $^{136}$Ce and $^{138}$Ce was realized with 732 g of deeply purified cerium oxide sample measured over 1900 h with the help of an ultra-low background HPGe $\\gamma$ detector with a volume of 465 cm$^3$ at the STELLA facility of the Gran Sasso National Laboratories of the INFN (Italy). New improved half-life limits on double beta processes in the cerium isotopes were set at the level of $\\lim T_{1/2}\\sim 10^{17}-10^{18}$~yr; many of them are even two orders of magnitude larger than the best previous results.

Belli, P; Boiko, R S; Cappella, F; Cerulli, R; Danevich, F A; Incicchitti, A; Kropivyansky, B N; Laubenstein, M; Poda, D V; Polischuk, O G; Tretyak, V I

2014-01-01

29

Search for double beta decay of 136Ce and 138Ce with HPGe gamma detector  

NASA Astrophysics Data System (ADS)

Search for double ? decay of 136Ce and 138Ce was realized with 732 g of deeply purified cerium oxide sample measured over 1900 h with the help of an ultra-low background HPGe ? detector with a volume of 465 cm3 at the STELLA facility of the Gran Sasso National Laboratories of the INFN (Italy). New improved half-life limits on double beta processes in the cerium isotopes were set at the level of lim?T1/2?1017-1018 yr; many of them are even two orders of magnitude larger than the best previous results.

Belli, P.; Bernabei, R.; Boiko, R. S.; Cappella, F.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Kropivyansky, B. N.; Laubenstein, M.; Poda, D. V.; Polischuk, O. G.; Tretyak, V. I.

2014-10-01

30

Simultaneous, coincident 2-D ACAR and DBAR using segmented HPGe detectors incorporating sub-pixel interpolation  

NASA Astrophysics Data System (ADS)

A three-dimensional Positron Annihilation Spectrometry System (3D PASS) for determination of 3D electron-positron (e--e+) momentum densities by measuring coincident annihilation photons was designed, constructed and characterized. 3D PASS collects a single data set including correlated photon energies and coincident photon positions which are typically collected separately by two-dimensional angular correlation of annihilation radiation (2D ACAR) and two-detector coincident Doppler broadening of annihilation radiation (CDBAR) spectrometry. 3D PASS is composed of two position-sensitive, high-purity germanium (HPGe) double-sided strip detectors (DSSD(s)) linked together by a 32-channel, 50 MHz digital electronics suite. The DSSDs data were analyzed to determine location of photon detection events using an interpolation method to achieve a spatial resolution less than the 5-mm width of the DSSDs' charge collection strips. The interpolation method relies on measuring a figure-of-merit proportional to the area of the transient charges observed on both strips directly adjacent to the charge collection strip detecting the full charge deposited by the annihilation photon. This sub-pixel resolution, corresponding to the error associated with event location within a sub-pixel was measured for both DSSDs using the approach outlined in Williams et al [1] and was on the order of ± 0.20 mm (± one-standard deviation). As a result of the sub-pixel resolution, the distance between the DSSDs and material sample was reduced by a factor of five compared to what is typically required in 2D ACAR systems was necessary to achieve 0.5-mrad angular resolution. This reduction in the system's footprint decreases attenuation of the annihilation photons in the air between the material sample and the DSSDs and increases the solid angle between the sample and the DSSDs, ultimately resulting in higher system detection efficiency. 3D PASS was characterized in the same manner comparable to state-of-the-art 2D ACAR and CDBAR spectrometers. 3D PASS spectra were collected and analyzed for single-crystal copper (Cu) and silicon carbide (6H SiC) and compared with the results in the literature.

Williams, Christopher S.; Burggraf, Larry W.; Adamson, Paul E.; Petrosky, James C.; Oxley, Mark E.

2010-04-01

31

Field analyses of (238)U and (226)Ra in two uranium mill tailings piles from Niger using portable HPGe detector.  

PubMed

The radioactivities of (238)U and (226)Ra in mill tailings from the U mines of COMINAK and SOMAÏR in Niger were measured and quantified using a portable High-Purity Germanium (HPGe) detector. The (238)U and (226)Ra activities were measured under field conditions on drilling cores with 600s measurements and without any sample preparation. Field results were compared with those obtained by Inductive Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and emanometry techniques. This comparison indicates that gamma-ray absorption by such geological samples does not cause significant deviations. This work shows the feasibility of using portable HPGe detector in the field as a preliminary method to observe variations of radionuclides concentration with the aim of identifying samples of interest. The HPGe is particularly useful for samples with strong secular disequilibrium such as mill tailings. PMID:25036918

Déjeant, Adrien; Bourva, Ludovic; Sia, Radia; Galoisy, Laurence; Calas, Georges; Phrommavanh, Vannapha; Descostes, Michael

2014-11-01

32

Scoping measurements of radionuclides in L Lake with an underwater HPGe detector  

SciTech Connect

This study of L Lake was conducted to determine whether the distribution of man-made radiation levels had changed from the time preceding the filling of the newly created lake in 1985. Overflight gamma measurements by EG&G in 1985 mapped the man-made radiation levels, indicating that significant levels were only detected from former stream beds that were to be covered by the lake. the present scoping gamma measurements were consistent with these earlier findings, indicating no major evidence of movement of the radioactivity. These results will be available to guide decisions concerning future plans for the lake. Gamma-emitting radionuclides of L Lake were examined in situ with an underwater HPGe detector and further studied by retrieving various sediment samples for analysis by HPGe gamma spectrometry in the Underground Counting Facility. The predominant man-made radionuclide detected was {sup 137}Cs; it had about 100 times greater activity than {sup 60}Co, which was the only other man-made radionuclide that was detected above trace levels.

Dunn, D.L.; Win, W.G.; Bresnahan, P.J.

1996-06-01

33

Hunting up low-mass bosons from the Sun using HPGe detector  

E-print Network

In this experiment we aim to look for keV-mass bosons emitted from the Sun, by looking at a process analogous to the photoelectric/Compton effect inside the HPGe detector. Their coupling to both electrons and nucleons is assumed. For masses above 25 keV, the mass dependence of our limit on the scalar-electron coupling reveals a constraint which proves stronger than that obtained recently and based on the very good agreement between the measured and predicted solar neutrino flux from the ^{8}B reaction. On the other hand, the mass dependence of our limit on the scalar-proton/electron coupling together entails a limit on a possible Yukawa addition to the gravitational inverse square low. Such a constraint on the Yukawa interactions proves much stronger than that derived from the latest AFM Casimir force measurement.

R. Horvat; D. Kekez; M. Krcmar; Z. Krecak; A. Ljubicic

2011-01-28

34

Measurements of radionuclide in Par Pond sediments with an underwater HPGe detector  

SciTech Connect

Savannah River Site (SRS) effluent gamma emitting radionuclides in Par Pond sediment were examined in situ with an underwater HPGe detector prior to and following a 19 ft drawdown of the pond in 1991 to address dam repairs. These measurements provide a map of the {sup 137}Cs concentrations of the pond sediment, indicating that 9.4 {plus_minus} 1.5 Ci is exposed by the drawdown and that 46.6 {plus_minus} 7.2 Ci is the entire pond inventory. The highest individual {sup 137}Cs concentration was 25 {mu}Ci/m{sup 2} for the exposed sediment and 50 {mu}Ci/m{sup 2} for the entire pond. The results are consistent with parallel studies conducted by SREL, as well as historical data. Aside from {sup 137}Cs, the only other SRS-produced isotope observed was {sup 60}Co, with activity of only about 1% of that for {sup 137}Cs. This observation was also confirmed in grab samples of pond sediment and vegetation, which were returned to the laboratory for ultra-low-level gamma spectrometry analysis. A special effort was required to calibrate the underwater HPGe detector, where both measurements and calculational models were used. The effects of sediment depth profiles for density and {sup 137}Cs concentration were addressed in the calibration. Calibration factors for sediment surface concentrations ({mu}Ci/m{sup 2}/cpm) and sediment mass concentrations (pCi/kg/cpm) were obtained. In general, the {mu}Ci/m{sup 2}/cpm factor is recommended, as the pCi/kg/cpm factor depends on the depth location of the sediment of interest. However, a pCi/kg/cpm factor, which is dependent on the depth within the sediment is presented to address dose calculations that require it.

Winn, W.G.

1993-11-01

35

Mapping radionuclide distribution in surface sediments using GIS and an underwater HPGe detector  

SciTech Connect

A radiological distribution survey at the L Lake on the Savannah River Site (SRS) was conducted by the Savannah River Technology Center (SRTC) during the summer of 1995 as part of a larger project to examine future alternatives for L Lake and other SRS water bodies. The primary purpose of the survey was to confirm previous radionuclide surveys of Cesium-137 (137Cs) in the L Lake area. EG and G Energy Measurements, Inc. conducted an aerial, baseline radiological survey of the L Lake area and the Steel Creek drainage basin in 1985. Overflight gamma mappings of the area by EG and G indicated that the only significant man-made radionuclides were located in the stream beds3, which were subsequently covered by the reservoir. The major concern was to see if any of the man-made radiation was redistributed over time away from the stream beds. In the current study an underwater HPGe detector was used to scope the possibility of sediment redistribution from the stream beds beneath L Lake. The underwater detector was positioned to view the bottom sediment and the geographic position of the pontoon boat used for deployment was recorded. The count rate at each position is proportional to the radiation level that would be observed if the lake water were absent, as in the 1985 overflight measurements. Thus, the 1995 study yields count rate profiles that are appropriate for comparison with the gamma mappings of 1985.

Dunn, D.L.; Winn, W.G.; Bresnahan, P.J.

1996-09-01

36

Interaction position resolution simulations and in-beam measurements of the AGATA HPGe detectors  

NASA Astrophysics Data System (ADS)

The interaction position resolution of the segmented HPGe detectors of an AGATA triple cluster detector has been studied through Monte Carlo simulations and in an in-beam experiment. A new method based on measuring the energy resolution of Doppler-corrected ?-ray spectra at two different target to detector distances is described. This gives the two-dimensional position resolution in the plane perpendicular to the direction of the emitted ?-ray. The ?-ray tracking was used to determine the full energy of the ?-rays and the first interaction point, which is needed for the Doppler correction. Five different heavy-ion induced fusion-evaporation reactions and a reference reaction were selected for the simulations. The results of the simulations show that the method works very well and gives a systematic deviation of <1 mm in the FWHM of the interaction position resolution for the ?-ray energy range from 60 keV to 5 MeV. The method was tested with real data from an in-beam measurement using a 30Si beam at 64 MeV on a thin 12C target. Pulse-shape analysis of the digitized detector waveforms and ?-ray tracking was performed to determine the position of the first interaction point, which was used for the Doppler corrections. Results of the dependency of the interaction position resolution on the ?-ray energy and on the energy, axial location and type of the first interaction point, are presented. The FWHM of the interaction position resolution varies roughly linearly as a function of ?-ray energy from 8.5 mm at 250 keV to 4 mm at 1.5 MeV, and has an approximately constant value of about 4 mm in the ?-ray energy range from 1.5 to 4 MeV.

Söderström, P.-A.; Recchia, F.; Nyberg, J.; Al-Adili, A.; Ataç, A.; Aydin, S.; Bazzacco, D.; Bednarczyk, P.; Birkenbach, B.; Bortolato, D.; Boston, A. J.; Boston, H. C.; Bruyneel, B.; Bucurescu, D.; Calore, E.; Colosimo, S.; Crespi, F. C. L.; Dosme, N.; Eberth, J.; Farnea, E.; Filmer, F.; Gadea, A.; Gottardo, A.; Grave, X.; Grebosz, J.; Griffiths, R.; Gulmini, M.; Habermann, T.; Hess, H.; Jaworski, G.; Jones, P.; Joshi, P.; Judson, D. S.; Kempley, R.; Khaplanov, A.; Legay, E.; Lersch, D.; Ljungvall, J.; Lopez-Martens, A.; Meczynski, W.; Mengoni, D.; Michelagnoli, C.; Molini, P.; Napoli, D. R.; Orlandi, R.; Pascovici, G.; Pullia, A.; Reiter, P.; Sahin, E.; Smith, J. F.; Strachan, J.; Tonev, D.; Unsworth, C.; Ur, C. A.; Valiente-Dobón, J. J.; Veyssiere, C.; Wiens, A.; Agata Collaboration

37

Estimation of immediate fallout after the accident at Fukushima Daiichi Nuclear Power Plant by using HPGe detector and EGS5 code.  

PubMed

After the accident at the Fukushima Daiichi nuclear power plant, we managed to carry out emergency measurements of the radioactive fallout. The included nuclides were identified via gamma-ray spectrometry using an HPGe detector. Quantifications of each radionuclide in the fallout were determined based on the efficiency calibrations and relevant corrections. The collected samples had a variety of shapes, densities, and compositions. EGS5 Monte Carlo code was used for the flexible estimation of these parameters. The measurement results show the temporal changes in the fallout quantity about a month after the accident. PMID:23570955

Unno, Yasuhiro; Yunoki, Akira; Sato, Yasushi; Hino, Yoshio

2013-11-01

38

Effect of a surface channel on the performance of a P-type Point Contact HPGe detector  

NASA Astrophysics Data System (ADS)

The observation of anomalous charge collection in a P-type Point Contact (PPC) High Purity Germanium (HPGe) detector is reported. By studying preamplifier charge signals from the detector, these anomalous events are shown to be consistent with charge carrier drift along the surface of the detector, prior to collection at the contact. It is believed that these events arise from the formation of a surface channel in the detector. By coupling analysis of these experimental signals with field calculations, an estimate of the radial drift velocity of holes at the surface has been made. This value is found to be around 40 times slower than the accepted value for saturated hole drift in the bulk, and is in good agreement with that calculated using a newly developed technique for modelling carrier transport.

Cooper, R. J.; Radford, D. C.; Hull, E.; Lagergren, K.; Mullowney, P.; Lin, M.-C.; Paul, K.; Athens, C.; Loh, M.

2012-07-01

39

An investigation of the performance of a coaxial HPGe detector operating in a magnetic resonance imaging field  

NASA Astrophysics Data System (ADS)

Nuclear medical imaging modalities such as positron emission tomography and single photon emission computed tomography are used to probe physiological functions of the body by detecting gamma rays emitted from biologically targeted radiopharmaceuticals. A system which is capable of simultaneous data acquisition for nuclear medical imaging and magnetic resonance imaging is highly sought after by the medical imaging community. Such a device could provide a more complete medical insight into the functions of the body within a well-defined structural context. However, acquiring simultaneous nuclear/MRI sequences are technically challenging due to the conventional photomultiplier tube readout employed by most existing scintillator detector systems. A promising solution is a nuclear imaging device composed of semiconductor detectors that can be operated with a standard MRI scanner. However, the influence of placing a semiconductor detector such as high purity germanium (HPGe) within or close to the bore of an MRI scanner, where high magnetic fields are present, is not well understood. In this paper, the performance of a HPGe detector operating in a high strength static ( BS) MRI field along with fast switching gradient fields and radiofrequency from the MRI system has been assessed. The influence of the BS field on the energy resolution of the detector has been investigated for various positions and orientations of the detector within the magnetic field. The results have then been interpreted in terms of the influence of the BS field on the charge collection properties. MRI images have been acquired with the detector situated at the entrance of the MRI bore to investigate the effects of simultaneous data acquisition on detector performance and MRI imaging.

Harkness, L. J.; Boston, A. J.; Boston, H. C.; Cole, P.; Cresswell, J. R.; Filmer, F.; Jones, M.; Judson, D. S.; Nolan, P. J.; Oxley, D. C.; Sampson, J. A.; Scraggs, D. P.; Slee, M. J.; Bimson, W. E.; Kemp, G. J.; Groves, J.; Headspith, J.; Lazarus, I.; Simpson, J.; Cooper, R. J.

2011-05-01

40

Gamma-ray multiplicity measurement of the spontaneous fission of 252Cf in a segmented HPGe/BGO detector array  

NASA Astrophysics Data System (ADS)

Coincident ? rays from a 252Cf source were measured using an array of six segmented high-purity germanium (HPGe) Clover detectors each enclosed by 16 bismuth-germanate (BGO) detectors. The detectors were arranged in a cubic pattern around a 1 ?Ci252Cf source to cover a large solid angle for ?-ray measurement with a reasonable reconstruction of the multiplicity. Neutron multiplicity was determined in certain cases by identifying the prompt ? rays from individual fission fragment pairs. Multiplicity distributions from previous experiments and theoretical models were convolved with the response function of the array and compared to the present results. These results suggest a ?-ray multiplicity spectrum broader than previous measurements and models, and provide no evidence of correlation with neutron multiplicity.

Bleuel, D. L.; Bernstein, L. A.; Burke, J. T.; Gibelin, J.; Heffner, M. D.; Mintz, J.; Norman, E. B.; Phair, L.; Scielzo, N. D.; Sheets, S. A.; Snyderman, N. J.; Stoyer, M. A.; Wiedeking, M.

2010-12-01

41

Uncertainty analysis of in-situ gamma spectrometry measurements of air cleaning filter cartridges and 200 L drums by a HPGe detector.  

PubMed

This work deals with most significant sources of uncertainty in determination of radionuclides massic activity in 200 L drums with radioactive waste (RAW) from decommissioning of nuclear power plant (NPP) A1 and operational air cleaning filters coming from different parts of NPP's ventilation system. It turned out that the most significant source of uncertainty is determination of photo peak detection efficiency, in particular measurement geometry. The detection efficiency of HPGe detector has been determined by calculation using ISOCS software (In Situ Object Counting System) and detector characteristics delivered by the manufacturer (LABSOCS). The detector efficiency is influenced by various factors like measurement geometry, deviation from standard geometry, environmental characteristics, sample properties (density, material composition), used collimator etc. Mentioned factors and their contributions to the uncertainty of detection efficiency and thus to the total uncertainty of massic activity determination have been individually evaluated in the paper. The main part of the work consists of evaluation of maximum uncertainty factor due to presence of hypothetical point source in measurement volume for both types of measurement geometry. PMID:19945884

Slaninka, Alojz; Slávik, Ondrej; Necas, Vladimír

2010-01-01

42

Charged-particle induced radiation damage of a HPGe gamma-ray detector during spaceflight  

NASA Astrophysics Data System (ADS)

The Mars Observer spacecraft was launched on September 26, 1992 with a planned arrival at Mars after an 11-month cruise. Among the scientific instruments carried on the spacecraft was a Gamma-Ray Spectrometer (GRS) experiment to measure the composition of Mars. The GRS used a passively cooled high-purity germanium detector for measurements in the 0.2-10MeV region. The sensor was a closed-end co-axial detector, 5.5cm diameter by 5.5cm long, and had an efficiency along its axis of 28% at 1332keV relative to a standard NaI(Tl) detector. The sensor was surrounded by a thin (0.5cm) plastic charged-particle shield. This was the first planetary mission to use a cooled Ge detector. It was expected that the long duration in space of three years would cause an increase in the energy resolution of the detector due to radiation damage and could affect the expected science return of the GRS. Shortly before arrival, on August 21, 1993, contact was lost with the spacecraft following the pressurization of the propellent tank for the orbital-insertion rocket motor. During much of the cruise to Mars, the GRS was actively collecting background data. The instrument provided over 1200h of data collection during periods of both quiescent sun and solar flares. From the charged particle interactions in the shield, the total number of cosmic ray hits on the detector could be determined. The average cosmic ray flux at the MO GRS was about 2.5cm-2s-1. The estimated fluence of charged particles during cruise was about 108 particles cm-2 with 31% of these occurring during a single solar proton event of approximately 10 days duration. During cruise, the detector energy resolution determined from a background gamma-ray at 1312keV degraded from 2.4keV full-width at half-maximum shortly after launch to 6.4keV 11 months later. This result agrees well with measurements from ground-based accelerator irradiations (at 1.5GeV) on a similar size detector.

Evans, L. G.; Starr, R.; Brückner, J.; Boynton, W. V.; Bailey, S. H.; Trombka, J. I.

1999-02-01

43

Monte-Carlo optimisation of a Compton suppression system for use with a broad-energy HPGe detector  

NASA Astrophysics Data System (ADS)

Monte-Carlo simulations are used to evaluate and optimise multiple components of a Compton Suppression System based upon a Broad-energy HPGe primary detector. Several materials for the secondary crystal are evaluated, including NaI(Tl), BGO and LaBr3(Ce). BGO was found to be the most effective across the required energy range, with the sizes of the proposed veto detector then optimised to extract the maximum performance for a given volume of material. Suppression factors are calculated for a range of nuclides (both single and cascade emitters) with improvements of 2 for the Compton Suppression Factors, and 10 for the continuum reduction when compared to the Compton suppression system currently in use. This equates to a reduction in the continuum by up to a factor of ~240 for radionuclides such as 60Co, which is crucial for the detection of low-energy, low-activity ? emitters typically swamped by such a continuum.

Britton, R.; Burnett, J. L.; Davies, A. V.; Regan, P. H.

2014-10-01

44

Distribution of lake-bottom radionuclides measured with an underwater HPGe detector  

SciTech Connect

This study at Savannah River was done to assist decisions on the future of L Lake, an artificial reservoir made in 1983-5 for additional cooling for L Reactor discharges. EG&G overflight NaI mappings prior to filling indicated that most of the man-made radionuclides were {sup 60}Co and (predominantly) {sup 137}Cs in the earlier stream beds lying beneath the lake. An underwater HPGe was used in 1995 to rapidly scope the present radiation levels at 96 locations in the lake. The present levels are in reasonable agreement with the earlier overflight mappings. 1 fig, 4 figs.

Winn, W.G.; Dunn, D.L.; Bresnahan, P.J.

1996-07-01

45

Response of AGATA segmented HPGe detectors to gamma rays up to 15.1 MeV  

NASA Astrophysics Data System (ADS)

The response of AGATA segmented HPGe detectors to gamma rays in the energy range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the reaction d(11B,n?)12C at Ebeam=19.1 MeV, while gamma rays between 2 and 9 MeV were produced using an Am-Be-Fe radioactive source. The energy resolution and linearity were studied and the energy-to-pulse-height conversion resulted to be linear within 0.05%.Experimental interaction multiplicity distributions are discussed and compared with the results of Geant4 simulations. It is shown that the application of gamma-ray tracking allows a suppression of background radiation caused by n-capture in Ge nuclei. Finally the Doppler correction for the 15.1 MeV gamma line, performed using the position information extracted with Pulse-shape analysis is discussed.

The AGATA Collaboration; Crespi, F. C. L.; Avigo, R.; Camera, F.; Akkoyun, S.; Ataç, A.; Bazzacco, D.; Bellato, M.; Benzoni, G.; Blasi, N.; Bortolato, D.; Bottoni, S.; Bracco, A.; Brambilla, S.; Bruyneel, B.; Ceruti, S.; Ciema?a, M.; Coelli, S.; Eberth, J.; Fanin, C.; Farnea, E.; Gadea, A.; Giaz, A.; Gottardo, A.; Hess, H.; Kmiecik, M.; Leoni, S.; Maj, A.; Mengoni, D.; Michelagnoli, C.; Million, B.; Montanari, D.; Nicolini, R.; Pellegri, L.; Recchia, F.; Reiter, P.; Riboldi, S.; Ur, C. A.; Vandone, V.; Valiente-Dobon, J. J.; Wieland, O.; Wiens, A.

2013-03-01

46

Response of AGATA segmented HPGe detectors to gamma rays up to 15.1 MeV  

NASA Astrophysics Data System (ADS)

The response of AGATA segmented HPGe detectors to gamma rays in the energy range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the reaction d(11B,n?)12C at Ebeam=19.1 MeV, while gamma rays between 2 and 9 MeV were produced using an Am-Be-Fe radioactive source. The energy resolution and linearity were studied and the energy-to-pulse-height conversion resulted to be linear within 0.05%.Experimental interaction multiplicity distributions are discussed and compared with the results of Geant4 simulations. It is shown that the application of gamma-ray tracking allows a suppression of background radiation caused by n-capture in Ge nuclei. Finally the Doppler correction for the 15.1 MeV gamma line, performed using the position information extracted with Pulse-shape analysis is discussed.

Crespi, F. C. L.; Avigo, R.; Camera, F.; Akkoyun, S.; Ataç, A.; Bazzacco, D.; Bellato, M.; Benzoni, G.; Blasi, N.; Bortolato, D.; Bottoni, S.; Bracco, A.; Brambilla, S.; Bruyneel, B.; Ceruti, S.; Ciema?a, M.; Coelli, S.; Eberth, J.; Fanin, C.; Farnea, E.; Gadea, A.; Giaz, A.; Gottardo, A.; Hess, H.; Kmiecik, M.; Leoni, S.; Maj, A.; Mengoni, D.; Michelagnoli, C.; Million, B.; Montanari, D.; Nicolini, R.; Pellegri, L.; Recchia, F.; Reiter, P.; Riboldi, S.; Ur, C. A.; Vandone, V.; Valiente-Dobon, J. J.; Wieland, O.; Wiens, A.; Agata Collaboration

47

High efficiency photoionization detector  

DOEpatents

A high efficiency photoionization detector using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36.+-.0.02 eV, and a vapor pressure of 0.35 torr at 20.degree. C.

Anderson, David F. (3055 Trinity, Los Alamos, NM 87544)

1984-01-01

48

High efficiency photoionization detector  

DOEpatents

A high efficiency photoionization detector is described using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36 [+-] 0.02 eV, and a vapor pressure of 0.35 torr at 20 C. 6 figs.

Anderson, D.F.

1984-01-31

49

Detection of pulsed, bremsstrahlung-induced, prompt neutron capture gamma-rays with HPGe detector  

SciTech Connect

The Idaho National Engineering Laboratory (INEL) is developing a novel photoneutron-based nondestructive evaluation technique which uses a pulsed, high-energy (up to 8-MeV) electron accelerator and gamma-ray spectrometry. Highly penetrating pulses of bremsstrahlung photons are produced by each pulse of electrons. Interrogating neutrons are generated by the bremsstrahlung photons interacting within a photoneutron source material. The interactions of the neutrons within a target result in the emission of elemental characteristic gamma-rays. Spectrometry is performed by analyzing the photoneutron-induced prompt gamma-rays acquired between accelerator pulses with a unique, high-purity germanium (HPGe) gamma-ray detection system using a modified transistor reset preamplifier. The detection system, the experimental configuration, and the accelerator operation used to characterize the detection system performance are described. Using a 6.5 MeV electron accelerator and a beryllium metal photoneutron source, gamma-ray spectra were successfully acquired for Al, Cu, polyethylene, NaC1, and depleted uranium targets as soon as 30 {mu}s after each bremsstrahlung (or x-ray) flash.

Jones, J.L.

1996-08-01

50

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

PubMed

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. PMID:11451249

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

2001-06-01

51

A background simulation method for cosmogenic nuclides inside HPGe detectors for rare event experiments  

NASA Astrophysics Data System (ADS)

Cosmogenic nuclides inside germanium detectors contribute background noise spectra quite different from ordinary external sources. We propose and discuss a nuclide decay and level transition model based on graph theory to understand the background contribution of the decay of cosmogenic nuclides inside a germanium crystal. In this work, not only the level transition process, but the detector response time was also taken into consideration to decide whether or not to apply coincidence summing-up. We simulated the background spectrum of the internal cosmogenic nuclides in a germanium detector, and found some unique phenomena caused by the coincidence summing-up effect in the simulated spectrum. Thus, the background spectrum of each cosmogenic nuclide can be quantitatively obtained.

Su, Jian; Zeng, Zhi; Ma, Hao; Yue, Qian; Cheng, Jianping; Li, Jin

2014-11-01

52

A background simulation method for cosmogenic nuclides inside HPGe detectors for rare event experiments  

E-print Network

Cosmogenic nuclides inside germanium detectors contribute background noise spectra quite different from ordinary external sources. We propose and discuss a nuclide decay and level transition model based on graph theory to understand the background contribution of the decay of cosmogenic nuclides inside a germanium crystal. In this work, not only was the level transition process, but the detector response time was also taken into consideration to decide whether or not to apply coincidence summing-up. We simulated the background spectrum of the internal cosmogenic nuclides in a germanium detector, and found some unique phenomena caused by the coincidence summing-up effect in the simulated spectrum. Thus, the background spectrum of each cosmogenic nuclide can be quantitatively obtained.

Jian Su; Zhi Zeng; Hao Ma; Qian Yue; Jianping Cheng; Jin Li

2013-12-05

53

An approach to evaluate the efficiency of ?-ray detectors to determine the radioactivity in environmental samples  

NASA Astrophysics Data System (ADS)

This work provides an approach to determine the efficiency of ?-ray detectors with a good accuracy in order to determine the concentrations of either naturally occurring or artificially prepared radionuclides. This approach is based on the efficiency transfer formula (ET), the effective solid angles, the self- absorptions of the source matrix, the attenuation by the source container and the detector housing materials on the detector efficiency. The experimental calibration process was done using radioactive (Cylindrical & Marinelli) sources, in different dimensions, that contain aqueous 152Eu radionuclide. The comparison point to a fine agreement between the experimental measured and calculated efficiencies for the (NaI & HPGe) detectors using volumetric radioactive sources.

Mohamed., S. Badawi; Ahmed., M. El-Khatib; Samah., M. Diab; Sherif., S. Nafee; Ekram., A. El-Mallah

2014-06-01

54

Charged-particle induced radiation damage of a HPGe gamma-ray detector during spaceflight  

Microsoft Academic Search

The Mars Observer spacecraft was launched on September 26, 1992 with a planned arrival at Mars after an 11-month cruise. Among the scientific instruments carried on the spacecraft was a Gamma-Ray Spectrometer (GRS) experiment to measure the composition of Mars. The GRS used a passively cooled high-purity germanium detector for measurements in the 0.2–10MeV region. The sensor was a closed-end

Larry G Evans; Richard Starr; Johannes Brückner; William V Boynton; S. H Bailey; J. I. Trombka

1999-01-01

55

Uranium Isotopic and Quantitative Analysis Using a Mechanically-Cooled HPGe Detector  

SciTech Connect

A new, portable high-resolution spectroscopy system based on a high-purity germanium detector cooled with a miniature Stirling-cycle cooler, ORTEC trans-SPEC, has recently become commercially available. The use of a long-life mechanical cooling system eliminates the need for liquid nitrogen. The purpose of this study was to determine the applicability of this new instrument for isotopic and quantitative analyses of uranium samples. The results of the performance of the trans-SPEC with the combination of PC-FRAM and ISOTOPIC software packages are described in this paper. An optimal set of analysis parameters for uranium measurements is proposed.

Solodov, Alexander A [ORNL

2008-01-01

56

Efficiencies of Quantum Optical Detectors  

E-print Network

We propose a definition for the efficiency that can be universally applied to all classes of quantum optical detectors. This definition is based on the maximum amount of optical loss that a physically plausible device can experience while still replicating the properties of a given detector. We prove that detector efficiency cannot be increased using linear optical processing. That is, given a set of detectors, as well as arbitrary linear optical elements and ancillary light sources, it is impossible to construct detection devices that would exhibit higher efficiencies than the initial set.

Daniel Hogg; Dominic W. Berry; A. I. Lvovsky

2014-08-01

57

The gender-specific chest wall thickness prediction equations for routine measurements of {sup 239}Pu and {sup 241}Am within the lungs using HPGE detectors  

SciTech Connect

The current chest wall thickness prediction equation is not applicable to use in routine lung counting measurements for detection of low energy photons (17-60 keV) within the lungs of male and female subjects. The current chest wall thickness prediction equation was derived for the NaI-CsI {open_quotes}phoswich{close_quotes} detection system, which is not the routine detection system in use; the subject position was supine, which is not the routine position; the equation did not account for the intercostal tissue thicknesses of muscle and adipose which significantly attenuate low energy photons (17-60 keV); it was derived from male subjects only and is used to predict the chest wall thickness of female subjects for whom it is not applicable. The current chest wall thickness prediction equation yields unacceptable percent errors in the HPGe detection efficiency calibration for {sup 239}Pu and {sup 241}Am (17- and 59.5-keV photons, respectively) relative to the gender-specific HPGe chest wall thickness prediction equations of this paper (+284% to -73% for {sup 239}Pu; +42% to -39% for {sup 241}Am). As a result, use of the current chest wall thickness prediction equation yields unacceptable percent errors (proportional in magnitude to the percent errors in the detection efficiency calibration) in the calculation of the minimum detectable activity (Bq) or in an initial assessment of a radioactive contamination exposure detected by a routine lung count measurement. 17 refs., 6 figs., 12 tabs.

Vickers, L.R. [Pantex Plant, Amarillo, TX (United States)

1996-03-01

58

The gender-specific chest wall thickness prediction equations for routine measurements of 239Pu and 241Am within the lungs using HPGe detectors.  

PubMed

The current chest wall thickness prediction equation is not applicable to use in routine lung counting measurements for detection of low energy photons (17--60 keV) within the lungs of male and female subjects. The current chest wall thickness prediction equation was derived for the NaI-CsI "phoswich" detection system, which is not the routine detection system in use; the subject position was supine, which is not the routine position; the equation did not account for the intercostal tissue thicknesses of muscle and adipose which significantly attenuate low energy photons (17--60keV); it was derived from male subjects only and is used to predict the chest wall thickness of female subjects for whom it is not applicable. The current chest wall thickness prediction equation yields unacceptable percent errors in the HPGe detection efficiency calibration for 239Pu and 241Am (17- and 59.5-keV photons, respectively) relative to the gender-specific HPGe chest wall thickness prediction equations of this paper (+284% to --73% for 239Pu; (+)42% to --39% for 241Am). As a result, use of the current chest wall thickness prediction equation yields unacceptable percent errors (proportional in magnitude to the percent errors in the detection efficiency calibration) in the calculation of the minimum detectable activity (Bq) or in an initial assessment of a radioactive contamination exposure detected by a routine lung count measurement. PMID:8609026

Vickers, L R

1996-03-01

59

First results of the experiment to search for double beta decay of 106Cd with 106CdWO4 crystal scintillator in coincidence with four crystals HPGe detector  

E-print Network

An experiment to search for double beta processes in 106Cd by using cadmium tungstate crystal scintillator enriched in 106Cd (106CdWO4) in coincidence with the four crystals HPGe detector GeMulti is in progress at the STELLA facility of the Gran Sasso underground laboratory of INFN (Italy). The 106CdWO4 scintillator is viewed by a low-background photomultiplier tube through a lead tungstate crystal light-guide produced from deeply purified archaeological lead to suppress gamma quanta from the photomultiplier tube. Here we report the first results of the experiment after 3233 hours of the data taking. A few new improved limits on double beta processes in 106Cd are obtained, in particular T1/2(2nuECb+) > 8.4e20 yr at 90% C.L.

V. I. Tretyak; P. Belli; R. Bernabei; V. B. Brudanin; F. Cappella; V. Caracciolo; R. Cerulli; D. M. Chernyak; F. A. Danevich; S. d'Angelo; A. Incicchitti; M. Laubenstein; V. M. Mokina; D. V. Poda; O. G. Polischuk; R. B. Podviyanuk; I. A. Tupitsyna

2013-12-19

60

High efficiency CCD detectors at UV wavelengths  

NASA Astrophysics Data System (ADS)

The Faint Intergalactic Redshifted Emission Balloon (FIREBall) is a NASA/CNES balloon-borne ultraviolet multi-object spectrograph designed to observe the diffuse gas around galaxies (the circumgalactic medium) via line emission redshifted to ~205 nm. FIREBall uses a ultraviolet-optimized delta doped e2v CCD201 with a custom designed high efficiency five layer anti-reflection coating. This combination achieves very high quantum efficiency (QE) and photon-counting capability, a first for a CCD detector in this wavelength range. We also present new work on red blocking mirror coatings to reduce red leak.

Hamden, Erika T.; Jewell, April D.; Gordon, Samuel; Hennessy, John; Hoenk, Michael E.; Nikzad, Shouleh; Schiminovich, David; Martin, D. Christopher

2014-07-01

61

Electromechanically cooled germanium radiation detector system  

NASA Astrophysics Data System (ADS)

We have successfully developed and fielded an electromechanically cooled germanium radiation detector (EMC-HPGe) at Lawrence Livermore National Laboratory (LLNL). This detector system was designed to provide optimum energy resolution, long lifetime, and extremely reliable operation for unattended and portable applications. For most analytical applications, high purity germanium (HPGe) detectors are the standard detectors of choice, providing an unsurpassed combination of high energy resolution performance and exceptional detection efficiency. Logistical difficulties associated with providing the required liquid nitrogen (LN) for cooling is the primary reason that these systems are found mainly in laboratories. The EMC-HPGe detector system described in this paper successfully provides HPGe detector performance in a portable instrument that allows for isotopic analysis in the field. It incorporates a unique active vibration control system that allows the use of a Sunpower Stirling cycle cryocooler unit without significant spectral degradation from microphonics. All standard isotopic analysis codes, including MGA and MGA++ [1], GAMANL [2], GRPANL [3]and MGAU [4], typically used with HPGe detectors can be used with this system with excellent results. Several national and international Safeguards organisations including the International Atomic Energy Agency (IAEA) and U.S. Department of Energy (DOE) have expressed interest in this system. The detector was combined with custom software and demonstrated as a rapid Field Radiometric Identification System (FRIS) for the U.S. Customs Service [5]. The European Communities' Safeguards Directorate (EURATOM) is field-testing the first Safeguards prototype in their applications. The EMC-HPGe detector system design, recent applications, and results will be highlighted.

Lavietes, Anthony D.; Joseph Mauger, G.; Anderson, Eric H.

1999-02-01

62

NEUTRON DETECTION EFFICIENCY OF THE CLAS12 DETECTOR  

E-print Network

NEUTRON DETECTION EFFICIENCY OF THE CLAS12 DETECTOR Mark Moog Mark Moog ! Neutron Detection of the Jefferson Lab 12 GeV upgrade, to obtain a preliminary estimate of it's neutron detection efficiency (NDE ! Neutron Detection Efficiency of the CLAS12 Detector 3 Figure 1: CLAS12 #12;The drift chambers consist

Gilfoyle, Jerry

63

Simulation of background reduction and Compton depression in low-background HPGe spectrometer at a surface laboratory  

E-print Network

High-purity germanium detectors are well suited to analysis the radioactivity of samples. In order to reduce the environmental background, low-activity lead and oxygen free copper are installed outside of the probe to shield gammas, outmost is a plastic scintillator to veto the cosmic rays, and an anti-Compton detector can improve the Peak-to-Compton ratio. Using the GEANT4 tools and taking into account a detailed description of the detector, we optimize the sizes of the detectors to reach the design indexes. A group of experimental data from a HPGe spectrometer in using were used to compare with the simulation. As to new HPGe Detector simulation, considering the different thickness of BGO crystals and anti-coincidence efficiency, the simulation results show that the optimal thickness is 5.5cm, and the Peak-to-Compton ratio of 40K is raised to 1000 when the anti-coincidence efficiency is 0.85. As the background simulation, 15 cm oxygen-free copper plus 10 cm lead can reduce the environmental gamma rays to 0.0...

Niu, ShunLi; Wu, ZhenZhong; Xie, YuGuang; Yu, BoXiang; Wang, ZhiGang; Fang, Jian; Sun, XiLei; Sun, LiJun; Liu, YingBiao; Gao, Long; Zhang, Xuan; Zhao, Hang; Zhou, Li; Lv, JunGuang; Hu, Tao

2014-01-01

64

Simulation of background reduction and Compton depression in low-background HPGe spectrometer at a surface laboratory  

E-print Network

High-purity germanium detectors are well suited to analysis the radioactivity of samples. In order to reduce the environmental background, low-activity lead and oxygen free copper are installed outside of the probe to shield gammas, outmost is a plastic scintillator to veto the cosmic rays, and an anti-Compton detector can improve the Peak-to-Compton ratio. Using the GEANT4 tools and taking into account a detailed description of the detector, we optimize the sizes of the detectors to reach the design indexes. A group of experimental data from a HPGe spectrometer in using were used to compare with the simulation. As to new HPGe Detector simulation, considering the different thickness of BGO crystals and anti-coincidence efficiency, the simulation results show that the optimal thickness is 5.5cm, and the Peak-to-Compton ratio of 40K is raised to 1000 when the anti-coincidence efficiency is 0.85. As the background simulation, 15 cm oxygen-free copper plus 10 cm lead can reduce the environmental gamma rays to 0.0024 cps/100 cm3 Ge (50keV~2.8MeV), which is about 10-5 of environmental background.

ShunLi Niu; Xiao Cai; ZhenZhong Wu; YuGuang Xie; BoXiang Yu; ZhiGang Wang; Jian Fang; XiLei Sun; LiJun Sun; YingBiao Liu; Long Gao; Xuan Zhang; Hang Zhao; Li Zhou; JunGuang Lv; Tao Hu

2014-10-16

65

Estimate of large CZT detector absolute efficiency  

Microsoft Academic Search

This paper presents a simulation of the spectroscopic performance of two large CZT coplanar detectors, 1.5 × 1.5 cm2 area and 1.0 cm thick, with coplanar anodes. A code, based on the GEANT libraries and classical Monte Carlo sampling, was developed to simulate experimental scenarios. This code adapts the GEANT capabilities for simulating complex detection systems for spectroscopic studies. Detectors

J. M. Perez; Z. He; D. K. Wehe; Y. F. Du

2002-01-01

66

Measurements of electron detection efficiencies in solid state detectors.  

NASA Technical Reports Server (NTRS)

Detailed laboratory measurement of the electron response of solid state detectors as a function of incident electron energy, detector depletion depth, and energy-loss discriminator threshold. These response functions were determined by exposing totally depleted silicon surface barrier detectors with depletion depths between 50 and 1000 microns to the beam from a magnetic beta-ray spectrometer. The data were extended to 5000 microns depletion depth using the results of previously published Monte Carlo electron calculations. When the electron counting efficiency of a given detector is plotted as a function of energy-loss threshold for various incident energies, the efficiency curves are bounded by a smooth envelope which represents the upper limit to the detection efficiency. These upper limit curves, which scale in a simple way, make it possible to easily estimate the electron sensitivity of solid-state detector systems.

Lupton, J. E.; Stone, E. C.

1972-01-01

67

High-efficiency fast-neutron detector. Memorandum report  

SciTech Connect

This report researches a concept for a high-efficiency detector of fast neutrons (several MeV), using solid-state charged-particle detectors overlaid with thick disks (about mm) of {sup 238}U. Experiments show a significant count rate in the mockup when exposed to a fast-neutron flux, but it appears insensitive to the slow/thermal neutron flux. Preliminary results indicate a system with an efficiency on the order of at least 5% could be developed.

August, R.A.; Phillips, G.W.; Cutchin, J.H.

1989-08-02

68

Hit efficiency study of CMS prototype forward pixel detectors  

SciTech Connect

In this paper the author describes the measurement of the hit efficiency of a prototype pixel device for the CMS forward pixel detector. These pixel detectors were FM type sensors with PSI46V1 chip readout. The data were taken with the 120 GeV proton beam at Fermilab during the period of December 2004 to February 2005. The detectors proved to be highly efficient (99.27 {+-} 0.02%). The inefficiency was primarily located near the corners of the individual pixels.

Kim, Dongwook; /Johns Hopkins U.

2006-01-01

69

Detective quantum efficiency of electron area detectors in electron microscopy  

PubMed Central

Recent progress in detector design has created the need for a careful side-by-side comparison of the modulation transfer function (MTF) and resolution-dependent detective quantum efficiency (DQE) of existing electron detectors with those of detectors based on new technology. We present MTF and DQE measurements for four types of detector: Kodak SO-163 film, TVIPS 224 charge coupled device (CCD) detector, the Medipix2 hybrid pixel detector, and an experimental direct electron monolithic active pixel sensor (MAPS) detector. Film and CCD performance was measured at 120 and 300 keV, while results are presented for the Medipix2 at 120 keV and for the MAPS detector at 300 keV. In the case of film, the effects of electron backscattering from both the holder and the plastic support have been investigated. We also show that part of the response of the emulsion in film comes from light generated in the plastic support. Computer simulations of film and the MAPS detector have been carried out and show good agreement with experiment. The agreement enables us to conclude that the DQE of a backthinned direct electron MAPS detector is likely to be equal to, or better than, that of film at 300 keV. PMID:19497671

McMullan, G.; Chen, S.; Henderson, R.; Faruqi, A.R.

2009-01-01

70

Monte Carlo Characterization of a Highly Efficient Photon Detector  

SciTech Connect

Highly efficient photon detectors play a major role in countless applications in physics, nuclear engineering, and medical physics. In nuclear engineering, radioactive waste can be characterized with techniques such as the nondestructive assay technique (PNDA). In medical physics, photon detectors are extensively used for diagnostic X-ray and computerized tomography (CT) imaging, nuclear medicine, and quite recently radiation therapy of cancer.1,2 In radiation therapy of cancer, ever more accurate delivery techniques spur the need for efficient detectors of the high-energetic photons in the mega-electron-volt energy range in order to allow the imaging of the patient during radiation delivery. In particular, in tomotherapy, a megavoltage detector is used for both CT imaging and verifying the dose received by the patients. Conventional megavoltage detection systems usually suffer from intrinsically low subject contrast.2 A high signal-to-noise ratio of the detection system can be achieved by keeping the noise as low as possible and/or by increasing the quantum efficiency of the detector. In this work, a candidate of a highly efficient detection system, i.e., an arc-shaped xenon gas ionization chamber, was characterized in terms of efficiency and spatial resolution.

Harry Keller; M. Glass; R. Hinderer; K. Ruchala; R. Jeraj; G. Olivera; T. R. Mackie; M. L. Corradini

2001-06-17

71

Existing NaI detectors; an efficient alternative to He-3 detectors  

NASA Astrophysics Data System (ADS)

Neutron detectors are important in various fields of research, safeguards, security, medicine, and industry. The most common methods for detecting neutrons involve utilization of the 10B(n,?), 6Li(n,?), or 3He(n,p) reactions; with the He-3 filled proportional counters being the most widely used because of their high detection efficiency and good gamma ray discrimination. However these counters have severe drawbacks in terms of detector size and scarcity of He-3. The aim of this work is to investigate an alternative neutron detection method by using a boron lining with existing NaI detectors and compare the results with those obtained from a He-3 detector. The results show a good sensitivity of the boron-lined NaI detector to neutrons at different source locations and a considerable improvement in efficiency compared to He-3 detectors. On top of this the NaI detectors are used to detect the gamma rays from the surrounding source and interacting media.

Metwally, Walid A.

2014-11-01

72

Charge Collection Efficiency Simulations of Irradiated Silicon Strip Detectors  

E-print Network

During the scheduled high luminosity upgrade of LHC, the world's largest particle physics accelerator at CERN, the position sensitive silicon detectors installed in the vertex and tracking part of the CMS experiment will face more intense radiation environment than the present system was designed for. Thus, to upgrade the tracker to required performance level, comprehensive measurements and simulations studies have already been carried out. Essential information of the performance of an irradiated silicon detector is obtained by monitoring its charge collection efficiency (CCE). From the evolution of CCE with fluence, it is possible to directly observe the effect of the radiation induced defects to the ability of the detector to collect charge carriers generated by traversing minimum ionizing particles (mip). In this paper the numerically simulated CCE and CCE loss between the strips of irradiated silicon strip detectors are presented. The simulations based on Synopsys Sentaurus TCAD framework were performed ...

Peltola, T

2014-01-01

73

Resonant infrared detector with substantially unit quantum efficiency  

NASA Technical Reports Server (NTRS)

A resonant infrared detector includes an infrared-active layer which has first and second parallel faces and which absorbs radiation of a given wavelength. The detector also includes a first tuned reflective layer, disposed opposite the first face of the infrared-active layer, which reflects a specific portion of the radiation incident thereon and allows a specific portion of the incident radiation at the given wavelength to reach the infrared-active layer. A second reflective layer, disposed opposite the second face of the infrared-active layer, reflects back into the infrared-active layer substantially all of the radiation at the given wavelength which passes through the infrared-active layer. The reflective layers have the effect of increasing the quantum efficiency of the infrared detector relative to the quantum efficiency of the infrared-active layer alone.

Farhoomand, Jam (inventor); Mcmurray, Robert E., Jr. (inventor)

1994-01-01

74

GRABGAM: A Gamma Analysis Code for Ultra-Low-Level HPGe SPECTRA  

SciTech Connect

The GRABGAM code has been developed for analysis of ultra-low-level HPGe gamma spectra. The code employs three different size filters for the peak search, where the largest filter provides best sensitivity for identifying low-level peaks and the smallest filter has the best resolution for distinguishing peaks within a multiplet. GRABGAM basically generates an integral probability F-function for each singlet or multiplet peak analysis, bypassing the usual peak fitting analysis for a differential f-function probability model. Because F is defined by the peak data, statistical limitations for peak fitting are avoided; however, the F-function does provide generic values for peak centroid, full width at half maximum, and tail that are consistent with a Gaussian formalism. GRABGAM has successfully analyzed over 10,000 customer samples, and it interfaces with a variety of supplementary codes for deriving detector efficiencies, backgrounds, and quality checks.

Winn, W.G.

1999-07-28

75

Determination of the Quantum Efficiency of a Light Detector  

ERIC Educational Resources Information Center

The "quantum efficiency" (QE) is an important property of a light detector. This quantity can be determined in the undergraduate physics laboratory. The experimentally determined QE of a silicon photodiode appeared to be in reasonable agreement with expected values. The experiment confirms the quantum properties of light and seems to be a useful…

Kraftmakher, Yaakov

2008-01-01

76

Determining the Efficiency of Si(Li) Detectors.  

National Technical Information Service (NTIS)

Following the comprehensive discussion on the feasibility of determining the efficiency of Si(Li) detectors, the most suitable method for the determination was selected for the energy range 1-10 keV. Comparative measurements were performed with a flow pro...

H. Weber

1979-01-01

77

Neutron efficiency of LaBr3:Ce detector  

NASA Astrophysics Data System (ADS)

We report on a measurement of the neutron detection efficiency in a LaBr3 detector in the energy range 0.1-2 MeV. The experiment was carried out using a 4 MV Van-de-Graaff accelerator which provided monoenergetic neutrons from T(p,n)3He and 7Li(p,n)7Be reactions. The five most intense ?-rays from the LaBr3(n, n??) reaction have been studied to deduce the neutron sensitivity of the detector. GEANT4 simulations with different nuclear data libraries have been done and a comparison with the data is provided.

Ebran, A.; Roig, O.; Méot, V.; Delaune, O.

2014-12-01

78

Charge Collection Efficiency Simulations of Irradiated Silicon Strip Detectors  

E-print Network

During the scheduled high luminosity upgrade of LHC, the world's largest particle physics accelerator at CERN, the position sensitive silicon detectors installed in the vertex and tracking part of the CMS experiment will face more intense radiation environment than the present system was designed for. Thus, to upgrade the tracker to required performance level, comprehensive measurements and simulations studies have already been carried out. Essential information of the performance of an irradiated silicon detector is obtained by monitoring its charge collection efficiency (CCE). From the evolution of CCE with fluence, it is possible to directly observe the effect of the radiation induced defects to the ability of the detector to collect charge carriers generated by traversing minimum ionizing particles (mip). In this paper the numerically simulated CCE and CCE loss between the strips of irradiated silicon strip detectors are presented. The simulations based on Synopsys Sentaurus TCAD framework were performed before and after irradiation for fluences up to $1.5\\times10^{15}$ $\\textrm{n}_{\\textrm{eq}}$cm$^{-2}$ for the n-on-p sensors. A two level and non-uniform three level defect models were applied for the proton irradiation simulations and two level model for neutrons. The results are presented together with the measurements of strip detectors irradiated by different particles and fluences and show considerable agreement for both CCE and its position dependency.

T. Peltola

2014-09-30

79

Investigation of the quantum efficiency of optical heterodyne detectors  

NASA Technical Reports Server (NTRS)

The frequency response and quantum efficiency of optical photodetectors for heterodyne receivers is investigated. The measurements utilized two spectral lines from the output of two lasers as input to the photodetectors. These lines are easily measurable in power and frequency and hence serve as known inputs. By measuring the output current of the photodetector the quantum efficiency is determined as a function of frequency separation between the two input signals. An investigation of the theoretical basis and accuracy of this type of measurement relative to similar measurements utilizing risetime is undertaken. A theoretical study of the heterodyne process in photodetectors based on semiconductor physics is included so that higher bandwidth detectors may be designed. All measurements are made on commercially available detectors and manufacturers' specifications for normal photodetector operation are compared to the measured heterodyne characteristics.

Batchman, T. E.

1984-01-01

80

Data encoding efficiency in binary strip detector readout  

NASA Astrophysics Data System (ADS)

A prescription to calculate the minimum number of bits needed for binary strip detector readout is presented. This permits a systematic analysis of the readout efficiency relative to this theoretical minimum number of bits. Different level efficiencies are defined to include context information and engineering properties needed for reliable transmission, such as DC-balance. A commonly used encoding method is analyzed as an example and found to have an efficiency only of order 50%. A new encoding method called Pattern Overlay Compression is introduced to illustrate how the systematic analysis can guide the construction of more efficient readout methods. Pattern Overlay Compression significantly outperforms the above example in the occupancy range of interest.

Garcia-Sciveres, M.; Wang, X.

2014-04-01

81

Monte Carlo simulation accuracy for calibrating germanium detector photon efficiency  

SciTech Connect

Over the past 30 years, Monte Carlo simulation of photons interacting with matter has gradually improved to the extent that it now appears suitable for calibrating germanium detectors for counting efficiency in gamma-ray spectral analysis. The process is particularly useful because it can be applied for a variety of source shapes and spatial relations between source and detector by simply redefining the geometry, whereas calibration with radioactive standards requires a separate set of measurements for each source shape and location relative to the detector. Simulation accuracy was evaluated for two large (126% and 110%) and one medium-sized (20%) detectors with radioactive point sources at distances of 10 m, 1.6 m, and 0.50 m and with aqueous solutions in a 0.5-L reentrant beaker and in jars of similar volume but various dimensions. The sensitivity in comparing measured and simulated results was limited by a combined uncertainty of about 3% in the radioactive standards and experimental conditions. Simulation was performed with the MCNP-4 code.

Kamboj, Sunita; Kahn, B.

1997-08-01

82

ETNA software used for efficiency transfer from a point source to other geometries.  

PubMed

The quality of the results of gamma spectrometry measurement depends directly on the accuracy of the detection efficiency in the specific measurement conditions. The purpose of this work is to examine the applicability of the efficiency transfer method using ETNA software for the computation of the efficiency in various measurement geometries on the basis of the measured efficiency for reference point source geometry located at 100 mm distance from the high purity germanium (HPGe) detector. PMID:19339191

Radu, Daniela; Stanga, Doru; Sima, Octavian

2009-09-01

83

Determination of TFTR far-field neutron detector efficiencies by local neutron flux spectrum measurement  

NASA Astrophysics Data System (ADS)

Neutron detectors have often been located on the tokamak fusion test reactor (TFTR) test cell floor 3 m or more from the vacuum vessel for ease of detector access, to reduce radiation damage, minimize count saturation problems, and to avoid high magnetic fields. These detectors include Si surface-barrier diodes, fission chambers, natural diamond detectors, and T2 production in a moderated 3He cell. To evaluate the performance of these detectors during deuterium-tritium (D-T) operation, we determined the neutron flux spectrum incident on the principal detector enclosure using nuclide sample sets containing Al, Ti, Fe, Co, Cu, Zn, Ni, Zr, Nb, In, and Au activation foils. Foils were installed and then removed after ample exposure to TFTR D-T neutrons. High efficiency, high purity Ge detectors were used for gamma spectroscopy of the irradiated foils. The incident neutron fluence and spectral distribution were unfolded from the measured results, and used to derive absolute detector efficiencies.

Jassby, D. L.; Ascione, G.; Kugel, H. W.; Roquemore, A. L.; Barcelo, T. W.; Kumar, A.

1997-01-01

84

Efficiency of composite boron nitride neutron detectors in comparison with helium-3 detectors  

Microsoft Academic Search

It has been clearly demonstrated that the composite boron nitride (BN) semiconductor polycrystalline bulk detectors with BN grains embedded in a polymer matrix operate as an effective detector of thermal neutrons even if they contain natural boron only. A reasonable signal to noise ratio has been achieved with detector thickness of about 1 mm. A Monte Carlo simulation of neutron

J. Uher; S. Pospisil; V. Linhart; M. Schieber

2007-01-01

85

Efficiently Coupling Light to Superconducting Nanowire Single-Photon Detectors  

E-print Network

We designed superconducting nanowire single-photon detectors (SNSPDs) integrated with silver optical antennae for free-space coupling and a dielectric waveguide for fiber coupling. According to our finite-element simulation, ...

Hu, Xiaolong

86

Investigations of 2β decay measured by low background HPGe spectrometer OBELIX  

NASA Astrophysics Data System (ADS)

A low background high sensitive HPGe spectrometer OBELIX was installed at the Modane Underground Laboratory (LSM, France, 4800 m w.e.). The detector was designed to measure a contamination of enriched isotopes and radio-impurities in construction materials, to investigate rare nuclear processes such as resonance neutrinoless double electron capture and two-neutrino double beta decay to excited states of daughter nuclei. Spectrometer sensitivity, contamination of NEMO-3 sources and results of 2?2?- decay of 100Mo to the 0+ (1130 keV) and 2+ (540 keV) excited states as well as future plans for OBELIX detector are given.

Rukhadze, Ekaterina; Obelix Collaboration, Supernemo Collaboration

2013-12-01

87

Three-dimensional imaging and detection efficiency performance of orthogonal coplanar CZT strip detectors  

Microsoft Academic Search

We report on recent three-dimensional imaging performance and detection efficiency measurements obtained with 5 mm thick prototype CdZnTe detectors fabricated with orthogonal coplanar anode strips. In previous work, we have shown that detectors fabricated using this design achieve both very good energy resolution and sub-millimeter spatial resolution with fewer electronic channels than are required for pixel detectors. As electron-only devices,

Mark L. McConnell; John R. Macri; James M. Ryan; Kipp Larson; Louis-Andre Hamel; G. Bernard; C. Pomerleau; Olivier Tousignant; Jean-Charles Leroux; Valentin T. Jordanov

2000-01-01

88

Development of a High-Efficiency, Glass Shell-Based, 3He-Filled Neutron Detector  

SciTech Connect

We have developed a new type of neutron sensor based on small, gas-filled, glass shells with external electrodes. The detector functions as a small (<1-cm-diameter) 3He ion chamber for applied bias voltages from roughly 50 V to 900 V. We have demonstrated that the detectors function with internal gas pressures from 6 to 10 atm. Charge transport times across the detector volume are a few microseconds. The detectors have very low gamma-ray sensitivity due to their small size as compared to the path-length of energetic electrons generated by gamma-ray interactions. Multiple shell detectors are intended to be deployed within a moderator block to form a single detector system. The resulting detector-moderator configuration approaches the efficiency of a homogeneous system. This paper presents device characterizations and performance data.

Kisner, Roger A [ORNL; Holcomb, David Eugene [ORNL; Stephan, Andrew Curtis [ORNL; Jardret, Vincent [ORNL; Britton Jr, Charles L [ORNL

2007-01-01

89

Efficient superconducting-nanowire single-photon detectors and their applications in quantum optics  

E-print Network

Superconducting-nanowire single-photon detectors (SNSPDs) are an emerging technology for infrared photon counting and detection. Their advantages include good device efficiency, fast operating speed, low dark-count rate, ...

Hu, Xiaolong, Ph. D. Massachusetts Institute of Technology

2011-01-01

90

THE SAL NEUTRON DETECTOR EFFICIENCY USING PHOTODISINTEGRATION OF THE DEUTERON  

E-print Network

to detect the neutrons from this reaction. The outgoing neutron energy and direction can be calculated from Hornidge, Terry Pilling, Carsten Muller, Shahram Alavian and Shi Fang who keep my life fun. I also want.1 Photonuclear Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 The SAL Neutron Detector E

Saskatchewan, University of

91

Quantum efficiency test set up performances for NIR detector characterization at ESTEC  

NASA Astrophysics Data System (ADS)

The Payload Technology Validation Section (Future mission preparation Office) at ESTEC is in charge of specific mission oriented validation activities, for science and robotic exploration missions, aiming at reducing development risks in the implementation phase. These activities take place during the early mission phases or during the implementation itself. In this framework, a test set up to characterize the quantum efficiency of near infrared detectors has been developed. The first detector to be tested will an HAWAII-2RG detector with a 2.5?m cut off, it will be used as commissioning device in preparation to the tests of prototypes European detectors developed under ESA funding. The capability to compare on the same setup detectors from different manufacturers will be a unique asset for the future mission preparation office. This publication presents the performances of the quantum efficiency test bench to prepare measurements on the HAWAII-2RG detector. A SOFRADIR Saturn detector has been used as a preliminary test vehicle for the bench. A test set up with a lamp, chopper, monochromator, pinhole and off axis mirrors allows to create a spot of 1mm diameter between 700nm and 2.5?m.The shape of the beam has been measured to match the rms voltage read by the Merlin Lock -in amplifier and the amplitude of the incoming signal. The reference detectors have been inter-calibrated with an uncertainty up to 3 %. For the measurement with HAWAII-2RG detector, the existing cryostat [1] has been modified to adapt cold black baffling, a cold filter wheel and a sapphire window. An statistic uncertainty of +/-2.6% on the quantum efficiency on the detector under test measurement is expected.

Crouzet, P.-E.; Duvet, L.; De Wit, F.; Beaufort, T.; Blommaert, S.; Butler, B.; Van Duinkerken, G.; ter Haar, J.; Heijnen, J.; van der Luijt, K.; Smit, H.; Viale, T.

2014-07-01

92

Efficient quantum key distribution with practical sources and detectors  

E-print Network

We consider the security of a system of quantum key distribution (QKD) using only practical devices. Currently, attenuated laser pulses are widely used and considered to be the most practical light source. For the receiver of photons, threshold (or on/off) photon detectors are almost the only choice. Combining the decoy-state idea and the security argument based on the uncertainty principle, we show that a QKD system composed of such practical devices can achieve the unconditional security without any significant penalty in the key rate and the distance limitation.

Masato Koashi

2006-09-23

93

Investigation of efficient termination structure for improved breakdown properties of semiconductor radiation detectors  

Microsoft Academic Search

Efficiency of a new junction termination structure for improvement of breakdown properties of semiconductor radiation detectors is investigated. The structure consists of a diffused resistor winding around the active junction in a spiral fashion. The current flow through the spiral enables controlled potential distribution along the spiral turns and thus controlled depletion spreading from the main junction, efficiently preventing premature

D. Krizaj; D. Resnik; D. Vrtacnik; S. Amon; V. Cindro

1998-01-01

94

CdTe detector efficiency calibration using thick targets of pure and stable compounds  

Microsoft Academic Search

Quantitative PIXE measurements require perfectly calibrated set-ups. Cooled CdTe detectors have good efficiency for energies above those covered by Si(Li) detectors and turn on the possibility of studying K X-rays lines instead of L X-rays lines for medium and eventually heavy elements, which is an important advantage in various cases, if only limited resolution systems are available in the low

P. C. Chaves; A. Taborda; M. A. Reis

95

Improved plutonium identification and characterization results with NaI(Tl) detector using ASEDRA  

NASA Astrophysics Data System (ADS)

The ASEDRA algorithm (Advanced Synthetically Enhanced Detector Resolution Algorithm) is a tool developed at the University of Florida to synthetically enhance the resolved photopeaks derived from a characteristically poor resolution spectra collected at room temperature from scintillator crystal-photomultiplier detector, such as a NaI(Tl) system. This work reports on analysis of a side-by-side test comparing the identification capabilities of ASEDRA applied to a NaI(Tl) detector with HPGe results for a Plutonium Beryllium (PuBe) source containing approximately 47 year old weapons-grade plutonium (WGPu), a test case of real-world interest with a complex spectra including plutonium isotopes and 241Am decay products. The analysis included a comparison of photopeaks identified and photopeak energies between the ASEDRA and HPGe detector systems, and the known energies of the plutonium isotopes. ASEDRA's performance in peak area accuracy, also important in isotope identification as well as plutonium quality and age determination, was evaluated for key energy lines by comparing the observed relative ratios of peak areas, adjusted for efficiency and attenuation due to source shielding, to the predicted ratios from known energy line branching and source isotopics. The results show that ASEDRA has identified over 20 lines also found by the HPGe and directly correlated to WGPu energies.

Detwiler, R.; Sjoden, G.; Baciak, J.; LaVigne, E.

2008-04-01

96

Reasons of low charge collection efficiency in CdTe-based x/? detectors with ohmic contacts  

NASA Astrophysics Data System (ADS)

Quantitative assessments of the possibility to improve the energy resolution of detectors based on CdTe crystals with two Ohmic contacts by varying the crystal thickness, applied voltage, temperature and lifetimes of charge carriers are presented. It is shown that a super-linear increase in the conductivity of Pt/CdTe/Pt detectors at larger voltages is caused by the space charge limited current, and the excess component over the linearly approximated current is virtually temperature independent. Due to such behavior of the excess current, cooling of the detector does not give the desired result. The calculations show that the effect of charge carrier recombination at the crystal surfaces can be ignored when V < 9-10 V, while trapping carriers in the crystal bulk for thick CdTe detectors can significantly degrade the charge collection efficiency. Thinning the crystal and lowering the applied voltage to maintain the same current value leads to considerable improving of the charge collection efficiency. In the case of the detector thickness of 0.25 mm, the collection efficiency is higher than 97-98% in the photon energy range of 10-1000 keV. The collection efficiency could exceed 99% if to perfect the crystal growth technology and thereby increase the charge carrier lifetime by one order of magnitude as compared to that in the currently used CdTe crystals (2-3 ?s)

Aoki, Toru; Maslyanchuk, O. L.; Kosyachenko, L. A.; Gnatyuk, V. A.

2013-09-01

97

High-efficiency microstructured semiconductor neutron detectors that are arrayed, dual-integrated, and stacked.  

PubMed

Silicon diodes with large aspect ratio 3D microstructures backfilled with 6LiF show a significant increase in neutron detection efficiency beyond that of conventional thin-film coated planar devices. Described in this work are advancements in the technology using detector stacking methods and summed-detector 6×6-element arraying methods to dramatically increase the sensitivity to thermal neutrons. The intrinsic detection efficiency of the 6×6 array for normal-incident 0.0253 eV neutrons was found 6.8% compared against a calibrated 3He proportional counter. PMID:22365111

Bellinger, Steven L; Fronk, Ryan G; Sobering, Timothy J; McGregor, Douglas S

2012-07-01

98

Critique of the Rowe 2001 Detector Efficiency Experiment  

E-print Network

The Rowe 2001 experiment scattered photons from two prepared 9Be+ ions. Measurement of the scattered photons used a single photomultiplier tube (PMT). The resultant histograms appear to be a superposition of the individual ions' distribution, but that is not correct. The PMT records the convolution of the joint probability density of the ions. There are many different joint densities which yield the same PMT histograms. Each density has a different correlation. For a fixed PMT histogram the range of those correlations can be large, e.g. -0.730 to +0.997. The reported correlations based on discriminator levels and the categories 'zero bright', 'one bright', and 'two bright' are unsupported. As such the claim that the detection efficiency loophole is closed is invalid. For this experiment, the detection loophole remains open.

Douglas G Danforth

2014-02-19

99

Soft x-ray quantum efficiency of silicon hybrid CMOS detectors  

NASA Astrophysics Data System (ADS)

Si Hybrid CMOS detectors (HCDs) are sensitive to X-rays between approximately 0.2 - 20 keV. HCDs can provide superior performance to traditional CCDs in multiple areas: faster read out time, windowed read out mode, less susceptible to radiation & micrometeoroid damage, and lower power consumption. X-ray detectors designed for use in astronomical observatories must have an optical blocking filter to prevent the detectors from being saturated by optical light. We have previously reported on the successful deposition of an Al optical blocking layer directly onto the surface of HCDs. These blocking filters were deposited with multiple thicknesses from 180 - 1000 Å and successfully block optical light at all thicknesses, with minimal impact expected on quantum efficiency at the energies of interest for these detectors. The thin Al layer is not expected to impact quantum efficiency at the energies of interest for these detectors. We report energy dependent soft X-ray quantum efficiency measurements for multiple HCDs with different optical blocking filter thicknesses.

Prieskorn, Zachary R.; Bongiorno, Stephen D.; Burrows, David N.; Falcone, Abraham D.; Griffith, Christopher V.; Nikoleyczik, Jonathan

2014-07-01

100

Detectors  

DOEpatents

The apparatus and method provide techniques through which both alpha and beta emission determinations can be made simultaneously using a simple detector structure. The technique uses a beta detector covered in an electrically conducting material, the electrically conducting material discharging ions generated by alpha emissions, and as a consequence providing a measure of those alpha emissions. The technique also offers improved mountings for alpha detectors and other forms of detectors against vibration and the consequential effects vibration has on measurement accuracy.

Orr, Christopher Henry (Calderbridge, GB); Luff, Craig Janson (Calderbridge, GB); Dockray, Thomas (Calderbridge, GB); Macarthur, Duncan Whittemore (Los Alamos, NM); Bounds, John Alan (Los Alamos, NM); Allander, Krag (Los Alamos, NM)

2002-01-01

101

Impact of geometry on light collection efficiency of scintillation detectors for cryogenic rare event searches  

E-print Network

Simulations of photon propagation in scintillation detectors were performed with the aim to find the optimal scintillator geometry, surface treatment, and shape of external reflector in order to achieve maximum light collection efficiency for detector configurations that avoid direct optical coupling, a situation that is commonly found in cryogenic scintillating bolometers in experimental searches for double beta decay and dark matter. To evaluate the light collection efficiency of various geometrical configurations we used the ZEMAX ray-tracing software. It was found that scintillators in the shape of a triangular prism with an external mirror shaped as truncated cone gives the highest light collection efficiency. The results of the simulations were confirmed by carrying out measurements of the light collection efficiencies of CaWO4 crystal scintillators. A comparison of simulated and measured values of light output shows good agreement

F. A. Danevich; V. V. Kobychev; R. V. Kobychev; H. Kraus; V. B. Mikhailik; V. M. Mokina; I. M. Solsky

2014-04-30

102

Impact of geometry on light collection efficiency of scintillation detectors for cryogenic rare event searches  

NASA Astrophysics Data System (ADS)

Simulations of photon propagation in scintillation detectors were performed with the aim to find the optimal scintillator geometry, surface treatment, and shape of external reflector in order to achieve maximum light collection efficiency for detector configurations that avoid direct optical coupling, a situation that is commonly found in cryogenic scintillating bolometers in experimental searches for double beta decay and dark matter. To evaluate the light collection efficiency of various geometrical configurations we used the ZEMAX ray-tracing software. It was found that scintillators in the shape of a triangular prism with an external mirror shaped as truncated cone gives the highest light collection efficiency. The results of the simulations were confirmed by carrying out measurements of the light collection efficiencies of CaWO4 crystal scintillators. A comparison of simulated and measured values of light output shows good agreement.

Danevich, F. A.; Kobychev, V. V.; Kobychev, R. V.; Kraus, H.; Mikhailik, V. B.; Mokina, V. M.; Solsky, I. M.

2014-10-01

103

A study of the validity of the efficiency transfer method to calculate the peak efficiency using ?-ray detectors at extremely large distances  

NASA Astrophysics Data System (ADS)

The full-energy peak efficiency (FEPE) curves of the (2? × 2? and 3? × 3?) NaI (Tl) detectors were measured at seven different axial positions from their surfaces. The calibration process was done using radioactive point sources, which produce a wide energy range from 59.53 up to 1,408.01 keV. This work has been undertaken to explain the effects of source energy and sourcE-to-detector distance on the detector efficiency calculations. The study provides an empirical formula to calculate FEPE based on the efficiency transfer method for different detectors using the effective solid angle ratio at very large distances and for higher energies. A remarkable agreement between the measured and calculated efficiencies for the detectors at the sourcE-to-detector distances <35 cm and above that slight difference was observed.

El-Khatib, Ahmed M.; Badawi, Mohamed S.; Elzaher, Mohamed A.; Thabet, Abouzeid A.

2014-04-01

104

Determination of the map of efficiency of the J-PET detector with the GATE package  

E-print Network

A novel PET detector consisting of strips of polymer scintillators is being developed by the J-PET Collaboration. The map of efficiency and the map of geometrical acceptance of the 2-strip J-PET scanner are presented. Map of efficiency was determined using the Monte Carlo simulation software GATE based on GEANT4. Both maps were compared using method based on the chi2 test.

Kowalski, P; Bednarski, T; Bia?as, P; Czerwi?ski, E; Giergiel, K; Kap?on, ?; Kochanowski, A; Korcyl, G; Kowal, J; Kozik, T; Krzemie?, W; Molenda, M; Moskal, I; Moskal, P; Nied?wiecki, Sz; Pa?ka, M; Pawlik-Nied?wiecka, M; Rudy, Z; Salabura, P; Sharma, N G; Silarski, M; S?omski, A; Smyrski, J; Strzelecki, A; Szyma?ski, K; Wi?licki, W; Witkowski, P; Zieli?ski, M; Zo?, N

2014-01-01

105

Coincidence summing corrections for a clover detector  

NASA Astrophysics Data System (ADS)

The true coincidence summing effect on the full energy peak efficiency calibration of a clover HPGe detector for point sources has been determined as a function of sample-to-detector distance using mono-energetic and multi-energetic gamma ray sources. The coincidence summing effect has been observed to increase at closer distances with the correction factors as high as 1.25 at closest distance studied. The correction factors for the total and the photopeak efficiencies have been obtained using the analytical method. The clover detector response has been simulated using MCNP code, taking care of the bevels and the flat surfaces of the clover detector. The geometry of the clover detector has been optimized to match the experimental and the theoretical efficiencies. The true coincidence summing correction factors (kTCS) have also been experimentally obtained by taking the ratio of corresponding mono-energetic extrapolated efficiencies to multi-energetic efficiencies. The kTCS obtained from analytical method has been found to match with the experimental kTCS with the simulated values within 1-5%.

Agarwal, Chhavi; Danu, L. S.; Gathibandhe, M.; Goswami, A.; Biswas, D. C.

2014-11-01

106

Efficient one-pair experimental system for spatial resolution demonstration of prototype PET detectors.  

PubMed

In the development of depth-of-interaction (DOI)-positron emission tomography (PET) detectors, one of the important steps toward their practical use is an evaluation of their imaging performance, such as the spatial resolution as measured by use of a point source and a one-pair experimental system which simulates actual PET geometries. The DOI-PET detectors have a broad field of view providing good imaging performance compared with conventional detectors. Therefore, evaluation including the region from the center to the periphery close to the detector ring is required in an effort to show their advanced performance regarding uniform spatial resolution. In this study, we aimed to develop and evaluate an efficient one-pair experimental system for demonstration of the DOI-PET detector performance. For this purpose, we propose a one-pair experimental system that can simulate an arbitrary ring diameter and acquire projection data efficiently by skipping unnecessary combinations according to the position of the point source. As a result, the proposed system and our measuring scheme could significantly reduce the total measurement time, especially for a large ring size such as that used in brain PET scanners and whole-body PET scanners. We used the system to evaluate the X'tal cube PET detector with a 2-mm cubic crystal array arranged in simulated PET geometries with ring diameters of 8.2 and 14.6 cm for 12 and 18 detector blocks, respectively. The results showed that a uniform spatial resolution was achieved even in the peripheral region, and measurements were obtained semi-automatically in a short time. PMID:24938490

Tashima, Hideaki; Yoshida, Eiji; Hirano, Yoshiyuki; Nishikido, Fumihiko; Inadama, Naoko; Murayama, Hideo; Yamaya, Taiga

2014-07-01

107

Bragg Magnifier: High-efficiency, High-resolution X-ray Detector  

NASA Astrophysics Data System (ADS)

X-ray computer microtomography is a powerful tool for non-destructive examinations in medicine, biology, and material sciences. The resolution of the presently used detector systems is restricted by scintillator properties, optical light transfer, and charge-coupled-device (CCD) granularity, which impose a practical limit of about one micrometer spatial resolution at detector efficiencies of a few percent. A recently developed detector, called Bragg Magnifier, achieves a breakthrough in this respect, satisfying the research requirements of an efficient advance towards the submicron range. The Bragg Magnifier uses the properties of asymmetric Bragg diffraction to increase the cross section of the diffracted X-ray beam. Magnifications up to 100×100 can be achieved even at hard X-rays energies (>20 keV). In this way the influence of the detector resolution can be reduced accordingly and the efficiency increased. Such a device has been developed and successfully integrated into the Tomography Station of the Materials Science Beamline of the Swiss Light Source (SLS). The device can be operated at energies ranging from 17.5 keV up to 22.75 keV, reaching theoretical pixel sizes of 140 nm.

Stampanoni, Marco; Groso, Amela; Borchert, Gunther; Abela, Rafael

2007-01-01

108

Absolute detection efficiencies for keV energy atoms incident on a microchannel plate detector  

NASA Astrophysics Data System (ADS)

The absolute detection efficiencies of a microchannel plate detector (MCP) were determined experimentally for neutral hydrogen, carbon, and tungsten atoms with impact energies of 0.5-4.5 keV. We measured detection efficiencies using our recently developed method, which uses coincidence counting between neutralized incident ions and ionized target atoms in single-electron capture collisions. The obtained detection efficiencies showed similar impact-energy and mass dependence to those of rare gas atoms (Ne, Ar, Kr, and Xe), measured previously using our method. The detection efficiencies increased with increasing impact energy and converged to the open area ratio (?50%) of the MCP used. The efficiencies at fixed energies decreased as the mass of the incident atom increased. The absolute detection efficiencies obtained for H, C, W, Ne, Ar, Kr, and Xe atoms could be scaled according to the average electron emission yield estimated using the formulas for electronic and nuclear stopping powers.

Takahashi, N.; Adachi, Y.; Saito, M.; Haruyama, Y.

2013-11-01

109

The utility of available low quantum efficiency detector arrays for tactical imaging  

NASA Astrophysics Data System (ADS)

A mosaic detector array which uses a charge coupled array to integrate and multiplex signals is significantly limited by charge saturation. Detection of warm targets by infrared sensing through the atmosphere tends to be limited more by clutter than by random fluctuations. For missions at television frame rates the important attributes of the detector array are good spatial resolution and uniformity of response. Responsive quantum efficiency is relatively unimportant. Operation at 3 to 4.2 microns offers advantages of resolution and larger rate of change of radiant signal with temperature.

Jamieson, J. A.

1980-01-01

110

High optical efficiency and photon noise limited sensitivity of microwave kinetic inductance detectors using phase readout  

E-print Network

We demonstrate photon noise limited performance in both phase and amplitude readout in microwave kinetic inductance detectors (MKIDs) consisting of NbTiN and Al, down to 100 fW of optical power. We simulate the far field beam pattern of the lens-antenna system used to couple radiation into the MKID and derive an aperture efficiency of 75%. This is close to the theoretical maximum of 80% for a single-moded detector. The beam patterns are verified by a detailed analysis of the optical coupling within our measurement setup.

Janssen, R M J; Endo, A; Ferrari, L; Yates, S J C; Baryshev, A M; Klapwijk, T M

2013-01-01

111

The effect of magnetic field on the intrinsic detection efficiency of superconducting single-photon detectors  

E-print Network

We experimentally investigate the effect of a magnetic field on photon detection in superconducting single-photon detectors. At low fields, the effect of a magnetic field is through the direct modification of the quasiparticle density of states of the superconductor, and magnetic field and bias current are interchangable, as is expected for homogeneous dirty-limit superconductors. At the field where a first vortex enters the detector, the effect of the magnetic field is reduced, up until the point where the critical current of the detector starts to be determined by flux flow. From this field on, increasing the magnetic field does not alter the detection of photons anymore, whereas it does still change the rate of dark counts. This result points at an intrinsic difference in dark and light counts, and also shows that no enhancement of the intrinsic detection efficiency of a straight SSPD wire is achievable in a magnetic field.

Renema, J J; Komen, I; Wang, Q; Gaudio, R; Hoog, K P M op 't; Zhou, Z; Sahin, D; Fiore, A; Kes, P; Aarts, J; van Exter, M P; de Dood, M J A; Driessen, E F C

2014-01-01

112

Novel Approach to Surface Processing for Improving the Efficiency of CdZnTe Detectors  

NASA Astrophysics Data System (ADS)

We emphasize an improvement of the surface processing procedures for cadmium zinc telluride (CZT) detectors, which is one of the principal problems limiting the technology. A rough surface enhances the leakage current into the medium, creating additional trapping centers and thereby degrading the detector's performance. Mechanical polishing followed by chemical treatment yields smoother surfaces as required, but chemical treatment, especially with bromine-based solutions, induces unwanted surface features, increases the surface conductivity, and generates chemical species that alter the material's surface and interfacial properties. It is essential to avoid such adverse consequences of surface etching in the manufacturing of highly efficient radiation detectors. We approached the problem of processing the crystals' surfaces by using two different solutions (a low-concentration bromine-based etchant mixture in conjunction with a surface-passivation reagent and a non-bromine-based etchant). The chemomechanical treatment yielded smooth nonconductive surfaces with fewer detrimental features, therefore allowing us to fabricate better devices. We determined the surface roughness using atomic force microscopy and optical profilometry (OP). We analyzed the surface structure, orientations of the crystals, and formation of chemical species by x-ray photoelectron spectroscopy techniques and delineated their effects on the devices' electrical properties and performance. Our experimental data revealed that our new chemical etching process produced nonconductive surfaces with fewer surface defects and so improved the detectors' charge transport and efficiency. We detail the results of our new etchants and compare them with those for conventional Br-methanol etchants.

Hossain, A.; Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; Jones, D.; Hall, J.; Kim, K. H.; Mwathi, J.; Tong, X.; Yang, G.; James, R. B.

2014-08-01

113

An Efficient, Movable Single-Particle Detector for Use in Cryogenic Ultra-High Vacuum Environments  

E-print Network

A compact, highly efficient single-particle counting detector for ions of keV/u kinetic energy, movable by a long-stroke mechanical translation stage, has been developed at the Max-Planck-Institut f\\"ur Kernphysik (Max Planck Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics, can operate at ambient temperatures down to $\\sim$ 10 K and consist fully of ultra-high vacuum (UHV) compatible, high-temperature bakeable and non-magnetic materials. The set-up is designed to meet the technical demands of MPIK's Cryogenic Storage Ring (CSR). We present a series of functional tests that demonstrate full suitability for this application and characterise the set-up with regard to its particle detection efficiency.

Spruck, Kaija; Fellenberger, Florian; Grieser, Manfred; von Hahn, Robert; Klinkhamer, Vincent; Novotný, Old?ich; Schippers, Stefan; Vogel, Stephen; Wolf, Andreas; Krantz, Claude

2014-01-01

114

Investigation of efficient termination structure for improved breakdown properties of semiconductor radiation detectors  

SciTech Connect

Efficiency of a new junction termination structure for improvement of breakdown properties of semiconductor radiation detectors is investigated. The structure consists of a diffused resistor winding around the active junction in a spiral fashion. The current flow through the spiral enables controlled potential distribution along the spiral turns and thus controlled depletion spreading from the main junction, efficiently preventing premature avalanche breakdown. Both multiple guard-ring structures and spiral junction termination structures have shown good breakdown properties typically three to five times higher than breakdown voltages of diodes without junction termination. The breakdown voltages of spiral junction termination structures are only weakly influenced by changes in substrate doping concentration caused by neutron irradiation. They can thus be considered for termination of future semiconductor radiation detectors.

Krizaj, D.; Resnik, D.; Vrtacnik, D.; Amon, S. [Univ. of Ljubljana (Slovenia). Faculty of Electrical Engineering] [Univ. of Ljubljana (Slovenia). Faculty of Electrical Engineering; Cindro, V. [Jozef Stefan Inst., Ljubljana (Slovenia)] [Jozef Stefan Inst., Ljubljana (Slovenia)

1998-06-01

115

Improvement of neutron detection efficiency with high sensitive CR39 track detector  

Microsoft Academic Search

Two subjects have been studied for establishing an efficient detection technique applicable to neutrons with an energy higher than 20MeV, for which personnel dosimetry becomes more important especially in space activities and radiation protection around high-energy accelerators.A performance of a new sensitive detector, recently developed copolymer of CR-39 and N-isopropylacrylamide, was checked in a D–T neutron field. It was confirmed

K Oda; H Ichijo; N Miyawaki; T Yamauchi; Y Nakane

2001-01-01

116

A biomimetic olfactory-based biosensor with high efficiency immobilization of molecular detectors.  

PubMed

The immobilization efficiency of molecular detectors is of great importance with regard to the performances of biosensors such as the sensitivity, stability, and reproducibility. This paper presents a biomimetic olfactory receptor-based biosensor with better performances by improving the immobilization efficiency of molecular detectors for odorant sensing. A mixed self-assembled monolayers (SAMs) functionalized with specific olfactory receptors (ODR-10) was constructed on the sensitive area of surface acoustic wave (SAW) chip. The immobilization of ODR-10 was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The responses of this biosensor to various odorants were recorded by monitoring the resonance frequency shifts of SAW, which is correlated to the mass loading on its sensitive area. All the results demonstrate this biosensor can specifically respond to the natural ligand of ODR-10, diacetyl, with high sensitivity and stability. The sensitivity is 4 kHz/ng, which is 2× higher than that of previous work. The detection limit is 1.2×10(-11) mM. The major advances on immobilization efficiency of molecular detectors presented in this work could substantially promote and accelerate the researches and applications of olfactory receptor-based biosensors with different transducers, such as quartz crystal microbalance (QCM), surface plasma resonance (SPR), and field effect transistors (FET). PMID:22040748

Wu, Chunsheng; Du, Liping; Wang, Di; Zhao, Luhang; Wang, Ping

2012-01-15

117

Efficiency as a function of MEQ-CWT for large area germanium detectors using LLNL phantom.  

PubMed

The lung counting system at Kalpakkam, India, used for the estimation of transuranics deposited in the lungs of occupational workers, consists of an array of three large area germanium detectors fixed in a single assembly. The efficiency calibration for low energy photons was carried out using ²?¹Am and ²³²Th lung sets of Lawrence Livermore National Laboratory phantom. The muscle equivalent chest wall thickness (MEQ-CWT) was derived for the three energies 59.5, 75.95 (average energy of ²³²Th) and 238.9 keV for the series of overlay plates made of different adipose mass ratios. Efficiency as a function of MEQ-CWT was calculated for individual detectors for the three energies. Variation of MEQ-CWT from 16 to 40 mm resulted in an efficiency variation of around 40 % for all the three energies. The array efficiency for different MEQ-CWT ranged from 1.4×10?³ to 3.2×10?³, 1.5×10?³ to 3.3×10?³ and 1.1×10?³ to 2.3×10?³ for 59.5, 75.95 and 238.9 keV, respectively. In the energy response, efficiency was observed to be maximum for 75.95 keV compared with 59.5 and 238.9 keV. PMID:21325369

Rajaram, S; Brindha, J Thulasi; Sreedevi, K R; Hegde, A G

2012-01-01

118

Proton light output function and neutron efficiency of a p-terphenyl detector using a 252Cf source  

NASA Astrophysics Data System (ADS)

The properties of a novel p-terphenyl neutron detector have been investigated using photon sources and neutrons from a time tagged 252Cf(sf) source. The electron light output scale has been calibrated by comparing the measured detector response to a Monte Carlo generated spectrum folded with a resolution function. Proton light output and efficiency functions have been determined in the energy range 0.8?En?4 MeV using the 252Cf(sf) source. The efficiency of the detector has been calculated by comparing the experimental 252Cf(sf) neutron energy spectrum to the Mannhart evaluation. A NE213-equivalent neutron detector has been used to cross-check our method and results. The results show that the p-terphenyl crystal has better energy resolution, increased proton light output and neutron efficiency when compared to a similar size NE213-equivalent neutron detector.

Matei, C.; Hambsch, F.-J.; Oberstedt, S.

2012-06-01

119

A 3-dimensional interdigitated electrode geometry for the enhancement of charge collection efficiency in diamond detectors  

NASA Astrophysics Data System (ADS)

In this work, a single crystal CVD diamond film with a novel three-dimensional (3D) interdigitated electrode geometry has been fabricated with the reactive ion etching (RIE) technique in order to increase the charge collection efficiency (CCE) with respect to that obtained by standard superficial electrodes. The geometrical arrangement of the electric field lines due to the 3D patterning of the electrodes results in a shorter travel path for the excess charge carriers, thus contributing to a more efficient charge collection mechanism. The CCE of the device was mapped by means of the ion beam induced charge (IBIC) technique. A 1 MeV proton micro-beam was raster-scanned over the active area of the diamond detector under different bias voltage conditions, enabling to probe the charge transport properties of the detector up to a depth of 8 ? \\text{m} below the sample surface. The experimental results, supported by the numerical simulations, show a significant improvement in the 3D detector performance (i.e. CCE, energy resolution, extension of the active area) if compared with the results obtained by standard surface metallic electrodes.

Forneris, J.; Lo Giudice, A.; Olivero, P.; Picollo, F.; Re, A.; Marinelli, Marco; Pompili, F.; Verona, C.; Verona Rinati, G.; Benetti, M.; Cannata, D.; Di Pietrantonio, F.

2014-10-01

120

Detection efficiency for measuring 241Am in axillary lymph nodes using different types and sizes of detectors.  

PubMed

The detection efficiency and interference susceptibility of four different types of low energy photon detectors, each with a unique geometric arrangement, were compared for direct measurement of Am deposited in the axillary lymph nodes. Although the most efficient detector was a single large 23,226 mm square phoswich detector, it was also the most susceptible to confounding depositions from activity deposited in adjacent organs. The array of two 2,800 mm high purity germanium detectors exhibited the highest efficiency per unit detector area with some resistance to confounding from activity deposited in the lungs. The array of two 4,560 mm NaI(Tl) detectors was the least susceptible to confounding and nearly as efficient per square millimeter as the high purity germanium detector array. Thus, selection of a detector system for in vivo measurement of activity deposited in the axillary lymph nodes should consider whether there is a likelihood for activity deposited in other organs, such as the lungs, skeleton, or liver, to create an interference that will confound the measurement result. PMID:22850233

Lobaugh, Megan L; Spitz, Henry B; Glover, Samuel E

2012-09-01

121

Detection efficiency of a BEGe detector using the Monte Carlo method and a comparison to other calibration methods  

E-print Network

In this paper we model by using the Monte Carlo simulation code PENELOPE [1, 2] a Broad Energy Germanium (BEGe) detector and determine its efficiency. The simulated geometry consists of a point source located close to the detector as well as volume sources with cylindrical geometry. A comparison of the simulation is made to experimental results as well as to analytical calculations.

Stefanakis, N

2014-01-01

122

High-speed and high-efficiency travelling wave single-photon detectors embedded in nanophotonic circuits  

PubMed Central

Ultrafast, high-efficiency single-photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. However, imperfect modal matching and finite photon absorption rates have usually limited their maximum attainable detection efficiency. Here we demonstrate superconducting nanowire detectors atop nanophotonic waveguides, which enable a drastic increase of the absorption length for incoming photons. This allows us to achieve high on-chip single-photon detection efficiency up to 91% at telecom wavelengths, repeatable across several fabricated chips. We also observe remarkably low dark count rates without significant compromise of the on-chip detection efficiency. The detectors are fully embedded in scalable silicon photonic circuits and provide ultrashort timing jitter of 18?ps. Exploiting this high temporal resolution, we demonstrate ballistic photon transport in silicon ring resonators. Our direct implementation of a high-performance single-photon detector on chip overcomes a major barrier in integrated quantum photonics. PMID:23271658

Pernice, W.H.P.; Schuck, C.; Minaeva, O.; Li, M.; Goltsman, G.N.; Sergienko, A.V.; Tang, H.X.

2012-01-01

123

Real time method and computer system for identifying radioactive materials from HPGe gamma-ray spectroscopy  

DOEpatents

A real-time method and computer system for identifying radioactive materials which collects gamma count rates from a HPGe gamma-radiation detector to produce a high-resolution gamma-ray energy spectrum. A library of nuclear material definitions ("library definitions") is provided, with each uniquely associated with a nuclide or isotope material and each comprising at least one logic condition associated with a spectral parameter of a gamma-ray energy spectrum. The method determines whether the spectral parameters of said high-resolution gamma-ray energy spectrum satisfy all the logic conditions of any one of the library definitions, and subsequently uniquely identifies the material type as that nuclide or isotope material associated with the satisfied library definition. The method is iteratively repeated to update the spectrum and identification in real time.

Rowland, Mark S. (Alamo, CA); Howard, Douglas E. (Livermore, CA); Wong, James L. (Dublin, CA); Jessup, James L. (Tracy, CA); Bianchini, Greg M. (Livermore, CA); Miller, Wayne O. (Livermore, CA)

2007-10-23

124

Statistics of the LS-detector in the case of low counting efficiency.  

PubMed

In the case of high-quenched 3H and 63Ni sources a distinct incompatibility of theoretical and experimental detection efficiency in the triple liquid scintillation (LS) detector was observed (Appl. Radiat. Isot. 52 (2000) 643). The authors concluded, that the Poisson distribution does not properly describe the detection process, when less than one photoelectron is expected in one of the photomultipliers. Application of other distributions of photoelectrons, e.g. binomial, does not solve the observable problem of incompatibility. Measurements of a set of 55Fe sources have been performed with phototubes defocusing and grey filters for decreasing the counting efficiency of the TDCR detector. Differences between counting results of the 55Fe source and the light emitting diode (LED), simulating the scintillation source, excited by a pulse generator have been observed. Various distributions (Poisson, binomial and Polya) were used for the determination of the theoretical counting efficiency in both cases. The Poisson law gave a good result in the case of the LED but the Polya law had to be applied in the case of 55Fe. The results were independent of the scintillator volume. It seems that the validity of the Polya law in the case of LS-sources is related to the scintillator itself. Measurements of the 3H solution confirmed that conclusion. PMID:14987684

Broda, R; Jeczmieniowski, A

2004-01-01

125

Parallel Beam Approximation for Calculation of Detection Efficiency of Crystals in PET Detector Arrays  

PubMed Central

In this work we propose a parallel beam approximation for the computation of the detection efficiency of crystals in a PET detector array. In this approximation the detection efficiency of a crystal is estimated using the distance between source and the crystal and the pre-calculated detection cross section of the crystal in a crystal array which is calculated for a uniform parallel beam of gammas. The pre-calculated detection cross sections for a few representative incident angles and gamma energies can be used to create a look-up table to be used in simulation studies or practical implementation of scatter or random correction algorithms. Utilizing the symmetries of the square crystal array, the pre-calculated look-up tables can be relatively small. The detection cross sections can be measured experimentally, calculated analytically or simulated using a Monte Carlo (MC) approach. In this work we used a MC simulation that takes into account the energy windowing, Compton scattering and factors in the “block effect”. The parallel beam approximation was validated by a separate MC simulation using point sources located at different positions around a crystal array. Experimentally measured detection efficiencies were compared with Monte Carlo simulated detection efficiencies. Results suggest that the parallel beam approximation provides an efficient and accurate way to compute the crystal detection efficiency, which can be used for estimation of random and scatter coincidences for PET data corrections.

Komarov, Sergey; Song, Tae Yong; Wu, Heyu; Tai, Yuan-Chuan

2014-01-01

126

Installation of a simple muon veto for HPGe low background counting at the LBNL Low Background Facility  

NASA Astrophysics Data System (ADS)

The Low Background Facility (LBF) at the Lawrence Berkeley National Laboratory (LBNL) performs low level counting of primordial radioisotope concentrations (U, Th, K) and neutron activation analysis for a variety of experiments and users. Many materials characterized at the facility are candidate construction materials for underground, low background experiments which require high standards of radio-purity within detector components. At the LBF, HPGe detectors are used at two unique sites to perform gamma assay: a local low background surface lab at LBNL and an underground site (600 ft. overburden) in Oroville, CA. Since the primary limitation in sensitivity at the surface location is presented by cosmic ray muons, a simple plastic scintillator system has been installed above a HPGe detector as a veto to lower the background continuum due to these events. This talk will summarize the installation and improvement of the system due to this upgrade and provide a general overview of the services that are available at the Low Background Facility.

Thomas, Keenan; Norman, Erick; Smith, Alan; Chan, Yuen-Dat

2012-10-01

127

Scintillation detector efficiencies for neutrons in the energy region above 20 MeV  

SciTech Connect

The computer program SCINFUL (for SCINtillator FUL1 response) is a program designed to provide a calculated complete pulse-height response anticipated for neutrons being detected by either an NE-213 (liquid) scintillator or an NE-110 (solid) scintillator in the shape of a right circular cylinder. The point neutron source may be placed at any location with respect to the detector, even inside of it. The neutron source may be monoenergetic, or Maxwellian distributed, or distributed between chosen lower and upper bounds. The calculational method uses Monte Carlo techniques, and it is relativistically correct. Extensive comparisons with a variety of experimental data have been made. There is generally overall good agreement (less than 10% differences) of results for SCINFUL calculations with measured integral detector efficiencies for the design incident neutron energy range of 0.1 to 80 MeV. Calculations of differential detector responses, i.e. yield versus response pulse height, are generally within about 5% on the average for incident neutron energies between 16 and 50 MeV and for the upper 70% of the response pulse height. For incident neutron energies between 50 and 80 MeV, the calculated shape of the response agrees with measurements, but the calculations tend to underpredict the absolute values of the measured responses. Extension of the program to compute responses for incident neutron energies greater than 80 MeV will require new experimental data on neutron interactions with carbon. 32 refs., 6 figs., 2 tabs.

Dickens, J.K.

1991-01-01

128

Efficiency Studies and Simulations of a Neutron Background Veto for Dark Matter Detectors  

NASA Astrophysics Data System (ADS)

In direct WIMP dark matter detection experiments, neutrons from cosmogenic sources and nuclear reactions in detector materials can provide backgrounds indistinguishable from WIMP signals. To reduce this background, an active neutron veto filled with a boron-loaded scintillator is being developed. The scintillator used will be pseudocumene, mixed with trimethyl borate as a boron source, and a PPO wavelength shifter. Such a veto would detect neutrons in the volume surrounding the detector, allowing coincident background events in the detector to be rejected. Neutrons are captured by the ^10B with a high cross section, resulting in an ? and ^7Li. The scintillation from the nuclear products is heavily quenched to an equivalent electron energy as low as 50 keV. To detect this, it is necessary to have high light collection efficiency. To model the neutron veto concept, light yield measurements were taken for a small prototype filled with the scintillator mixture and lined with a Lumirror reflector. These results were reproduced in GEANT4 and in an independent simulation. We then applied the simulations to the DarkSide-50 neutron veto to predict its neutron rejection power. Results from measurements taken with the prototype and from the simulation will be presented.

Westerdale, Shawn; Shields, Emily; Xu, Jingke; Calaprice, Frank

2013-04-01

129

Derivation of sensitivity of a Geiger mode APDs detector from a given efficiency for QKD experiments  

E-print Network

The detection sensitivity (DS) of the commercial single-photon-receiver based on InGaAs gate-mode avalanche photodiode is estimated. Instalment of a digital-blanking-system (DBS) to reduce dark current makes the difference between DS, which is an efficiency of the detector during its open-gate/active state, and the total/overall detection efficiency (DE). By numerical simulations, it is found that the average number of light-pulses, blanked by DBS, following a registered pulse is 0.333. DS is estimated at 0.216, which can be used for estimating DE for an arbitrary photon arriving rate and a gating frequency of the receiver.

Kiyotaka Hammura; David Williams

2009-01-05

130

Numerical Simulations of Pillar Structured Solid State Thermal Neutron Detector Efficiency and Gamma Discrimination  

SciTech Connect

This work reports numerical simulations of a novel three-dimensionally integrated, {sup 10}boron ({sup 10}B) and silicon p+, intrinsic, n+ (PIN) diode micropillar array for thermal neutron detection. The inter-digitated device structure has a high probability of interaction between the Si PIN pillars and the charged particles (alpha and {sup 7}Li) created from the neutron - {sup 10}B reaction. In this work, the effect of both the 3-D geometry (including pillar diameter, separation and height) and energy loss mechanisms are investigated via simulations to predict the neutron detection efficiency and gamma discrimination of this structure. The simulation results are demonstrated to compare well with the measurement results. This indicates that upon scaling the pillar height, a high efficiency thermal neutron detector is possible.

Conway, A; Wang, T; Deo, N; Cheung, C; Nikolic, R

2008-06-24

131

ELENA MCP detector: absolute detection efficiency for low-energy neutral atoms  

NASA Astrophysics Data System (ADS)

Microchannel Plates (MCP) detectors are frequently used in space instrumentation for detecting a wide range of radiation and particles. In particular, the capability to detect non-thermal low energy neutral species is crucial for the sensor ELENA (Emitted Low-Energy Neutral Atoms), part of the package SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) on board the BepiColombo mission of ESA to Mercury to be launched in 2015. ELENA is a Time of Flight (TOF) sensor, based on a novel concept using an ultra-sonic oscillating shutter (Start section), which is operated at frequencies up to 50 kHz; a MCP detector is used as a Stop detector. The scientific objective of ELENA is to detect energetic neutral atoms in the range 10 eV - 5 keV, within 76° FOV, perpendicular to the S/C orbital plane. ELENA will monitor the emission of neutral atoms from the whole surface of Mercury thanks to the spacecraft motion. The major scientific objectives are the interaction between the plasma environment and the planet’s surface, the global particle loss-rate and the remote sensing of the surface properties. In particular, surface release processes are investigated by identifying particles released from the surface, via solar wind-induced ion sputtering (< 1eV - < 100 eV) as well as Hydrogen back-scattered at hundreds eV. MCP absolute detection efficiency for very low energy neutral atoms (E < 30 eV) is a crucial point for this investigation. At the MEFISTO facility of the Physical Institute of the University of Bern (CH), measurements on three different types of MCP (with and without coating) have been performed providing the detection efficiencies in the energy range 10eV - 1keV. Outcomes from such measurements are discussed here.

Rispoli, R.; De Angelis, E.; Colasanti, L.; Vertolli, N.; Orsini, S.; Scheer, J. A.; Mura, A.; Milillo, A.; Wurz, P.; Selci, S.; Di Lellis, A. M.; Leoni, R.; D'Alessandro, M.; Mattioli, F.; Cibella, S.

2012-09-01

132

Direct-reaction studies by particle-{gamma} coincidence spectroscopy using Csi-Hpge and Si-Hpge arrays  

SciTech Connect

Particle-{gamma} and particle-{gamma}-{gamma} coincidence spectroscopy has several advantages in the study of direct reactions (particularly in inverse kinematics) since it can generally allow determination of: decay paths; high-precision level energies; multipolarities of transitions; and cross sections. Techniques for studying direct reactions by particle-{gamma} coincidence spectroscopy are presented for two cases: (1) heavy-ion reactions with CsI-HPGe, and (2) light-ion reactions with Si-HPGe. Future direct-reaction studies with radioactive ion beams (RIBs) will mostly involve low beam intensities and inverse kinematics (i.e., A{sub beam}>A{sub target}), which eliminates the traditional use of magnetic spectrometers. Particle-{gamma} coincidence spectroscopy currently provides the most viable method to study direct reactions with nuclei of any level density. In the present study, the capabilities and limitations of the technique are explored.

Allmond, J. M. [Joint Institute for Heavy Ion Research, Oak Ridge National Laboratory, Oak Ridge TN 37831 (United States)

2013-04-19

133

Direct-Reaction Studies by Particle-Gamma Coincidence Spectroscopy Using HPGe-CsI and HPGe-Si Arrays  

SciTech Connect

Particle- and particle- - coincidence spectroscopy has several advantages in the study of direct reactions(particularly in inverse kinematics) since it can generally allow determination of: decay paths; high-precision level energies; multipolarities of transitions; and cross sections. Techniques for studying direct reactions by particle- coincidence spectroscopy are presented for two cases: (1) heavy-ion reactions with HPGe-CsI, and (2) light-ion reactions with HPGe-Si. Future direct-reaction studies with radioactive ion beams (RIBs) will mostly involve low beam intensities and inverse kinematics (i.e., Abeam>Atarget), which eliminates the traditional use of magnetic spectrometers. Particle- coincidence spectroscopy currently provides the most viable method to study direct reactions with nuclei of any level density. In the present study, the capabilities and limitations of the technique are explored.

Allmond, James M [ORNL] [ORNL

2013-01-01

134

Gamma Ray Efficiency Comparisons for Si(Li), Ge, CdTe and HgI2 Detectors  

Microsoft Academic Search

Gamma-ray efficiency measurements were made for Si(Li), Ge, CdTe and HgI2 spectrometers and detectors of comparable sizes for gamma ray energies from 60 keV to 3.85 MeV. Full energy efficiency measurements of cooled Si(Li) and Ge spectrometers and a room temperature CdTe spectrometer show that the efficiencies improve in going from silicon (Z= 14) to germanium (Z= 32) to cadmium

H. L. Malm; T. W. Raudorf; M. Martini; K. R. Zanio

1973-01-01

135

Reducing the Read Noise of H2RG Detector Arrays by more Efficient use of Reference Signals  

NASA Technical Reports Server (NTRS)

We present a process for characterizing the correlation properties of the noise in large two-dimensional detector arrays, and describe an efficient process for its removal. In the case of the 2k x 2k HAWAII-2RG detectors (H2RG) detectors from Teledyne which are being used on the Near Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST), we find that we can reduce the read noise by thirty percent. Noise on large spatial scales is dramatically reduced. With this relatively simple process, we provide a performance improvement that is equivalent to a significant increase in telescope collecting area for high resolution spectroscopy with NIRSpec.

Rauscher, Bernard J.; Arendt, Richard G.; Fixen, D. J.; Lindler, Don; Loose, Markus; Moseley, S. H.; Wilson, D. V.

2011-01-01

136

Determination of TFTR far-field neutron detector efficiencies by local neutron flux spectrum measurement  

Microsoft Academic Search

Neutron detectors have often been located on the tokamak fusion test reactor (TFTR) test cell floor 3 m or more from the vacuum vessel for ease of detector access, to reduce radiation damage, minimize count saturation problems, and to avoid high magnetic fields. These detectors include Si surface-barrier diodes, fission chambers, natural diamond detectors, and T2 production in a moderated

D. L. Jassby; G. Ascione; H. W. Kugel; A. L. Roquemore; T. W. Barcelo; A. Kumar

1997-01-01

137

Determination of TFTR far-field neutron detector efficiencies by local neutron flux spectrum measurement  

Microsoft Academic Search

Neutron detectors have often been located on the tokamak fusion test reactor (TFTR) test cell floor 3 m or more from the vacuum vessel for ease of detector access, to reduce radiation damage, minimize count saturation problems, and to avoid high magnetic fields. These detectors include Si surface-barrier diodes, fission chambers, natural diamond detectors, and Tâ production in a moderated

D. L. Jassby; G. Ascione; H. W. Kugel; A. L. Roquemore; T. W. Barcelo; A. Kumar

1997-01-01

138

A high efficiency veto to increase the sensitivity of ZEPLIN-III, a WIMP detector  

SciTech Connect

An active veto detector to complement the ZEPLIN-III two phase Xenon, direct dark matter device is described. The proposed design consists of 52 plastic scintillator segments, individually read out by high efficiency photomultipliers, coupled to a Gd loaded passive polypropylene shield. Experimental work was performed to determine the plastic scintillator characteristics which were used to inform a complete end-to-end Monte Carlo simulation of the expected performance of the new instrument, both operating alone and as an active veto detector for ZEPLIN-III. The veto device will be capable of tagging over 65% of coincident nuclear recoil events in the energy range of interest in ZEPLIN-III, and over 12% for gamma ray rejection, while contributing no significant additional background. In addition it will also provide valuable diagnostic capabilities. The inclusion of the veto to ZEPLIN-III will aid to significantly improve the sensitivity to spin independent WIMP-nucleon cross sections below 10{sup -8} pb.

Barnes, E. J. [School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom)

2009-09-08

139

Intercomparison of a correlated-photon-based method to measure detector quantum efficiency  

NASA Astrophysics Data System (ADS)

We report on the absolute calibration of photodetector quantum efficiency by using correlated photon sources, performed independently at two laboratories, the National Institute of Standards and Technology and the Istituto Elettrotecnico Nazionale (IEN). The goal is to use an interlaboratory comparison to demonstrate the inherent absoluteness of the photon correlation technique by showing its independence from the particular experimental setup. We find that detector nonuniformity limited this comparison rather than uncertainty inherent in the method itself. The ultimate goal of these investigations is development of a robust measurement protocol that allows the uncertainties of individual measurements to be determined experimentally and verified operationally. Furthermore, to demonstrate the generality of the procedure, the IEN measurement setup was also used to calibrate a fiber-coupled avalanche photodiode module. Uncertainties are evaluated for the detector both with and without fiber coupling and differences are discussed. The current IEN setup using a thinner and higher transmittance nonlinear crystal for the generation of correlated photons shows a significant improvement in overall accuracy with respect to previously reported results from IEN [Metrologia 32, 501-503 (1996)].

Migdall, Alan; Castelletto, Stefania; Degiovanni, Ivo Pietro; Rastello, Maria Luisa

2002-05-01

140

Efficient waveguide-integrated tunnel junction detectors at 1.6 mum.  

PubMed

Near-infrared detectors based on metal-insulator-metal tunnel junctions integrated with planarized silicon nanowire waveguides are presented, which we believe to be the first of their kind. The junction is coupled to the waveguide via a thin-film metal antenna feeding a plasmonic travelling wave structure that includes the tunnel junction. These devices are inherently broadband; the design presented here operates throughout the 1500-1700 nm region. Careful design of the antenna and travelling wave region substantially eliminates losses due to poor mode matching and RC rolloff, allowing efficient operation. The antennas are made from multilayer stacks of gold and nickel, and the active devices are Ni-NiO-Ni edge junctions. The waveguides are made via shallow trench isolation technology, resulting in a planar oxide surface with the waveguides buried a few nanometres beneath.The antennas are fabricated using directional deposition through a suspended Ge shadow mask, using a single level of electron-beam lithography. The waveguides are patterned with conventional 248-nm optical lithography and reactive-ion etching, then planarized using shallow-trench isolation technology. We also present measurements showing overall quantum efficiencies of 6% (responsivity 0.08 A/W at 1.605 mum), thus demonstrating that the previously very low overall quantum efficiencies reported for antenna-coupled tunnel junction devices are due to poor electromagnetic coupling and poor choices of antenna metal, not to any inherent limitations of the technology. PMID:19550928

Hobbs, Philip C D; Laibowitz, Robert B; Libsch, Frank R; Labianca, Nancy C; Chiniwalla, Punit P

2007-12-10

141

Characterization and Efficiency of the Versatile Array of Neutron Detectors at Low Energy (VANDLE)  

NASA Astrophysics Data System (ADS)

The Versatile Array of Neutron Detectors at Low Energy (VANDLE) is a new array of plastic scintillator bars being developed at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL). The modular design enables optimization of different configurations for particular experiments, such as (d,n) and beta-delayed neutron-decay experiments, with rare ion beams. Twenty prototype modules, of two different sizes, have been put together and characterized for dynamic range and scintillator attenuation. Proof-of-principle experiments have been performed for both beta-delayed neutron-decay and (d,n) reactions. In addition, we plan to measure the absolute efficiency of a few modules using a calibrated ^27Al(d,n) reaction at the Edwards Accelerator Laboratory at Ohio University. We also have access to a sealed ^252Cf source to measure relative efficiencies and for use with experiment setup design. Results from the characterization and efficiency tests of the modules and preliminary results from the proof-of-principle experiments will be presented.

Peters, William; Matei, C.; Spassova, I.; Bardayan, D. W.; Blackmon, J. C.; Cizewski, J. A.; O'Malley, P. D.; Manning, B.; Merino, E.; Massey, T.; Brune, C.; Grzywacz, R. K.; Maduga, M.; Paulauskas, S.; Sarazin, F.; Raiola, F.; Walter, D.

2010-11-01

142

Photo detector IC for Blu-ray-Disc applications: a realization applying efficient design methodologies  

NASA Astrophysics Data System (ADS)

A high-speed photo detector IC for application in Blu-ray/DVD/CD drives is presented. Bandwidths for the highest gain of 254 MHz and 221 MHz for 405 nm (Blu-ray) and 635 nm (DVD) wavelengths, respectively, were achieved by applying novel design methodologies. The combination of this outstanding speed performance with its low power dissipation of 192 mW at 5V supply and the low noise power of -72 dBm at 300 MHz makes it the best in literature reported optical transceiver IC for Blu-ray and Blu-ray/DVD/CD multi drives. Beside the excellent performance results, the usage of the novel design methodologies gave us an increased design efficiency with 25% compared to earlier similar design processes.

Lange, S.; Reich, T.; Nowak, J.; Dimov, B.; Meister, M.; Hennig, E.

2011-08-01

143

Low efficiency 2-dimensional position-sensitive neutron detector for beam profile measurement  

NASA Astrophysics Data System (ADS)

A gas-filled position-sensitive wire detector has been developed for monitoring thermal neutron beams with flux up to 10 7 n/cm 2/s over an area ?80 cm 2. It is filled with CF 4(4 atm) and a small quantity of 3He, has 1.2 mm spatial resolution, 0.1% efficiency (at 0.18 nm) and can achieve a count rate of 350 kHz. Experiments at the 30 MW HANARO reactor showed that the fabricated PSD is a very useful and convenient tool for adjusting neutron monochromators, especially focusing monochromators, and for monitoring monochromatic beams. It can be used for various neutron optics experiments.

Moon, Myung-Kook; Nam, Uk-Won; Lee, Chang-Hee; Em, V. T.; Choi, Young-Hyun; Cheon, Jong-Kyu; Kong, Kyung-Nam

2005-02-01

144

Measurement of the Charge Collection Efficiency After Heavy Non-Uniform Irradiation in BABAR Silicon Detectors  

SciTech Connect

We have investigated the depletion voltage changes, leakage current increase and charge collection efficiency of a silicon microstrip detector identical to those used in the inner layers of the BABAR Silicon Vertex Tracker (SVT) after heavy nonuniform irradiation. A full SVT module with the front-end electronics connected has been irradiated with a 0.9 GeV electron beam up to a peak fluence of 3.5 x 10{sup 14} e{sup -}/cm{sup 2}, well beyond the level causing substrate type inversion. We have irradiated the silicon with a nonuniform profile having {sigma} = 1.4 mm that simulates the conditions encountered in the BABAR experiment by the modules intersecting the horizontal machine plane. The position dependence of the charge collection properties and the depletion voltage have been investigated in detail using a 1060 nm LED and an innovative measuring technique based only on the digital output of the chip.

Bettarini, S.; Bondioli, M.; Calderini, G.; Forti, F.; Marchiori, G.; Rizzo, G.; Giorgi, M.A.; /INFN, Pisa /Pisa U. /SLAC; Bosisio, L.; Dittongo, S.; /INFN, Trieste; Campagnari, C.; /UC, Santa Barbara

2006-03-01

145

Three-dimensional diamond detectors: Charge collection efficiency of graphitic electrodes  

NASA Astrophysics Data System (ADS)

Implementation of 3D-architectures in diamond detectors promises to achieve unreached performances in the radiation-harsh environment of future high-energy physics experiments. This work reports on the collection efficiency under ?-irradiation of graphitic 3D-electrodes, created by laser pulses in the domains of nanoseconds (ns-made-sensors) and femtoseconds (fs-made-sensors). Full collection is achieved with the fs-made-sensors, while a loss of 25%-30% is found for the ns-made-sensors. The peculiar behaviour of ns-made sensors has been explained by the presence of a nano-structured sp3-carbon layer around the graphitic electrodes, evidenced by micro-Raman imaging, by means of a numerical model of the charge transport near the electrodes.

Lagomarsino, S.; Bellini, M.; Corsi, C.; Gorelli, F.; Parrini, G.; Santoro, M.; Sciortino, S.

2013-12-01

146

HAND-HELD GAMMA-RAY SPECTROMETER BASED ON HIGH-EFFICIENCY FRISCH-RING CdZnTe DETECTORS.  

SciTech Connect

Frisch-ring CdZnTe detectors have demonstrated good energy resolution, el% FWHM at 662 keV, and good efficiency for detecting gamma rays. This technique facilitates the application of CdZnTe materials for high efficiency gamma-ray detection. A hand-held gamma-ray spectrometer based on Frisch-ring detectors is being designed at Brookhaven National Laboratory. It employs an 8x8 CdZnTe detector array to achieve a high volume of 19.2 cm3, so that detection efficiency is significantly improved. By using the front-end ASICs developed at BNL, this spectrometer has a small profile and high energy resolution. The spectrometer includes signal processing circuit, digitization and storage circuit, high-voltage module, and USB interface. In this paper, we introduce the details of the system structure and report our test results with it.

CUI,Y.

2007-05-01

147

Absolute detection efficiencies of a microchannel plate detector for 0.5-5 keV neutrals  

NASA Astrophysics Data System (ADS)

The absolute detection efficiencies of a microchannel plate detector for neutral atoms were measured using the coincidence method for neutralized incident ions and ionized target atoms in electron capture collisions. This method does not require knowledge of the absolute electron-capture rates for determination of the detection efficiencies. Results for Ne, Ar, and Kr atoms at energies of 0.5-5 keV are reported. The detection efficiencies for all atomic species increase concomitantly with increasing impact energy and plateau at the efficiency of about 50%. For low impact energies, the efficiency decreases with increasing mass of the impact atom at a given energy.

Hosokawa, S.; Takahashi, N.; Saito, M.; Haruyama, Y.

2010-06-01

148

ELENA MCP detector: absolute efficiency measurement for low energy neutral atoms  

NASA Astrophysics Data System (ADS)

MicroChannel plates (MCP) detectors are frequently used in space instrumentation for detecting a wide range of radiation and particles. In particular, the capability to detect non-thermal low energy neutral species is crucial for the sensor ELENA (Emitted Low-Energy Neutral Atoms), part of the package SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) on board the BepiColombo mission to Mercury to be launched in 2014. ELENA is a TOF sensor, based on a novel concept ultra-sonic oscillating shutter (Start section)which is operated at frequencies up to 50 kHz; a MCP detector is used as a Stop section. It is aimed to detect neutral atoms in the range 10 eV - 5 keV, within 70° FOV, perpendicular to the S/C orbital plane. ELENA will monitor the emission of neutral atoms from the whole surface of Mercury thanks to the spacecraft motion. The major scientific objectives are the interaction between the environment and the planet, the global particle loss-rate and the remote sensing of the surface properties. In particular, surface release processes are investigated by identifying particles release from the surface, via solar wind-induced ion sputtering (<1eV and >100 eV) as well as Hydrogen back-scattered at hundreds eV. MCP absolute detection efficiency for very low energy neutral atoms (E< 30eV) is a crucial point not yet investigated. At the MEFISTO facility of the Physical Institute of University of Bern (CH), measurements on three different type of MCPs coating have been performed providing the behaviors of MCP detection efficiency in the range 10eV-1keV. Outcomes from such measurements are here discussed.

Rispoli, R.; De Angelis, E.; Colasanti, L.; Vertolli, N.; Orsini, S.; Scheer, J.; Mura, A.; Milillo, A.; Wurz, P.; Selci, S.; Di Lellis, A. M.; Leoni, R.; D'Alessandro, M.; Mattioli, F.; Cibella, S.

2012-04-01

149

GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra  

SciTech Connect

The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.

Winn, W.G.

1999-07-28

150

High efficiency microfluidic beta detector for pharmacokinetic studies in small animals  

NASA Astrophysics Data System (ADS)

New radiotracers are continuously being developed to improve diagnostic efficiency using Single Photon Emission Computed Tomography (SPECT) or Positron Emission Tomography (PET). The characterization of their pharmacokinetics requires blood radioactivity monitoring over time during the scan and is very challenging in small animals because of the low volume of blood available. In this work, a prototype microfluidic blood counter made of a microchannel atop a silicon substrate containing PIN photodiodes is proposed to improve beta detection efficiency in a small volume by eliminating unnecessary interfaces between fluid and detector. A flat rectangular-shaped epoxy channel, 36 ?m×1.26 mm cross section and 31.5 mm in length, was microfabricated over a die containing an array of 2×2 mm 2 PIN photodiodes, leaving only a few micrometers of epoxy floor layer between the fluid and the photodiode sensitive surface. This geometry leads to a quasi 2D source, optimizing geometrical detection efficiency that was estimated at 41% using solid angle calculation. CV- IV measurements were made at each fabrication step to confirm that the microchannel components had no significant effects on the diodes' electrical characteristics. The chip was wire-bonded to a PCB and connected to charge sensitive preamplifier and amplifier modules for pulse shaping. Energy spectra recorded for different isotopes showed continuous beta distribution for PET isotopes and monoenergetic conversion electron peaks for 99mTc. Absolute sensitivity was determined for the most popular PET and SPECT radioisotopes and ranged from 26% to 33% for PET tracers ( 18F, 13N, 11C, 68Ga) and more than 2% for 99mTc. Input functions were successfully simulated with 18F, confirming the setup's suitability for pharmacokinetic modeling of PET and SPECT radiotracers in animal experiments. By using standard materials and procedures, the fabrication process is well suited to on-chip microfluidic functionality, allowing full characterization of new radiotracers.

Convert, Laurence; Girard-Baril, Frédérique; Renaudin, Alan; Grondin, Étienne; Jaouad, Abdelatif; Aimez, Vincent; Charette, Paul; Lecomte, Roger

2011-10-01

151

Efficient Bell state analyzer for time-bin qubits with fast-recovery WSi superconducting single photon detectors.  

PubMed

We experimentally demonstrate a high-efficiency Bell state measurement for time-bin qubits that employs two superconducting nanowire single-photon detectors with short dead-times, allowing projections onto two Bell states, |?-? and |?+?. Compared to previous implementations for time-bin qubits, this yields an increase in the efficiency of Bell state analysis by a factor of thirty. PMID:25322025

Valivarthi, R; Lucio-Martinez, I; Rubenok, A; Chan, P; Marsili, F; Verma, V B; Shaw, M D; Stern, J A; Slater, J A; Oblak, D; Nam, S W; Tittel, W

2014-10-01

152

Self-powered micro-structured solid state neutron detector with very low leakage current and high efficiency  

E-print Network

Self-powered micro-structured solid state neutron detector with very low leakage current and high efficiency R. Dahal,1,2 K. C. Huang,1 J. Clinton,2 N. LiCausi,1 J.-Q. Lu,1 Y. Danon,2,a) and I. Bhat1,b) 1 to 5 Ã? 5 mm2 . A thermal neutron detection efficiency of 4.5% 6 0.5% with discrimination setting of 500

Danon, Yaron

153

Charge collection efficiency and space charge formation in CdTe gamma and X-ray detectors  

Microsoft Academic Search

A new extended model for the charge collection efficiency in CdTe gamma and X ray detectors is presented which allows to derive from apparent experimental gamma spectra of a quasi-monochromatic source, an 241Am source in the present case, not only the ?? products of electrons and holes individually but also the sign, spatial distribution, and temporal evolution of the net

R Matz; M Weidner

1998-01-01

154

Development of a New Method for Measurement of Neutron Detector Efficiency up to 20 MeV  

NASA Astrophysics Data System (ADS)

A new approach to neutron detector efficiency detemination has been taken. A neutron detector has been calibrated with a 252Cf source at low energy. The calibration can be extended to energies above 8 MeV with accelerator-based neutron sources. This techniques uses the fact that the cross section for a symmetric reaction with nucleus of atomic number A yielding a final nucleus with atomic number (2A-1) and a neutron A+A?(2A-1)+n. This reaction must be symmetric about 90? in the center-of-mass system. The laboratory energies for the neutrons at the paired energies differ substantially. Thus, an efficiency known at one of the two angles can be used to determine the efficiency to higher energies or, for a negative Q, to lower neutron energies.

Kornilov, N. V.; Grimes, S. M.; Massey, T. N.; Brient, C. E.; Carter, D. E.; O'Donnell, J. E.; Bateman, F. B.; Carlson, A. D.; Haight, R. C.; Boukharouba, N.

2014-05-01

155

High quantum efficiency megavoltage imaging with thick scintillator detectors for image guided radiation therapy  

NASA Astrophysics Data System (ADS)

In image guided radiation therapy (IGRT), imaging devices serve as guidance systems to aid patient set-up and tumor volume localization. Traditionally, 2-D megavoltage x-ray imagers, referred to as electronic portal imaging devices (EPIDs), have been used for planar target localization, and have recently been extended to perform 3-D volumetric reconstruction via cone-beam computed tomography (CBCT). However, current EPIDs utilize thin and inefficient phosphor screen detectors and are subsequently limited by poor soft tissue visualization, which limits their use for CBCT. Therefore, the use of thick scintillation media as megavoltage x-ray detectors for greater x-ray sensitivity and enhanced image quality has recently been of significant interest. In this research, two candidates for thick scintillators: CsI(Tl) and terbium doped scintillation glass were investigated in separate imaging configurations. In the first configuration, a thick scintillation crystal (TSC) consisting of a thick, monolithic slab of CsI(Tl) was coupled to a mirror-lens-camera system. The second configuration is based on a fiber-optic scintillation glass array (FOSGA), wherein the scintillation glass is drawn into long fiber-optic conduits, inserted into a grid-type housing constructed out of polymer-tungsten alloy, and coupled to an array of photodiodes for digital read-out. The imaging prototypes were characterized using theoretical studies and imaging measurements to obtain fundamental metrics of imaging performance. Spatial resolution was measured based on a modulation transfer function (MTF), noise was evaluated in terms of a noise power spectrum (NPS), and overall contrast was characterized in the form of detective quantum efficiency (DQE). The imaging studies were used to optimize the TSC and FOSGA imagers and propose prototype configurations for order-of-magnitude improvements in overall image quality. In addition, a fast and simple technique was developed to measure the MTF, NPS, and DQE metrics for clinical EPID and CBCT systems based on a novel adaptation of a traditional line-pair resolution bar-pattern. This research provides two significant benefits to radiotherapy: the characterization of a new generation of thick scintillator based megavoltage x-ray imagers for CBCT based IGRT, and the novel adaptation of fundamental imaging metrics from imaging research to routine clinical performance monitoring.

Gopal, Arun

156

The feasibility of using a photoelectric cigarette smoke detector for energy-efficient air quality control  

Microsoft Academic Search

The object of this study was to determine the feasibility of using a smoke sensor to monitor and control cigarette smoke levels in occupied spaces and also to determine whether the use of such a detector could result in energy savings. A smoke detector was built and tested. The experimental results show that the smoke sensor output is a function

R. M. Nelson; L. E. Alevantis

1985-01-01

157

Analytical approach to calculate the efficiency of 4? NaI(Tl) gamma-ray detectors for extended sources  

NASA Astrophysics Data System (ADS)

The 4? NaI(Tl) detectors are usually utilized for low-level radioactivity measurements of environmental samples in gamma-ray spectroscopy due to the near 4? solid angle and high full-energy peak and total efficiencies. An analytical theoretical approach is presented here and used to calibrate a 4 ? NaI(Tl) (2 a×2 b× 2c) detector, with a central rectangle hole (2 l×2 m×2 c) was left empty for sample access, for isotropic radiating (point, plane and volumetric) sources. The approach depends on the accurate calculation of two important factors; the path length d, the photon traverses within the active volume of a gamma detector, and the geometrical solid angle ?, subtended by the source to the detector at the point of entrance. The comparisons with the experimental and Monte Carlo method works reported in the literature indicate that the present approach is useful in the efficiency calibration of such complicated gamma-ray spectrometer.

Abbas, Mahmoud I.

2010-03-01

158

Multimode fiber-coupled superconducting nanowire single-photon detector with 70% system efficiency at visible wavelength.  

PubMed

We report the development of the multimode fiber-coupled superconducting nanowire single-photon detector with high system detection efficiency at visible wavelength. The detector consists of a 10.5-nm-thick and 150-nm-wide NbN nanowire meander fabricated on a Si substrate with a multilayer dielectric mirror and a quarter wavelength cavity for obtaining high optical absorptance. The meander area was 35 µm in diameter and coupled with the GRIN-lensed multimode optical fiber with a core diameter of 50 µm. The system reached detection efficiency of 70% with dark count rate of 100 Hz at the wavelength of 635 nm, 3 dB roll-off response counting rate of 8.5 Mcps, and timing jitter of 76 ps. PMID:25321497

Liu, Dengkuan; Miki, Shigehito; Yamashita, Taro; You, Lixing; Wang, Zhen; Terai, Hirotaka

2014-09-01

159

Self-powered micro-structured solid state neutron detector with very low leakage current and high efficiency  

SciTech Connect

We report on the design, fabrication, and performance of solid-state neutron detector based on three-dimensional honeycomb-like silicon micro-structures. The fabricated detectors use boron filled deep holes with aspect ratio of over 12 and showed a very low leakage current density of {approx}7 Multiplication-Sign 10{sup -7} A/cm{sup 2} at -1 V for device sizes varying from 2 Multiplication-Sign 2 to 5 Multiplication-Sign 5 mm{sup 2}. A thermal neutron detection efficiency of 4.5% {+-} 0.5% with discrimination setting of 500 keV and gamma to neutron sensitivity of (1.1 {+-} 0.1) Multiplication-Sign 10{sup -5} for single layer was measured without external bias for these devices. Monte-Carlo simulation predicts a maximum efficiency of 45% for such devices filled with 95% enriched {sup 10}boron.

Dahal, R. [Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Huang, K. C.; LiCausi, N.; Lu, J.-Q.; Bhat, I. [Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Clinton, J.; Danon, Y. [Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2012-06-11

160

Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton-proton collision data  

E-print Network

The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton-proton collision data collected in 2011 at $\\sqrt{s}$ = 7 TeV and corresponding to an integrated luminosity of 4.7 fb$^{-1}$. Tag-and-probe methods using events with leptonic decays of $W$ and $Z$ bosons and $J/\\psi$ mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil level for electron transverse energy greater than 30 GeV.

Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Agatonovic-Jovin, Tatjana; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Ahlen, Steven; Ahmad, Ashfaq; Ahmadov, Faig; Aielli, Giulio; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Alimonti, Gianluca; Alio, Lion; Alison, John; Allbrooke, Benedict; Allison, Lee John; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amaral Coutinho, Yara; Amelung, Christoph; Amidei, Dante; Ammosov, Vladimir; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amram, Nir; Amundsen, Glenn; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Anduaga, Xabier; Angelidakis, Stylianos; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Araque, Juan Pedro; Arce, Ayana; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arslan, Ozan; Artamonov, Andrei; Artoni, Giacomo; Asai, Shoji; Asbah, Nedaa; Ashkenazi, Adi; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Atkinson, Markus; Atlay, Naim Bora; Auerbach, Benjamin; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Azuelos, Georges; Azuma, Yuya; Baak, Max; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Backus Mayes, John; Badescu, Elisabeta; Bagiacchi, Paolo; Bagnaia, Paolo; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Sarah; Balek, Petr; Balli, Fabrice; Banas, Elzbieta; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bannoura, Arwa A E; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Barnovska, Zuzana; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Bartoldus, Rainer; Barton, Adam Edward; Bartos, Pavol; Bartsch, Valeria; Bassalat, Ahmed; Basye, Austin; Bates, Richard; Batkova, Lucia; Batley, Richard; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becot, Cyril; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Beermann, Thomas; Begel, Michael; Behr, Katharina; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belloni, Alberto; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernard, Clare; Bernat, Pauline; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Berta, Peter; Bertella, Claudia; Bertolucci, Federico; Besana, Maria Ilaria; Besjes, Geert-Jan; Bessidskaia, Olga; Besson, Nathalie; Betancourt, Christopher; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilbao De Mendizabal, Javier; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Black, Curtis

2014-01-01

161

Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton-proton collision data  

NASA Astrophysics Data System (ADS)

Many of the interesting physics processes to be measured at the LHC have a signature involving one or more isolated electrons. The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton-proton collision data collected in 2011 at TeV and corresponding to an integrated luminosity of 4.7 fb. Tag-and-probe methods using events with leptonic decays of and bosons and mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil level for electron transverse energy greater than 30 GeV.

Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Khalek, S. Abdel; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmad, A.; Ahmadov, F.; Aielli, G.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Gonzalez, B. Alvarez; Alviggi, M. G.; Amako, K.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Ammosov, V. V.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Bella, L. Aperio; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Mayes, J. Backus; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Balek, P.; Balli, F.; Banas, E.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bannoura, A. A. E.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Costa, J. Barreiro Guimarães da; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bartsch, V.; Bassalat, A.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Garcia, J. A. Benitez; Benjamin, D. P.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Kuutmann, E. Bergeaas; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernard, C.; Bernat, P.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Bessidskaia, O.; Besson, N.; Betancourt, C.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; De Mendizabal, J. Bilbao; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boek, T. T.; Bogaerts, J. A.; Bogdanchikov, A. G.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borri, M.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Brendlinger, K.; Brennan, A. J.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, G.; Brown, J.; Renstrom, P. A. Bruckman de; Bruncko, D.

2014-07-01

162

Detective quantum efficiency of direct flat-panel x-ray imaging detectors for fluoroscopy  

Microsoft Academic Search

Our goal is to develop a large area, flat panel solid-state detector for fluoroscopy. The detector employs a layer of photoconductor to convert incident x-rays directly to a charge image, which is then read out in real-time using a two dimensional array of thin film transistors (TFTs), or 'active matrix.' In order to guide the design of an optimum fluoroscopic

Dylan C. Hunt; Wei Zhao; John A. Rowlands

1998-01-01

163

High efficiency and rapid response superconducting NbN nanowire single photon detector based on asymmetric split ring metamaterial  

NASA Astrophysics Data System (ADS)

With asymmetric split ring metamaterial periodically placed on top of the niobium nitride (NbN) nanowire meander, we theoretically propose a kind of metal-insulator-metallic metamaterial nanocavity to enhance absorbing efficiency and shorten response time of the superconducting NbN nanowire single photon detector (SNSPD) operating at wavelength of 1550 nm. Up to 99.6% of the energy is absorbed and 96.5% dissipated in the nanowire. Meanwhile, taking advantage of this high efficiency absorbing cavity, we implement a more sparse arrangement of the NbN nanowire of the filling factor 0.2, which significantly lessens the nanowire and crucially boosts the response time to be only 40% of reset time in previous evenly spaced meander design. Together with trapped mode resonance, a standing wave oscillation mechanism is presented to explain the high efficiency and broad bandwidth properties. To further demonstrate the advantages of the nanocavity, a four-pixel SNSPD on 10 ?m × 10 ?m area is designed to further reduce 75% reset time while maintaining 70% absorbing efficiency. Utilizing the asymmetric split ring metamaterial, we show a higher efficiency and more rapid response SNSPD configuration to contribute to the development of single photon detectors.

Li, Guanhai; Wang, Shao-Wei; Chen, Xiaoshuang; Lu, Wei

2014-06-01

164

A detector module with highly efficient surface-alpha event rejection operated in CRESST-II Phase 2  

E-print Network

The cryogenic dark matter experiment CRESST-II aims at the direct detection of WIMPs via elastic scattering off nuclei in scintillating CaWO$_4$ crystals. We present a new, highly improved, detector design installed in the current run of CRESST-II Phase 2 with an efficient active rejection of surface-alpha backgrounds. Using CaWO$_4$ sticks to hold the target crystal a detector housing with fully-scintillating inner surface could be realized. The presented detector (TUM40) provides an excellent threshold of ${\\sim}\\,0.60\\,$keV and a resolution of $\\sigma\\,{\\approx}\\,0.090\\,$keV (at 2.60$\\,$keV). With significantly reduced background levels, TUM40 sets stringent limits on the spin-independent WIMP-nucleon scattering cross section and probes a new region of parameter space for WIMP masses below 3$\\,$GeV/c$^2$. In this paper, we discuss the novel detector design and the surface-alpha event rejection in detail.

Strauss, R; Bento, A; Bucci, C; Canonica, L; Erb, A; Feilitzsch, F v; Ferreiro, N; Gorla, P; Gütlein, A; Hauff, D; Jochum, J; Kiefer, M; Kluck, H; Kraus, H; Lanfranchi, J -C; Loebell, J; Münster, A; Petricca, F; Potzel, W; Pröbst, F; Reindl, F; Roth, S; Rottler, K; Sailer, C; Schäffner, K; Schieck, J; Scholl, S; Schönert, S; Seidel, W; Sivers, M v; Stanger, M; Stodolsky, L; Strandhagen, C; Tanzke, A; Uffinger, M; Ulrich, A; Usherov, I; Wawoczny, S; Willers, M; Wüstrich, M; Zöller, A

2014-01-01

165

ANGLE v2.1—New version of the computer code for semiconductor detector gamma-efficiency calculations  

NASA Astrophysics Data System (ADS)

New version of the commercially available ANGLE software for semiconductor detector gamma-efficiency calculations is presented. ANGLE allows for accurate determination of the activities of gamma spectroscopic samples for which no "replicate" standard exists, in terms of geometry and matrix. A semi-empirical ("efficiency transfer") approach is applied, based on the effective solid angle calculations. Advantages of both absolute (Monte Carlo) and relative (calibrated-source-based) methods are combined—while minimizing potential for systematic errors in the former and reducing practical limitations of the latter. ANGLE is broadly applicable, accounting for most of counting arrangements in gamma-spectrometry practice (in respect to detector types and configuration, source shapes and volumes, matrix composition, source-to-detector distance, etc.). Besides the years of practical utilization in many gamma-spectrometry laboratories, accuracy of the software is successfully tested in a recent IAEA-organized intercomparison exercise—ANGLE scored 0.65% average deviation from the exercise mean for E ?>20keV energies.

Jovanovic, S.; Dlabac, A.; Mihaljevic, N.

2010-10-01

166

High detection efficiency micro-structured solid-state neutron detector with extremely low leakage current fabricated with continuous p-n junction  

E-print Network

High detection efficiency micro-structured solid-state neutron detector with extremely low leakage pressure chemical vapor deposition for solid-state thermal neutron detection applications. Optimized filled honeycomb structured neutron detector with a continuous pþ -n junction. The neutron detection

Danon, Yaron

167

Towards high efficiency solid-state thermal and fast neutron detectors This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-print Network

of applications of fast neutron detection utilize thermal neutron detectors and moderators. Examples include in the development of solid-state neutron detectors. These operate by detection of charged particles emitted from neutron interactions with a converter material. In order to increase neutron detection efficiency

Danon, Yaron

168

Free-running InGaAs single photon detector with 1 dark count per second at 10% efficiency  

NASA Astrophysics Data System (ADS)

We present a free-running single photon detector for telecom wavelengths based on a negative feedback avalanche photodiode (NFAD). A dark count rate as low as 1 cps was obtained at a detection efficiency of 10%, with an afterpulse probability of 2.2% for 20 ?s of deadtime. This was achieved by using an active hold-off circuit and cooling the NFAD with a free-piston stirling cooler down to temperatures of -110 °C. We integrated two detectors into a practical, 625 MHz clocked quantum key distribution system. Stable, real-time key distribution in the presence of 30 dB channel loss was possible, yielding a secret key rate of 350 bps.

Korzh, B.; Walenta, N.; Lunghi, T.; Gisin, N.; Zbinden, H.

2014-02-01

169

Effect of an aerosol deposition pattern in the lung on the counting efficiency of a large area germanium detector array.  

PubMed

The Human Monitoring Laboratory has extended the use of sliced lungs containing planar sources to simulate heterogeneous radionuclide deposition patterns. This work examined two deposition patterns and their effect on the counting efficiency of low-energy photons. The results have shown that heterogenous distributions can be difficult to detect in some cases and can still lead to large uncertainties (up to a factor of 2.5) in the activity estimate, especially at low photon energies. At higher energies ( approximately 60 keV), the effect of the heterogeneous distribution is greatly reduced and errors in the activity estimate reduced to approximately 25%. The presence of a heterogenous distribution can be detected by comparing the ratio of the individual detector counts with the expected values obtained from measuring multiple lungs sets that contained a homogeneous distribution. The distributions tested in this paper were detectable (at 2sigma) as heterogeneous by two of the four detectors in the counting array. PMID:18003713

Kramer, Gary H; Hauck, Barry M

2008-01-01

170

Monte Carlo simulation of the BEGe detector response function for in vivo measurements of 241Am in the skull  

NASA Astrophysics Data System (ADS)

This paper reports on the procedure of the BEGe detector characterization for the Monte Carlo calibrations. A project is under way to improve the counting and operating capabilities of the Whole Body Counter (WBC) installed in SÚRO, v.v.i. (NRPI) Prague, Czech Republic. Possible emergency monitoring should mainly benefit from the rapid, safe and flexible operation of the WBC. The system of the WBC for the detection of low energy X and gamma radiation comprises four HPGe detectors intended for the routine, emergency, and research measurements of persons internally contaminated with low-energy photon emitters, mainly actinides. Among them, 241Am is the main subject of interest. A precise detection efficiency calibration of the detector is required for the measurement of activity in individual organs and tissues. The use of physical phantoms in the calibrations is often supplemented with the application of voxel phantoms and a Monte Carlo technique that are used for the calculation of the detector response function and the full energy peak efficiency. Both experimental and computational approaches have been used for the calibration of the BEGe (Broad Energy Germanium) detector. In this paper, the process of the Monte Carlo simulation of the detector response function and the peak efficiency calculation is described. Results of the simulations are provided in the paper and discussed.

Fantínová, K.; Fojtík, P.

2014-11-01

171

A new design for a high resolution, high efficiency CZT gamma camera detector  

Microsoft Academic Search

We have designed a CZT gamma camera detector that provides an array of CZT pixels and associated front-end electronics – including an ASIC – and permits gamma camera measurements using the method patented by CEA-LETI and reported by Verger et al. [1]. Electron response in each CZT pixel is registered by correcting pulse height for position of interaction based on

C. Mestais; N. Baffert; J. P. Bonnefoy; A. Chapuis; A. Koenig; O. Monnet; P. Ouvrier Buffet; J. P. Rostaing; F. Sauvage; L. Verger

2001-01-01

172

High resolution energy dispersive spectroscopy with high purity germanium detectors and digital pulse processing  

Microsoft Academic Search

Energy dispersive spectroscopy (EDS) has traditionally been performed with analytical instrumentation systems comprised of cryogenically cooled lithium-drifted silicon (Si(Li)) X-ray spectrometers and analog amplification electronics. Improved X-ray microanalysis systems have been developed and are commercially available that utilize high purity germanium (HPGe) detectors and digital pulse processing. HPGe offers several distinct advantages over lithium-drifted silicon for the detection and quantitative

Sarah A. Audet; John J. Friel; Thomas P. Gagliardi; Richard B. Mott; J. I. Patel; Charles G. Waldman

1994-01-01

173

Status and Performance of an AGATA asymmetric detector  

SciTech Connect

High-resolution gamma-ray detectors based on high-purity germanium crystals (HPGe) are one of the key workhorses of experimental nuclear science. The technical development of such detector technology has been dramatic in recent years. Large volume, high-granularity, electrically segmented HPGe detectors have been realised and a methodology to improve position sensitivity using pulse-shape analysis coupled with the novel technique of gamma-ray tracking has been developed. Collaborations have been established in Europe (AGATA)[1] and the USA (GRETA/GRETINA)[2] to build gamma-ray tracking spectrometers. This paper discusses the performance of the first AGATA (Advanced GAmma Tracking Array) asymmetric detector that has been tested at the University of Liverpool. The use of a fully digital data acquisition system has allowed detector charge pulse shapes from a selection of well defined photon interaction positions to be analysed, yielding important information on the position sensitivity of the detector.

Boston, A. J.; Dimmock, M. R.; Unsworth, C.; Boston, H. C.; Cooper, R. J.; Grint, A. N.; Harkness, L. J.; Jones, M.; Nolan, P. J.; Oxley, D. C.; Slee, M. [Department of Physics, University of Liverpool, L69 7ZE (United Kingdom); Lazarus, I. H.; Simpson, J. [STFC Daresbury Laboratory, Daresbury, WA4 4AD (United Kingdom)

2009-03-31

174

Improving photon detector efficiency using a high-fidelity optical CNOT gate  

E-print Network

A significant problem for optical quantum computing is inefficient, or inaccurate photo-detectors. It is possible to use CNOT gates to improve a detector by making a large cat state then measuring every qubit in that state. In this paper we develop a code that compares five different schemes for making multiple measurements, some of which are capable of detecting loss and some of which are not. We explore how each of these schemes performs in the presence of different errors, and derive a formula to find at what probability of qubit loss is it worth detecting loss, and at what probability does this just lead to further errors than the loss introduces.

Katherine L Brown; Joshua H. Mendez Plaskus; Hanna E. Broadus; Jonathan P Dowling

2013-08-12

175

First demonstration of plasmonic GaN quantum cascade detectors with enhanced efficiency at normal incidence.  

PubMed

We have designed, fabricated and measured the first plasmon-assisted normal incidence GaN/AlN quantum cascade detector (QCD) making use of the surface plasmon resonance of a two-dimensional nanohole Au array integrated on top of the detector absorption region. The spectral response of the detector at room temperature is peaked at the plasmon resonance of 1.82 ?m. We show that the presence of the nanohole array induces an absolute enhancement of the responsivity by a factor of ~30 over that of the bare device at normal incidence and by a factor of 3 with respect to illumination by the 45° polished side facet. We show that this significant improvement arises from two phenomena, namely, the polarization rotation of the impinging light from tangential to normal induced by the plasmonic structure and from the enhancement of the absorption cross-section per quantum well due to the near-field optical intensity of the plasmonic wave. PMID:25321307

Pesach, Asaf; Sakr, Salam; Giraud, Etienne; Sorias, Ofir; Gal, Lior; Tchernycheva, Maria; Orenstein, Meir; Grandjean, Nicolas; Julien, Francois H; Bahir, Gad

2014-08-25

176

Enhanced quantum efficiency of high-purity silicon imaging detectors by ultralow temperature surface modification using Sb doping  

NASA Technical Reports Server (NTRS)

A low temperature process for Sb doping of silicon has been developed as a backsurface treatment for high-purity n-type imaging detectors. Molecular beam epitaxy (MBE) is used to achieve very high dopant incorporation in a thin, surface-confined layer. The growth temperature is kept below 450 (deg)C for compatibility with Al-metallized devices. Imaging with MBE-modified 1kx1k charge coupled devices (CCDs) operated in full depletion has been demonstrated. Dark current is comparable to the state-of-the-art process, which requires a high temperature step. Quantum efficiency is improved, especially in the UV, for thin doped layers placed closer to the backsurface. Near 100% internal quantum efficiency has been demonstrated in the ultraviolet for a CCD with a 1.5 nm silicon cap layer.

Blacksberg, Jordana; Hoenk, Michael E.; Elliott, S. Tom; Holland, Stephen E.; Nikzad, Shouleh

2005-01-01

177

Solar Panel Energetic Efficiency Optimization Method, based on an Specific Detector and Orientation Microsystem  

Microsoft Academic Search

The increase of the solar cells efficiency implies high technological and scientific efforts. A significant efficiency increase of the photovoltaic panels can be also obtained by optimal exposure of the panels to the sunlight, using automatic solar trackers. For wide scale use of these control systems, it is very important to find low cost and reliable solutions. In the current

O. Oltu; P. L. Milea; M. Dragulinescu; E. Franti

2007-01-01

178

Comparison of two methods for high purity germanium detector efficiency calibration for charcoal canister radon measurement.  

PubMed

The charcoal canister method of radon measurement according to US Environment Protection Agency protocol 520/5-87-005 is widely used for screening. This method is based on radon adsorption on coal and measurement of gamma radiation of radon daughters. For the purpose of gamma spectrometry, appropriate efficiency calibration of the measuring system must be performed. The most usual method of calibration is using standard canister, a sealed canister with the same matrix and geometry as the canisters used for measurements, but with the known activity of radon. In the absence of standard canister, a different method of efficiency calibration has to be implemented. This study presents the results of efficiency calibration using the EFFTRAN efficiency transfer software. Efficiency was calculated using a soil matrix cylindrical secondary reference material as a starting point. Calculated efficiency is then compared with the one obtained using standard canister and applied to a realistic measurement in order to evaluate the results of the efficiency transfer. PMID:25377751

Nikolic, J; Pantelic, G; Zivanovic, M; Rajacic, M; Todorovic, D

2014-11-01

179

Simulation study comparing high-purity germanium and cadmium zinc telluride detectors for breast imaging.  

PubMed

We conducted simulations to compare the potential imaging performance for breast cancer detection with High-Purity Germanium (HPGe) and Cadmium Zinc Telluride (CZT) systems with 1% and 3.8% energy resolution at 140?keV, respectively. Using the Monte Carlo N-Particle (MCNP5) simulation package, we modelled both 5?mm-thick CZT and 10?mm-thick HPGe detectors with the same parallel-hole collimator for the imaging of a breast/torso phantom. Simulated energy spectra were generated, and planar images were created for various energy windows around the 140?keV photopeak. Relative sensitivity and scatter and the torso fractions were calculated along with tumour contrast and signal-to-noise ratios (SNR). Simulations showed that utilizing a ±1.25% energy window with an HPGe system better suppressed torso background and small-angle scattered photons than a comparable CZT system using a -5%/+10% energy window. Both systems provided statistically similar contrast and SNR, with HPGe providing higher relative sensitivity. Lowering the counts of HPGe images to match CZT count density still yielded equivalent contrast between HPGe and CZT. Thus, an HPGe system may provide equivalent breast imaging capability at lower injected radioactivity levels when acquiring for equal imaging time. PMID:25360792

Campbell, D L; Peterson, T E

2014-11-21

180

Calibration Analyses and Efficiency Studies for the Anti Coincidence Detector on the Fermi Gamma Ray Space Telescope  

SciTech Connect

The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope provides charged particle rejection for the Large Area Telescope (LAT). We use two calibrations used by the ACD to conduct three studies on the performance of the ACD. We examine the trending of the calibrations to search for damage and find a timescale over which the calibrations can be considered reliable. We also calculated the number of photoelectrons counted by a PMT on the ACD from a normal proton. Third, we calculated the veto efficiencies of the ACD for two different veto settings. The trends of the calibrations exhibited no signs of damage, and indicated timescales of reliability for the calibrations of one to two years. The number of photoelectrons calculated ranged from 5 to 25. Large errors in the effect of the energy spectrum of the charged particles caused these values to have very large errors of around 60 percent. Finally, the veto efficiencies were found to be very high at both veto values, both for charged particles and for the lower energy backsplash spectrum. The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope is a detector system built around the silicon strip tracker on the Large Area Telescope (LAT). The purpose of the ACD is to provide charged particle rejection for the LAT. To do this, the ACD must be calibrated correctly in flight, and must be able to efficiently veto charged particle events while minimizing false vetoes due to 'backsplash' from photons in the calorimeter. There are eleven calibrations used by the ACD. In this paper, we discuss the use of two of these calibrations to preform three studies on the performance of the ACD. The first study examines trending of the calibrations to check for possible hardware degradation. The second study uses the calibrations to explore the efficiency of an on-board hardware veto. The third study uses the calibrations to calculate the number of photoelectrons seen by each PMT when a minimum ionizing particle is detected, which is a useful value for performing simulations.

Kachulis, Chris; /Yale U. /SLAC

2011-06-22

181

The neutron detection efficiency of NE213 detectors measured by means of a 252Cf source  

Microsoft Academic Search

The neutron detection efficiency of a NE213 scintillator was determined by comparing the measured neutron time-of-flight spectrum of a 252Cf source with its reference neutron energy distribution. Below En = 8 MeV an accuracy of better than 3% could be achieved. The measured efficiency agreed reasonably well in shape with a Monte Carlo simulation in the entire energy range 0.8

J. Cub; E. Finckh; K. Gebhardt; K. Geissdörfer; R. Lin; J. Strate; H. Klein

1989-01-01

182

Fast electron temperature and conversion efficiency measurements in laser-irradiated foil targets using a bremsstrahlung x-ray detector  

NASA Astrophysics Data System (ADS)

Measurements of fast electron temperature and conversion efficiencies using bremsstrahlung x-rays emitted from laser-produced, fast electrons are presented. Experiments were carried out using the Titan laser (150 J, 1.5 ps) at the Lawrence Livermore National Laboratory. The maximum intensity was 2 × 1020 W/cm2 on 250 ?m thick silver foil targets. The emission of bremsstrahlung x-rays from the fast electrons in the target was measured using a filter-stack based detector. The conversion efficiency of laser energy into fast electrons and the electron temperature were studied as a function of incident laser energy. Several models of the electron divergence angle were investigated, and the effect of the assumed divergence angle on the inferred conversion efficiency was quantified. This allows for upper and lower bounds on the conversion efficiency to be established for a range of possible divergence angles. The value for upper bound is 60% (from a 75° divergence angle model) and for the lower bound is 25% (from a 0° divergence angle model).

Westover, B.; Chen, C. D.; Patel, P. K.; Key, M. H.; McLean, H.; Stephens, R.; Beg, F. N.

2011-06-01

183

Fast electron temperature and conversion efficiency measurements in laser-irradiated foil targets using a bremsstrahlung x-ray detector  

SciTech Connect

Measurements of fast electron temperature and conversion efficiencies using bremsstrahlung x-rays emitted from laser-produced, fast electrons are presented. Experiments were carried out using the Titan laser (150 J, 1.5 ps) at the Lawrence Livermore National Laboratory. The maximum intensity was 2 x 10{sup 20} W/cm{sup 2} on 250 {mu}m thick silver foil targets. The emission of bremsstrahlung x-rays from the fast electrons in the target was measured using a filter-stack based detector. The conversion efficiency of laser energy into fast electrons and the electron temperature were studied as a function of incident laser energy. Several models of the electron divergence angle were investigated, and the effect of the assumed divergence angle on the inferred conversion efficiency was quantified. This allows for upper and lower bounds on the conversion efficiency to be established for a range of possible divergence angles. The value for upper bound is 60% (from a 75 deg. divergence angle model) and for the lower bound is 25% (from a 0 deg. divergence angle model).

Westover, B. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, 92093 (United States); Chen, C. D.; Patel, P. K.; Key, M. H.; McLean, H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Stephens, R. [General Atomics, San Diego, California 92186 (United States); Beg, F. N. [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, 92093 (United States)

2011-06-15

184

Spatial resolution and efficiency of microchannel plate detectors with neutron converter films  

NASA Astrophysics Data System (ADS)

An investigation into the potential neutron detection efficiency gains that could be made to microchannel plates (MCPs) has been conducted by a GEANT4 simulation. Thin-film neutron converters are coupled to the upstream-side of the MCP. MCPs with and without pre-existing neutron sensitivity were examined. A study into potential film materials favors a Gd2O3 converter film utilized in thin-film and pillar geometries for straight-channel MCPs. The objective was to increase thermal neutron detection efficiency without sacrificing the spatial resolution of the system by studying (1) the balance between capture efficiency and charged particle product production and range to optimize detection efficiency, and (2) the extent of radial straggling that the reaction products undergo as they are transmitted through the neutron converter and MCP, which affects spatial resolution. Our investigation reveals that an increase in efficiency of 9.9% can be achieved for an MCP without preexisting neutron sensitivity using a film geometry neutron converter of 4-?m thickness. An increase in efficiency of 4.3% can be achieved for a neutron-sensitive MCP using a pillar-type converter of 4-?m thickness. Degradation of spatial resolution is not significant for either film or pillar geometries with thicknesses in the range 0.5-10 ?m.

Cazalas, Edward; Trivelpiece, Cory; Jovanovic, Igor

2014-12-01

185

Low ? activity measurement of meteorites using HPGe-NaI detector system  

NASA Astrophysics Data System (ADS)

The radioactivity in natural samples like cosmogenic isotopes in meteorites, in Moon samples, in earth and ice in Antarctica, produced by protons, neutrons, ? mesons and other charged particles, is very low, usually below 0.001 disintegration per minute per gram. Therefore, very special techniques are required, particularly if the sample cannot be destroyed for chemical separation and system must have possibility of counting large amount of sample. For this purpose we have developed a highly selective Ge-NaI coincidence spectrometer, operating in the underground Laboratory of Monte dei Cappuccini (INAF) in Torino. We have then improved it by developing a multiparametric acquisition system, which allows better selectivity of the coincidence windows (e.g., in meteorites, to disentangle cosmogenic 44Ti signal from overlapping 214Bi, originated by naturally occurring 238U). Applications of this system to the study of meteorites (chondrite, achondrite and iron samples) are described.

Colombetti, P.; Taricco, C.; Bhandari, N.; Sinha, N.; Di Martino, M.; Cora, A.; Vivaldo, G.

2013-08-01

186

Standoff Performance of HPGe Detectors in Identification of Gamma-Ray Radiation Sources  

Microsoft Academic Search

The detection and identification of radiation sources at distances in the range of 15 meters or more is becoming increasingly important for illicit materials interdiction and the location of lost or orphan sources. In most locations, there is a considerable gamma-ray flux from natural background (NORM) and cosmic- induced nuclides. This gamma-ray flux varies with time, weather conditions, location, and

Ronald M. Keyser; Timothy R. Twomey; Sam Hitch

187

Mapping radionuclide distribution in surface sediments using GIS and an underwater HPGe detector  

Microsoft Academic Search

A radiological distribution survey at the L Lake on the Savannah River Site (SRS) was conducted by the Savannah River Technology Center (SRTC) during the summer of 1995 as part of a larger project to examine future alternatives for L Lake and other SRS water bodies. The primary purpose of the survey was to confirm previous radionuclide surveys of Cesium-137

D. L. Dunn; W. G. Winn; P. J. Bresnahan

1996-01-01

188

Mapping radionuclide distribution in surface sediments using GIS and an underwater HPGe detector.  

National Technical Information Service (NTIS)

A radiological distribution survey at the L Lake on the Savannah River Site (SRS) was conducted by the Savannah River Technology Center (SRTC) during the summer of 1995 as part of a larger project to examine future alternatives for L Lake and other SRS wa...

D. L. Dunn, W. G. Winn, P. J. Bresnahan

1996-01-01

189

A high-efficiency Transition Radiation Detector for high-counting-rate environments  

NASA Astrophysics Data System (ADS)

A prototype Transition Radiation Detector (TRD) with a new configuration was built and tested. The prototype consists of two individual multiwire proportional chambers (MWPC) that share a thin common central pad readout electrode. Measurements with a 55Fe source and e, ? and p of 1.5 GeV/ c showed a very good energy, position resolution and a better e/? discrimination compared to the standard structure with a single MWPC. No significant deterioration of the resolutions is observed up to counting rates of 2×105 particles cm-2 s-1. These results open the possibility of constructing TRDs with a high e/? discrimination and granularity even for high-counting rate experiments with a reasonable number of layers.

Petrovici, M.; Petri?, M.; Berceanu, I.; Simion, V.; Barto?, D.; C?t?nescu, V.; Herghelegiu, A.; M?gureanu, C.; Mois?, D.; Radu, A.; Klein-Bösing, M.; Wessels, J. P.; Wilk, A.; Andronic, A.; Garabatos, C.; Simon, R.; Uhlig, F.

2007-09-01

190

New analytical approach to calculate the detector efficiencies of NaI(Tl) using coaxial and off-axis rectangular and parallelepiped sources  

NASA Astrophysics Data System (ADS)

In this paper, we introduce a direct analytical mathematical method for calculating the geometrical and absolute total efficiencies of gamma-ray NaI(Tl) scintillation detectors using coaxial and off-axis plane (rectangular) sources. The calculations of geometrical and absolute total efficiencies of coaxial and off-axis plane (rectangular) sources are extended to include coaxial and off-axis volumetric (parallelepiped) sources. The current theoretical and the published efficiency values are in good agreement.

Hamzawy, A.

2014-12-01

191

Detective quantum efficiency of a silicon microstrip photon-counting detector having edge-on geometry under mammography imaging condition  

NASA Astrophysics Data System (ADS)

We have investigated the image quality of a silicon microstrip detector system operated in single-photon counting mode under mammography imaging condition. The detector has an edge-on geometry with a tilting angle of 5 degrees to the normal direction of X-ray incidence. It is composed of four modules and each module employs 256 silicon microstrips. Using a slanted-edge knife technique, the modulation-transfer function (MTF) without aliasing was determined. Noise-power spectrum (NPS) was determined using two-dimensional (2D) Fourier analysis on the line-scanned 2D images. Based on the measured MTF and NPS results, detective quantum efficiency (DQE) was calculated. These systematic procedures were repeated at various energy thresholds. Asymmetric MTF properties between two perpendicular directions were observed because of the scan motion. Spectral densities in NPS were white for spatial frequencies. The best DQE value around zero-spatial frequency was about 0.7. It was observed that the DQE was independent of the level of X-ray exposure, which is desirable for low-dose mammography.

Yun, S.; Kim, H. K.; Youn, H.; Joe, O.; Kim, S.; Park, J.; Kang, D. G.; Sung, Y. H.; Marchal, J.; Tanguay, J.; Cunningham, I. A.

2011-12-01

192

High quantum efficiency and low dark count rate in multi-layer superconducting nanowire single-photon detectors  

NASA Astrophysics Data System (ADS)

In this paper, we theoretically show that a multi-layer superconducting nanowire single-photon detector (SNSPD) is capable of approaching characteristics of an ideal SNSPD in terms of the quantum efficiency, dark count, and band-width. A multi-layer structure improves the performance in two ways. First, the potential barrier for thermally activated vortex crossing, which is the major source of dark counts and the reduction of the critical current in SNSPDs is elevated. In a multi-layer SNSPD, a vortex is made of 2D-pancake vortices that form a stack. It will be shown that the stack of pancake vortices effectively experiences a larger potential barrier compared to a vortex in a single-layer SNSPD. This leads to an increase in the experimental critical current as well as significant decrease in the dark count rate. In consequence, an increase in the quantum efficiency for photons of the same energy or an increase in the sensitivity to photons of lower energy is achieved. Second, a multi-layer structure improves the efficiency of single-photon absorption by increasing the effective optical thickness without compromising the single-photon sensitivity.

Jafari Salim, A.; Eftekharian, A.; Hamed Majedi, A.

2014-02-01

193

Characterization measurement of a thick CdTe detector for BNCT-SPECT - detection efficiency and energy resolution.  

PubMed

Author?s group is carrying out development of BNCT-SPECT with CdTe device, which monitors the therapy effect of BNCT in real-time. From the design calculations, the dimensions were fixed to 1.5×2×30mm(3). For the collimator it was confirmed that it would have a good spatial resolution and simultaneously the number of counts would be acceptably large. After producing the CdTe crystal, the characterization measurement was carried out. For the detection efficiency an excellent agreement between calculation and measurement was obtained. Also, the detector has a very good energy resolution so that gamma-rays of 478keV and 511keV could be distinguished in the spectrum. PMID:24581600

Murata, Isao; Nakamura, Soichiro; Manabe, Masanobu; Miyamaru, Hiroyuki; Kato, Itsuro

2014-06-01

194

New measurement of the Fano factor of mercuric iodide. [astronomical x-ray detector charge collection efficiency  

NASA Technical Reports Server (NTRS)

It is pointed out that mercuric iodide (HgI2) shows great promise as a high-resolution X-ray detector for use in X-ray astronomy. Development of mercuric iodide for astronomical work has required investigation of the temperature dependence of the HgI2 crystal parameters such as leakage current, resolution, and mobility of the charge carriers. The first studies in connection with these investigations have led to a new value of the Fano factor of 0.19 + or - 0.03. The best value previously reported was 0.27 measured at room temperature. The new upper limit of 0.19 for the HgI2 Fano factor was determined by cooling the HgI2 crystal and preamp to -20 C. It is concluded that room-temperature energy resolution of HgI2 is not limited by charge generation statistics but rather by collection efficiency.

Ricker, G. R.; Vallerga, J. V.; Dabrowski, A. J.; Iwanczyk, J. S.; Entine, G.

1982-01-01

195

High-detection efficiency and picosecond timing compact detector modules with red-enhanced SPADs  

NASA Astrophysics Data System (ADS)

In the last years many progresses have been made in the field of silicon Single Photon Avalanche Diodes (SPAD) thanks to the improvements both in device design and in fabrication technology. Particularly, the Dipartimento di Elettronica e Informazione of Politecnico di Milano and the CNR-IMM of Bologna have been in the forefront of this research activity by designing and fabricating a new device structure enabling the fabrication of SPADs with red enhanced photon detection efficiency. In this paper we present a compact photon counting and timing module that fills the gap between the high temporal resolution and the high detection efficiency systems. The module exploits Red-Enhanced SPAD technology to attain a Photon Detection Efficiency (PDE) as high as 37% at 800 nm (peak of 58% at 600 nm) while maintaining a temporal resolution of about 100 ps FWHM, even with light diffused across the whole active area. A thermo-electric cooling system guarantees a noise as low as few counts per second for a 50 ?m diameter SPAD while a low threshold avalanche pick-up circuit assures a limited shift in the temporal response.

Giudice, Andrea; Simmerle, Georg; Veronese, Daniele; Biasi, Roberto; Gulinatti, Angelo; Rech, Ivan; Ghioni, Massimo; Maccagnani, Piera

2012-06-01

196

12C(?,?)16O studied with the Karlsruhe 4? BaF2 detector  

NASA Astrophysics Data System (ADS)

The 12C(?,?)16O reaction is one of the most important in nuclear astrophysics since it determines the ratio of 12C to 16O during stellar helium burning. Experimental data, however, are still subject to large uncertainties due to the almost vanishing cross section at stellar energies. So far, most measurements have been performed with germanium detectors. To compensate for their low efficiency, the highest beam currents had to be used, resulting in target degradation and beam-induced backgrounds. Instead, the present measurement was performed with high-efficiency detectors and low beam currents, using the Karlsruhe 4? BaF2 detector and the pulsed 3.7-MV Van de Graaff accelerator at Karlsruhe Institute of Technology. The 12C(?,?)16O cross sections have been measured at center-of-mass energies E between 1002 and 1510 keV, and the E1 and E2 components were derived with an accuracy comparable to the previous best data obtained with HPGe detectors.

Plag, R.; Reifarth, R.; Heil, M.; Käppeler, F.; Rupp, G.; Voss, F.; Wisshak, K.

2012-07-01

197

Characterization of detection efficiency as function of energy for soft x-ray detectors  

SciTech Connect

A new technique has been especially developed for determining the detection efficiency of the silicon surface barrier diodes used for tomography reconstructions at Tore Supra, as function of the energy of the x-ray photons, in the range of 4-25 keV. The response of these diodes has been studied for different bias voltages (0-120 V), with a portable x-ray electronic tube and a cooled Si-p-i-n diode, working in photon counting mode, for the absolute calibration.

Pacella, D.; Romano, A.; Pizzicaroli, G. [Associazione Euratom-ENEA sulla Fusione, Centro Ricerche Frascati, Via E. Fermi, 45-00044 Frascati, Rome (Italy); Mazon, D.; Malard, P. [Euratom-CEA Association, DSM-DRFC, Cadarache 13108, St. Paul lez Durance (France)

2008-10-15

198

GEANT4 Calibration of Gamma Spectrometry Efficiency for Measurements of Airborne Radioactivity on Filter Paper.  

PubMed

A simple method of efficiency calibration for gamma spectrometry was performed. This method, which focused on measuring airborne radioactivity collected on filter paper, was based on Monte Carlo simulations using the toolkit GEANT4. Experimentally, the efficiency values of an HPGe detector were calculated for a multi-gamma disk source. These efficiency values were compared to their counterparts produced by a computer code that simulated experimental conditions. Such comparison revealed biases of 24, 10, 1, 3, 7, and 3% for the radionuclides (photon energies in keV) of Ce (166), Sn (392), Cs (662), Co (1,173), Co (1,333), and Y (1,836), respectively. The output of the simulation code was in acceptable agreement with the experimental findings, thus validating the proposed method. PMID:25271933

Alrefae, Tareq

2014-11-01

199

Compact high-efficiency linear cryocooler in single-piston moving magnet design for HOT detectors  

NASA Astrophysics Data System (ADS)

State of the art Mid Wave IR-technology has the potential to rise the FPA temperature from 77K to 130-150K (High Operation Temperature, HOT). Using a HOT FPA will significantly lower SWaP and keep those parameters finally dominated by the employed cryocooler. Therefore, compact high performance cryocoolers are mandatory. AIM has developed the SX040 cooler, optimized for FPA temperatures of about 95K (presented at SPIE 2010). The SX040 cooler incorporates a high efficient dual piston driving mechanism resulting in a very compact compressor of less than 100mm length. Higher compactness - especially shorter compressors - can be achieved by change from dual to single piston design. The new SX030 compressor has such a single piston Moving Magnet driving mechanism resulting in a compressor length of about 60mm. Common for SX040 and SX030 family is a Moving Magnet driving mechanism with coils placed outside the helium vessel. In combination with high performance plastics for the piston surfaces this design enables lifetimes in excess of 20,000h MTTF. Because of the higher FPA temperature and a higher operating frequency also a new displacer needs to be developed. Based on the existing 1/4" coldfinger interface AIM developed a new displacer optimized for an FPA temperature of 140K and above. This paper gives an overview on the development of this new compact single piston cryocooler. Technical details and performance data will be shown.

Rühlich, I.; Mai, M.; Rosenhagen, C.; Withopf, A.; Zehner, S.

2012-06-01

200

Study on the novel neutron-to-proton concept for improving the detection efficiency of triple GEM based fast neutron detector  

E-print Network

A high-efficiency fast neutron detector prototype based on a triple Gas Electron Multiplier (GEM) detector, which coupled with a novel multi-layered High-Density PolyEthylene (HDPE) as a neutron-to-proton converter for improving the neutron detection efficiency, is introduced and tested with the Am-Be neutron source in Institute of Modern Physics (IMP) at Lanzhou in present work. Firstly, the developed triple GEM detector is tested by measuring its effective gain and energy resolution with $^{55}$Fe X-ray source to ensure that it has a good performance. The effective gain and obtained energy resolution is 5.0$\\times$10$^{4}$ and around of 19.2\\%, respectively. And secondly, the novel multi-layered HDPE converter is coupled with the cathode of the triple GEM detector make it a high-effective fast neutron detector. And its effective neutron response is four times higher than that of the traditional single-layered conversion technique when the converter layer number is 38.

Wang, Xiao-Dong; Ren, Zhong-Guo; Zhang, Jun-Wei; Yang, Lei; Zhang, Chun-Hui; Ha, Ri-Ba-La; An, Lv-Xing

2014-01-01

201

FOUR PI CALIBRATION AND MODELING OF A BARE GERMANIUM DETECTOR IN A CYLINDRICAL FIELD SOURCE  

SciTech Connect

In reference 1 the authors described {gamma}-ray holdup assay of a Mossbauer spectroscopy instrument where they utilized two axial symmetric cylindrical shell acquisitions and two disk source acquisitions to determine Am-241 and Np-237 contamination. The measured contents of the two species were determined using a general detector efficiency calibration taken from a 12-inch point source.2 The authors corrected the raw spectra for container absorption as well as for geometry corrections to transform the calibration curve to the applicable axial symmetric cylindrical source - and disk source - of contamination. The authors derived the geometry corrections with exact calculus that are shown in equations (1) and (2) of our Experimental section. A cylindrical shell (oven source) acquisition configuration is described in reference 3, where the authors disclosed this configuration to gain improved sensitivity for holdup measure of U-235 in a ten-chamber oven. The oven was a piece of process equipment used in the Savannah River Plant M-Area Uranium Fuel Fabrication plant for which a U-235 holdup measurement was necessary for its decontamination and decommissioning in 2003.4 In reference 4 the authors calibrated a bare NaI detector for these U-235 holdup measurements. In references 5 and 6 the authors calibrated a bare HpGe detector in a cylindrical shell configuration for improved sensitivity measurements of U-235 in other M-Area process equipment. Sensitivity was vastly improved compared to a close field view of the sample, with detection efficiency of greater than 1% for the 185.7-keV {gamma}-ray from U-235. In none of references 3 - 7 did the authors resolve the exact calculus descriptions of the acquisition configurations. Only the empirical efficiency for detection of the 185.7-keV photon from U-235 decay was obtained. Not until the 2010 paper of reference 1 did the authors derive a good theoretical description of the flux of photons onto the front face of a detector from an axially symmetric cylindrical shell. Subsequent to publication of 1, the theoretical treatment of the cylindrical shell and disk source acquisition sources was recognized by the Los Alamos National Laboratory as suitable for including in the Safeguards Training Program.8 Therefore, we felt it was important to accurately demonstrate the calculus describing the cylindrical shell configuration for the HpGe detector and to theoretically account for the observed bare-detector efficiencies measured in references (3-6). In this paper we demonstrate the applicability of the cylindrical shell derivation to a flexible planar sheet of known Am-241, Eu-152, and Cs-137 activity that we rolled into a symmetrical cylindrical shell of radioactivity. Using the geometry correction equation of reference 1, we calculate geometry correction values using the known detector and source dimensions combined with source to detector distances. We then compare measured detection efficiencies from a cylindrical shell of activity for the 185.7-keV photon (U-235) and for the 414.3-keV photon (Pu-239) with those determined for a 12-inch point source(2,7) to demonstrate agreement between experiment and the theoretically calculated values derived by the Savannah River National Laboratory (SRNL) authors of reference 1. We demonstrate this geometry correction first for the 185.7- and 414.3-keV {gamma}-rays. But because the detector was point source calibrated at 12 inches for the energy range (60 -1700) keV (using two distinct sources) to map its intrinsic efficiency, the geometry correction for any acquisition configuration holds for all photon energies.2 We demonstrate that for ten photon energies in the range 121 keV to 967 keV. The good agreement between experiment and calculation is demonstrated at five source to detector distances using the identical shielded HpGe detector of references 4-7 as well as with a separate HpGe detector. We then extend the measurement to include a single acquisition where the flexible source is wrapped around the bare detector in a symmetrical cylinder tha

Dewberry, R.; Young, J.

2011-04-29

202

Cascaded-systems analyses and the detective quantum efficiency of single-Z x-ray detectors including photoelectric, coherent and incoherent interactions  

SciTech Connect

Purpose: Theoretical models of the detective quantum efficiency (DQE) of x-ray detectors are an important step in new detector development by providing an understanding of performance limitations and benchmarks. Previous cascaded-systems analysis (CSA) models accounted for photoelectric interactions only. This paper describes an extension of the CSA approach to incorporate coherent and incoherent interactions, important for low-Z detectors such as silicon and selenium. Methods: A parallel-cascade approach is used to describe the three types of x-ray interactions. The description of incoherent scatter required developing expressions for signal and noise transfer through an 'energy-labeled reabsorption' process where the parameters describing reabsorption are random functions of the scatter photon energy. The description of coherent scatter requires the use of scatter form factors that may not be accurate for some crystalline detector materials. The model includes the effects of scatter reabsorption and escape, charge collection, secondary quantum sinks, noise aliasing, and additive noise. Model results are validated by Monte Carlo calculations for Si and Se detectors assuming free-atom atomic form factors. Results: The new signal and noise transfer expressions were validated by showing agreement with Monte Carlo results. Coherent and incoherent scatter can degrade the DQE of Si and sometimes Se detectors depending on detector thickness and incident-photon energy. Incoherent scatter can produce a substantial low-frequency drop in the modulation transfer function and DQE. Conclusions: A generally useful CSA model of the DQE is described that is believed valid for any single-Z material up to 10 cycles/mm at both mammographic and radiographic energies within the limitations of Fourier-based linear-systems models and the use of coherent-scatter form factors. The model describes a substantial low-frequency drop in the DQE of Si systems due to incoherent scatter above 20-40 keV.

Yun, Seungman [Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, 100 Perth Drive, London, Ontario N6A 5K8 (Canada); School of Mechanical Engineering, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Tanguay, Jesse; Cunningham, Ian A. [Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, 100 Perth Drive, London, Ontario N6A 5K8 (Canada); Kim, Ho Kyung [School of Mechanical Engineering, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

2013-04-15

203

High-resolution high-efficiency X-ray imaging system based on the in-line Bragg magnifier and the Medipix detector.  

PubMed

The performance of a recently developed full-field X-ray micro-imaging system based on an in-line Bragg magnifier is reported. The system is composed of quasi-channel-cut crystals in combination with a Medipix single-photon-counting detector. A theoretical and experimental study of the imaging performance of the crystals-detector combination and a comparison with a standard indirect detector typically used in high-resolution X-ray imaging schemes are reported. The spatial resolution attained by our system is about 0.75?µm, limited only by the current magnification. Compared with an indirect detector system, this system features a better efficiency, signal-to-noise ratio and spatial resolution. The optimal working resolution range of this system is between ?0.4?µm and 1?µm, filling the gap between transmission X-ray microscopes and indirect detectors. Applications for coherent full-field imaging of weakly absorbing samples are shown and discussed. PMID:23254668

Vagovi?, Patrik; Korytár, Dušan; Cecilia, Angelica; Hamann, Elias; Svéda, Libor; Pelliccia, Daniele; Härtwig, Jürgen; Záprazný, Zdenko; Oberta, Peter; Dolbnya, Igor; Shawney, Kawal; Fleschig, Uwe; Fiederle, Michael; Baumbach, Tilo

2013-01-01

204

Small Scale Assessment of Spatial and Vertical Redistribution of Fukushima Fallouts Radiocaesium in Contaminated Soil Using in-situ HPGe Gamma Ray Spectrometry  

NASA Astrophysics Data System (ADS)

After Tohoku earthquake on March 11th 2011, the subsequent tsunami and the resulting Fukushima Daiichi Nuclear Power Plant disaster, gamma emitting particles, first release into the atmosphere, were quickly deposited on the soil surface, with potentially harmful level in the surroundings of the nuclear power plant. Thus, the evaluation of soil deposition pattern, depth migration and afterward radionuclides redistribution and export by erosion and hydrological processes is fundamental for contamination assessments and to plan future actions. Our study site is located 37km from Fukushima power plant, inside the evacuated zone. In this study, we used a bounded erosion plot of 22.1m x 5m to assess global export of sediments and 137Cs. This plot, previously cropped with tobacco, is morphologically divided into inter-rill areas separated by rills that formed into former wheel tracks. The bottom of the plot is subject to deposition of sediments. In order to determine and quantify the internal processes responsible of the export of sediment, the depth distribution of 137Cs is estimated using a portable High Purity Germanium (HPGe) detector. Such a portable device, associated to the high radiation levels, allow an acquisition of spatially distributed data within the plot in a reasonable time (1 min/sample). At the same time, depth distribution of 137Cs are measured using the scrapper plate technique, adapted to obtain a fine resolution in the first, highly contaminated, centimeters of soil. Finally, 137Cs depth profiles, associated with in situ and laboratory gamma spectrums acquired with the portable detector, allow for the detector calibration. Although the initial deposit can reasonably be supposed homogeneous at the plot scale, the dataset obtained 3 months later shows high spatial and temporal variability due to erosion processes. Measurements with the portable HPGe detector proved to be useful at this small scale, avoiding the needs of a large number of soil samples, and our results are promising to understand erosion at larger scale where horizontal patterns of deposition and redistribution are usually supposed homogeneous over quite larger areas.

Patin, J.; Onda, Y.; Yoda, H.; Kato, H.

2011-12-01

205

Novel and efficient 10B lined tubelet detector as a replacement for 3He neutron proportional counters  

NASA Astrophysics Data System (ADS)

This paper presents a novel and robust proportional detector which addresses the well publicized shortage of 3He gas by using a 10B lining applied to a tubelet configuration. The advantage of the tubelet structure is that it yields a detector maintaining the form factor of a conventional 3He tube whilst achieving a sensitivity of up to 75% of a 3 atm 3He device. The design and fabrication of the tubelet detector is presented and discussed with test data comparing the new detector to existing 3He and BF 3 tubes. The application of the tubelet design to security and industrial applications including retro-fitting to existing portals and suitability for high integrity oil and gas installations is addressed.

Tsorbatzoglou, Kyriakos; McKeag, Robert D.

2011-10-01

206

Neutrino Detectors: Challenges and Opportunities  

SciTech Connect

This paper covers possible detector options suitable at future neutrino facilities, such as Neutrino Factories, Super Beams and Beta Beams. The Magnetised Iron Neutrino Detector (MIND), which is the baseline detector at a Neutrino Factory, will be described and a new analysis which improves the efficiency of this detector at low energies will be shown. Other detectors covered include the Totally Active Scintillating Detectors (TASD), particularly relevant for a low energy Neutrino Factory, emulsion detectors for tau detection, liquid argon detectors and megaton scale water Cherenkov detectors. Finally the requirements of near detectors for long-baseline neutrino experiments will be demonstrated.

Soler, F. J. P. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

2011-10-06

207

Strategy of HPGe screening measurements in the SuperNEMO experiment  

SciTech Connect

SuperNEMO is a double beta decay experiment that will use a tracko-calorimeter technique. The goal is to reach a sensitivity of T{sub 1/2}(0?)>10{sup 26} y corresponding to an effective Majorana neutrino mass of 0.04-0.11 eV with 100 kg of {sup 82}Se. The general strategy of the HPGe screening measurements is described for the materials of the SuperNEMO demonstrator, regarding their radiopurity and their location. The two platforms, PRISNA and LSM, used for this screening are also briefly described.

Perrot, Frédéric [Université de Bordeaux, Centre d'Etudes Nucléaires de Bordeaux Gradignan, UMR 5797, Chemin du Solarium, Le Haut-Vigneau, BP120, F-33175 Gradignan, France and CNRS/IN2P3, Centre d'Etudes Nucléaires de Bordeaux Gradignan, UMR 5797 (France)] [Université de Bordeaux, Centre d'Etudes Nucléaires de Bordeaux Gradignan, UMR 5797, Chemin du Solarium, Le Haut-Vigneau, BP120, F-33175 Gradignan, France and CNRS/IN2P3, Centre d'Etudes Nucléaires de Bordeaux Gradignan, UMR 5797 (France); Collaboration: SuperNEMO Collaboration

2013-08-08

208

An experimental method for determining the total efficiency and the response function of a gamma-ray detector in the range 0.5-10 MeV  

NASA Astrophysics Data System (ADS)

An experimental method is presented for the determination of the total efficiency and the response function of a ?-ray detector in the range 0.5-10 MeV. It consists of observing (p, ?) resonance reactions with two detectors: the one to be calibrated, in this case a cylindrical deuterated hexabenzene liquid scintillator, and a Ge detector used to select and resolve the main two-step cascades of the reaction. Efficiencies and response functions were obtained for thirteen ?-rays via the coincidence method, using targets of 26Mg at proton energies of 1001 and 2220 keV, of 30Si at 1398 keV and of 34S at 1211 keV. The weighting function derived from these data was used to determine the capture area of the 1.15 keV neutron resonance in 56Fe. By normalizing the data to the 5.2 eV resonance in 109Ag, a value ( g?n??/ ?) = 57.1 ± 2.1 meV was obtained, in excellent agreement with the result of recent transmission measurements.

Corvi, F.; Prevignano, A.; Liskien, H.; Smith, P. B.

1988-03-01

209

An experimental method for determining the total efficiency and the response function of a gamma-ray detector in the range 0.5-10 MeV  

NASA Astrophysics Data System (ADS)

An experimental method is presented for the determination of the total efficiency and the response function of a ?-ray detector in the range 0.5-10 MeV. It consists of observing (p, ?) resonance reactions with two detectors: the one to be calibrated, in this case a cylindrical deuterated hexabenzene liquid scintillator, and a Ge detector used to select and resolve the main two-step cascades of the reaction. Efficiencies and response functions were obtained for thirteen ?-rays via the coincidence method, using targets of 26Mg at proton energies of 1001 and 2220 keV, of 30Si at 1398 keV and of 34S at 1211 keV. The weighting function derived from these data was used to determine the capture area of the 1.15 keV neutron resonance in 56Fe. By normalizing the data to the 5.2 eV resonance in 109Ag, a value (g?n??/?) = 57.1 +/- 2.1 meV was obtained, in excellent agreement with the result of recent transmission measurements.

Corvi, F.; Prevignano, A.; Liskien, H.; Smith, P. B.

1998-03-01

210

Photon detectors  

SciTech Connect

J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF{sub 2} windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission.

Va`vra, J.

1995-10-01

211

DETECTORS AND EXPERIMENTAL METHODS: Measurement of the response function and the detection efficiency of an organic liquid scintillator for neutrons between 1 and 30 MeV  

NASA Astrophysics Data System (ADS)

The light output function of a varphi50.8 mm × 50.8 mm BC501A scintillation detector was measured in the neutron energy region of 1 to 30 MeV by fitting the pulse height (PH) spectra for neutrons with the simulations from the NRESP code at the edge range. Using the new light output function, the neutron detection efficiency was determined with two Monte-Carlo codes, NEFF and SCINFUL. The calculated efficiency was corrected by comparing the simulated PH spectra with the measured ones. The determined efficiency was verified at the near threshold region and normalized with a Proton-Recoil-Telescope (PRT) at the 8-14 MeV energy region.

Huang, Han-Xiong; Ruan, Xi-Chao; Chen, Guo-Chang; Zhou, Zu-Ying; Li, Xia; Bao, Jie; Nie, Yang-Bo; Zhong, Qi-Ping

2009-08-01

212

Gamma-ray detection efficiency of the microchannel plate installed as an ion detector in the low energy particle instrument onboard the GEOTAIL satellite  

SciTech Connect

A microchannel plate (MCP) assembly has been used as an ion detector in the low energy particle (LEP) instrument onboard the magnetospheric satellite GEOTAIL. Recently the MCP assembly has detected gamma rays emitted from an astronomical object and has been shown to provide unique information of gamma rays if they are intense enough. However, the detection efficiency for gamma rays was not measured before launch, and therefore we could not analyze the LEP data quantitatively. In this article, we report the gamma-ray detection efficiency of the MCP assembly. The measured efficiencies are 1.29%{+-}0.71% and 0.21%{+-}0.14% for normal incidence 60 and 662 keV gamma rays, respectively. The incident angle dependence is also presented. Our calibration is crucial to study high energy astrophysical phenomena by using the LEP.

Tanaka, Y. T.; Yoshikawa, I.; Yoshioka, K.; Terasawa, T.; Saito, Y.; Mukai, T. [Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)

2007-03-15

213

Enhanced detection efficiency of direct conversion X-ray detector using polyimide as hole-blocking layer.  

PubMed

In this article we demonstrate the performance of a direct conversion amorphous selenium (a-Se) X-ray detector using biphenyldisnhydride/1,4 phenylenediamine (BPDA/PPD) polyimide (PI) as a hole-blocking layer. The use of a PI layer with a-Se allows detector operation at high electric fields (?10 V/?m) while maintaining low dark current, without deterioration of transient performance. The hole mobility of the PI/a-Se device is measured by the time-of-flight method at different electric fields to investigate the effect of the PI layer on detector performance. It was found that hole mobility as high as 0.75 cm(2)/Vs is achievable by increasing the electric field in the PI/a-Se device structure. Avalanche multiplication is also shown to be achievable when using PI as a blocking layer. Increasing the electric field within a-Se reduces the X-ray ionization energy, increases hole mobility, and improves the dynamic range and sensitivity of the detector. PMID:24285255

Abbaszadeh, Shiva; Scott, Christopher C; Bubon, Oleksandr; Reznik, Alla; Karim, Karim S

2013-01-01

214

Calibration Analyses and Efficiency Studies for the Anti Coincidence Detector on the Fermi Gamma Ray Space Telescope.  

National Technical Information Service (NTIS)

The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope provides charged particle rejection for the Large Area Telescope (LAT). We use two calibrations used by the ACD to conduct three studies on the performance of the ACD. We examine t...

C. Kachulis

2011-01-01

215

500 MHz neutron detector  

SciTech Connect

A {sup 10}B-loaded scintillation detector was built for neutron transmission measurements at the Los Alamos Neutron Scattering Center. The efficiency of the detector is nearly 100% for neutron energies from 0 to 1 keV. The neutron moderation time in the scintillator is about 250 ns and is energy independent. The detector and data processing system are designed to handle an instantaneous rate as high as 500 MHz. The active area of the detector is 40 cm in diameter.

Yen, Yi-Fen; Bowman, J.D. [Los Alamos National Lab., NM (United States); Matsuda, Y. [Kyoto Univ. (Japan). Dept. of Physics

1993-12-01

216

Dose efficiency and low-contrast detectability of an amorphous silicon x-ray detector for digital radiography  

Microsoft Academic Search

The effect of dose reduction on low-contrast detectability is investigated theoretically and experimentally for a production grade amorphous silicon (a-Si) x-ray detector and compared with a standard thoracic screen-film combination. A non-prewhitening matched filter observer model modified to include a spatial response function and internal noise for the human visual system (HVS) is used to calculate a signal-to-noise ratio (SNR)

Richard Aufrichtig; Ping Xue

2000-01-01

217

Efficiency of real-time Gaussian transient detectors: comparing the Karhunen-Loeve and the wavelet decompositions  

Microsoft Academic Search

In general, finite-dimensional discrete-time representations of continuous-time Gaussian transients is not complete. Such representations typically lead to suboptimal detectors, where the compromise between computational complexity and processor performance requires optimization, specially when real-time processing is mandatory. This paper proposes a procedure for the optimization of the processor parameters, using the Bhattacharyya distance to evaluate the resemblance between the original continuous-time

Francisco M. Garcia; Isabel M. G. Lourtie

2000-01-01

218

Monte Carlo simulation of a PhosWatch detector using Geant4 for xenon isotope beta-gamma coincidence spectrum profile and detection efficiency calculations.  

PubMed

A simulation tool has been developed using the Geant4 Toolkit to simulate a PhosWatch single channel beta-gamma coincidence detection system consisting of a CsI(Tl)/BC404 Phoswich well detector and pulse shape analysis algorithms implemented digital signal processor. The tool can be used to simulate the detector's response for all the gamma rays and beta particles emitted from (135)Xe, (133m)Xe, (133)Xe, (131m)Xe and (214)Pb. Two- and three-dimensional beta-gamma coincidence spectra from the PhosWatch detector can be produced using the simulation tool. The accurately simulated spectra could be used to calculate system coincidence detection efficiency for each xenon isotope, the corrections for the interference from the various spectral components from radon and xenon isotopes, and system gain calibration. Also, it can generate two- and three-dimensional xenon reference spectra to test beta-gamma coincidence spectral deconvolution analysis software. PMID:19647444

Mekarski, P; Zhang, W; Ungar, K; Bean, M; Korpach, E

2009-10-01

219

Empirical assessment of the detection efficiency of CR-39 at high proton fluence and a compact, proton detector for high-fluence applications  

NASA Astrophysics Data System (ADS)

CR-39 solid-state nuclear track detectors are widely used in physics and in many inertial confinement fusion (ICF) experiments, and under ideal conditions these detectors have 100% detection efficiency for ˜0.5-8 MeV protons. When the fluence of incident particles becomes too high, overlap of particle tracks leads to under-counting at typical processing conditions (5 h etch in 6N NaOH at 80 °C). Short etch times required to avoid overlap can cause under-counting as well, as tracks are not fully developed. Experiments have determined the minimum etch times for 100% detection of 1.7-4.3-MeV protons and established that for 2.4-MeV protons, relevant for detection of DD protons, the maximum fluence that can be detected using normal processing techniques is ?3 × 106 cm-2. A CR-39-based proton detector has been developed to mitigate issues related to high particle fluences on ICF facilities. Using a pinhole and scattering foil several mm in front of the CR-39, proton fluences at the CR-39 are reduced by more than a factor of ˜50, increasing the operating yield upper limit by a comparable amount.

Rosenberg, M. J.; Séguin, F. H.; Waugh, C. J.; Rinderknecht, H. G.; Orozco, D.; Frenje, J. A.; Johnson, M. Gatu; Sio, H.; Zylstra, A. B.; Sinenian, N.; Li, C. K.; Petrasso, R. D.; Glebov, V. Yu.; Stoeckl, C.; Hohenberger, M.; Sangster, T. C.; LePape, S.; Mackinnon, A. J.; Bionta, R. M.; Landen, O. L.; Zacharias, R. A.; Kim, Y.; Herrmann, H. W.; Kilkenny, J. D.

2014-04-01

220

Mathematical efficiency calibration with uncertain source geometries using smart optimization  

SciTech Connect

The In Situ Object Counting Software (ISOCS), a mathematical method developed by CANBERRA, is a well established technique for computing High Purity Germanium (HPGe) detector efficiencies for a wide variety of source shapes and sizes. In the ISOCS method, the user needs to input the geometry related parameters such as: the source dimensions, matrix composition and density, along with the source-to-detector distance. In many applications, the source dimensions, the matrix material and density may not be well known. Under such circumstances, the efficiencies may not be very accurate since the modeled source geometry may not be very representative of the measured geometry. CANBERRA developed an efficiency optimization software known as 'Advanced ISOCS' that varies the not well known parameters within user specified intervals and determines the optimal efficiency shape and magnitude based on available benchmarks in the measured spectra. The benchmarks could be results from isotopic codes such as MGAU, MGA, IGA, or FRAM, activities from multi-line nuclides, and multiple counts of the same item taken in different geometries (from the side, bottom, top etc). The efficiency optimization is carried out using either a random search based on standard probability distributions, or using numerical techniques that carry out a more directed (referred to as 'smart' in this paper) search. Measurements were carried out using representative source geometries and radionuclide distributions. The radionuclide activities were determined using the optimum efficiency and compared against the true activities. The 'Advanced ISOCS' method has many applications among which are: Safeguards, Decommissioning and Decontamination, Non-Destructive Assay systems and Nuclear reactor outages maintenance. (authors)

Menaa, N. [AREVA/CANBERRA Nuclear Measurements Business Unit, Saint Quentin-en-Yvelines 78182 (France); Bosko, A.; Bronson, F.; Venkataraman, R.; Russ, W. R.; Mueller, W. [AREVA/CANBERRA Nuclear Measurements Business Unit, Meriden, CT (United States); Nizhnik, V. [International Atomic Energy Agency, Vienna (Austria); Mirolo, L. [AREVA/CANBERRA Nuclear Measurements Business Unit, Saint Quentin-en-Yvelines 78182 (France)

2011-07-01

221

Study of the material photon and electron background and the liquid argon detector veto efficiency of the CDEX-10 experiment  

E-print Network

The China Dark Matter Experiment (CDEX) is located at the China Jinping underground laboratory (CJPL) and aims to directly detect the WIMP flux with high sensitivity in the low mass region. Here we present a study of the predicted photon and electron backgrounds including the background contribution of the structure materials of the germanium detector, the passive shielding materials, and the intrinsic radioactivity of the liquid argon that serves as an anti-Compton active shielding detector. A detailed geometry is modeled and the background contribution has been simulated based on the measured radioactivities of all possible components within the GEANT4 program. Then the photon and electron background level in the energy region of interest (<10^-2 events kg-1 day-1 keV-1 (cpkkd)) is predicted based on Monte Carlo simulations. The simulated result is consistent with the design goal of CDEX-10 experiment, 0.1 cpkkd, which shows that the active and passive shield design of CDEX-10 is effective and feasible.

Su, Jian; MA, Hao; Yue, Qian; Cheng, Jian-Ping; Chang, Jian-Ping; Chen, Nan; Chen, Ning; Chen, Qing-Hao; Chen, Yun-Hua; Chuang, Yo-Chun; Deng, Zhi; Du, Qiang; Gong, Hui; Hao, Xi-Qing; He, Qing-Ju; Huang, Han-Xiong; Huang, Teng-Rui; Jiang, Hao; Kang, Ke-Jun; Li, Hau-Bin; Li, Jian-Min; Li, Jin; Li, Jun; Li, Xia; Li, Xin-Ying; Li, Xue-Qian; Li, Yu-Lan; Li, Yuan-Jing; Liao, Heng-Yi; Lin, Fong-Kay; Lin, Shin-Ted; Liu, Shu-Kui; Lü, Lan-Chun; Mao, Shao-Ji; Qin, Jian-Qiang; Ren, Jie; Ren, Jing; Ruan, Xi-Chao; Shen, Man-Bin; Singh, Lakhwinder; Singh, Manoj Kumar; Soma, Arun Kumar; Tang, Chang-Jian; Tseng, Chao-Hsiung; Wang, Ji-Min; Wang, Li; Wang, Qing; Wong, Henry Tsz-King; Wu, Shi-Yong; Wu, Yu-Cheng; Xing, Hao-Yang; Xu, Yin; Xue, Tao; Yang, Li-Tao; Yang, Song-Wei; Yi, Nan; Yu, Chun-Xu; Yu, Hao; Yu, Xun-Zhen; Zeng, Xiong-Hui; Zhang, Lan; Zhang, Yun-Hua; Zhao, Ming-Gang; Zhao, Wei; Zhou, Zu-Ying; Zhu, Jing-Jun; Zhu, Wei-Bin; Zhu, Xue-Zhou; Zhu, Zhong-Hua

2014-01-01

222

Study of the material photon and electron background and the liquid argon detector veto efficiency of the CDEX-10 experiment  

E-print Network

The China Dark Matter Experiment (CDEX) is located at the China Jinping underground laboratory (CJPL) and aims to directly detect the WIMP flux with high sensitivity in the low mass region. Here we present a study of the predicted photon and electron backgrounds including the background contribution of the structure materials of the germanium detector, the passive shielding materials, and the intrinsic radioactivity of the liquid argon that serves as an anti-Compton active shielding detector. A detailed geometry is modeled and the background contribution has been simulated based on the measured radioactivities of all possible components within the GEANT4 program. Then the photon and electron background level in the energy region of interest (<10^-2 events kg-1 day-1 keV-1 (cpkkd)) is predicted based on Monte Carlo simulations. The simulated result is consistent with the design goal of CDEX-10 experiment, 0.1 cpkkd, which shows that the active and passive shield design of CDEX-10 is effective and feasible.

Jian Su; Zhi Zeng; Hao MA; Qian Yue; Jian-Ping Cheng; Jian-Ping Chang; Nan Chen; Ning Chen; Qing-Hao Chen; Yun-Hua Chen; Yo-Chun Chuang; Zhi Deng; Qiang Du; Hui Gong; Xi-Qing Hao; Qing-Ju He; Han-Xiong Huang; Teng-Rui Huang; Hao Jiang; Ke-Jun Kang; Hau-Bin Li; Jian-Min Li; Jin Li; Jun Li; Xia Li; Xin-Ying Li; Xue-Qian Li; Yu-Lan Li; Yuan-Jing Li; Heng-Yi Liao; Fong-Kay Lin; Shin-Ted Lin; Shu-Kui Liu; Lan-Chun Lü; Shao-Ji Mao; Jian-Qiang Qin; Jie Ren; Jing Ren; Xi-Chao Ruan; Man-Bin Shen; Lakhwinder Singh; Manoj Kumar Singh; Arun Kumar Soma; Chang-Jian Tang; Chao-Hsiung Tseng; Ji-Min Wang; Li Wang; Qing Wang; Henry Tsz-King Wong; Shi-Yong Wu; Yu-Cheng Wu; Hao-Yang Xing; Yin Xu; Tao Xue; Li-Tao Yang; Song-Wei Yang; Nan Yi; Chun-Xu Yu; Hao Yu; Xun-Zhen Yu; Xiong-Hui Zeng; Lan Zhang; Yun-Hua Zhang; Ming-Gang Zhao; Wei Zhao; Zu-Ying Zhou; Jing-Jun Zhu; Wei-Bin Zhu; Xue-Zhou Zhu; Zhong-Hua Zhu

2014-02-19

223

Advanced UV Detectors and Detector Arrays  

NASA Technical Reports Server (NTRS)

Gallium Nitride (GaN) with its wide energy bandgap of 3.4 eV holds excellent promise for solar blind UV detectors. We have successfully designed, fabricated and tested GaN p-i-n detectors and detector arrays. The detectors have a peak responsivity of 0.14A/W at 363 nm (3.42 eV) at room temperature. This corresponds to an internal quantum efficiency of 56%. The responsivity decreases by several orders of magnitude to 0.008 A/W at 400 nm (3.10 eV) giving the excellent visible rejection ratio needed for solar-blind applications.

Pankove, Jacques I.; Torvik, John

1998-01-01

224

High-resolution gamma-ray measurement systems using a compact electro- mechanically cooled detector system and intelligent software  

SciTech Connect

Obtaining high-resolution gamma-ray measurements using high-purity germanium (HPGe) detectors in the field has been of limited practicality due to the need to use and maintain a supply of liquid nitrogen (LN{sub 2}). This same constraint limits high-resolution gamma measurements in unattended safeguards or treaty Verification applications. We are developing detectors and software to greatly extend the applicability of high-resolution germanium-based measurements for these situations.

Buckley, W.M.; Carlson, J.B.; Neufeld, K.W.

1995-09-27

225

Preliminary uranium enrichment analysis results using cadmium zinc telluride detectors  

SciTech Connect

Lawrence Livermore National Laboratory (LLNL) and EG&G ORTEC have jointly developed a portable ambient-temperature detection system that can be used in a number of application scenarios. The detection system uses a planar cadmium zinc telluride (CZT) detector with custom-designed detector support electronics developed at LLNL and is based on the recently released MicroNOMAD multichannel analyzer (MCA) produced by ORTEC. Spectral analysis is performed using software developed at LLNL that was originally designed for use with high-purity germanium (HPGe) detector systems. In one application, the CZT detection system determines uranium enrichments ranging from less than 3% to over 75% to within accuracies of 20%. The analysis was performed using sample sizes of 200 g or larger and acquisition times of 30 min. The authors have demonstrated the capabilities of this system by analyzing the spectra gathered by the CZT detection system from uranium sources of several enrichments. These experiments demonstrate that current CZT detectors can, in some cases, approach performance criteria that were previously the exclusive domain of larger HPGe detector systems.

Lavietes, A.D.; McQuaid, J.H. [Lawrence Livermore National Lab., CA (United States); Paulus, T.J. [EG& G ORTEC, Oak Ridge, TN (United States)

1995-09-08

226

Neutron detector  

DOEpatents

A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

Stephan, Andrew C. (Knoxville, TN); Jardret; Vincent D. (Powell, TN)

2011-04-05

227

Modelling of a Single-Channel Beta-Gamma Coincidence Phoswich Detector Using Geant4 for the Conversion Electron Energy Peak Resolution and Beta-Gamma Coincidence Efficiency Improvement  

NASA Astrophysics Data System (ADS)

In this study, an optimized single-channel phoswich well detector design has been proposed and assessed in order to improve beta-gamma coincidence measurement sensitivity of xenon radioisotopes. This newly designed phoswich well detector consists of a plastic beta counting cell (BC404) embedded in a CsI (Tl) crystal coupled to a photomultiplier tube. The BC404 is configured in a cylindrical pipe shape to minimise light collection deterioration. The CsI (Tl) crystal consists of a rectangular part and a semi-cylinder scintillation part as a light reflector to increase light gathering. Compared with a PhosWatch detector, the final optimized detector geometry showed 15 % improvement in the energy resolution of a 131mXe 129.4 keV conversion electron peak. The predicted beta-gamma coincidence efficiencies of xenon radioisotopes have also been improved accordingly.

Zhang, Weihua; Mekarski, Pawel; Bean, Marc; Yi, Jing; Ungar, Kurt

2014-03-01

228

The DELPHI microvertex detector  

Microsoft Academic Search

The main characteristics of the DELPHI Microvertex Detector are presented. The performance in terms of impact parameter resolution, association efficiency, and ambiguity is evaluated after two years of data taking at LEP.

M. Caccia; H. Borner; V. Chabaud; H. Dijkstra; P. Eerola; E. Gross; B. Hyams; R. Horisberger; L. Hubbeling; M. Karlsson; G. Maehlum; I. Roditi; J. Straver; W. Trischuk; P. Weilhammer; Y. Dufour; P. Brueckman; P. JaLOcha; P. Kapusta; M. TuraLA; A. Zalewska; J. Lindgren; R. Orava; K. Österberg; C. Ronnqvist; H. Saarikko; J. P. Saarikko; T. Tuuva; B. D'Almagne; P. Bambade; F. Couchot; F. Fulda; A. Amery; P. S. L. Booth; A. R. Campion; R. McNulty; N. A. Smith; A. Andreazza; M. Battaglia; P. Biffi; V. Bonvicini; W. Kucewicz; C. Meroni; N. Redaelli; A. Stocchi; C. Troncon; G. Vegni; P. Dauncey; M. Mazzucato; M. Pegoraro; A. Peisert; M. Baubillier; J. Chauveau; W. da Silva; J. F. Genat; F. Rossel; T. Adye; R. Apsimon; L. Denton; G. E. Kalmus; J. Lidbury; P. Seller; M. Tyndel; W. Dulinski; D. Husson; A. Lounis; M. Schaeffer; R. Turchetta; R. Brenner; E. Sundell; M Schäffer

1992-01-01

229

New electronically black neutron detectors  

SciTech Connect

Two neutron detectors are described that can function in a continuous radiation background. Both detectors identify neutrons by recording a proton recoil pulse followed by a characteristic capture pulse. This peculiar signature indicates that the neutron has lost all its energy in the scintillator. Resolutions and efficiencies have been measured for both detectors.

Drake, D.M.; Feldman, W.C.; Hurlbut, C.

1986-03-01

230

A simultaneous measurement of the $b$-tagging efficiency scale factor and the $t\\bar{t}$ Production Cross Section at the Collider Detector at Fermilab  

SciTech Connect

The ability to compare results between Monte Carlo and data is imperative in modern experimental high-energy physics analyses. The b-tagging efficiency Scale Factor (SF) allows for an accurate comparison of b quark identification in data samples and Monte Carlo. This thesis presents a simultaneous measurement of the SF for the SecVtx algorithm and the t{bar t} production cross section using 5.6 fb{sup -1} of p{bar p} collision data at {radical}s = 1.96 TeV collected by the Collider Detector at Fermilab (CDF) experiment. The t{bar t} cross section was measured to be 7.26 {+-} 0.47 pb, consistent with prior CDF analyses. The tight SF value was measured to be 0.925 {+-} 0.032 and the loose SF value was measured at 0.967 {+-} 0.033. These are the most precise SF SecVtx measurements to be performed at CDF to date.

Hussain, Nazim; /McGill U.

2011-07-01

231

GLAS 532nm Optical Detector  

NASA Technical Reports Server (NTRS)

This report documents fabrication and testing of 532nm optical detectors. Testing procedures included 532nm quantum efficiency, detector gain, and photon counting performance, in particular, photon counting efficiency. 532nm quantum efficiency was measured to be 36% to 39% for the detectors fabricated. Detectors with a GaAs APD anode had measured gains of 12,000 to 15,000 maximum. Photon counting efficiency for the detector with an APD anode was measured to be approximately 80% with a detector gain of 11,000. Measurements made on an identical detector, not fabricated under this contract, had a photon counting efficiency exceeding 90% with a gain of 13,000. A formula is derived in which the photon counting efficiency is determined by the system preamp noise and the peak single photon pulse height which is proportional to detector gain. This formula agrees well with the measured results and indicates that a detector gain of 15,000 is sufficient to provide a counting efficiency of 99.6%.

LaRue, Ross A.

1997-01-01

232

Semiconductor Detectors (Solid State Detectors)  

E-print Network

Semiconductor Detectors (Solid State Detectors) energy, position particles & photons energy loss conversion electron-hole pairs energetic "cheap" improved resolution #12;Semiconductor Detectors (Solid State electrons holes ni = Nc Nv exp -Eg 2kT = AT 3/ 2 exp -Eg 2kT #12;Semiconductor Detectors how

Peletier, Reynier

233

LEDs for Efficient Energy  

ERIC Educational Resources Information Center

Light-emitting diodes (LEDs) are described and three classroom experiments are given, one to prove the, low power requirements and efficiency of LEDs, an LED on-off detector circuit, and the third an LED photoelectric smoke detector. (BB)

Guerin, David A.

1978-01-01

234

The determination of the absolute response function of a deuterated benzene total energy detector to 6.13 MeV ?-rays  

NASA Astrophysics Data System (ADS)

The ?-ray response function of a 0.4 1 deuterated benzene liquid scintillation detector, used in the measurement of total neutron capture cross sections has been measured at 6.13 MeV and compared with spectra generated by the comprehensive Monte Carlo electron—gamma tracking code EGS-4. The experiment was performed in a nearly monoenergetic photon calibration field generated using the 19F(p, ??) 16O reaction by bombarding a thin CaF 2/Ta target with protons from the Harwell 6 MV Van de Graaff accelerator. The absolute yield of photons was measured using a 101 cm 3 HPGe ?-ray spectrometer whose efficiency had been previously determined using a combination of radionuclide and thermal neutron capture ?-ray sources. A secondary calibration, based on measurements with a standard 3 in. × 3 in. NaI(Tl) scintillator, gave consistent results. A particularly open irradiation geometry was used so as to minimise the importance of scattered radiation and to enable the geometry to be accurately represented in the computer simulations. Satisfactory agreement between the experiment and the Monte Carlo simulations was only obtained when the transport of secondary radiations produced in the target assembly and other materials close to the detector were included in the calculation. The calculated spectra exhibit rather more fine structure when was actually observed. Subsidiary measurements however, made using intensity calibrated radionuclide sources, indicate that below 1.5 MeV agreement between the predicted and observed response is excellent.

Croft, S.; Bailey, M.

1991-04-01

235

Particle Detectors  

NASA Astrophysics Data System (ADS)

Preface to the first edition; Preface to the second edition; Introduction; 1. Interactions of particles and radiation with matter; 2. Characteristic properties of detectors; 3. Units of radiation measurements and radiation sources; 4. Accelerators; 5. Main physical phenomena used for particle detection and basic counter types; 6. Historical track detectors; 7. Track detectors; 8. Calorimetry; 9. Particle identification; 10. Neutrino detectors; 11. Momentum measurement and muon detection; 12. Ageing and radiation effects; 13. Example of a general-purpose detector: Belle; 14. Electronics; 15. Data analysis; 16. Applications of particle detectors outside particle physics; 17. Glossary; 18. Solutions; 19. Resumé; Appendixes; Index.

Grupen, Claus; Shwartz, Boris

2008-03-01

236

Particle Detectors  

NASA Astrophysics Data System (ADS)

Preface to the first edition; Preface to the second edition; Introduction; 1. Interactions of particles and radiation with matter; 2. Characteristic properties of detectors; 3. Units of radiation measurements and radiation sources; 4. Accelerators; 5. Main physical phenomena used for particle detection and basic counter types; 6. Historical track detectors; 7. Track detectors; 8. Calorimetry; 9. Particle identification; 10. Neutrino detectors; 11. Momentum measurement and muon detection; 12. Ageing and radiation effects; 13. Example of a general-purpose detector: Belle; 14. Electronics; 15. Data analysis; 16. Applications of particle detectors outside particle physics; 17. Glossary; 18. Solutions; 19. Resumé; Appendixes; Index.

Grupen, Claus; Shwartz, Boris

2011-09-01

237

Study of the counting efficiency of a WBC setup by using a computational 3D human body library in sitting position based on polygonal mesh surfaces.  

PubMed

A realistic computational 3D human body library, called MaMP and FeMP (Male and Female Mesh Phantoms), based on polygonal mesh surface geometry, has been created to be used for numerical calibration of the whole body counter (WBC) system of the nuclear power plant (NPP) in Doel, Belgium. The main objective was to create flexible computational models varying in gender, body height, and mass for studying the morphology-induced variation of the detector counting efficiency (CE) and reducing the measurement uncertainties. First, the counting room and an HPGe detector were modeled using MCNPX (Monte Carlo radiation transport code). The validation of the model was carried out for different sample-detector geometries with point sources and a physical phantom. Second, CE values were calculated for a total of 36 different mesh phantoms in a seated position using the validated Monte Carlo model. This paper reports on the validation process of the in vivo whole body system and the CE calculated for different body heights and weights. The results reveal that the CE is strongly dependent on the individual body shape, size, and gender and may vary by a factor of 1.5 to 3 depending on the morphology aspects of the individual to be measured. PMID:24562069

Fonseca, T C Ferreira; Bogaerts, R; Lebacq, A L; Mihailescu, C L; Vanhavere, F

2014-04-01

238

Photon detectors with gaseous amplification  

SciTech Connect

Gaseous photon detectors, including very large 4{pi}-devices such as those incorporated in SLD and DELPHI, are finally delivering physics after many years of hard work. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photoelectrons. Among detector builders, there is hardly anybody who did not make mistakes in this area, and who does not have a healthy respect for the problems involved. This point is stressed in this paper, and it is suggested that only a very small operating phase space is available for running gaseous photon detectors in a very large system with good efficiency and few problems. In this paper the authors discuss what was done correctly or incorrectly in first generation photon detectors, and what would be their recommendations for second generation detectors. 56 refs., 11 figs.

Va`vra, J.

1996-08-01

239

New setup for the characterisation of the AGATA detectors  

NASA Astrophysics Data System (ADS)

A crucial step in the process of ?-ray tracking is related to the location of the interaction points of all the ?-rays within the AGATA (Advanced GAmma Tracking Array) segmented detectors. This requires a full understanding of the sensitivity of each highly segmented high-purity germanium (HPGe) detectors via the characterisation of the 2D and 3D position response. In this paper, we describe the experimental scanning setup that we developed at Orsay for the AGATA detectors. A collimated 137Cs source on an automated x-y positioning table was used for the front face scanning of the AGATA symmetric prototype detector. The 3D scanning measurement is performed using coincidence techniques based on ?-ray Compton scattering from the AGATA detector into an ancillary coupled detector. In our setup, TOHR (high resolution tomograph developed for small animal imaging) is used as an ancillary detector. The data is collected using TIGRESS cards for digital signal processing. The data flow, readout and storage is NARVAL as used for the full AGATA project. The analysis of the collected data and the obtained results is shown to illustrate our device performances.

Ha, T. M. H.; Korichi, A.; Le Blanc, F.; Désesquelles, P.; Dosme, N.; Grave, X.; Karkour, N.; Leboutelier, S.; Legay, E.; Linget, D.; Travers, B.; Pariset, P.

2013-01-01

240

An experimental approach to efficiency calibration for gamma-ray spectrometric analysis of large air particulate filters  

NASA Astrophysics Data System (ADS)

A full-energy-peak efficiency (FEPE) calibration procedure for gamma-ray spectrometric analysis of air particulate samples collected on large filters is described herein. The experimental results are obtained for an unconventional measurement geometry, termed a "packet-sample". The sample is obtained from a large cellulose filter (45 cm×45 cm) used to collect air particulate samples that is resized to dimensions suitable for spectrometric measurements (6 cm×6 cm×0.7 cm). To determine the FEPEs, many standards were created, i.e., some filters containing a small amount of ThO2 and others containing a known amount of KCl. Efficiency curves obtained through best fits to experimental data for three high-purity germanium (HPGe) detectors, one of them for X-ray measurement, cover the energy range from 40 keV to 2600 keV. To validate the efficiency calibration procedure two experimental tests with the use of calibrated sources were conducted and, as application example, airborne concentrations of 131I (particulate matter), 134Cs and 137Cs at Palermo (Italy) in the days following the Fukushima accident in Japan were evaluated.

Tomarchio, Elio

2013-04-01

241

Pocked surface neutron detector  

DOEpatents

The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

McGregor, Douglas (Whitmore Lake, MI); Klann, Raymond (Bolingbrook, IL)

2003-04-08

242

Tracing the phosphorus contamination sources and reducing the phosphorus contamination in HPGe crystal growth  

NASA Astrophysics Data System (ADS)

The net impurity concentration and the dislocation density for the grown crystals must be controlled within a narrow range of values to produce crystals acceptable for large-volume coaxial germanium detector fabrication. Phosphorus is the main shallow level donor in high purity germanium crystal. The phosphorus contamination is a disaster for growing p-type high-purity germanium crystal. The phosphorus contamination mainly comes from crucible, insulation, ambient gas or crystal growth chamber. Regrowth method was used to trace the phosphorus contamination sources. The contamination level from sources was discussed in detail in this paper. For different contamination source, targeted approaches were used to reduce the contamination.

Wang, Guojian; Guan, Yutong; Yang, Gang; Govani, Jayesh; Khizar, Muhammad; Mei, Hao; Mei, Dongming

2013-03-01

243

Comparative Measurements of the Photon Detection Efficiency of KETEK SiPM Detectors for the LHCb SciFi Upgrade Project  

E-print Network

The LHCb SciFi detector is conceived to employ arrays of SiPM detectors to detect scintillation light from ribbons of 2.5 m long scintillating fibres of 250 $\\mu$m diameter. The fibres of type Kuraray SCSF-78 are blue emitting with an emission maximum at 440 nm. However, as a consequence of the radiation damage mainly from charged hadrons in the LHCb experiments, the effective emission spectrum at the end of the fibre will shift to longer wavelengths. A simulation of the light absorption in the fibre, assuming an ionizing dose distribution along the fibre as predicted by the FLUKA code, is able to predict the emission spectrum. Fig. 1 shows the emission spectra (in arbitrary units) for 10 cm intervals along the fibre. At 250 cm, where the ionization dose is expected to reach over the full lifetime of the upgrade LHCb detector about 30 kGy, the average wavelength of emission is approximately 500 nm. The sensitivity spectrum of the SiPM detector should be tuned to match this emission spectrum, i.e. the PDE shou...

Joram, Christian

2014-01-01

244

High-efficiency single photon detector combined with an ultra-small APD module and a self-training discriminator for high-speed quantum cryptosystems  

E-print Network

A single-photon avalanche detector (SPAD) for high-speed quantum-key generation has successfully been developed. It has the highest photon detection repetition frequency and the lowest dark count rate in the world, as a board-mountable sub-system. The SPAD consists of an ultra-small dual-avalanche photodiode (APD) module and a novel discriminator. The APD module design is consistent with cooling capability and high-frequency characteristics. The new module has a 3 GHz bandwidth enabling 1 GHz gate-pulse repetition. The bandwidth is extended 15-fold relative to the most wideband peltier cooled APD module. The discriminator has a self-training mechanism to compensate charge pulse. Dark count rare of the SPAD is reduced 1/10th relative to the lowest dark count single photon detector. The SPAD allows 3.2-fold multiplying the quantum key generation rate in theoretical estimation.

Seigo Takahashi; Akio Tajima; Akihisa Tomita

2007-12-27

245

Mobility-lifetime product of CdTe\\/CdZnTe crystals from charge collection efficiency of X-ray detectors  

Microsoft Academic Search

In this study we obtain the mobility-lifetime product of the material from the dependence of the average charge collection efficiency upon the bias voltage. We evaluate the efficiency by measuring the spectra for given sources. The measurement is based on monitoring the “energy locations” of known peaks. In the case of complete charge collection, a photon of energy Eph yields

A. Ruzin; J. Gorelik; Y. Nemirovsky

1995-01-01

246

Response of a LaBr3(Ce) Detector to 2-11 MeV Gamma Rays  

SciTech Connect

The development of lanthanum halide scintillation detectors has great potential application in field-portable prompt-gamma neutron activation analysis systems. Because the low-energy response of these detectors has already been well-characterized [1[-[2], we have measured their response to higher energy gamma rays in the region between 2 and 11 MeV. We have measured the response of a 2-inch (5.08 cm) by 2-inch long LaBr3(Ce) detector to high energy gamma rays produced by neutron interactions on chlorine, hydrogen, iron, nitrogen, phosphorous, and sulfur. The response of the LaBr3(Ce) detector is compared to that of HPGe and NaI(Tl) detectors.

Not Available

2006-10-01

247

A Feasibility Study to Determine Cooling Time and Burnup of ATR Fuel Using a Nondestructive Technique and Three Types of Gamma-ray Detectors  

SciTech Connect

A Feasibility Study to Determine Cooling Time and Burnup of ATR Fuel Using a Nondestructive Technique1 Rahmat Aryaeinejad, Jorge Navarro, and David W Nigg Idaho National Laboratory Abstract Effective and efficient Advanced Test Reactor (ATR) fuel management require state of the art core modeling tools. These new tools will need isotopic and burnup validation data before they are put into production. To create isotopic, burn up validation libraries and to determine the setup for permanent fuel scanner system a feasibility study was perform. The study consisted in measuring short and long cooling time fuel elements at the ATR canal. Three gamma spectroscopy detectors (HPGe, LaBr3, and HPXe) and two system configurations (above and under water) were used in the feasibility study. The first stage of the study was to investigate which detector and system configuration would be better suited for different scenarios. The second stage of the feasibility study was to create burnup and cooling time calibrations using experimental isotopic data collected and ORIGEN 2.2 burnup data. The results of the study establish that a better spectra resolution is achieve with an above the water configuration and that three detectors can be used in the permanent fuel scanner system for different situations. In addition it was conclude that a number of isotopic ratios and absolute measurements could be used to predict ATR fuel burnup and cooling times. 1This work was supported by the U.S. Depart¬ment of Energy (DOE) under Battelle Energy Alliance, LLC Contract No. DE-AC07-05ID14517.

Jorge Navarro; Rahmat Aryaeinejad,; David W. Nigg

2011-05-01

248

Measurements of the photon identification efficiency with the ATLAS detector using 4.9 fb?1 of pp collision data collected in 2011  

E-print Network

The efficiency of the tight selection criteria used in the 2011 dataset by the ATLAS experiment to identify photons is measured using 4.9 fb?1 of pp collision data. Three in- dependent data-driven methods are used to estimate the identification efficiency in different regions of pseudorapidity ? and as a function of the photon transverse momentum ET in the 15 ? 300 GeV range. The three measurements give consistent results, and are combined in the overlapping ET regions into a single data-driven efficiency map. The comparison of this data-driven efficiency map with that predicted by the ATLAS simulation shows significant disagreements in some ? and ET regions, where the simula- tion systematically predicts higher photon identification efficiency values. A simple data- driven correction procedure, implemented by slightly shifting the simulated electromagnetic shower shapes, restores the agreement with the data-driven values within ±5%.

The ATLAS collaboration

2012-01-01

249

Lanthanum Bromide Detectors for Safeguards Measurements  

SciTech Connect

Lanthanum bromide has advantages over other popular inorganic scintillator detectors. Lanthanum bromide offers superior resolution, and good efficiency when compared to sodium iodide and lanthanum chloride. It is a good alternative to high purity germanium detectors for some safeguards applications. This paper offers an initial look at lanthanum bromide detectors. Resolution of lanthanum bromide will be compared lanthanum chloride and sodium-iodide detectors through check source measurements. Relative efficiency and angular dependence will be looked at. Nuclear material spectra, to include plutonium and highly enriched uranium, will be compared between detector types.

Wright, J.

2011-05-25

250

MS Detectors  

SciTech Connect

Good eyesight is often taken for granted, a situation that everyone appreciates once vision begins to fade with age. New eyeglasses or contact lenses are traditional ways to improve vision, but recent new technology, i.e. LASIK laser eye surgery, provides a new and exciting means for marked vision restoration and improvement. In mass spectrometry, detectors are the 'eyes' of the MS instrument. These 'eyes' have also been taken for granted. New detectors and new technologies are likewise needed to correct, improve, and extend ion detection and hence, our 'chemical vision'. The purpose of this report is to review and assess current MS detector technology and to provide a glimpse towards future detector technologies. It is hoped that the report will also serve to motivate interest, prompt ideas, and inspire new visions for ion detection research.

Koppenaal, David W.; Barinaga, Charles J.; Denton, M Bonner B.; Sperline, Roger P.; Hieftje, Gary M.; Schilling, G. D.; Andrade, Francisco J.; Barnes IV., James H.

2005-11-01

251

A method to determine 238U activity in environmental soil samples by using 63.3-keV-photopeak-gamma HPGe spectrometer  

Microsoft Academic Search

The paper presents a method of measuring 238U activity in environmental soil samples by a low background HPGe spectrometer at the 63.3keV gamma photopeak. The low 238U activity requires a large size soil sample with a mass of about 100g. The geometrical and self-absorption effects as well as the density dependence of soil samples were then investigated. A procedure of

N. Q. Huy; T. V. Luyen

2004-01-01

252

Optimization of high purity germanium (HPGe) crystals growth rate through the simulation and modeling of growth system geometry  

NASA Astrophysics Data System (ADS)

The growth rate and quality of high-purity germanium (HPGe) single crystals depend largely on the control of the thermal field such as the temperature profile and heat transfer. The control parameters of the thermal field can only be regulated externally through the growth system geometry, hydrogen and argon gas pressure, flow rate, pulling rate, and power and frequency of a RF heater. Since quantitative determination of the control parameters is exceptionally challenging and expensive, computer modeling and simulation of CZ growth processes play an imperative role in the advances of innovative pulling procedures and augmentation of Ge crystal quality. We present a detailed modeling and simulation study of radial and vertical temperature gradient, radial and vertical heat flux, temperature profile, thermo-elastic stresses, and defect density analysis for different crystal positions and diverse growth system geometry. We also virtually studied the consequences of targeted growth rate on temperature gradient and induction heating. A comparative analysis of simulated and available experimental results is also presented. In this effort, we have demonstrated the importance of simulation and modeling as it helps reducing the number of growth experiments significantly for the optimization of crystal quality and targeted growth rate.

Govani, Jayesh; Mei, Dongming; Wang, Guojian; Yang, Gang

2012-02-01

253

The BES detector  

Microsoft Academic Search

The Beijing Spectrometer (BES) is a general purpose solenoidal detector at the Beijing Electron Positron Collider (BEPC). It is designed to study exclusive final states in e+e- annihilations at the center of mass energy from 3.0 to 5.6 GeV. This requires large solid angle coverage combined with good charged particle momentum resolution, good particle identification and high photon detection efficiency

J. Z. Bai; Q. Bian; G. M. Chen; L. J. Chen; S. N. Chen; Y. Q. Chen; Z. Q. Chen; Y. K. Chi; H. C. Cui; X. Z. Cui; S. S. Deng; Y. W. Deng; H. L. Ding; B. Z. Dong; X. S. Dong; X. Du; Z. Z. Du; C. Feng; Z. Feng; Z. S. Fu; C. S. Gao; M. L. Gao; S. Q. Gao; W. X. Gao; Y. N. Gao; S. D. Gu; W. X. Gu; Y. Z. Guan; H. F. Guo; Y. N. Guo; Y. Y. Guo; S. W. Han; Y. Han; W. Hao; J. He; K. R. He; M. J. He; X. J. Hou; G. Y. Hu; J. S. Hu; J. W. Hu; D. Q. Huang; Y. Z. Huang; Q. P. Jia; C. H. Jiang; Q. Ju; Y. F. Lai; P. F. Lang; D. S. Li; F. Li; H. Li; Jia Li; J. T. Li; Jin Li; L. L. Li; P. Q. Li; Q. M. Li; R. B. Li; S. Q. Li; W. Li; Z. X. Li; G. N. Liang; F. C. Lin; S. Z. Lin; W. Lin; Q. Liu; R. G. Liu; W. Liu; X. Liu; Z. A. Liu; Z. Y. Liu; C. G. Lu; W. D. Lu; Z. Y. Lu; J. G. Lu; D. H. Ma; E. C. Ma; J. M. Ma; H. S. Mao; Z. P. Mao; X. C. Meng; H. L. Ni; J. Nie; Z. D. Nie; W. P. Niu; L. J. Pan; N. D. Qi; J. J. Qian; Y. H. Qu; Y. K. Que; G. Rong; T. Z. Ruan; Y. Y. Shao; B. W. Shen; D. L. Shen; J. Shen; H. Y. Sheng; J. P. Sheng; H. Z. Shi; X. F. Song; H. S. Sun; F. K. Tang; S. Q. Tang; W. H. Tian; F. Wang; G. Y. Wang; J. G. Wang; J. Y. Wang; L. S. Wang; L. Z. Wang; M. Wang; P. Wang; S. M. Wang; S. Q. Wang; T. J. Wang; X. W. Wang; Y. Y. Wang; Z. H. Wang; Z. J. Wang; C. L. Wei; Z. Z. Wei; J. W. Wu; S. H. Wu; S. Q. Wu; W. M. Wu; X. D. Wu; Z. D. Wu; D. M. Xi; X. M. Xia; J. Xiao; P. P. Xie; X. X. Xie; J. G. Xu; R. S. Xu; Z. Q. Xu; B. C. Xuan; S. T. Xue; J. Yan; S. P. Yan; W. G. Yan; C. Z. Yang; C. M. Yang; C. Y. Yang; X. F. Yang; X. R. Yang; M. H. Ye; C. H. Yu; C. S. Yu; Z. Q. Yu; B. Y. Zhang; C. D. Zhang; C. C. Zhang; C. Y. Zhang; D. H. Zhang; G. Zhang; H. Y. Zhang; H. L. Zhang; J. W. Zhang; L. S. Zhang; S. Q. Zhang; Y. P. Zhang; Y. M. Zhang; D. X. Zhao; J. W. Zhao; M. Zhao; P. D. Zhao; P. P. Zhao; W. R. Zhao; Z. G. Zhao; Z. Q. Zhao; J. P. Zheng; L. S. Zheng; M. Zheng; W. S. Zheng; Z. P. Zheng; G. P. Zhong; G. P. Zhou; H. S. Zhou; J. Zhou; Li Zhou; Lin Zhou; M. Zhou; Y. S. Zhou; Y. H. Zhou; G. S. Zhu; Q. M. Zhu; S. G. Zhu; Y. C. Zhu; Y. S. Zhu; B. A. Zhuang

1994-01-01

254

Pyroelectric detectors  

NASA Technical Reports Server (NTRS)

The multi-agency, long-term Global Change programs, and specifically NASA's Earth Observing system, will require some new and advanced photon detector technology which must be specifically tailored for long-term stability, broad spectral range, cooling constraints, and other parameters. Whereas MCT and GaAs alloy based photovoltaic detectors and detector arrays reach most impressive results to wavelengths as long as 12 microns when cooled to below 70 K, other materials, such as ferroelectrics and pyroelectrics, appear to offer special opportunities beyond 12 microns and above 70 K. These materials have found very broad use in a wide variety of room temperature applications. Little is known about these classes of materials at sub-room temperatures and no photon detector results have been reported. From the limited information available, researchers conclude that the room temperature values of D asterisk greater than or equal to 10(exp 9) cm Hz(exp 1/2)/W may be improved by one to two orders of magnitude upon cooling to temperatures around 70 K. Improvements of up to one order of magnitude appear feasible for temperatures achievable by passive cooling. The flat detector response over a wavelength range reaching from the visible to beyond 50 microns, which is an intrinsic advantage of bolometric devices, makes for easy calibration. The fact that these materials have been developed for reduced temperature applications makes ferro- and pyroelectric materials most attractive candidates for serious exploration.

Haller, Eugene E.; Beeman, Jeffrey; Hansen, William L.; Hubbard, G. Scott; Mcmurray, Robert E., Jr.

1990-01-01

255

Pyroelectric detectors  

NASA Astrophysics Data System (ADS)

The multi-agency, long-term Global Change programs, and specifically NASA's Earth Observing system, will require some new and advanced photon detector technology which must be specifically tailored for long-term stability, broad spectral range, cooling constraints, and other parameters. Whereas MCT and GaAs alloy based photovoltaic detectors and detector arrays reach most impressive results to wavelengths as long as 12 microns when cooled to below 70 K, other materials, such as ferroelectrics and pyroelectrics, appear to offer special opportunities beyond 12 microns and above 70 K. These materials have found very broad use in a wide variety of room temperature applications. Little is known about these classes of materials at sub-room temperatures and no photon detector results have been reported. From the limited information available, researchers conclude that the room temperature values of D asterisk greater than or equal to 10(exp 9) cm Hz(exp 1/2)/W may be improved by one to two orders of magnitude upon cooling to temperatures around 70 K. Improvements of up to one order of magnitude appear feasible for temperatures achievable by passive cooling. The flat detector response over a wavelength range reaching from the visible to beyond 50 microns, which is an intrinsic advantage of bolometric devices, makes for easy calibration. The fact that these materials have been developed for reduced temperature applications makes ferro- and pyroelectric materials most attractive candidates for serious exploration.

Haller, Eugene E.; Beeman, Jeffrey; Hansen, William L.; Hubbard, G. Scott; McMurray, Robert E., Jr.

1990-07-01

256

Biological Applications of Cryogenic Detectors  

SciTech Connect

High energy resolution and broadband efficiency are enabling the use of cryogenic detectors in biological research. Two areas where they have found initial application are X-ray absorption spectroscopy (XAS) and time-of-flight mass spectrometry (TOF-MS). In synchrotron-based fluorescence-detected XAS cryogenic detectors are used to examine the role of metals in biological systems by measuring their oxidation states and ligand symmetries. In time-of-flight mass spectrometry cryogenic detectors increase the sensitivity for biomolecule detection and identification for masses above {approx}50 kDa, and thus enable TOF-MS on large protein complexes or even entire viruses. More recently, cryogenic detectors have been proposed as optical sensors for fluorescence signals from biomarkers. We discuss the potential for cryogenic detectors in biological research, as well as the challenges the technology faces.

Friedrich, S

2003-12-03

257

Microwave detector  

DOEpatents

A microwave detector (10) is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite (26, 28) produces a magnetization field flux that links a B-dot loop (16, 20). The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means (18, 22) are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

Meldner, Heiner W. (Moss Beach, CA); Cusson, Ronald Y. (Chapel Hill, NC); Johnson, Ray M. (San Ramon, CA)

1986-01-01

258

Hydrogen detector  

DOEpatents

A hydrogen detector of the type in which the interior of the detector is partitioned by a metal membrane into a fluid section and a vacuum section. Two units of the metal membrane are provided and vacuum pipes are provided independently in connection to the respective units of the metal membrane. One of the vacuum pipes is connected to a vacuum gauge for static equilibrium operation while the other vacuum pipe is connected to an ion pump or a set of an ion pump and a vacuum gauge both designed for dynamic equilibrium operation.

Kanegae, Naomichi (Mito, JP); Ikemoto, Ichiro (Mito, JP)

1980-01-01

259

Neutron detectors comprising boron powder  

DOEpatents

High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

Wang, Zhehui; Morris, Christopher; Bacon, Jeffrey Darnell; Makela, Mark F; Spaulding, Randy Jay

2013-05-21

260

Microwave kinetic inductance detectors  

NASA Astrophysics Data System (ADS)

Low temperature detectors have been a subject of intense interest to the scientific community over the last decade. These detectors work at very low temperatures, often well below 1 Kelvin, to minimize the noise in the measurement of photons. This leads to very powerful detectors applicable to a broad wavelength range. Since these detectors are so sensitive even single pixels and small arrays (up to several hundred pixels) enable deeper explorations of the cosmos than ever before. Instruments based on these technologies have been used at submillimeter, optical, and X-ray wavelengths. The scientific prospects for these detectors increase as they grow in pixel count. For some applications, especially for Cosmic Microwave Background (CMB) polarization work, a large focal plane will not only increase efficiency but will also enable new and vital science. Current superconducting technologies, such as Transition Edge Sensors (TESs), can currently deliver extremely high sensitivity in the submillimeter and read- noise free imaging spectroscopy at Optical/UV and X-ray wavelengths, but the largest arrays contain less that 100 pixels. In order to make real progress these arrays must contain many thousands of pixels. This is a formidable technical challenge. This thesis will explore a promising emerging technology called Microwave Kinetic Inductance Detectors (MKIDs). MKIDs make use of the change in the surface impedance of a superconductor as incoming photons break up Cooper pairs. This is accomplished by making the strip of superconductor part of a microwave resonant circuit, and monitoring the phase of a signal transmitted through (or past) the resonator. The primary advantage of this technology is that by using resonant circuits with high quality factors, passive frequency domain multiplexing will allow up to thousands of resonators to be read out through a single coaxial cable and a single HEMT amplifier. This eliminates the cryogenic electronics (SQUIDS) and wiring problems associated with current superconducting devices. Inexpensive and powerful room-temperature readout electronics can leverage the microwave integrated circuits developed for wireless communications.

Mazin, Benjamin A.

2005-11-01

261

Determination of Barium and selected rare-earth elements in geological materials employing a HpGe detector by radioisotope excited x-ray fluorescence  

Microsoft Academic Search

The laterite material (geological) from Cerro Impacto was first studied by air radiometric techniques in the 1970's and was found to have an abnormally high radioactive background. Further studies showed this deposit to be rich in thorium, columbium, barium and rare-earth elements (mostly La, Ce, Pr and Nd). A similar work has been reported for the analysis of Brazil's lateritic

J. J. LaBrecque; I. L. Preiss

1984-01-01

262

Characteristics of Signals Originating near the Lithium-Diffused N+ Contact of High Purity Germanium P-Type Point Contact Detectors  

SciTech Connect

A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein.

Aguayo, E. [Pacific Northwest National Laboratory (PNNL); Amman, M. [Lawrence Berkeley National Laboratory (LBNL); Avignone, F. T. [University of South Carolina/ORNL; Barabash, A.S. [Institute of Theoretical & Experimental Physics, Moscow, Russia; Barton, P. J. [Lawrence Berkeley National Laboratory (LBNL); Beene, James R [ORNL; Bertrand Jr, Fred E [ORNL; Boswell, M. [Los Alamos National Laboratory (LANL); Brudanin, V. [Joint Institute for Nuclear Research, Dubna, Russia; Busch, M. [Duke University; Chan, Y-D [Lawrence Berkeley National Laboratory (LBNL); Christofferson, C. D. [South Dakota School of Mines & Technology, Rapid City, SD; Collar, Juan I. [University of Chicago; Combs, D. C. [University of North Carolina / Triangle Universities Nuclear Lababoratory, Durham; Cooper, Reynold J [ORNL; Detwiler, J.A. [Lawrence Berkeley National Laboratory (LBNL); Doe, P. J. [University of Washington; Efremenko, Yuri [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Egorov, V. [Joint Institute for Nuclear Research, Dubna, Russia; Ejiri, H. [Osaka University; Elliott, S. R. [Los Alamos National Laboratory (LANL); Esterline, J. [Duke University; Fast, J.E. [Pacific Northwest National Laboratory (PNNL); Fields, N. [University of Chicago; Finnerty, P. [University of North Carolina / Triangle Universities Nuclear Lababoratory, Durham; Fraenkle, F. M. [University of North Carolina / Triangle Universities Nuclear Lababoratory, Durham; Galindo-Uribarri, Alfredo {nmn} [ORNL; Gehman, V. M. [Los Alamos National Laboratory (LANL); Giovanetti, G. K. [Univ, of North Carolina & Triangle Universities Nucl. Lab - Durham, NC; Green, M. P. [University of North Carolina / Triangle Universities Nuclear Lababoratory, Durham; Guiseppe, V.E. [University of South Dakota; Gusey, K. [Joint Institute for Nuclear Research, Dubna, Russia; Hallin, A. L. [University of Alberta, Edmonton, Canada; Hazama, R. [Osaka University; Henning, R. [Univ, of North Carolina & Triangle Universities Nucl. Lab - Durham, NC; Hoppe, E.W. [Pacific Northwest National Laboratory (PNNL); Horton, M. [South Dakota School of Mines & Technology, Rapid City, SD; Howard, S. [South Dakota School of Mines and Technology; Howe, M. A. [University of North Carolina / Triangle Universities Nuclear Lababoratory, Durham; Johnson, R. A. [University of Washington, Seattle; Keeter, K.J. [Black Hills State University, Spearfish, SD; Kidd, M. F. [Los Alamos National Laboratory (LANL); Knecht, A. [University of Washington, Seattle; Kochetov, O. [Joint Institute for Nuclear Research, Dubna, Russia; Konovalov, S.I. [Institute of Theoretical & Experimental Physics, Moscow, Russia; Kouzes, R. T. [Pacific Northwest National Laboratory (PNNL); LaFerriere, B. D. [Pacific Northwest National Laboratory (PNNL); Leon, J. [University of Washington, Seattle; Leviner, L. E. [University of North Carolina / Triangle Universities Nuclear Lababoratory, Durham; Loach, J.C. [Lawrence Berkeley National Laboratory (LBNL); Looker, Q. [Lawrence Berkeley National Laboratory (LBNL); Luke, P.N. [Lawrence Berkeley National Laboratory (LBNL); MacMullin, S. [University of North Carolina / Triangle Universities Nuclear Lababoratory, Durham; Marino, M. G. [University of Washington, Seattle; Martin, R.D. [Lawrence Berkeley National Laboratory (LBNL); Merriman, J. H. [Pacific Northwest National Laboratory (PNNL); Miller, M. L. [University of Washington, Seattle; Mizouni, L. [PPNL/Univ. of South Carolina; Nomachi, M. [Osaka University; Orrell, John L. [Pacific Northwest National Laboratory (PNNL); Overman, N. R. [Pacific Northwest National Laboratory (PNNL); Perumpilly, G. [University of South Dakota; Phillips II, D. G. [University of North Carolina / Triangle Universities Nuclear Lababoratory, Durham; Poon, A.W.P. [Lawrence Berkeley National Laboratory (LBNL); et al.

2013-01-01

263

Characteristics of signals originating near the lithium-diffused N+ contact of high purity germanium p-type point contact detectors  

NASA Astrophysics Data System (ADS)

A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein.

Aguayo, E.; Amman, M.; Avignone, F. T.; Barabash, A. S.; Barton, P. J.; Beene, J. R.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y.-D.; Christofferson, C. D.; Collar, J. I.; Combs, D. C.; Cooper, R. J.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Fields, N.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E. W.; Horton, M.; Howard, S.; Howe, M. A.; Johnson, R. A.; Keeter, K. J.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; Laferriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; Looker, Q.; Luke, P. N.; Macmullin, S.; Marino, M. G.; Martin, R. D.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; Overman, N. R.; Perumpilly, G.; Phillips, D. G.; Poon, A. W. P.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Steele, D.; Strain, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vetter, K.; Vorren, K.; Wilkerson, J. F.; Yakushev, E.; Yaver, H.; Young, A. R.; Yu, C.-H.; Yumatov, V.; Majorana Collaboration

2013-02-01

264

Detector Detail  

NSDL National Science Digital Library

This game requires users to match the âÂÂshower shapesâ and the energies of particles produced in a particle collision. There is also a movie (or animated gif) in the Calorimetry section which allows students to see the workings of the detector. It is part of a collection of games that allows students to explore concepts in particle physics.

2008-07-23

265

Vertex detectors  

SciTech Connect

The purpose of a vertex detector is to measure position and angles of charged particle tracks to sufficient precision so as to be able to separate tracks originating from decay vertices from those produced at the interaction vertex. Such measurements are interesting because they permit the detection of weakly decaying particles with lifetimes down to 10{sup {minus}13} s, among them the {tau} lepton and charm and beauty hadrons. These two lectures are intended to introduce the reader to the different techniques for the detection of secondary vertices that have been developed over the past decades. The first lecture includes a brief introduction to the methods used to detect secondary vertices and to estimate particle lifetimes. It describes the traditional technologies, based on photographic recording in emulsions and on film of bubble chambers, and introduces fast electronic registration of signals derived from scintillating fibers, drift chambers and gaseous micro-strip chambers. The second lecture is devoted to solid state detectors. It begins with a brief introduction into semiconductor devices, and then describes the application of large arrays of strip and pixel diodes for charged particle tracking. These lectures can only serve as an introduction the topic of vertex detectors. Time and space do not allow for an in-depth coverage of many of the interesting aspects of vertex detector design and operation.

Lueth, V.

1992-07-01

266

Spatial resolution attainable in germanium detectors by pulse shape analysis  

SciTech Connect

There are several applications for which it is desirable to calculate the locations and energies of individual gamma-ray interactions within a high purity germanium (HPGe) detector. These include gamma-ray imaging and Compton suppression. With a segmented detector this can be accomplished by analyzing the pulse shapes of the signals from the various segments. We examine the fundamental limits to the spatial resolution attainable with this approach. The primary source of error is the series noise of the field effect transistors (FETs) at the inputs of the charge amplifiers. We show how to calculate the noise spectral density at the output of the charge amplifiers due to an optimally selected FET. This calculation is based only on the detector capacitance and a noise constant for the FET technology. We show how to use this spectral density to calculate the uncertainties in parameters, such as interaction locations and energies, that are derived from pulse shape analysis using maximum likelihood estimation (MLE) applied to filtered and digitized recordings of the charge signals. Example calculations are given to illustrate our approach. Experimental results are given that demonstrate that one can construct complete systems, from detector through data analysis, that come near the theoretical limits.

Blair, J., Bechtel, NV; Beckedahl, D.; Kammeraad, J.; Schmid, G., LLNL

1998-05-01

267

Array of germanium detectors for nuclear safeguards  

SciTech Connect

Our gamma-ray spectrometer system, designed for field use, offers high efficiency and high resolution for safeguards applications. The system consists of three 40% high-purity germanium detectors and a LeCroy 3500 data-acquisition system that calculates a composite spectrum for the three detectors. The LeCroy 3500 mainframe can be operated remotely from the detector array with control exercised through moderns and the telephone system. System performance with a mixed source of /sup 125/Sb, /sup 154/Eu, and /sup 155/Eu confirms the expected efficiency of 120% with an overall resolution that is between the resolution of the best detector and that of the worst.

Moss, C.E.; Bernard, W.; Dowdy, E.J.; Garcia, C.; Lucas, M.C.; Pratt, J.C.

1983-01-01

268

High-efficiency p-i-n detectors for the visible spectral range based on ZnSTe-ZnTe superlattices  

NASA Astrophysics Data System (ADS)

We demonstrate that ZnSTe-ZnTe superlattices, which are grown lattice matched on GaAs substrates by molecular-beam epitaxy, are well suited as a material for light detection in the visible spectral range. Due to their type-II band alignment, these superlattices have a small band gap compared to ZnSe and allow light detection for photon energies between 2.1 and 3.2 eV. In combination with ZnMgSSe, the response curve of the diodes shows a strong dependence on the applied reverse bias, so that they can be used as two-color devices. The obtained external quantum efficiencies are as high as 70%, and dark currents as low as 10-12 A/mm2 were obtained.

Faschinger, W.; Ehinger, M.; Schallenberg, T.; Korn, M.

1999-05-01

269

Angle detector  

NASA Technical Reports Server (NTRS)

An angle detector for determining a transducer's angular disposition to a capacitive pickup element is described. The transducer comprises a pendulum mounted inductive element moving past the capacitive pickup element. The capacitive pickup element divides the inductive element into two parts L sub 1 and L sub 2 which form the arms of one side of an a-c bridge. Two networks R sub 1 and R sub 2 having a plurality of binary weighted resistors and an equal number of digitally controlled switches for removing resistors from the networks form the arms of the other side of the a-c bridge. A binary counter, controlled by a phase detector, balances the bridge by adjusting the resistance of R sub 1 and R sub 2. The binary output of the counter is representative of the angle.

Parra, G. T. (inventor)

1978-01-01

270

Flame Detector  

NASA Technical Reports Server (NTRS)

Scientific Instruments, Inc. has now developed a second generation, commercially available instrument to detect flames in hazardous environments, typically refineries, chemical plants and offshore drilling platforms. The Model 74000 detector incorporates a sensing circuit that detects UV radiation in a 100 degree conical field of view extending as far as 250 feet from the instrument. It operates in a bandwidth that makes it virtually 'blind' to solar radiation while affording extremely high sensitivity to ultraviolet flame detection. A 'windowing' technique accurately discriminates between background UV radiation and ultraviolet emitted from an actual flame, hence the user is assured of no false alarms. Model 7410CP is a combination controller and annunciator panel designed to monitor and control as many as 24 flame detectors. *Model 74000 is no longer being manufactured.

1990-01-01

271

Neutron-burst detectors for cold-fusion experiments  

Microsoft Academic Search

We have designed several neutron detectors for use in measuring neutrons from cold-fusion experiments. The high-efficiency detectors are based on 3He gas tubes in a CH2 moderator. The total efficiency of our most advanced detector for 2.3 MeV (252Cf) neutrons is 44%. The detector consists of two independent segments making up inner and outer rings of 3He tubes. The inner

H. O. Menlove; M. C. Miller

1990-01-01

272

Determination of the Crystal Axis Orientations of Ge detectors for the Majorana Demonstrator  

NASA Astrophysics Data System (ADS)

High purity germanium (HPGe) crystals will be used for the Majorana Demonstrator, where they serve as both the source and the detector for neutrinoless double beta decays. Sophisticated pulse shape analysis (PSA) is crucial in distinguishing certain background events in the energy region of interest. It is also well known that the charge-carrier mobility in Ge crystals has considerable dependence on the crystallographic axes, resulting in a crystal axis dependence of the PSA. Meanwhile, as within the Peccei-Quinn solution to the strong CP problem and as a dark matter candidate, axions have been searched for in many experiments. It has been suggested that the postulated solar axions could coherently covert to photons by the Primakeoff effect in a periodic lattice, such as that found in the Ge crystals used by the Demonstrator, with conversion rates depending on the crystal axis orientation. In order to use the Demonstrator to search for solar axions, the Ge crystal axes need to be measured. In this talk, we will present our experimental measurements to characterize crystal axes with P-type point contact (PPC) HPGe detectors, which are cylindrical in shape with point contacts at the bottom.

Xu, Wenqin; Busch, Matthew; Elliott, Steven; Green, Matthew; Hegai, Alex; Henning, Reyco; Ronquest, Michael; Snavely, Kyle; Zitin, Ari

2013-04-01

273

Reverse Schottky-asymmetry spin current detectors  

NASA Astrophysics Data System (ADS)

By reversing the Schottky barrier-height asymmetry in hot-electron semiconductor-metal-semiconductor ballistic spin filtering spin detectors, we have achieved the following: (1) demonstration of >50% spin polarization in silicon, resulting from the increase of detection efficiency by elimination of the ferromagnet/silicon interface on the transport channel detector contact and (2) evidence of spin transport at temperatures as high as 260 K, enabled by an increase in detector Schottky barrier height.

Lu, Yuan; Appelbaum, Ian

2010-10-01

274

THE 15 LAYER SILICON DRIFT DETECTOR TRACKER IN EXPERIMENT 896.  

SciTech Connect

Large linear silicon drift detectors have been developed and are in production for use in several experiments. Recently 15 detectors were used as a tracking device in BNL-AGS heavy ion experiment (E896). The detectors were successfully operated in a 6.2 T magnetic field. The behavior of the detectors, such as drift uniformity, resolution, and charge collection efficiency are presented. The effect of the environment on the detector performance is discussed. Some results from the experimental run are presented. The detectors performed well in an experimental environment. This is the first tracking application of these detectors.

PANDY,S.U.

1998-11-08

275

Corner detector using invariant analysis  

NASA Astrophysics Data System (ADS)

Corner detection has been shown to be very useful in many computer vision applications. Some valid approaches have been proposed, but few of them are accurate, efficient and suitable for complex applications (such as DSP). In this paper, a corner detector using invariant analysis is proposed. The new detector assumes an ideal corner of a gray level image should have a good corner structure which has an annulus mask. An invariant function was put forward, and the value of which for the ideal corner is a constant value. Then, we could verify the candidate corners by compare their invariant function value with the constant value. Experiments have shown that the new corner detector is accurate and efficient and could be used in some complex applications because of its simple calculation.

Zhu, Chengfei; Li, Shuxiao; Song, Yi; Chang, Hongxing

2013-07-01

276

Flexible composite radiation detector  

DOEpatents

A flexible composite scintillator was prepared by mixing fast, bright, dense rare-earth doped powdered oxyorthosilicate (such as LSO:Ce, LSO:Sm, and GSO:Ce) scintillator with a polymer binder. The binder is transparent to the scintillator emission. The composite is seamless and can be made large and in a wide variety of shapes. Importantly, the composite can be tailored to emit light in a spectral region that matches the optimum response of photomultipliers (about 400 nanometers) or photodiodes (about 600 nanometers), which maximizes the overall detector efficiency.

Cooke, D. Wayne (Santa Fe, NM); Bennett, Bryan L. (Los Alamos, NM); Muenchausen, Ross E. (Los Alamos, NM); Wrobleski, Debra A. (Los Alamos, NM); Orler, Edward B. (Los Alamos, NM)

2006-12-05

277

Pillar Structured Thermal Neutron Detector  

SciTech Connect

This work describes an innovative solid state device structure that leverages advanced semiconductor fabrication technology to produce an efficient device for thermal neutron detection which we have coined the 'Pillar Detector'. State-of-the-art thermal neutron detectors have shortcomings in simultaneously achieving high efficiency, low operating voltage while maintaining adequate fieldability performance. By using a three dimensional silicon PIN diode pillar array filled with isotopic {sup 10}boron ({sup 10}B), a high efficiency device is theoretically possible. Here we review the design considerations for going from a 2-D to 3-D device and discuss the materials trade-offs. The relationship between the geometrical features and efficiency within our 3-D device is investigated by Monte Carlo radiation transport method coupled with finite element drift-diffusion carrier transport simulations. To benchmark our simulations and validate the predicted efficiency scaling, experimental results of a prototype device are illustrated. The fabricated pillar structures reported in this work are composed of 2 {micro}m diameter silicon pillars with a 2 {micro}m spacing and pillar height of 12 {micro}m. The pillar detector with a 12 {micro}m height achieved a thermal neutron detection efficiency of 7.3% at a reverse bias of -2 V.

Nikolic, R; Conway, A; Reinhardt, C; Graff, R; Wang, T; Deo, N; Cheung, C

2008-06-10

278

Improved Scintillator Materials for Compact Electron Antineutrino Detectors  

SciTech Connect

Developments in the fields of chemistry and materials science provide new components that hold the potential to improve the performance of liquid scintillation electron antineutrino detectors used for the monitoring of nuclear reactors. New compounds can provide for more efficient, stable, and safer operation of these detectors. Current detectors and their detector materials raise issues regarding size, quantum efficiency, stability, and spatial resolution for the vertex detection. For compact detectors (1 m{sup 3} active volume) improvement of these issues with existing liquid scintillation cocktails can be obtained by means of developing stable and efficient neutron capture agents. These agents comprise of boron or lithium containing coordination compounds, in addition advances in fluorescence detection technologies and optimization of solvent characteristics can improve the overall efficiency. Focus points of the new detector material design are to enable a compact, robust, and direction sensitive electron antineutrino detector.

Dijkstra, Peter; Wortche, Heinrich J. [INCAS3 (Innovative Centre for Advanced Sensors and Sensor Systems), P.O. Box 797, 9400AT, Assen (Netherlands); Browne, Wesley R. [Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)

2011-04-27

279

Physics and Detector Response Simulations  

NASA Astrophysics Data System (ADS)

As the complexity and resolution of modern detectors increases, the need for detailed simulation of the experimental setup also becomes more important. Designing detector systems composed of many disparate subsystems requires ef?cient tools to simulate the detector response and reconstruct the events. Comparisons of different technology options, or geometric layouts, are facilitated if the results can be obtained with a common simulation and reconstruction framework. We have developed efficient and ?exible tools for detailed physics and detector response simulation as well as event reconstruction and analysis. The primary goal has been to develop a software toolkit and computing infrastructure to allow physicists from universities and labs to quickly and easily conduct physics analyses and contribute to detector research and development with a minimal investment of time and effort. The application harnesses the full power of the Geant4 toolkit without requiring the end user to have any experience with either Geant4 or C++, thereby allowing the user to concentrate on the physics of the detector system. The reconstruction software and analysis environment are written in Java, providing a modern, object-oriented platform which is independent of the computing operating system.

Graf, Norman A.; McCormick, Jeremy

280

Imperfect Detectors in Linear Optical Quantum Computers  

E-print Network

We discuss the effects of imperfect photon detectors suffering from loss and noise on the reliability of linear optical quantum computers. We show that for a given detector efficiency, there is a maximum achievable success probability, and that increasing the number of ancillary photons and detectors used for one controlled sign flip gate beyond a critical point will decrease the probability that the computer will function correctly. We have also performed simulations of some small logic gates and estimate the efficiency and noise levels required for the linear optical quantum computer to function properly.

Scott Glancy; J. M. LoSecco; H. M. Vasconcelos; C. E. Tanner

2002-01-11

281

Radiation induced polarization in CdTe detectors  

Microsoft Academic Search

Polarization induced by irradiation with intense gamma ray sources has been studied in chlorine-compensated CdTe detectors. The influence of several parameters, such as applied field strength, temperature and incident photon flux, on the polarization effect have been investigated. A relationship was found between the degree of polarization, detector efficiency and detector leakage current.

D. Vartsky; M. Goldberg; Y. Eisen; Y. Shamai; R. Dukhan; P. Siffert; J. M. Koebel; R. Regal; J. Gerber

1988-01-01

282

PIXSCAN: Pixel detector CT-scanner for small animal imaging  

Microsoft Academic Search

The PIXSCAN is a small animal CT-scanner based on hybrid pixel detectors. These detectors provide very large dynamic range of photons counting at very low detector noise. They also provide high counting rates with fast image readout. Detection efficiency can be optimized by selecting the sensor medium according to the working energy range. Indeed, the use of CdTe allows a

P. Delpierre; F. Debarbieux; S. Basolo; J. F. Berar; A. Bonissent; N. Boudet; P. Breugnon; B. Caillot; F. Cassol Brunnera; B. Chantepie; J. C. Clemens; B. Dinkespiler; R. Khouri; I. Koudobine; V. Mararazzo; C. Meessen; M. Menouni; C. Morel; C. Mouget; P. Pangaud; F. Peyrin; G. Rougon; D. Sappey-Marinier; S. Valton; E. Vigeolas

2007-01-01

283

National Detector Dog Manual.  

National Technical Information Service (NTIS)

The National Detector Dog Manual covers background information, procedures, health care, and training related to detector dog activities. The procedures have a national focus to guide detector dog activities, and they are supplemental to general operation...

2004-01-01

284

Important detector parameters: 1. Quantum efficiency  

E-print Network

of photography first sky object photographs (daguerrotypes): 1840 Moon J.W. Draper 1843 Solar spectrum ,, 1845 photography dominated astronomical detection for more than a century: ~1870-1980 pro's and con) · enormous storage capacity (106 -108 `pix'/cm2 ) · high resolution (grains ~ 1-10 µm) · wavelength coverage

Peletier, Reynier

285

Operational experience with the ATLAS Pixel Detector  

E-print Network

The ATLAS Pixel Detector is the innermost element of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Ince, T; The ATLAS collaboration

2012-01-01

286

Present status of microstructured semiconductor neutron detectors  

NASA Astrophysics Data System (ADS)

Semiconductor diode detectors coated with neutron reactive materials have been investigated as neutron detectors for many decades, and are fashioned mostly as planar diodes coated with boron-10 (10B), lithium-6 fluoride (6LiF) or gadolinium (Gd). Although effective, these detectors are limited in efficiency (the case for boron and LiF coatings) or in the ability to distinguish background radiations from neutron-induced interactions (the case for Gd coatings). Over the past decade, a renewed effort has been made to improve diode designs to achieve up to a 10-fold increase in neutron detection efficiency over the simple planar diode designs. These new semiconductor neutron detectors are fashioned with a matrix of microstructured patterns etched deeply into the substrate and, subsequently, backfilled with neutron reactive materials. Intrinsic thermal-neutron detection efficiencies exceeding 40% have been achieved with devices no thicker than 1 mm while operating on less than 5 V.

McGregor, Douglas S.; Bellinger, Steven L.; Shultis, J. Kenneth

2013-09-01

287

Future of Semiconductor Based Thermal Neutron Detectors  

SciTech Connect

Thermal neutron detectors have seen only incremental improvements over the last decades. In this paper we overview the current technology of choice for thermal neutron detection--{sup 3}He tubes, which suffer from, moderate to poor fieldability, and low absolute efficiency. The need for improved neutron detection is evident due to this technology gap and the fact that neutrons are a highly specific indicator of fissile material. Recognizing this need, we propose to exploit recent advances in microfabrication technology for building the next generation of semiconductor thermal neutron detectors for national security requirements, for applications requiring excellent fieldability of small devices. We have developed an innovative pathway taking advantage of advanced processing and fabrication technology to produce the proposed device. The crucial advantage of our Pillar Detector is that it can simultaneously meet the requirements of high efficiency and fieldability in the optimized configuration, the detector efficiency could be higher than 70%.

Nikolic, R J; Cheung, C L; Reinhardt, C E; Wang, T F

2006-02-22

288

CdTe detector use for PIXE characterization of TbCoFe thin films  

Microsoft Academic Search

Peltier cooled CdTe detectors have good efficiency beyond the range of energies normally covered by Si(Li) detectors, the most common detectors in PIXE applications. An important advantage of CdTe detectors is the possibility of studying K X-rays lines instead the L X-rays lines in various cases since CdTe detectors present an energy efficiency plateau reaching 70 keV or more. The

P. C. Chaves; A. Taborda; N. P. Barradas; M. A. Reis

2010-01-01

289

CdTe detector use for PIXE characterization of TbCoFe thin films  

Microsoft Academic Search

Peltier cooled CdTe detectors have good efficiency beyond the range of energies normally covered by Si(Li) detectors, the most common detectors in PIXE applications. An important advantage of CdTe detectors is the possibility of studying K X-rays lines instead the L X-rays lines in various cases since CdTe detectors present an energy efficiency plateau reaching 70keV or more. The ITN

P. C. Chaves; A. Taborda; N. P. Barradas; M. A. Reis

2010-01-01

290

Microwave characteristics of GaAs MMIC integratable optical detectors  

NASA Technical Reports Server (NTRS)

Interdigitated photoconductive detectors were fabricated on microwave device structures, making them easily integratable with Monolithic Microwave Integrated Circuits (MMIC). Detector responsivity as high as 2.5 A/W and an external quantum efficiency of 3.81 were measured. Response speed was nearly independent of electrode geometry, and all detectors had usable response at frequencies to 6 GHz. A small signal model of the detectors based on microwave measurements was also developed.

Claspy, Paul C.; Hill, Scott M.; Bhasin, Kul B.

1989-01-01

291

Three radioactivity detectors for liquid-chromatographic systems compared  

SciTech Connect

Three radioactivity detectors coupled to a ''high-performance'' liquid-chromatography system are compared with regard to static efficiency, dynamic efficiency, background measurements, and within- and between-day variabilities. Their advantages and disadvantages are discussed.

Frey, B.M.; Frey, F.J.

1982-04-01

292

Detector simulation needs for detector designers  

SciTech Connect

Computer simulation of the components of SSC detectors and of the complete detectors will be very important for the designs of the detectors. The ratio of events from interesting physics to events from background processes is very low, so detailed understanding of detector response to the backgrounds is needed. Any large detector for the SSC will be very complex and expensive and every effort must be made to design detectors which will have excellent performance and will not have to undergo major rebuilding. Some areas in which computer simulation is particularly needed are pattern recognition in tracking detectors and development of shower simulation code which can be trusted as an aid in the design and optimization of calorimeters, including their electron identification performance. Existing codes require too much computer time to be practical and need to be compared with test beam data at energies of several hundred GeV. Computer simulation of the processing of the data, including electronics response to the signals from the detector components, processing of the data by microprocessors on the detector, the trigger, and data acquisition will be required. In this report we discuss the detector simulation needs for detector designers.

Hanson, G.G.

1987-11-01

293

Photon detector for MEGA  

SciTech Connect

During the past year, we have continued work on the photon detector for the MEGA experiment at Los Alamos, a search for the rare decay {mu} {yields} e{gamma} to a sensitivity of a few parts in 10{sup 13}. The MEGA photon detector is designed to observe the 52.38 MeV photon produced in a {mu} {yields} e{gamma} decay with an energy resolution of 1.25 MeV, a position resolution of 2 {times} 5 mm{sup 2}, a directional resolution of 10{degrees}, a time resolution of 500 ps, and an efficiency of 7%. It will consists of four independent concentric cylindrical pair spectrometers mounted within a 1.5 T magnetic field produced by a superconducting solenoid magnet. Each pair spectrometer includes two thin Pb foils to convert photons into e{sup +}e{sup {minus}} pairs, and thereby, determine both their locations and their vector momenta. The inner drift chamber layer includes a delay line cathode to determine the z coordinates needed for track reconstruction. An MWPC located between two Pb layers identifies the conversion layer so that energy loss corrections may be applied, while plastic scintillators provide timing information. Our, group together with a group from the University of Houston, is responsible for the design and construction of the photon detector, as well as developing the computer codes necessary for Monte Carlo simulations and data analysis. During the past year, our efforts have focused primarily on two tasks, delay line cathode read-out and software development. This report describes our recent work on delay lines and data analysis along with a discussion of the new plans for multiplexing in the photon arm.

Gagliardi, C.A.; Tribble, R.E.

1991-01-01

294

Coded IR proximity detector  

Microsoft Academic Search

The coded IR proximity detector is able to generate an electrical signal when the distance between the detector and a certain object becomes shorter than a preset value. The detector may be used as an automotive indicator and control. The detector consists of four parts: a controller, a transmitter, a receiver and the optical system, used both for transmission and

Tudor Zisu; Sorin Miclos

2001-01-01

295

Gas detectors for neutrons  

SciTech Connect

The principles involved in gas detectors for neutrons and the techniques for position encoding in such detectors are reviewed. This forms the basis for a discussion of the limitations on gas detector position resolution and maximum data rates, and of the aging effects in such detectors. Current capabilities and possible areas for improvement are noted.

Crawford, R.K.

1995-07-01

296

PAU camera: detectors characterization  

NASA Astrophysics Data System (ADS)

The PAU Camera (PAUCam) [1,2] is a wide field camera that will be mounted at the corrected prime focus of the William Herschel Telescope (Observatorio del Roque de los Muchachos, Canary Islands, Spain) in the next months. The focal plane of PAUCam is composed by a mosaic of 18 CCD detectors of 2,048 x 4,176 pixels each one with a pixel size of 15 microns, manufactured by Hamamatsu Photonics K. K. This mosaic covers a field of view (FoV) of 60 arcmin (minutes of arc), 40 of them are unvignetted. The behaviour of these 18 devices, plus four spares, and their electronic response should be characterized and optimized for the use in PAUCam. This job is being carried out in the laboratories of the ICE/IFAE and the CIEMAT. The electronic optimization of the CCD detectors is being carried out by means of an OG (Output Gate) scan and maximizing it CTE (Charge Transfer Efficiency) while the read-out noise is minimized. The device characterization itself is obtained with different tests. The photon transfer curve (PTC) that allows to obtain the electronic gain, the linearity vs. light stimulus, the full-well capacity and the cosmetic defects. The read-out noise, the dark current, the stability vs. temperature and the light remanence.

Casas, Ricard; Ballester, Otger; Cardiel-Sas, Laia; Castilla, Javier; Jiménez, Jorge; Maiorino, Marino; Pío, Cristóbal; Sevilla, Ignacio; de Vicente, Juan

2012-07-01

297

Optimizing indium antimonide (InSb) detectors for low background operation. [infrared astronomy  

NASA Technical Reports Server (NTRS)

The various noise sources that affect InSb detectors (and similar voltaic devices) are discussed and calculated. Methods are given for measuring detector resistance, photon loading, detector and amplifier capacitance, amplifier frequency response, amplifier noise, and quantum efficiency. A photovoltaic InSb detector with increased sensitivity in the 1 to 5.6 mu region is dicussed.

Treffers, R. R.

1978-01-01

298

Test results of heavily irradiated Si detectors  

NASA Astrophysics Data System (ADS)

A large use of silicon microstrip detectors is foreseen for the intermediate part of the CMS tracker. A specific research and development program has been carried out with the aim of finding design layouts and technological solutions for allowing silicon microstrip detectors to be reliably used on a high radiation level environment. As a result of this work single sided, AC-coupled, polysilicon biased, 300 ? m thick, p + on n substrate detectors were chosen. Irradiation tests have been performed on prototypes up to fluence 2×10 14 n/cm 2. The detector performances do not significantly change if the detectors are biased well above the depletion voltage. S/ N is reduced by less than 20%, still enough to insure a good efficiency and space resolution. Multiguard structures has been developed in order to reach high voltage operation (above 500 V).

Albergo, S.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Bartalini, P.; Basti, A.; Biggeri, U.; Bilei, G. M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Breuker, H.; Bruzzi, M.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Civinini, C.; Connotte, J.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; de Palma, M.; Dell'Orso, R.; Della Marina, R.; Eklund, C.; Elliott-Peisert, A.; Feld, L.; Fiore, L.; Focardi, E.; French, M.; Freudenreich, K.; Giassi, A.; Giraldo, A.; Glessing, B.; Gu, W. H.; Hall, G.; Hammerstrom, R.; Hrubec, J.; Huhtinen, M.; Karimaki, V.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Martignon, G.; Mc Evoy, B.; Meschini, M.; Messineo, A.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Raffaelli, F.; Raso, G.; Raymond, M.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Skog, K.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P. G.; Viertel, G.; Xie, Z.; Wang, Y.; Watts, S.; Wittmer, B.

1999-02-01

299

Neutron-chamber detectors and applications  

SciTech Connect

Detector applications in Nuclear Safeguards and Waste Management have included measuring neutrons from fission and (alpha,n) reactions with well-moderated neutron proportional counters, often embedded in a slab of polyethylene. Other less-moderated geometries are useful for detecting both bare and moderated fission-source neutrons with good efficiency. The neutron chamber is an undermoderated detector design comprising a large, hollow, polyethylene-walled chamber containing one or more proportional counters. Neutron-chamber detectors are relatively inexpensive; can have large apertures, usually through a thin chamber wall; and offer very good detection efficiency per dollar. Neutron-chamber detectors have also been used for monitoring vehicles and for assaying large crates of transuranic waste. Our Monte Carlo calculations for a new application (monitoring low-density waste for concealed plutonium) illustrate the advantages of the hollow-chamber design for detecting moderated fission sources. 9 refs., 6 figs., 2 tabs.

Fehlau, P.E.; Atwater, H.F.; Coop, K.L.

1990-01-01

300

Large area germanium detector arrays for lung counting: what is the optimum number of detectors?  

PubMed

Using the Lawrence Livermore National Laboratory (LLNL) torso phantom to calibrate a lung counting system can lead to the conclusion that three large area (i.e. >70 mm diameter) Ge detectors will outperform a four-detector array and provide a lower MDA as a four-detector array of large area Ge detectors covers a significant portion of inactive tissue (i.e. non-lung tissue). The lungs of the LLNL phantom, which are approximately 10 cm too short compared with real lungs, also suggests that a two-detector array could be used under limited circumstances. When tested with modified lungs that are more human-like, it was found that the four-detector array showed the best counting efficiency and the lowest MDA. Fortunately, these findings indicate that, although the LLNL phantom's lungs are too short, there is no adverse impact on the calibration of a lung counter. PMID:17151008

Kramer, Gary H; Hauck, Barry M

2007-01-01

301

Large area liquid argon detectors for interrogation systems  

NASA Astrophysics Data System (ADS)

Measurements of the efficiency, pulse shape, and energy and time resolution of liquid argon (LAr) detectors are presented. Liquefied noble gas-based (LNbG) detectors have been developed for the detection of dark matter and neutrinoless double-beta decay. However, the same qualities that make LNbG detectors ideal for these applications, namely their size, cost, efficiency, pulse shape discrimination and resolution, make them promising for portal screening and the detection of Special Nuclear Materials (SNM). Two 18-liter prototype detectors were designed, fabricated, and tested, one with pure LAr and the other doped with liquid Xe (LArXe). The LArXe detector presented the better time and energy resolution of 3.3 ns and 20% at 662 KeV, respectively. The total efficiency of the detector was measured to be 35% with 4.5% of the total photons detected in the photopeak.

Gary, Charles; Kane, Steve; Firestone, Murray I.; Smith, Gregory; Gozani, Tsahi; Brown, Craig; Kwong, John; King, Michael J.; Nikkel, James A.; McKinsey, Dan

2013-04-01

302

A calibrated detector for the vacuum ultraviolet  

Microsoft Academic Search

A detector has been made using a guard-ring photodiode and a phosphor disk and the reproducibility and stability of the phosphor examined. The absolute quantum efficiency of the detector at wavelengths between 584 AA(0.65%) and 1216 AA(0.83%) has been obs. using a thermopile and a rare gas ionization chamber. The theory of a new mode of use of the ionization

J. D. Branch; D. W. O. Heddle; M. J. H. Mogridge

1971-01-01

303

The upgraded DØ detector  

NASA Astrophysics Data System (ADS)

The DØ experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DØ.

Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, D. L.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahmed, S. N.; Ahn, S. H.; Ahsan, M.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Anastasoaie, M.; Andeen, T.; Anderson, J. T.; Anderson, S.; Andrieu, B.; Angstadt, R.; Anosov, V.; Arnoud, Y.; Arov, M.; Askew, A.; Åsman, B.; Assis Jesus, A. C. S.; Atramentov, O.; Autermann, C.; Avila, C.; Babukhadia, L.; Bacon, T. C.; Badaud, F.; Baden, A.; Baffioni, S.; Bagby, L.; Baldin, B.; Balm, P. W.; Banerjee, P.; Banerjee, S.; Barberis, E.; Bardon, O.; Barg, W.; Bargassa, P.; Baringer, P.; Barnes, C.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bhattacharjee, M.; Baturitsky, M. A.; Bauer, D.; Bean, A.; Baumbaugh, B.; Beauceron, S.; Begalli, M.; Beaudette, F.; Begel, M.; Bellavance, A.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Besson, A.; Beuselinck, R.; Beutel, D.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Binder, M.; Biscarat, C.; Bishoff, A.; Black, K. M.; Blackler, I.; Blazey, G.; Blekman, F.; Blessing, S.; Bloch, D.; Blumenschein, U.; Bockenthien, E.; Bodyagin, V.; Boehnlein, A.; Boeriu, O.; Bolton, T. A.; Bonamy, P.; Bonifas, D.; Borcherding, F.; Borissov, G.; Bos, K.; Bose, T.; Boswell, C.; Bowden, M.; Brandt, A.; Briskin, G.; Brock, R.; Brooijmans, G.; Bross, A.; Buchanan, N. J.; Buchholz, D.; Buehler, M.; Buescher, V.; Burdin, S.; Burke, S.; Burnett, T. H.; Busato, E.; Buszello, C. P.; Butler, D.; Butler, J. M.; Cammin, J.; Caron, S.; Bystricky, J.; Canal, L.; Canelli, F.; Carvalho, W.; Casey, B. C. K.; Casey, D.; Cason, N. M.; Castilla-Valdez, H.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chandra, A.; Chapin, D.; Charles, F.; Cheu, E.; Chevalier, L.; Chi, E.; Chiche, R.; Cho, D. K.; Choate, R.; Choi, S.; Choudhary, B.; Chopra, S.; Christenson, J. H.; Christiansen, T.; Christofek, L.; Churin, I.; Cisko, G.; Claes, D.; Clark, A. R.; Clément, B.; Clément, C.; Coadou, Y.; Colling, D. J.; Coney, L.; Connolly, B.; Cooke, M.; Cooper, W. E.; Coppage, D.; Corcoran, M.; Coss, J.; Cothenet, A.; Cousinou, M.-C.; Cox, B.; Crépé-Renaudin, S.; Cristetiu, M.; Cummings, M. A. C.; Cutts, D.; da Motta, H.; Das, M.; Davies, B.; Davies, G.; Davis, G. A.; Davis, W.; De, K.; de Jong, P.; de Jong, S. J.; De La Cruz-Burelo, E.; De La Taille, C.; De Oliveira Martins, C.; Dean, S.; Degenhardt, J. D.; Déliot, F.; Delsart, P. A.; Del Signore, K.; DeMaat, R.; Demarteau, M.; Demina, R.; Demine, P.; Denisov, D.; Denisov, S. P.; Desai, S.; Diehl, H. T.; Diesburg, M.; Doets, M.; Doidge, M.; Dong, H.; Doulas, S.; Dudko, L. V.; Duflot, L.; Dugad, S. R.; Duperrin, A.; Dvornikov, O.; Dyer, J.; Dyshkant, A.; Eads, M.; Edmunds, D.; Edwards, T.; Ellison, J.; Elmsheuser, J.; Eltzroth, J. T.; Elvira, V. D.; Eno, S.; Ermolov, P.; Eroshin, O. V.; Estrada, J.; Evans, D.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Fagan, J.; Fast, J.; Fatakia, S. N.; Fein, D.; Feligioni, L.; Ferapontov, A. V.; Ferbel, T.; Ferreira, M. J.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fleck, I.; Fitzpatrick, T.; Flattum, E.; Fleuret, F.; Flores, R.; Foglesong, J.; Fortner, M.; Fox, H.; Franklin, C.; Freeman, W.; Fu, S.; Fuess, S.; Gadfort, T.; Galea, C. F.; Gallas, E.; Galyaev, E.; Gao, M.; Garcia, C.; Garcia-Bellido, A.; Gardner, J.; Gavrilov, V.; Gay, A.; Gay, P.; Gelé, D.; Gelhaus, R.; Genser, K.; Gerber, C. E.; Gershtein, Y.; Gillberg, D.; Geurkov, G.; Ginther, G.; Gobbi, B.; Goldmann, K.; Golling, T.; Gollub, N.; Golovtsov, V.; Gómez, B.; Gomez, G.; Gomez, R.; Goodwin, R.; Gornushkin, Y.; Gounder, K.; Goussiou, A.; Graham, D.; Graham, G.; Grannis, P. D.; Gray, K.; Greder, S.; Green, D. R.; Green, J.; Green, J. A.; Greenlee, H.; Greenwood, Z. D.; Gregores, E. M.; Grinstein, S.; Gris, Ph.; Grivaz, J.-F.; Groer, L.; Grünendahl, S.; Grünewald, M. W.; Gu, W.; Guglielmo, J.; Gupta, A.; Gurzhiev, S. N.; Gutierrez, G.; Gutierrez, P.; Haas, A.; Hadley, N. J.; Haggard, E.; Haggerty, H.; Hagopian, S.; Hall, I.; Hall, R. E.; Han, C.; Han, L.; Hance, R.; Hanagaki, K.; Hanlet, P.; Hansen, S.; Harder, K.; Harel, A.; Harrington, R.; Hauptman, J. M.; Hauser, R.; Hays, C.; Hays, J.; Hazen, E.; Hebbeker, T.; Hebert, C.; Hedin, D.; Heinmiller, J. M.; Heinson, A. P.; Heintz, U.; Hensel, C.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hohlfeld, M.; Hong, S. J.; Hooper, R.; Hou, S.; Houben, P.; Hu, Y.; Huang, J.; Huang, Y.; Hynek, V.; Huffman, D.; Iashvili, I.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jacquier, Y.; Jaffré, M.; Jain, S.; Jain, V.; Jakobs, K.; Jayanti, R.; Jenkins, A.; Jesik, R.; Jiang, Y.; Johns, K.; Johnson, M.; Johnson, P.; Jonckheere, A.; Jonsson, P.; Jöstlein, H.; Jouravlev, N.; Juarez, M.; Juste, A.; Kaan, A. P.; Kado, M. M.; Käfer, D.; Kahl, W.; Kahn, S.; Kajfasz, E.

2006-09-01

304

High resolution gamma ray spectroscopy with CdTe detector systems  

Microsoft Academic Search

Energy resolution and photopeak efficiency of the nowadays CdTe detector material can be improved using several detector shapes or electronic signal processing. Current results obtained in our laboratory with different detector geometries and pulse discrimination methods are presented and compared. Finally, we report on a new charge loss compensation method which improves both energy resolution and photopeak efficiency.

M. Richter; P. Siffert

1992-01-01

305

A panoramic photon-counting detector system  

NASA Astrophysics Data System (ADS)

The characteristics and implementation of the Laval Image Photon-Counting System (LIPS) are described. LIPS is a flexible, compact, and transportable two-dimensional detector system which is currently in use in the spectroscopic mode on the 1.6 m telescope at the Mont Megantic Observatory. The detector is described, including the quantum efficiency, resolution, linearity, noise characteristics, and distortions. The data acquisition and display module is considered, including the computer, image display unit, Direct Memory Access Board which controls the detector, and control and data-acquisition program. Spectroscopy using LIPS is briefly addressed. The present assessment of the system and its future use are discussed.

Durand, Daniel; Hardy, Eduardo; Couture, Jean

1987-07-01

306

Silicon Detectors Applied to Medical Imaging  

NASA Astrophysics Data System (ADS)

In this laboratory we will see some to those characteristics of silicon detectors which make them very useful in the fields of Medical Physics. One of the application of these devices that we will work with is in detecting low energy X-ray radiation (from 6 to 30KeV). In this laboratory we will learn something of the aquisition system (LabVIEW), the readout system (PCI-1200 card, buffer, RX64 chip and the silicon detector on the printed circuit board) and the measurements of the X rays (coming from a radiation source) for different positions of the detector, in searching for improving the efficiency of detection.

Montaño Zetina, Luis Manuel

2003-07-01

307

Operational Experience with the CMS Pixel Detector  

E-print Network

In the first LHC running period the CMS-pixel detector had to face various operational challenges and had to adapt to the rapidly changing beam conditions. In order to maximize the physics potential and the quality of the data, online and offline calibrations were performed on a regular basis. The detector performed excellently with an average hit efficiency above 99% for all layers and disks. In this contribution the operational challenges of the silicon pixel detector in the first LHC run and the current long shutdown are summarized and the expectations for 2015 are discussed.

János Karancsi

2014-11-15

308

Neutron detection with imaging plates Part II. Detector characteristics  

Microsoft Academic Search

On the basis of the physical processes described in Neutron detection with imaging plates – part I: image storage and readout [Nucl. Instr. and Meth. A 424 (1999) 26–33] detector characteristics, such as quantum efficiency, detective quantum efficiency, sensitivity to neutron- and ?-radiation, readout time and dynamic range are predicted. It is estimated that quantum efficiencies and detective quantum efficiencies

M. Thoms

1999-01-01

309

Development of {gamma}-ray detectors for {sup 16}O(p,p'{gamma}) experiment  

SciTech Connect

The {gamma} ray production in neutral-current (NC) neutrino-oxygen interaction is very important to the detection of neutrinos from supernova explosion in a neutrino experiment, since those {gamma} rays can become extra signals or unexpected background in the energy region from 5 MeV to 30 MeV. We propose the experiment to measure {gamma} rays in {sup 16}O(p,p') reaction at Research Center for Nuclear Physics (RCNP, Osaka) to provide good information on the {gamma}-ray emission spectra in neutrino-oxygen reactions. We present the design of {gamma}-ray detectors (NaI, CsI, HPGe), which will be used in proposed experiment.

Mori, T.; Izumi, T.; Ou, I.; Yano, T.; Sakuda, M.; Tamii, A.; Suzuki, T.; Yosoi, M. [Department of physiscs, Okayama University, Okaymaa 700-8530 (Japan); Research Center for Nuclear Physics (RCNP), Ibaraki, Osaka 567-0047 (Japan)

2012-11-12

310

Plasmonic photoconductive detectors for enhanced terahertz detection sensitivity.  

PubMed

A photoconductive terahertz detector based on plasmonic contact electrodes is presented. The use of plasmonic electrodes mitigates the inherent tradeoff between high quantum efficiency and ultrafast operation of the employed photoconductor, enabling significantly higher detection sensitivities compared to conventional photoconductive terahertz detectors. Prototypes of comparable photoconductive detectors with and without plasmonic contact electrode gratings were fabricated and characterized in a time-domain terahertz spectroscopy setup under the same operation conditions. The experimental results show that the plasmonic photoconductive detector offers more than 30 times higher terahertz detection sensitivities compared to the comparable conventional photoconductive detector without plasmonic contact electrodes over 0.1-1.5 THz frequency band. PMID:23938568

Wang, Ning; Hashemi, Mohammad R; Jarrahi, Mona

2013-07-15

311

Infrared Detector: Card Model  

NSDL National Science Digital Library

This resource describes the physics of a simple infra-red detector. A simulation is used to illustrate energy level dependence and electron transitions in the detector. Discussion problems and comparison with other physical applications are included.

Zollman, Dean

2010-08-10

312

Tin Can Radiation Detector.  

ERIC Educational Resources Information Center

Provides instructions for making tin can radiation detectors from empty aluminum cans, aluminum foil, clear plastic, copper wire, silica gel, and fine, unwaxed dental floss put together with tape or glue. Also provides suggestions for activities using the detectors. (JN)

Crull, John L.

1986-01-01

313

Asynchronous Failure Detectors  

E-print Network

Failure detectors -- oracles that provide information about process crashes -- are an important abstraction for crash tolerance in distributed systems. The generality of failure-detector theory, while providing great ...

Cornejo, Alejandro

2013-01-30

314

Asynchronous failure detectors  

E-print Network

Failure detectors - oracles that provide information about process crashes - are an important abstraction for crash tolerance in distributed systems. Although current failure-detector theory provides great generality and ...

Cornejo, Alejandro

315

Asynchronous Failure Detectors  

E-print Network

Failure detectors -- oracles that provide information about process crashes -- are an important abstraction for crash tolerance in distributed systems. The generality of failure-detector theory, while providing great ...

Cornejo, Alejandro

2013-10-10

316

Transient fault detectors  

Microsoft Academic Search

We present fault detectors for transient faults, (i.e., corruptions of the memory of the processors, but not of the code of\\u000a the processors). We distinguish fault detectors for tasks (i.e., the problem to be solved) from failure detectors for implementations (i.e., the algorithm that solves the problem). The aim of our fault detectors is to detect a memory corruption as

Joffroy Beauquier; Sylvie Delaët; Shlomi Dolev; Sébastien Tixeuil

2007-01-01

317

The upgraded DØ detector  

Microsoft Academic Search

The DØ experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward

V. M. Abazov; B. Abbott; M. Abolins; B. S. Acharya; D. L. Adams; M. Adams; T. Adams; M. Agelou; J.-L. Agram; S. N. Ahmed; S. H. Ahn; M. Ahsan; G. D. Alexeev; G. Alkhazov; A. Alton; G. Alverson; G. A. Alves; M. Anastasoaie; T. Andeen; J. T. Anderson; S. Anderson; B. Andrieu; R. Angstadt; V. Anosov; Y. Arnoud; M. Arov; A. Askew; B. Åsman; A. C. S. Assis Jesus; O. Atramentov; C. Autermann; C. Avila; L. Babukhadia; T. C. Bacon; F. Badaud; A. Baden; S. Baffioni; L. Bagby; B. Baldin; P. W. Balm; P. Banerjee; S. Banerjee; E. Barberis; O. Bardon; W. Barg; P. Bargassa; P. Baringer; C. Barnes; J. Barreto; J. F. Bartlett; U. Bassler; M. Bhattacharjee; M. A. Baturitsky; D. Bauer; A. Bean; B. Baumbaugh; S. Beauceron; M. Begalli; F. Beaudette; M. Begel; A. Bellavance; S. B. Beri; G. Bernardi; R. Bernhard; I. Bertram; M. Besançon; A. Besson; R. Beuselinck; D. Beutel; V. A. Bezzubov; P. C. Bhat; V. Bhatnagar; M. Binder; C. Biscarat; A. Bishoff; K. M. Black; I. Blackler; G. Blazey; F. Blekman; S. Blessing; D. Bloch; U. Blumenschein; E. Bockenthien; V. Bodyagin; A. Boehnlein; O. Boeriu; T. A. Bolton; P. Bonamy; D. Bonifas; F. Borcherding; G. Borissov; K. Bos; T. Bose; C. Boswell; M. Bowden; A. Brandt; G. Briskin; R. Brock; G. Brooijmans; A. Bross; N. J. Buchanan; D. Buchholz; M. Buehler; V. Buescher; S. Burdin; S. Burke; T. H. Burnett; E. Busato; C. P. Buszello; D. Butler; J. M. Butler; J. Cammin; S. Caron; J. Bystricky; L. Canal; F. Canelli; W. Carvalho; B. C. K. Casey; D. Casey; N. M. Cason; H. Castilla-Valdez; S. Chakrabarti; D. Chakraborty; K. M. Chan; A. Chandra; D. Chapin; F. Charles; E. Cheu; L. Chevalier; E. Chi; R. Chiche; D. K. Cho; R. Choate; S. Choi; B. Choudhary; S. Chopra; J. H. Christenson; T. Christiansen; L. Christofek; I. Churin; G. Cisko; D. Claes; A. R. Clark; B. Clément; C. Clément; Y. Coadou; D. J. Colling; L. Coney; B. Connolly; M. Cooke; W. E. Cooper; D. Coppage; M. Corcoran; J. Coss; A. Cothenet; M.-C. Cousinou; B. Cox; S. Crépé-Renaudin; M. Cristetiu; M. A. C. Cummings; D. Cutts; H. da Motta; M. Das; B. Davies; G. Davies; G. A. Davis; W. Davis; K. de; P. de Jong; S. J. de Jong; E. De La Cruz-Burelo; C. De La Taille; C. De Oliveira Martins; S. Dean; J. D. Degenhardt; F. Déliot; P. A. Delsart; K. Del Signore; R. Demaat; M. Demarteau; R. Demina; P. Demine; D. Denisov; S. P. Denisov; S. Desai; H. T. Diehl; M. Diesburg; M. Doets; M. Doidge; H. Dong; S. Doulas; L. V. Dudko; L. Duflot; S. R. Dugad; A. Duperrin; O. Dvornikov; J. Dyer; A. Dyshkant; M. Eads; D. Edmunds; T. Edwards; J. Ellison; J. Elmsheuser; J. T. Eltzroth; V. D. Elvira; S. Eno; P. Ermolov; O. V. Eroshin; J. Estrada; D. Evans; H. Evans; A. Evdokimov; V. N. Evdokimov; J. Fagan; J. Fast; S. N. Fatakia; D. Fein; L. Feligioni; A. V. Ferapontov; T. Ferbel; M. J. Ferreira; F. Fiedler; F. Filthaut; W. Fisher; H. E. Fisk; I. Fleck; T. Fitzpatrick; E. Flattum; F. Fleuret; R. Flores; J. Foglesong; M. Fortner; H. Fox; C. Franklin; W. Freeman; S. Fu; S. Fuess; T. Gadfort; C. F. Galea; E. Gallas; E. Galyaev; M. Gao; C. Garcia; A. Garcia-Bellido; J. Gardner; V. Gavrilov; A. Gay; P. Gay; D. Gelé; R. Gelhaus; K. Genser; C. E. Gerber; Y. Gershtein; D. Gillberg; G. Geurkov; G. Ginther; B. Gobbi; K. Goldmann; T. Golling; N. Gollub; V. Golovtsov; B. Gómez; G. Gomez; R. Gomez; R. Goodwin; Y. Gornushkin; K. Gounder; A. Goussiou; D. Graham; G. Graham; P. D. Grannis; K. Gray; S. Greder; D. R. Green; J. Green; H. Greenlee; Z. D. Greenwood; E. M. Gregores; S. Grinstein; Ph. Gris; J.-F. Grivaz; L. Groer; S. Grünendahl; M. W. Grünewald; W. Gu; J. Guglielmo; A. Gupta; S. N. Gurzhiev; G. Gutierrez; P. Gutierrez; A. Haas; N. J. Hadley; E. Haggard; H. Haggerty; S. Hagopian; I. Hall; R. E. Hall; C. Han; L. Han; R. Hance; K. Hanagaki; P. Hanlet; S. Hansen; K. Harder; A. Harel; R. Harrington; J. M. Hauptman; R. Hauser; C. Hays; J. Hays; E. Hazen; T. Hebbeker; C. Hebert; D. Hedin; J. M. Heinmiller; A. P. Heinson; U. Heintz; C. Hensel; G. Hesketh; M. D. Hildreth; R. Hirosky; J. D. Hobbs; B. Hoeneisen; M. Hohlfeld; S. J. Hong; R. Hooper; S. Hou; P. Houben; Y. Hu; J. Huang; Y. Huang; V. Hynek; D. Huffman; I. Iashvili; R. Illingworth; A. S. Ito; S. Jabeen; Y. Jacquier; M. Jaffré; S. Jain; V. Jain; K. Jakobs; R. Jayanti; A. Jenkins; R. Jesik; Y. Jiang; K. Johns; M. Johnson; P. Johnson; A. Jonckheere; P. Jonsson; H. Jöstlein; N. Jouravlev; M. Juarez; A. Juste; A. P. Kaan; M. M. Kado; D. Käfer; W. Kahl; S. Kahn; E. Kajfasz; A. M. Kalinin; J. Kalk; S. D. Kalmani; D. Karmanov; J. Kasper; I. Katsanos; D. Kau; R. Kaur; Z. Ke; R. Kehoe; S. Kermiche; S. Kesisoglou; A. Khanov; A. Kharchilava; Y. M. Kharzheev; H. Kim; K. H. Kim; T. J. Kim; N. Kirsch; B. Klima; M. Klute; J. M. Kohli; J.-P. Konrath; E. V. Komissarov; M. Kopal; V. M. Korablev; A. Kostritski; J. Kotcher; B. Kothari; A. V. Kotwal; A. Koubarovsky; A. V. Kozelov; J. Kozminski; A. Kryemadhi; O. Kouznetsov

2006-01-01

318

Tevatron detector upgrades  

SciTech Connect

The D0 and CDF experiments are in the process of upgrading their detectors to cope with the high luminosities projected for the remainder of Tevatron Run II. They discuss the expected Tevatron environment through 2009, the detector challenges due to increasing luminosity in this period, and the solutions undertaken by the two experiments to mitigate detector problems and maximize physics results.

Lipton, R.; /Fermilab

2005-01-01

319

Gamma ray detector shield  

DOEpatents

A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

Ohlinger, R.D.; Humphrey, H.W.

1985-08-26

320

Detectors for lightwave communication  

Microsoft Academic Search

Lightwave communication links need photodetectors and optical receivers to demodulate the optical signals and to convert them into electrical outputs. Photodetectors include simple thermal detectors, which respond to the energy of the incident radiation, and photon detectors, which respond to the arrival rate of the photons. The photon detectors which were found to be most suitable for lightwave communication at

Hans Melchior

1977-01-01

321

Differential optical proximity detector  

NASA Technical Reports Server (NTRS)

Updated detector can operate under ambient light and uses multiple detectors to locate objects in several different spacial volumes. Sensitivity is approved by scanning field-of-view twice: once with coherent light source turned on and once with background light only. Detector outputs for two cases are amplified and subtracted for each photodiode sensor in array, to eliminate effect of background light.

Johnston, A. R.; Shimada, K.; Tippins, H. H., Jr.

1977-01-01

322

Optical detectors for spectroscopy  

NASA Technical Reports Server (NTRS)

The modes of operation of photoconductive and photoemissive array detectors are described, and their performance characteristics compared and contrasted, with emphasis on their suitability for use as detectors for optical spectroscopy. The prospects for future developments of the array detectors are discussed.

Timothy, J. G.

1983-01-01

323

CALIFA Barrel prototype detector characterisation  

NASA Astrophysics Data System (ADS)

Well established in the field of scintillator detection, Caesium Iodide remains at the forefront of scintillators for use in modern calorimeters. Recent developments in photosensor technology have lead to the production of Large Area Avalanche Photo Diodes (LAAPDs), a huge advancement on traditional photosensors in terms of high internal gain, dynamic range, magnetic field insensitivity, high quantum efficiency and fast recovery time. The R3B physics programme has a number of requirements for its calorimeter, one of the most challenging being the dual functionality as both a calorimeter and a spectrometer. This involves the simultaneous detection of ?300 MeV protons and gamma rays ranging from 0.1 to 20 MeV. This scintillator - photosensor coupling provides an excellent solution in this capacity, in part due to the near perfect match of the LAAPD quantum efficiency peak to the light output wavelength of CsI(Tl). Modern detector development is guided by use of Monte Carlo simulations to predict detector performance, nonetheless it is essential to benchmark these simulations against real data taken with prototype detector arrays. Here follows an account of the performance of two such prototypes representing different polar regions of the Barrel section of the forthcoming CALIFA calorimeter. Measurements were taken for gamma-ray energies up to 15.1 MeV (Maier-Leibnitz Laboratory, Garching, Germany) and for direct irradiation with a 180 MeV proton beam (The Svedberg Laboratoriet, Uppsala, Sweden). Results are discussed in light of complementary GEANT4 simulations.

Pietras, B.; Gascón, M.; Álvarez-Pol, H.; Bendel, M.; Bloch, T.; Casarejos, E.; Cortina-Gil, D.; Durán, I.; Fiori, E.; Gernhäuser, R.; González, D.; Kröll, T.; Le Bleis, T.; Montes, N.; Nácher, E.; Robles, M.; Perea, A.; Vilán, J. A.; Winkel, M.

2013-11-01

324

Test vehicle detector characterization system for the Boeing YAL-1 airborne laser  

E-print Network

The test vehicle detector characterization system provides a convenient and efficient tool for rapidly evaluating the optical sensitivity of the GAP6012, GAP100, GAP300, and GAP1000 indium gallium arsenide detectors used ...

Steininger-Holmes, Jason Thomas

2008-01-01

325

Coated Fiber Neutron Detector Test  

SciTech Connect

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Reported here are the results of tests of the 6Li/ZnS(Ag)-coated non-scintillating plastic fibers option. This testing measured the required performance for neutron detection efficiency and gamma ray rejection capabilities of a system manufactured by Innovative American Technology (IAT).

Lintereur, Azaree T.; Ely, James H.; Kouzes, Richard T.; Stromswold, David C.

2009-10-23

326

High-energy detector  

DOEpatents

The preferred embodiments are directed to a high-energy detector that is electrically shielded using an anode, a cathode, and a conducting shield to substantially reduce or eliminate electrically unshielded area. The anode and the cathode are disposed at opposite ends of the detector and the conducting shield substantially surrounds at least a portion of the longitudinal surface of the detector. The conducting shield extends longitudinally to the anode end of the detector and substantially surrounds at least a portion of the detector. Signals read from one or more of the anode, cathode, and conducting shield can be used to determine the number of electrons that are liberated as a result of high-energy particles impinge on the detector. A correction technique can be implemented to correct for liberated electron that become trapped to improve the energy resolution of the high-energy detectors disclosed herein.

Bolotnikov, Aleksey E. (South Setauket, NY); Camarda, Giuseppe (Farmingville, NY); Cui, Yonggang (Upton, NY); James, Ralph B. (Ridge, NY)

2011-11-22

327

Improving the spectral resolution of a highly pixelated detector by applying a pixel-by-pixel energy calibration for investigating the spectral properties of the anode heel effect  

NASA Astrophysics Data System (ADS)

The energy deposition spectrum measured with highly pixelated photon-counting pixel detectors with a semiconductor sensor layer (e.g. silicon) differs significantly from the impinging X-ray spectrum. This is the main disadvantage compared to commonly known X-ray spectrometers, e.g. high purity Germanium (hpGe) detector. On the other hand, those hpGe-detectors have a lack of spatial resolution and can not be used for energy-resolved imaging. In case of measurements with highly pixelated detectors, a set of monoenergetic detector response functions is needed for the deconvolution of the measured distribution into the impinging spectrum. We have investigated the possibility of applying a pixel-by-pixel calibration on a highly pixelated detector for gaining a higher energy resolution and for lowering the minimal flux needed for the deconvolution. As a result it is now possible to utilize small ROIs of the pixel matrix for the deconvolution. With this analysis method the detector enables spectral X-ray imaging of high photon rates. This is in particular shown for the angular dependency of the anode heel effect on the emitted spectrum.

Sievers, P.; Klammer, J.; Michel, T.; Hupe, O.; Anton, G.

2012-07-01

328

The vertex detector for the Lepton/Photon collaboration  

SciTech Connect

The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two con- centric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity ({nu}) distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed.

Sullivan, J.P.; Boissevain, J.G.; Fox, D.; Hecke, H. van; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E. [Los Alamos National Lab., NM (United States)

1991-12-31

329

Operational Experience with the ATLAS Pixel Detector at the LHC  

E-print Network

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as B-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification.

Lapoire, C; The ATLAS collaboration

2012-01-01

330

Operational experience with the ATLAS Pixel Detector at the LHC  

E-print Network

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Lapoire, C; The ATLAS collaboration

2011-01-01

331

Operational experience with the ATLAS Pixel Detector at the LHC  

E-print Network

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.7% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Hirschbuehl, D; The ATLAS collaboration

2011-01-01

332

Operational experience with the ATLAS Pixel Detector at the LHC  

E-print Network

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.8% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Ince, T; The ATLAS collaboration

2011-01-01

333

Operational Experience with the ATLAS Pixel Detector at the LHC  

E-print Network

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump- bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, a...

Lange, C; The ATLAS collaboration

2011-01-01

334

Operational experience with the ATLAS Pixel detector at the LHC  

E-print Network

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5\\% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, ...

Deluca, C; The ATLAS collaboration

2011-01-01

335

Monolithic short wave infrared (SWIR) detector array  

NASA Technical Reports Server (NTRS)

A monolithic self-scanned linear detector array was developed for remote sensing in the 1.1- 2.4-micron spectral region. A high-density IRCCD test chip was fabricated to verify new design approaches required for the detector array. The driving factors in the Schottky barrier IRCCD (Pdsub2Si) process development are the attainment of detector yield, uniformity, adequate quantum efficiency, and lowest possible dark current consistent with radiometric accuracy. A dual-band module was designed that consists of two linear detector arrays. The sensor architecture places the floating diffusion output structure in the middle of the chip, away from the butt edges. A focal plane package was conceptualized and includes a polycrystalline silicon substrate carrying a two-layer, thick-film interconnecting conductor pattern and five epoxy-mounted modules. A polycrystalline silicon cover encloses the modules and bond wires, and serves as a radiation and EMI shield, thermal conductor, and contamination seal.

1983-01-01

336

Ion Technique for Identifying Gamma Detector Candidates  

SciTech Connect

Recent demands for radiation detector materials with better energy resolution at room temperature have prompted research efforts on both accelerated material discovery and efficient analysis techniques. Ions can easily deposit their energy in thin films or small crystals and the radiation response can be used to identify material properties relevant to detector performance. In an effort to identify gamma detector candidates using small crystals or film samples, an ion technique is developed to measure relative light yield and energy resolution of candidate materials and to evaluate radiation detection performance. Employing a unique time-of-flight (TOF) telescope, light yield and energy resolution resulting from ion excitation are investigated over a continuous energy region. The efficiency of this ion technique is demonstrated using both organic (plastic scintillator) and inorganic (CaF2:Eu, YAP:Ce, CsI:Tl and BGO) scintillators.

Zhang, Yanwen; Xiang, Xia; Rausch, Julie L.; Zu, Xiaotao T.; Weber, William J.

2009-06-15

337

Neutron Detection Efficiency of the  

E-print Network

Neutron Detection Efficiency of the CLAS12 Detector M. Moog and G. Gilfoyle University Of Richmond - Department of Physics Software We simulated the neutron detection efficiency of the forward time of flight plots and perform the final analysis of the simulation. Introduction Knowledge of the neutron detection

Gilfoyle, Jerry

338

Spectrometric characteristic improvement of CdTe detectors  

Microsoft Academic Search

A new pulse shape correction method combined with a pulse shape selection method has been proposed for a CdTe detectors energy resolution improvement and increasing the total absorption peak efficiency. The capabilities of the new technique for the spectrometric characteristic improvement are based on using specific features of the CdTe detectors output pulses. The energy resolution of about 1% FWHM

V. I. Ivanov; V. A. Garbusin; P. G. Dorogov; A. E. Loutchanski; V. V. Kondrashov

1995-01-01

339

CZT drift strip detectors for high energy astrophysics  

Microsoft Academic Search

Requirements for X- and gamma ray detectors for future High Energy Astrophysics missions include high detection efficiency and good energy resolution as well as fine position sensitivity even in three dimensions.We report on experimental investigations on the CZT drift detector developed DTU Space. It is operated in the planar transverse field (PTF) mode, with the purpose of demonstrating that the

I. Kuvvetli; C. Budtz-Jørgensen; E. Caroli; N. Auricchio

2010-01-01

340

Author's personal copy Perforated diode neutron detector modules fabricated from  

E-print Network

to thermal neutrons. The prototype devices deliver 4.7% thermal neutron detection efficiency while operatingAuthor's personal copy Perforated diode neutron detector modules fabricated from high 66506-2503, USA a r t i c l e i n f o PACS: 29.40.Wk Keywords: Semiconductor neutron detectors

Shultis, J. Kenneth

341

BATSE spectroscopy detector calibration  

NASA Technical Reports Server (NTRS)

We describe the channel-to-energy calibration of the Spectroscopy Detectors of the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (GRO). These detectors consist of NaI(TI) crystals viewed by photomultiplier tubes whose output in turn is measured by a pulse height analyzer. The calibration of these detectors has been complicated by frequent gain changes and by nonlinearities specific to the BATSE detectors. Nonlinearities in the light output from the NaI crystal and in the pulse height analyzer are shifted relative to each other by changes in the gain of the photomultiplier tube. We present the analytical model which is the basis of our calibration methodology, and outline how the empirical coefficients in this approach were determined. We also describe the complications peculiar to the Spectroscopy Detectors, and how our understanding of the detectors' operation led us to a solution to these problems.

Band, D.; Ford, L.; Matteson, J.; Lestrade, J. P.; Teegarden, B.; Schaefer, B.; Cline, T.; Briggs, M.; Paciesas, W.; Pendleton, G.

1992-01-01

342

Detectors (4/5)  

ScienceCinema

This lecture will serve as an introduction to particle detectors and detection techniques. In the first lecture, a historic overview of particle detector development will be given. In the second lecture, some basic techniques and concepts for particle detection will be discussed. In the third lecture, the interaction of particles with matter, the basis of particle detection, will be presented. The fourth and fifth lectures will discuss different detector types used for particle tracking, energy measurement and particle identification.

None

2011-10-06

343

Detectors (5/5)  

ScienceCinema

This lecture will serve as an introduction to particle detectors and detection techniques. In the first lecture, a historic overview of particle detector development will be given. In the second lecture, some basic techniques and concepts for particle detection will be discussed. In the third lecture, the interaction of particles with matter, the basis of particle detection, will be presented. The fourth and fifth lectures will discuss different detector types used for particle tracking, energy measurement and particle identification.

None

2011-10-06

344

Detectors of gravitational waves  

NASA Astrophysics Data System (ADS)

Gravitational waves Motion of test bodies in a g.w. field Energy carried by gravitational waves Gravitational-wave sources Spinning star Double-star systems Fall into a Schwarzschild black hole Radiation from gravitational collapse Gravitational-wave detectors The nonresonant detectors The resonant detectors Electromechnical transducers Piezoelectric ceramic The capacitor The inductor Data analysis The Brownian noise The back-action The wide-band noise, data analysis and optimization The resonant transducer The Wiener-Kolmogoroff filter The cross-section and the effective temperature The antenna bandwidth The gravitational-wave experiments in the world The laser interferometers The resonant detectors

Pizzella, G.

345

SNM Detection with a Large Water Cerenkov Detector  

SciTech Connect

Special Nuclear Material (SNM) can either spontaneously fission, or be induced to do so. Either case results in neutron emission. Since neutrons are highly penetrating and difficult to shield, they could, potentially, be detected escaping even a well shielded cargo container. Obviously, if the shielding is sophisticated, detecting it would require a highly efficient detector with close to 4{pi} solid angle coverage. Water Cerenkov detectors may be a cost effective way to achieve that goal if it can be shown that the neutron capture signature is large enough and if sufficient background rejection can be employed as detectors get larger. In 2008 the LLNL Advanced Detector Group reported the successful detection of neutrons with a 1/4 ton gadolinium doped water Cerenkov prototype. We have now built a 4 ton version. This detector is not only bigger, it was designed with photon detection efficiency in mind from the beginning. We are employing increased photocathode coverage and more reflective walls, coated with PTFE. The increased efficiency should allow better energy resolution. We expect that the better diffusive wall reflectivity will reduce the overall dependence of the detector response on particle direction, again producing a more consistent response. We also believe that as detectors get larger, both uncorrelated and correlated backgrounds due to gamma-rays and cosmic ray interactions near the detector will increase. To prove the effectiveness of the technology we must develop new ways to reject these backgrounds while maintaining our sensitivity to SNM neutrons. Better energy resolution will enable us to reject more of the low energy gamma-ray backgrounds on this basis. Overcoming cosmic ray induced neutrons is perhaps an even larger concern as detectors get larger. Our detector is designed so that we can test various segmentation schemes - effectively dividing the detector up into smaller ones. In this presentation, we will describe our detector in detail.

Dazeley, S; Bernstein, A; Bowden, N; Ouedraogo, S; Svoboda, R; Sweeny, M

2009-06-04

346

Radiation Effect On Gas Electron Multiplier Detector Performance  

SciTech Connect

Gas Electron Multiplier (GEM) detector is a gas device with high gain and high efficiency. These detectors use chemically perforated 65 {mu}m thick copper clad Kapton polyimide foils. Given its potential for detecting X-rays and other radiations, GEM detectors may be used in an environment with high radioactivity. The Kapton foils manufacturer, Du Pont Inc., claims that the foils are radioactive resistant. To verify whether the GEM detector performance is affected by the exposure to radiation, several GEM foils were irradiated to a {sup 60}Co source at the gamma-ray irradiation facility at Sterigenics, Tustin, CA. Four sets of GEM foils were exposed to the level of 10 kGy, 100 kGy, 1,000 kGy and 10,000 kGy. The output signal from the GEM detectors with irradiated GEM foils were measured and compared to the detector with no irradiation. We observed that the shapes of the peaks from 5.9 KeV {sup 55}Fe X-ray were distorted and that the detector gain increased compared to that of the un-irradiated detector. In particular, the detector with 10,000 kGy irradiation appeared to have the biggest peak distortion and increased gain. It was also found from that additional electrons from radiation-induced free radicals in the Kapton film contribute to output signal of the irradiated GEM detectors. Further studies are needed to explain the mechanism of these detector performance changes.

Park, Kwang June [Korean Atomic Energy Research Institute, Daejeon, 305-600 (Korea, Republic of); Baldeloma, Edwin; Park, Seongtae; White, Andrew P.; Yu, Jaehoon [Department of Physics, University of Texas at Arlington, Arlington TX 76019 (United States)

2011-06-01

347

Comparison of the LLNL and JAERI torso phantoms using Ge detectors and phoswich detectors.  

PubMed

The Human Monitoring Laboratory has compared the LLNL and JAERI torso phantoms using its germanium detector lung counting system by measuring the counting efficiencies for radioactive materials in the phantoms at photon energies of 17.7 keV, 59.5 keV, 121.8 keV, and 344 keV to assess the similarity (or differences) in performance characteristics. The counting efficiencies obtained from the two phantoms were compared by converting the Chest Wall Thickness data and Adipose Mass Fractions of the phantoms to Muscle Equivalent Chest Wall Thicknesses. The counting efficiencies for the two phantoms were found to be within a factor of 1.44 of each other at 17.7 keV, 1.30 at 59.5 keV, 1.25 at 121.8 keV, and 1.17 at 344 keV when using a four detector array (JAERI efficiency divided by LLNL efficiency). However, individual detector responses show that the counting efficiencies from the two phantoms differ considerably in the region of the heart (up to a factor of 6 at 17 keV). Other areas above the lungs give counting efficiencies that are similar to each other. A routine intercomparison exercise with Cameco Corporation has shown that the counting efficiencies derived from the LLNL and JAERI phantoms were found to be within a factor of 1.18 (JAERI/LLNL) when a natural uranium lung set was used to calibrate a lung counter consisting of phoswich detectors. This work has also shown that over the energy range 63 keV-185 keV the LLNL phantom can be used to calibrate phoswich detector systems that are positioned on the back of the subject. PMID:9570163

Kramer, G H; Hauck, B M; Allen, S A

1998-05-01

348

Assessing CZT detector performance for environmental radioactivity investigations.  

PubMed

Cadmium zinc telluride (CdZnTe or CZT) is the leading semiconductor detector for gamma spectroscopy at room temperature. In the present study, a coplanar-grid CZT detector was used for gamma-ray measurements of environmental radioactivity on a contaminated saltmarsh sediment core in comparison with results from a coaxial high-purity germanium detector to assess their comparative performance. The findings reveal that the CZT performs well for both (241)Am and (137)Cs measurements over a broad range of activities, despite limited detector efficiency, and can be used to good effect in the study of environmental radioactivity in contaminated estuarine settings. PMID:23060429

Rahman, Rubina; Plater, A J; Nolan, P J; Appleby, P G

2013-05-01

349

Scintillation detectors in gamma spectral logging; geometry, absorption and calibration  

USGS Publications Warehouse

The theory for the evaluation of the effects of geometry in gamma ray absorption is developed for cylindrical scintillation detectors as applicable to borehole gamma spectrometry. The results of a laboratory experiment are shown for comparison. A calibration procedure to determine detector efficiency is given for application to borehole probes. It is shown that the response of a crystal can be separated in terms of geometric effects and instrumentation effects. It is also shown that approximating crystal detectors with point detectors in mathematical theory is grossly oversimplified. (USGS)

Schimschal, Ulrich

1980-01-01

350

First sensitivity limits of the ALPS TES detector  

E-print Network

The Any Light Particle Search II (ALPS II) requires a sensitive detection of 1064 nm photons. Thus, a low dark count rate (DC) and a high detection efficiency (DE) is needed. ALPS has set up a transition-edge sensor (TES) detector system, namely the ALPS TES detector. It is found that thermal photons from room temperature surfaces are the main contribution of dark counts for 1064 nm photon signals. Furthermore, the current setup of the ALPS TES detector shows an improvement compared to using the ALPS I detector.

Dreyling-Eschweiler, Jan

2014-01-01

351

Status of the D0 fiber tracker and preshower detectors  

SciTech Connect

In this report we focus on the performance of the D0 central fiber tracker and preshower detectors during the high luminosity p{bar p} collisions at {radical}s = 1.96 GeV delivered by the Tevatron collider at Fermilab (Run IIb). Both fiber tracker and preshower detectors utilize a similar readout system based on high quantum efficiency solid state photo-detectors capable of converting light into electrical signals. We also give a brief description of the D0 detector and the central track trigger, and conclude with a summary on the central tracker performance.

Smirnov, Dmitri; /Notre Dame U.; ,

2009-01-01

352

Plasmonic lens enhanced mid-infrared quantum cascade detector  

NASA Astrophysics Data System (ADS)

We demonstrate monolithic integrated quantum cascade detectors enhanced by plasmonic lenses. Surface normal incident mid-infrared radiation is coupled to surface plasmon polaritons guided to and detected by the active region of the detector. The lens extends the optical effective active area of the device up to a 5 times larger area than for standard mesa detectors or pixel devices while the electrical active region stays the same. The extended optical area increases the absorption efficiency of the presented device as well as the room temperature performance while it offers a flexible platform for various detector geometries. A photocurrent response increase at room temperature up to a factor of 6 was observed.

Harrer, Andreas; Schwarz, Benedikt; Gansch, Roman; Reininger, Peter; Detz, Hermann; Zederbauer, Tobias; Andrews, Aaron Maxwell; Schrenk, Werner; Strasser, Gottfried

2014-10-01

353

Photon detectors for the HERA-B rich  

SciTech Connect

A summary of experimental studies of different photon detectors is presented. A CsI photocathode in a multiwire proportional chamber, a TMAE based gaseous photon detector and a new Hamamatsu multianode photomultiplier tube have been investigated in order to evaluate their suitability as photon detectors in the ring imaging Cherenkov counter of HERA-B. The results of the present work suggest that only the MA-PMT meets the demanding requirements of the HERA-B experimental environment. The CsI-MWPC cannot be routinely produced and maintained with sufficiently high quantum efficiency and the TMAE photon detectors lose gain as a result of relatively quick anode wire ageing.

Krizan, P.; Staric, M.; Stanovnik, A. [Univ. of Ljubljana (Slovenia)] [and others

1996-12-31

354

Smoke Detectors and Legislation.  

ERIC Educational Resources Information Center

This manual, one of a series for use in public education, provides an in-depth review of the current status of state and local smoke detector legislation. First, for the community considering a smoke detector law or ordinance, six decision points are discussed: which residential occupancy sub-classes will be affected; what the time factors are for…

National Fire Prevention and Control Administration (DOC), Washington, DC.

355

Optical proximity detector  

NASA Technical Reports Server (NTRS)

Sensitive, relatively inexpensive instrument uses phase-detection techniques to sense presence of objects. Phase-sensitive detectors, LED, photodiode with response matched to LED output, and filtering lens allow detector to operate over narrow radiation band, giving selectivity over stray light.

Hermann, W. A.; Johnston, A. R.

1977-01-01

356

Transient detector apparatus  

Microsoft Academic Search

A transient detector apparatus utilizing peak and slope detectors to determine the presence of transient signal in a logic signal. Individual slope measurements of the input signal are compared with a logic criteria to establish the occurrence of a transient. The peak voltage and pulse width of a transient are digitized in order to time tag or isolate a transient

Lapeyrolerie

1985-01-01

357

The TESLA Detector  

E-print Network

For the superconducting linear collider TESLA a multi purpose detector has been designed. This detector is optimised for the important physics processes expected at a next generation linear collider up to around 1 TeV and is designed for the specific environment of a superconducting collider.

Klaus Moenig

2001-11-05

358

Physics detector simulation facility system software description  

SciTech Connect

Large and costly detectors will be constructed during the next few years to study the interactions produced by the SSC. Efficient, cost-effective designs for these detectors will require careful thought and planning. Because it is not possible to test fully a proposed design in a scaled-down version, the adequacy of a proposed design will be determined by a detailed computer model of the detectors. Physics and detector simulations will be performed on the computer model using high-powered computing system at the Physics Detector Simulation Facility (PDSF). The SSCL has particular computing requirements for high-energy physics (HEP) Monte Carlo calculations for the simulation of SSCL physics and detectors. The numerical calculations to be performed in each simulation are lengthy and detailed; they could require many more months per run on a VAX 11/780 computer and may produce several gigabytes of data per run. Consequently, a distributed computing environment of several networked high-speed computing engines is envisioned to meet these needs. These networked computers will form the basis of a centralized facility for SSCL physics and detector simulation work. Our computer planning groups have determined that the most efficient, cost-effective way to provide these high-performance computing resources at this time is with RISC-based UNIX workstations. The modeling and simulation application software that will run on the computing system is usually written by physicists in FORTRAN language and may need thousands of hours of supercomputing time. The system software is the glue'' which integrates the distributed workstations and allows them to be managed as a single entity. This report will address the computing strategy for the SSC.

Allen, J.; Chang, C.; Estep, P.; Huang, J.; Liu, J.; Marquez, M.; Mestad, S.; Pan, J.; Traversat, B.

1991-12-01

359

Physics detector simulation facility system software description  

SciTech Connect

Large and costly detectors will be constructed during the next few years to study the interactions produced by the SSC. Efficient, cost-effective designs for these detectors will require careful thought and planning. Because it is not possible to test fully a proposed design in a scaled-down version, the adequacy of a proposed design will be determined by a detailed computer model of the detectors. Physics and detector simulations will be performed on the computer model using high-powered computing system at the Physics Detector Simulation Facility (PDSF). The SSCL has particular computing requirements for high-energy physics (HEP) Monte Carlo calculations for the simulation of SSCL physics and detectors. The numerical calculations to be performed in each simulation are lengthy and detailed; they could require many more months per run on a VAX 11/780 computer and may produce several gigabytes of data per run. Consequently, a distributed computing environment of several networked high-speed computing engines is envisioned to meet these needs. These networked computers will form the basis of a centralized facility for SSCL physics and detector simulation work. Our computer planning groups have determined that the most efficient, cost-effective way to provide these high-performance computing resources at this time is with RISC-based UNIX workstations. The modeling and simulation application software that will run on the computing system is usually written by physicists in FORTRAN language and may need thousands of hours of supercomputing time. The system software is the ``glue`` which integrates the distributed workstations and allows them to be managed as a single entity. This report will address the computing strategy for the SSC.

Allen, J.; Chang, C.; Estep, P.; Huang, J.; Liu, J.; Marquez, M.; Mestad, S.; Pan, J.; Traversat, B.

1991-12-01

360

Pyroelectric detector arrays  

NASA Technical Reports Server (NTRS)

A pryoelectric detector array and the method for making it are described. A series of holes formed through a silicon dioxide layer on the surface of a silicon substrate forms the mounting fixture for the pyroelectric detector array. A series of nontouching strips of indium are formed around the holes to make contact with the backside electrodes and form the output terminals for individual detectors. A pyroelectric detector strip with front and back electrodes, respectively, is mounted over the strip. Biasing resistors are formed on the surface of the silicon dioxide layer and connected to the strips. A metallized pad formed on the surface of the layer is connected to each of the biasing resistors and to the film to provide the ground for the pyroelectric detector array.

Fripp, A. L.; Robertson, J. B.; Breckenridge, R. A. (inventors)

1982-01-01

361

Pyroelectric detector arrays  

NASA Technical Reports Server (NTRS)

A pyroelectric detector array and the method for using it are described. A series of holes formed through a silicon dioxide layer on the surface of a silicon substrate forms the mounting fixture for the pyroelectric detector array. A series of nontouching strips of indium are formed around the holes to make contact with the backside electrodes and form the output terminals for individual detectors. A pyroelectric detector strip with front and back electrodes, respectively, is mounted over the strips. Biasing resistors are formed on the surface of the silicon dioxide layer and connected to the strips. A metallized pad formed on the surface of layer is connected to each of the biasing resistors and to the film to provide the ground for the pyroelectric detector array.

Fripp, A. L.; Robertson, J. B.; Breckenridge, R. (inventors)

1982-01-01

362

Nanomechanical resonance detector  

DOEpatents

An embodiment of a nanomechanical frequency detector includes a support structure and a plurality of elongated nanostructures coupled to the support structure. Each of the elongated nanostructures has a particular resonant frequency. The plurality of elongated nanostructures has a range of resonant frequencies. An embodiment of a method of identifying an object includes introducing the object to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the object. An embodiment of a method of identifying a molecular species of the present invention includes introducing the molecular species to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the molecular species.

Grossman, Jeffrey C; Zettl, Alexander K

2013-10-29

363

Background studies for NaI(Tl) detectors in the ANAIS dark matter project  

NASA Astrophysics Data System (ADS)

Several large NaI(Tl) detectors, produced by different companies, have been operated in the Canfranc Underground Laboratory (LSC) in the frame of the ANAIS (Annual modulation with NaI Scintillators) project devoted to the direct detection of dark matter. A complete background model has been developed for a 9.6 kg detector (referred as ANAIS-0 prototype) after a long data taking at LSC. Activities from the natural chains of 238U and 232Th, and 40K in the NaI(Tl) crystal were evaluated applying different methods: discrimination of alpha particles vs beta/gamma background by Pulse Shape Analysis for quantifying the content of the natural chains and coincidence techniques for 40K. Radioactive contaminations in the detector and shielding components were also determined by HPGe spectrometry. Monte Carlo simulations using Geant4 package were carried out to evaluate their contribution. At high energies, most of the measured background is nicely reproduced; at low energy some non-explained components are still present, although some plausible background sources have been analyzed. The 40K content of the NaI(Tl) crystal has been confirmed to be the dominant contributor to the measured background with this detector. In addition, preliminary results of the background characterization, presently underway at the LSC, of two recently produced NaI(Tl) detectors, with 12.5 kg mass each, will be presented: cosmogenic induced activity has been clearly observed and is being quantified, and 40K activity at a level ten times lower than in ANAIS-0 has been determined.

Amaré, J.; Borjabad, S.; Cebrián, S.; Cuesta, C.; Fortuño, D.; García, E.; Ginestra, C.; Gómez, H.; Martínez, M.; Oliván, M. A.; Ortigoza, Y.; Ortiz de Solórzano, A.; Pobes, C.; Puimedón, J.; Sarsa, M. L.; Villar, J. A.; Villar, P.

2013-08-01

364

Using induced signals to sense position from a microchannel plate detector  

NASA Astrophysics Data System (ADS)

We demonstrate a novel concept for a position sensitive microchannel plate detector. This detector provides sub-millimeter spatial resolution by examining the signal induced on a wire harp by the electron cloud from a microchannel plate detector. Wires in the harp are efficiently read out by coupling them to a delay line.

deSouza, R. T.; Gosser, Z. Q.; Hudan, S.

2012-05-01

365

Development of a 24×24 CZT-FEE pixel detector block for the CSTD project  

Microsoft Academic Search

The CSTD project aims at developing a gamma pixel detector to be used as first detector in a Compton imager. Due to the strong requirements demanded by this application, the detector must provide high energy and spatial resolution, together with high detection efficiency in the energy range of interest, namely, between 15 keV and 1 MeV. A first family of

Javier Castilla; Jorge Carrascal; Anna Bulycheva; Matthew D. Wilson; Vladimir Gostilo; Paul Seller; Jose M. Perez

2008-01-01

366

Readout and performance of thick CZT strip detectors with orthogonal coplanar anodes  

Microsoft Academic Search

We report progress in the study of CZT strip detectors featuring orthogonal coplanar anode contacts. The work includes laboratory and simulation studies aimed at optimizing and developing compact, efficient, high performance detector modules for 0.05 to 1 MeV gamma radiation measurements. The novel coplanar anode strip configuration retains many of the performance advantages of pixel detectors yet requires far fewer

John R. Macri; Burçin Dönmez; Louis-Andre Hamel; Manuel Julien; Mickel McClish; Mark L. McConnell; Richard S. Miller; James M. Ryan; Mark Widholm

2002-01-01

367

BIOTELEMETRY BASED ON CdTe-DETECTORS J. BOJSEN, N. ROSSING, O. SOEBERG and S. VADSTRUP  

E-print Network

of the spectra at the two tempe- ratures are equal, which means the efficiency of the CdTe detector probe361 BIOTELEMETRY BASED ON CdTe-DETECTORS J. BOJSEN, N. ROSSING, O. SOEBERG and S. VADSTRUP radionuclide detectors (CdTe) 2-3 mm3 (developed by C. R. N. Strasbourg) have been tested with special

Paris-Sud XI, Université de

368

Small-Angle X-Ray Scattering System with Linear Position-Sensitive Detector.  

National Technical Information Service (NTIS)

A linear position-sensitive detector has been constructed for use in small-angle x-ray scattering experiments. It is a one dimensional, pressurized gas-filled detector with a delay line read out. Calculated efficiency of the detector at 8.04 keV and 45 ps...

A. R. Forouhi, B. Sleaford, V. Perez-Mendez, D. de Fontaine, J. Fodor

1981-01-01

369

6Li foil thermal neutron detector  

SciTech Connect

In this paper we report on the design of a multilayer thermal neutron detector based on {sup 6}Li reactive foil and thin film plastic scintillators. The {sup 6}Li foils have about twice the intrinsic efficiency of {sup 10}B films and about four times higher light output due to a unique combination of high energy of reaction particles, low self absorption, and low ionization density of tritons. The design configuration provides for double sided readout of the lithium foil resulting in a doubling of the efficiency relative to a classical reactive film detector and generating a pulse height distribution with a valley between neutron and gamma signals similar to {sup 3}He tubes. The tens of microns thickness of plastic scintillator limits the energy deposited by gamma rays, which provides the necessary neutron/gamma discrimination. We used MCNPX to model a multilayer Li foil detector design and compared it with the standard HLNCC-II (18 {sup 3}He tubes operated at 4 atm). The preliminary results of the {sup 6}Li configuration show higher efficiency and one third of the die-away time. These properties, combined with the very short dead time of the plastic scintillator, offer the potential of a very high performance detector.

Ianakiev, Kiril D [Los Alamos National Laboratory; Swinhoe, Martyn T [Los Alamos National Laboratory; Favalli, Andrea [Los Alamos National Laboratory; Chung, Kiwhan [Los Alamos National Laboratory; Macarthur, Duncan W [Los Alamos National Laboratory

2010-01-01

370

Graphene vertical hot-electron terahertz detectors  

NASA Astrophysics Data System (ADS)

We propose and analyze the concept of the vertical hot-electron terahertz (THz) graphene-layer detectors (GLDs) based on the double-GL and multiple-GL structures with the barrier layers made of materials with a moderate conduction band off-set (such as tungsten disulfide and related materials). The operation of these detectors is enabled by the thermionic emissions from the GLs enhanced by the electrons heated by incoming THz radiation. Hence, these detectors are the hot-electron bolometric detectors. The electron heating is primarily associated with the intraband absorption (the Drude absorption). In the frame of the developed model, we calculate the responsivity and detectivity as functions of the photon energy, GL doping, and the applied voltage for the GLDs with different number of GLs. The detectors based on the cascade multiple-GL structures can exhibit a substantial photoelectric gain resulting in the elevated responsivity and detectivity. The advantages of the THz detectors under consideration are associated with their high sensitivity to the normal incident radiation and efficient operation at room temperature at the low end of the THz frequency range. Such GLDs with a metal grating, supporting the excitation of plasma oscillations in the GL-structures by the incident THz radiation, can exhibit a strong resonant response at the frequencies of several THz (in the range, where the operation of the conventional detectors based on A3B5 materials, in particular, THz quantum-well detectors, is hindered due to a strong optical phonon radiation absorption in such materials). We also evaluate the characteristics of GLDs in the mid- and far-infrared ranges where the electron heating is due to the interband absorption in GLs.

Ryzhii, V.; Satou, A.; Otsuji, T.; Ryzhii, M.; Mitin, V.; Shur, M. S.

2014-09-01

371

Barrier infrared detectors  

NASA Astrophysics Data System (ADS)

In 1959, Lawson and co-workers publication triggered development of variable band gap Hg1-xCdxTe (HgCdTe) alloys providing an unprecedented degree of freedom in infrared detector design. Over the five decades, this material system has successfully fought off major challenges from different material systems, but despite that it has more competitors today than ever before. It is interesting however, that none of these competitors can compete in terms of fundamental properties. They may promise to be more manufacturable, but never to provide higher performance or, with the exception of thermal detectors, to operate at higher temperatures. In the last two decades a several new concepts of photodetectors to improve their performance have been proposed including trapping detectors, barrier detectors, unipolar barrier photodiodes, and multistage detectors. This paper describes the present status of infrared barrier detectors. It is especially addressed to the group of III-V compounds including type-II superlattice materials, although HgCdTe barrier detectors are also included. It seems to be clear that certain of these solutions have merged as a real competitions of HgCdTe photodetectors.

Martyniuk, P.; Kopytko, M.; Rogalski, A.

2014-06-01

372

ACCESS: Detector Performance  

NASA Astrophysics Data System (ADS)

ACCESS, Absolute Color Calibration Experiment for Standard Stars, is a series of rocket-borne sub-orbital missions and ground-based experiments that will enable improvements in the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving power of 500 across the 0.35 to 1.7 micron bandpass (overview Kaiser et al.). The flight detector and detector spare have been integrated with their electronics and flight mount. The controller electronics have been flight qualified. Vibration testing to launch loads and thermal vacuum testing of the detector, mount, and housing have been performed. The flight detector controller boards have been installed into a ruggedized flight housing. They have been successfully vacuum tested for periods significantly longer than the flight length, and components have been heat-sunk and reinforced as necessary. Thermal stability tests have been performed, and results will be presented. Goddard Space Flight Center’s Detector Characterization Lab (DCL) executed initial characterization tests for the flight detector in 2007. These were repeated in 2012, to ensure and establish baseline performance. Current lab characterization tests at Johns Hopkins are ongoing, and results will be presented. NASA sounding rocket grant NNX08AI65G supports this work.

Morris, Matthew J.; Kaiser, M.; Rauscher, B. J.; Kimble, R. A.; Kruk, J. W.; Mott, D. B.; Wen, Y.; Foltz, R.; McCandliss, S. R.; Pelton, R. S.; Wright, E. L.; Feldman, P. D.; Moos, H. W.; Riess, A. G.; Benford, D. J.; Gardner, J. P.; Woodgate, B. E.; Bohlin, R.; Deustua, S. E.; Dixon, W. V.; Sahnow, D. J.; Kurucz, R. L.; Lampton, M.; Perlmutter, S.

2013-01-01

373

Study of solid-conversion gaseous detector based on GEM for high energy X-ray industrial CT.  

PubMed

The general gaseous ionization detectors are not suitable for high energy X-ray industrial computed tomography (HEICT) because of their inherent limitations, especially low detective efficiency and large volume. The goal of this study was to investigate a new type of gaseous detector to solve these problems. The novel detector was made by a metal foil as X-ray convertor to improve the conversion efficiency, and the Gas Electron Multiplier (hereinafter "GEM") was used as electron amplifier to lessen its volume. The detective mechanism and signal formation of the detector was discussed in detail. The conversion efficiency was calculated by using EGSnrc Monte Carlo code, and the transport course of photon and secondary electron avalanche in the detector was simulated with the Maxwell and Garfield codes. The result indicated that this detector has higher conversion efficiency as well as less volume. Theoretically this kind of detector could be a perfect candidate for replacing the conventional detector in HEICT. PMID:24865206

Zhou, Rifeng; Zhou, Yaling

2014-01-01

374

The HOTWAXS detector  

NASA Astrophysics Data System (ADS)

The development and testing of the HOTWAXS position-sensitive X-ray detector for Synchrotron Radiation Sources is described. Funded from a facility development grant, the aim of the project was to produce a high counting rate, parallax-free photon counting detector to be used in the combined studies of X-ray absorption fine structure and X-ray diffraction (XAFS/XRD), and also in the technique of small angle and wide angle X-ray scattering (SAXS/WAXS). The detector system is described together with results of experiments carried out at the Daresbury Laboratory Synchrotron Radiation Source.

Bateman, J. E.; Derbyshire, G. E.; Diakun, G.; Duxbury, D. M.; Fairclough, J. P. A.; Harvey, I.; Helsby, W. I.; Lipp, J. D.; Marsh, A. S.; Salisbury, J.; Sankar, G.; Spill, E. J.; Stephenson, R.; Terrill, N. J.

2007-10-01

375

Impurity conduction photoconductor detectors  

NASA Astrophysics Data System (ADS)

A radiation hardening of photoconductive infrared detectors for the application in space instrumentation is under development on the basis of the blocked impurity band concept. These detectors are Impurity Conduction Band (ICB) detectors based on thin epitaxial layers. Both linear and two dimensional arrays have been fabricated out of this material. Their internal structure and layout and their photoconductive performance are outlined. Current responsivities between 5 A/W and 10 A/W and noise equivalent power values in the order of 10 to the minus 17th power W/square root of Hz are obtained.

Engemann, D.; Faymonville, R.; Felten, R.; Frenzl, O.; Haschberger, D.

1992-12-01

376

Simulation and characterization of a dual-type 3-dimensional silicon detector  

NASA Astrophysics Data System (ADS)

A three-dimensional (3D) silicon detector is an alternative semiconductor detector for high radiation environments. The 3D detector has several advantages such as radiation hardness so it can be used for a longer period of time in a high radiation environment without replacement. A dual-type 3D silicon detector is simulated, and the full depletion voltage, capacitance, response time and charge collection efficiency are measured.

Choi, Jihoon; Lee, Kyungmin; Won, Eunil

2012-06-01

377

Extrinsic germanium Blocked Impurity Bank (BIB) detectors  

NASA Technical Reports Server (NTRS)

Ge:Ga blocked-impurity-band (BIB) detectors with long wavelength thresholds greater than 190 microns and peak quantum efficiencies of 4 percent, at an operating temperature of 1.8 K, have been fabricated. These proof of concept devices consist of a high purity germanium blocking layer epitaxially grown on a Ga-doped Ge substrate. This demonstration of BIB behavior in germanium enables the development of far infrared detector arrays similar to the current silicon-based devices. Present efforts are focussed on improving the chemical vapor deposition process used to create the blocking layer and on the lithographic processing required to produce monolithic detector arrays in germanium. Approaches to test the impurity levels in both the blocking and active layers are considered.

Krabach, Timothy N.; Huffman, James E.; Watson, Dan M.

1989-01-01

378

Ultrafast neutron detector  

DOEpatents

A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

Wang, C.L.

1985-06-19

379

Lightning Current Detector  

NASA Technical Reports Server (NTRS)

Lightning Current Detector (LCD) was developed to monitor the magnitude of lightning strikes. Information it supplies is useful in evaluating lightning protection designs for such systems as telephone cables, radio broadcast towers, power transmission equipment and oil well towers.

1981-01-01

380

SRAM Detector Calibration  

NASA Technical Reports Server (NTRS)

Custom proton sensitive SRAM chips are being flown on the BMDO Clementine missions and Space Technology Research Vehicle experiments. This paper describes the calibration procedure for the SRAM proton detectors and their response to the space environment.

Soli, G. A.; Blaes, B. R.; Beuhler, M. G.

1994-01-01

381

Inverter ratio failure detector  

NASA Technical Reports Server (NTRS)

A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (inventors)

1974-01-01

382

PHENIX detector overview  

NASA Astrophysics Data System (ADS)

The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented.

Adcox, K.; Adler, S. S.; Aizama, M.; Ajitanand, N. N.; Akiba, Y.; Akikawa, H.; Alexander, J.; Al-Jamel, A.; Allen, M.; Alley, G.; Amirikas, R.; Aphecetche, L.; Arai, Y.; Archuleta, J. B.; Archuleta, J. R.; Armendariz, R.; Armijo, V.; Aronson, S. H.; Autrey, D.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Baldisseri, A.; Banning, J.; Barish, K. N.; Barker, A. B.; Barnes, P. D.; Barrette, J.; Barta, F.; Bassalleck, B.; Bathe, S.; Batsouli, S.; Baublis, V. V.; Bazilevsky, A.; Begay, R.; Behrendt, J.; Belikov, S.; Belkin, R.; Bellaiche, F. G.; Belyaev, S. T.; Bennett, M. J.; Berdnikov, Y.; Bhaganatula, S.; Biggs, J. C.; Bland, A. W.; Blume, C.; Bobrek, M.; Boissevain, J. G.; Boose, S.; Borel, H.; Borland, D.; Bosze, E.; Botelho, S.; Bowers, J.; Britton, C.; Britton, L.; Brooks, M. L.; Brown, A. W.; Brown, D. S.; Bruner, N.; Bryan, W. L.; Bucher, D.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Burward-Hoy, J.; Butsyk, S. A.; Cafferty, M. M.; Carey, T. A.; Chai, J. S.; Chand, P.; Chang, J.; Chang, W. C.; Chappell, R. B.; Chavez, L. L.; Chernichenko, S.; Chi, C. Y.; Chiba, J.; Chiu, M.; Chollet, S.; Choudhury, R. K.; Christ, T.; Chujo, T.; Chung, M. S.; Chung, P.; Cianciolo, V.; Clark, D. J.; Cobigo, Y.; Cole, B. A.; Constantin, P.; Conway, R.; Cook, K. C.; Crook, D. W.; Cunitz, H.; Cunningham, R.; Cutshaw, M.; D'Enterria, D. G.; Dabrowski, C. M.; Danby, G.; Daniels, S.; Danmura, A.; David, G.; Debraine, A.; Delagrange, H.; Demoss, J.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dietzsch, O.; Dinesh, B. V.; Drachenberg, J. L.; Drapier, O.; Drees, A.; Du Rietz, R.; Durum, A.; Dutta, D.; Ebisu, K.; Echave, M. A.; Efremenko, Y. V.; El Chenawi, K.; Emery, M. S.; Engo, D.; Enokizono, A.; Enosawa, K.; En'yo, H.; Ericson, N.; Esumi, S.; Evseev, V. A.; Ewell, L.; Fackler, O.; Fellenstein, J.; Ferdousi, T.; Ferrierra, J.; Fields, D. E.; Fleuret, F.; Fokin, S. L.; Fox, B.; Fraenkel, Z.; Frank, S.; Franz, A.; Frantz, J. E.; Frawley, A. D.; Fried, J.; Freidberg, J. P.; Fujisawa, E.; Funahashi, H.; Fung, S.-Y.; Gadrat, S.; Gannon, J.; Garpman, S.; Gastaldi, F.; Gee, T. F.; Gentry, R.; Ghosh, T. K.; Giannotti, P.; Glenn, A.; Godoi, A. L.; Gonin, M.; Gogiberidze, G.; Gosset, J.; Goto, Y.; Granier de Cassagnac, R.; Greene, S. V.; Griffin, V.; Grosse Perdekamp, M.; Gupta, S. K.; Guryn, W.; Gustafsson, H.-Å.; Hachiya, T.; Haggerty, J. S.; Hahn, S.; Halliwell, J.; Hamagaki, H.; Hance, R. H.; Hansen, A. G.; Hara, H.; Harder, J.; Hart, G. W.; Hartouni, E. P.; Harvey, A.; Hawkins, L.; Hayano, R. S.; Hayashi, H.; Hayashi, N.; He, X.; Heine, N.; Heistermann, F.; Held, S.; Hemmick, T. K.; Heuser, J. M.; Hibino, M.; Hicks, J. S.; Higuchi, R.; Hill, J. C.; Hirano, T.; Ho, D. S.; Hoade, R.; Holzmann, W.; Homma, K.; Hong, B.; Hoover, A.; Honaguchi, T.; Hunter, C. T.; Hurst, D. E.; Hutter, R.; Ichihara, T.; Ikonnikov, V. V.; Imai, K.; Inaba, M.; Ippolitov, M. S.; Davis Isenhower, L.; Donald Isenhower, L.; Ishihara, M.; Issah, M.; Ivanov, V. I.; Jacak, B. V.; Jackson, G.; Jackson, J.; Jaffe, D.; Jagadish, U.; Jang, W. Y.; Jayakumar, R.; Jia, J.; Johnson, B. M.; Johnson, J.; Johnson, S. C.; Jones, J. P.; Jones, K.; Joo, K. S.; Jouan, D.; Kahn, S.; Kajihara, F.; Kametani, S.; Kamihara, N.; Kamyshkov, Y.; Kandasamy, A.; Kang, J. H.; Kann, M. R.; Kapoor, S. S.; Kapustinsky, J.; Karadjev, K. V.; Kashikhin, V.; Kato, S.; Katou, K.; Kehayias, H.-J.; Kelley, M. A.; Kelly, S.; Kennedy, M.; Khachaturov, B.; Khanzadeev, A. V.; Khomutnikov, A.; Kikuchi, J.; Kim, D. J.; Kim, D.-W.; Kim, G.-B.; Kim, H. J.; Kim, S. Y.; Kim, Y. G.; Kinnison, W. W.; Kistenev, E.; Kiyomichi, A.; Klein-Boesing, C.; Klinksiek, S.; Kluberg, L.; Kobayashi, H.; Kochetkov, V.; Koehler, D.; Kohama, T.; Komkov, B. G.; Kopytine, M. L.; Koseki, K.; Kotchenda, L.; Kotchetkov, D.; Koutcheryaev, Iou. A.; Kozlov, A.; Kozlov, V. S.; Kravtsov, P. A.; Kroon, P. J.; Kuberg, C. H.; Kudin, L. G.; Kurata-Nishimura, M.; Kuriatkov, V. V.; Kurita, K.; Kuroki, Y.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Labounty, J. J.; Lacey, R.; Lajoie, J. G.; Lauret, J.; Lebedev, A.; Lebedev, V. A.; Lebedev, V. D.; Lee, D. M.; Lee, S.; Leitch, M. J.; Lenz, M.; Lenz, W.; Li, X. H.; Li, Z.; Libby, B.; Libkind, M.; Liccardi, W.; Lim, D. J.; Lin, S.; Liu, M. X.; Liu, X.; Liu, Y.; Liu, Z.; Lockner, E.; Longbotham, N.; Lopez, J. D.; Machnowski, R.; Maguire, C. F.; Mahon, J.; Makdisi, Y. I.; Manko, V. I.; Mao, Y.; Marino, S.; Mark, S. K.; Markacs, S.; Markushin, D. G.; Martinez, G.; Martinez, X. B.; Marx, M. D.; Masaike, A.; Matathias, F.; Matsumoto, T.; McGaughey, P. L.; McCain, M. C.; Mead, J.; Melnikov, E.; Melnikov, Y.; Meng, W. Z.; Merschmeyer, M.; Messer, F.; Messer, M.; Miake, Y.; Miftakhov, N. M.; Migluolio, S.; Milan, J.; Miller, T. E.; Milov, A.; Minuzzo, K.; Mioduszewski, S.; Mischke, R. E.; Mishra, G. C.

383

Gaseous dark matter detectors  

E-print Network

Dark matter (DM) detectors with directional sensitivity have the potential of yielding an unambiguous positive observation of WIMPs as well as discriminating between galactic DM halo models. In this paper, we introduce the ...

Martoff, C. J.

384

Improved CO [lidar detector  

SciTech Connect

A high sensitivity, CO{sub 2} lidar detector, based on recent advances in ultra-low noise, readout integrated circuits (ROIC), is being developed. This detector will combine a high speed, low noise focal plane array (FPA) with a dispersive grating spectrometer. The spectrometer will filter the large background flux, thereby reducing the limiting background photon shot noise. In order to achieve the desired low noise levels, the HgCdTe FPA will be cooled to {approximately}50K. High speed, short pulse operation of the lidar system should enable the detector to operate with the order of a few noise electrons in the combined detector/ ROIC output. Current receiver design concepts will be presented, along with their expected noise performance.

Jacobson, P.L.; Busch, G.E.; Thompson, D.C.; Remelius, D.K.; Wells, F.D.

1999-07-18

385

Two new flame detectors  

NASA Astrophysics Data System (ADS)

Two new IR flame detectors equipped with pyroelectric sensors are demonstrated. Both detectors are totally new on the world market. With the help of a new method of flame detection it is possible to distinguish flame from all interference radiation with great reliability. Applications: indoor and outdoor fire detection applications such as warehouses, hangars, ships, oil refineries etc. for fires involving all carbonaceous materials such as petrol, oil products, alcohol, wood and plastics.

Tar, D.

1985-02-01

386

The DELPHI Microvertex detector  

Microsoft Academic Search

The DELPHI Microvertex detector, which has been in operation since the start of the 1990 LEP run, consists of three layers of silicon microstrip detectors at average radii of 6.3, 9.0 and 11.0 cm. The 73728 readout strips, oriented along the beam, have a total active area of 0.42 m2. The strip pitch is 25 mum and every other strip

N. Bingefors; H. Borner; R. Boulter; M. Caccia; V. Chabaud; H. Dijkstra; P. Eerola; E. Gross; R. Horisberger; L. Hubbeling; B. Hyams; M. Karlsson; G. Maehlum; K. Ratz; I. Roditi; J. Straver; W. Trischuk; P. Weilhammer; Y. Dufour; P. Brückman; P. Jalocha; P. Kapusta; M. Turala; A. Zalewska; J. Lindgren; R. Orava; K. Österberg; C. Ronnqvist; H. Saarikko; J. P. Saarikko; T. Tuuva; B. D'Almagne; P. Bambade; F. Couchot; F. Fulda; A. Amery; P. S. L. Booth; A. R. Campion; R. McNulty; N. A. Smith; A. Andreazza; M. Battaglia; P. Biffi; V. Bonvicini; W. Kucewicz; C. Meroni; N. Redaelli; A. Stocchi; C. Troncon; G. Vegni; P. Dauncey; M. Mazzucato; M. Pegoraro; A. Peisert; M. Baubillier; J. Chauveau; W. da Silva; J. F. Genat; F. Rossel; T. Adye; R. Apsimon; J. Bizell; L. Denton; G. E. Kalmus; J. Lidbury; P. Seller; M. Tyndel; W. Dulinski; D. Husson; A. Lounis; M. Schaeffer; R. Turchetta; R. Brenner; E. Sundell

1993-01-01

387

The DMTPC detector  

E-print Network

Directional detection of Dark Matter allows for unambiguous direct detection of WIMPs as well as discrimination between various Dark Matter models in our galaxy. The DMTPC detector is a low-pressure TPC with optical readout designed for directional direct detection of WIMPs. By using CF4 gas as the active material, the detector also has excellent sensitivity to spin-dependent interactions of Dark Matter on protons.

G. Sciolla; J. Battat; T. Caldwell; B. Cornell; D. Dujmic; P. Fisher; S. Henderson; R. Lanza; A. Lee; J. Lopez; A. Kaboth; G. Kohse; J. Monroe; T. Sahin; R. Vanderspek; R. Yamamoto; H. Yegoryan; S. Ahlen; D. Avery; K. Otis; A. Roccaro; H. Tomita; A. Dushkin; H. Wellenstein

2008-11-18

388

Compact infrared detector  

NASA Technical Reports Server (NTRS)

Broadband IR detector integrated into compact package for pollution monitoring and weather prediction is small, highly responsive, and immune to high noise. Sensing material is transparent sheet metalized with reflecting coating and overcoated with black material on same side. Pulse produced by chopping of infrared source beam creates transient "thermal lens" that temporarily defocuses laser beam probe. Detector monitoring beam measures defocusing which parallels infrared intensity.

Gupta, A.; Hong, S.; Moacanin, J.

1981-01-01

389

Gamma ray detector modules  

NASA Technical Reports Server (NTRS)

A radiation detector assembly has a semiconductor detector array substrate of CdZnTe or CdTe, having a plurality of detector cell pads on a first surface thereof, the pads having a contact metallization and a solder barrier metallization. An interposer card has planar dimensions no larger than planar dimensions of the semiconductor detector array substrate, a plurality of interconnect pads on a first surface thereof, at least one readout semiconductor chip and at least one connector on a second surface thereof, each having planar dimensions no larger than the planar dimensions of the interposer card. Solder columns extend from contacts on the interposer first surface to the plurality of pads on the semiconductor detector array substrate first surface, the solder columns having at least one solder having a melting point or liquidus less than 120 degrees C. An encapsulant is disposed between the interposer circuit card first surface and the semiconductor detector array substrate first surface, encapsulating the solder columns, the encapsulant curing at a temperature no greater than 120 degrees C.

Capote, M. Albert (Inventor); Lenos, Howard A. (Inventor)

2009-01-01

390

Signal Formation in Various Detectors  

E-print Network

In this write up we present the general theory of the signal formation in various detectors. We follow a pedagogical analysis and presentation such that the results could easily understood and applied by the interested reader to the different detector configurations. We include few applications to gaseous detectors, namely, Monitored Drift Tubes (MDT) and microstrip pattern detector of the micromegas type.

Manolis Dris; Theo Alexopoulos

2014-06-12

391

A vertex detector for SLD  

Microsoft Academic Search

The SLAC Linear Collider is currently being commissioned. A second-generation detector for SLC, known as SLD, is now under construction. In the centre of this 4000 ton detector there will be a vertex detector (VXD) consisting of 4 barrels of 2-dimensional CCDs, approximately 250 CCDs in total. This detector will be used as a tracking microscope, able to pinpoint the

C. J. S. Damerell; R. L. English; A. R. Gillman; A. L. Lintern; D. Phillips; G. Rong; C. Sutton; F. J. Wickens; G. Agnew; P. Clarke; S. Hedges; S. J. Watts

1989-01-01

392

Beam Test of a Large Area nonn Silicon Strip Detector with Fast Binary Readout Electronics  

E-print Network

Beam Test of a Large Area n­on­n Silicon Strip Detector with Fast Binary Readout Electronics Y test was carried out for the non­irradiated and the irradiated detector modules. Efficiency, noise occupancy and performance in the edge regions were analyzed using the beam test data. High efficiency

393

Characterization of 3D thermal neutron semiconductor detectors  

NASA Astrophysics Data System (ADS)

Neutron semiconductor detectors for neutron counting and neutron radiography have an increasing importance. Simple silicon neutron detectors are combination of a planar diode with a layer of an appropriate neutron converter such as 6LiF. These devices have limited detection efficiency of not more than 5%. The detection efficiency can be increased by creating a 3D microstructure of dips, trenches or pores in the detector and filling it with a neutron converter. The first results related to the development of such devices are presented. Silicon detectors were fabricated with pyramidal dips on the surface covered with 6LiF and then irradiated by thermal neutrons. Pulse height spectra of the energy deposited in the sensitive volume were compared with simulations. The detection efficiency of these devices was about 6.3%. Samples with different column sizes were fabricated to study the electrical properties of 3D structures. Charge collection efficiencies in silicon columns from 10 to 800 ?m wide and 80-200 ?m high were measured with alpha particles. The neutron detection efficiency of a full 3D structure was simulated. The results indicate an increase in detection efficiency by a factor of 6 in comparison with a standard planar neutron detector.

Uher, J.; Fröjdh, C.; Jak?bek, J.; Kenney, C.; Kohout, Z.; Linhart, V.; Parker, S.; Petersson, S.; Pospíšil, S.; Thungström, G.

2007-06-01

394

Charged-coupled detector sky surveys.  

PubMed

Sky surveys have played a fundamental role in advancing our understanding of the cosmos. The current pictures of stellar evolution and structure and kinematics of our Galaxy were made possible by the extensive photographic and spectrographic programs performed in the early part of the 20th century. The Palomar Sky Survey, completed in the 1950s, is still the principal source for many investigations. In the past few decades surveys have been undertaken at radio, millimeter, infrared, and x-ray wavelengths; each has provided insights into new astronomical phenomena (e.g., quasars, pulsars, and the 3 degrees cosmic background radiation). The advent of high quantum efficiency, linear solid-state devices, in particular charged-coupled detectors, has brought about a revolution in optical astronomy. With the recent development of large-format charged-coupled detectors and the rapidly increasing capabilities of data acquisition and processing systems, it is now feasible to employ the full capabilities of electronic detectors in projects that cover an appreciable fraction of the sky. This talk reviews the first "large scale" charged-coupled detector survey. This program, designed to detect very distant quasars, reveals the powers and limitations of charged-coupled detector surveys. PMID:11607431

Schneider, D P

1993-11-01

395

Histogram-based morphological edge detector  

SciTech Connect

The authors present a new edge detector for automatic extraction of oceanographic (mesoscale) features present in infrared (IR) images obtained from the Advanced Very High Resolution Radiometer (AVHRR). Conventional edge detectors are very sensitive to edge fine structure, which makes it difficult to distinguish the weak gradients that are useful in this application from noise. Mathematical morphology has been used in the past to develop efficient and statistically robust edge detectors. Image analysis techniques use the histogram for operations such as thresholding and edge extraction in a local neighborhood in the image. An efficient computational framework is discussed for extraction of mesoscale features present in IR images. The technique presented here, the Histogram-Based Morphological Edge Detector (HMED), extracts all the weak gradients, yet retains the edge sharpness in the image. The authors also present new morphological operations defined in the domain of the histogram of an image. They provide interesting experimental results from applying the HMED technique to oceanographic data in which certain features are known to have edge gradients of varying strength.

Krishnamurthy, S.; Iyengar, S.S. (Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Computer Science); Holyer, R.J.; Lybanon, M. (Naval Research Lab., Stennis Space Center, MS (United States). Remote Sensing Branch)

1994-07-01

396

Direct digital conversion detector technology  

NASA Astrophysics Data System (ADS)

Future imaging sensors for the aerospace and commercial video markets will depend on low cost, high speed analog-to-digital (A/D) conversion to efficiently process optical detector signals. Current A/D methods place a heavy burden on system resources, increase noise, and limit the throughput. This paper describes a unique method for incorporating A/D conversion right on the focal plane array. This concept is based on Sigma-Delta sampling, and makes optimum use of the active detector real estate. Combined with modern digital signal processors, such devices will significantly increase data rates off the focal plane. Early conversion to digital format will also decrease the signal susceptibility to noise, lowering the communications bit error rate. Computer modeling of this concept is described, along with results from several simulation runs. A potential application for direct digital conversion is also reviewed. Future uses for this technology could range from scientific instruments to remote sensors, telecommunications gear, medical diagnostic tools, and consumer products.

Mandl, William J.; Fedors, Richard

1995-06-01

397

Development of lightning current detector  

NASA Technical Reports Server (NTRS)

A lightning current detector to record the maximum current amplitude of a lightning strike to the 150 meter weather tower at KSC was developed. The principle of operation of the detector is discussed, materials chosen to build the detector are described, and calibration tests performed on the detector are given. Field results of the detectors from two separate lightning strikes to the tower are included.

Livermore, S.

1976-01-01

398

Radiation detectors: needs and prospects  

SciTech Connect

Important applications for x- and ..gamma..-ray spectroscopy are found in prospecting, materials characterization, environmental monitoring, the life sciences, and nuclear physics. The specific requirements vary for each application with varying degrees of emphasis on either spectrometer resolution, detection efficiency, or both. Since no one spectrometer is ideally suited to this wide range of needs, compromises are usually required. Gas and scintillation spectrometers have reached a level of maturity, and recent interest has concentrated on semiconductor spectrometers. Germanium detectors are showing continuing refinement and are the spectrometers of choice for high resolution applications. The new high-Z semiconductors, such as CdTe and HgI/sub 2/, have shown steady improvement but are limited in both resolution and size and will likely be used only in applications which require their unique properties.

Armantrout, G.A.

1981-01-01

399

Microchannel Plate Imaging Detectors for the Ultraviolet  

NASA Technical Reports Server (NTRS)

There has been significant progress over the last few years in the development of technologies for microchannel plate imaging detectors in the Ultraviolet (UV). Areas where significant developments have occurred include enhancements of quantum detection efficiency through improved photocathodes, advances in microchannel plate performance characteristics, and development of high performance image readout techniques. The current developments in these areas are summarized, with their applications in astrophysical instrumentation.

Siegmund, O. H. W.; Gummin, M. A.; Stock, J.; Marsh, D.

1992-01-01

400

The gender-specific chest wall thickness prediction equations for routine measurements of ²³⁹Pu and ²⁴¹Am within the lungs using HPGE detectors  

Microsoft Academic Search

The current chest wall thickness prediction equation is not applicable to use in routine lung counting measurements for detection of low energy photons (17-60 keV) within the lungs of male and female subjects. The current chest wall thickness prediction equation was derived for the NaI-CsI {open_quotes}phoswich{close_quotes} detection system, which is not the routine detection system in use; the subject position

L. R. Vickers

1996-01-01

401

A beta-ray spectrometer based on a two-or three silicon detector coincidence telescope  

NASA Astrophysics Data System (ADS)

This report describes the operation of a beta-ray energy spectrometer based on a silicon detector telescope using two or three elements. The front detector is a planar, totally-depleted, silicon surface barrier detector that is 97 ?m thick, the back detector is a room-temperature, lithium compensated, silicon detector that is 5000 ?m thick, and the intermediate detector is similar to the front detector but 72 ?m thick and intended to be used only in intense photon fields. The three detectors are mounted in a light-tight aluminum housing. The capability of the spectrometer to reject photons is based upon the fact that the incident photon will have a small probability of simultaneously losing detectable energy in two detectors, and an even smaller probability of losing detectable energy in all three detectors. Electrons will, however, almost always record measurable events in either the front two or all three detectors. A coincidence requirement between the detectors thus rejects photon induced events. With a 97 ?m thick detector the lower energy coincidence threshold is approximately 110 keV. With an ultra-thin 40 ?m thick front detector, and operated at 15°C, the spectrometer is capable of detecting even 60-70 keV electrons with a coincidence efficiency of 60%. The spectrometer has been used to measure beta radiation fields in CANDU reactor working environments, and the spectral information is intended to support dose algorithms for the LiF TLD chips used in the Ontario Hydro dosimetry program.

Horowitz, Y. S.; Weizman, Y.; Hirning, C. R.

1996-02-01

402

An experimental characterisation of a Broad Energy Germanium detector  

NASA Astrophysics Data System (ADS)

The spectroscopic and charge collection performance of a BE2825 Broad Energy Germanium (BEGe) detector has been experimentally investigated. The efficiency and energy resolution of the detector have been measured as a function of energy and the noise contributions to the preamplifier signal have been determined. Collimated gamma-ray sources mounted on an automated 3-axis scanning table have been used to study the variation in preamplifier signal shape with gamma-ray interaction position in the detector, so that the position-dependent charge collection process could be characterised. A suite of experimental measurements have also been undertaken to investigate the performance of the detector as a function of bias voltage and we report on anomalous behaviour observed when the detector was operating close to the depletion voltage.

Harkness-Brennan, L. J.; Judson, D. S.; Boston, A. J.; Boston, H. C.; Colosimo, S. J.; Cresswell, J. R.; Nolan, P. J.; Adekola, A. S.; Colaresi, J.; Cocks, J. F. C.; Mueller, W. F.

2014-10-01

403

Recent advances in the development of semiconductor detectors for SLHC  

NASA Astrophysics Data System (ADS)

For the luminosity upgrade of the LHC, the SLHC, the tracking systems of the LHC experiments need to be replaced and upgraded. A main concern is the extreme radiation hardness requirements, up to 1×10 16 cm -2. This paper describes recent results on the radiation hardening technologies developed within the CERN RD50 Collaboration for the LHC upgrade. Silicon detectors have been designed and produced on n- and p-type 4/6 in. wafers made by Float Zone, epitaxy and Czochralski technology. Their charge collection efficiency after irradiation with protons, neutron and mixed irradiation has been studied. Novel detector concepts, as 3D detectors, have been designed, produced and studied as well. Radiation induced microscopic disorder has been also investigated in Si detectors with fluences up to 10 16 cm -2 and correlated with the performance degradation of irradiated detectors.

Tuovinen, Esa

2010-11-01

404

Performance Improvement of CZT Detectors by Line Electrode Geometry  

NASA Astrophysics Data System (ADS)

Due to their high efficiency and high energy resolution, applications of CdZnTe (CZT) detectors have spread into many areas such as room temperature detectors. To improve the performance and decrease the effects of hole trapping and crystal non-uniformity, special contact geometries are applied to the detectors, such as Coplanar, 3D pixel, Frisch grid, Capture and so on. In this paper, we introduce a new line electrode geometry to greatly improve CZT detector performance. A line anode collects electrons, while a planar cathode collects holes. Due to the low electric field close to the cathode and the low hole ?? value, this geometry is also a single charge sensitive structure. The calculated energy resolution of a 20 mm x 20 mm x 15 mm detector could be improved up to 1.51% for 662 keV gamma rays. Both simulations and experimental results are presented here.

Zhang, Lan; Zhang, Wei; Li, Jun; Liu, Yanqing; Li, Yulan; Li, Yuanjing; Liu, Yinong; Fu, Jianqiang; Jiang, Hao; Deng, Zhi; Xue, Tao; Luo, Jie

2014-02-01

405

Two dimensional and linear scintillation detectors for fast neutron imaging — comparative analysis  

NASA Astrophysics Data System (ADS)

The paper was aimed to compare performance capabilities of two types of scintillation detectors commonly used for fast neutron imaging: two dimensional and linear ones. Best-case values of quantum efficiency, spatial resolution and capacity were estimated for detectors with plastic converter-screen in case of 14 MeV neutrons. For that there were examined nuclear reactions produced in converter-screen by fast neutrons, spatial distributions of energy release of emerged charged particles and amplitude distributions of scintillations generated by these particles. The paper shows that the efficiency of the linear detector is essentially higher and this detector provides potentially better spatial resolution in comparison with the two dimensional detector. But, the two dimensional detector surpasses the linear one in capacity. The presented results can be used for designing radiographic fast neutron detectors with organic scintillators.

Mikerov, V. I.; Koshelev, A. P.; Ozerov, O. V.; Sviridov, A. S.; Yurkov, D. I.

2014-05-01

406

Velocity map imaging using an in-vacuum pixel detector  

NASA Astrophysics Data System (ADS)

The use of a new type in-vacuum pixel detector in velocity map imaging (VMI) is introduced. The Medipix2 and Timepix semiconductor pixel detectors (256×256 square pixels, 55×55 ?m2) are well suited for charged particle detection. They offer high resolution, low noise, and high quantum efficiency. The Medipix2 chip allows double energy discrimination by offering a low and a high energy threshold. The Timepix detector allows to record the incidence time of a particle with a temporal resolution of 10 ns and a dynamic range of 160 ?s. Results of the first time application of the Medipix2 detector to VMI are presented, investigating the quantum efficiency as well as the possibility to operate at increased background pressure in the vacuum chamber.

Gademann, Georg; Huismans, Ymkje; Gijsbertsen, Arjan; Jungmann, Julia; Visschers, Jan; Vrakking, Marc J. J.

2009-10-01

407

Velocity map imaging using an in-vacuum pixel detector.  

PubMed

The use of a new type in-vacuum pixel detector in velocity map imaging (VMI) is introduced. The Medipix2 and Timepix semiconductor pixel detectors (256 x 256 square pixels, 55 x 55 microm2) are well suited for charged particle detection. They offer high resolution, low noise, and high quantum efficiency. The Medipix2 chip allows double energy discrimination by offering a low and a high energy threshold. The Timepix detector allows to record the incidence time of a particle with a temporal resolution of 10 ns and a dynamic range of 160 micros. Results of the first time application of the Medipix2 detector to VMI are presented, investigating the quantum efficiency as well as the possibility to operate at increased background pressure in the vacuum chamber. PMID:19895052

Gademann, Georg; Huismans, Ymkje; Gijsbertsen, Arjan; Jungmann, Julia; Visschers, Jan; Vrakking, Marc J J

2009-10-01

408

High voltage optimization in CdZnTe detectors  

NASA Astrophysics Data System (ADS)

The focus of this paper is to investigate, experimentally and theoretical, the optimum operating bias, in cadmium zinc telluride Cd 0.9Zn0.1Te (CZT) crystals grown using the traveling heater method (THM), required to achieve maximum energy resolution. It was found that 5 mm thick detectors that have low electron trapping, (??)e?1×10-2 cm2/V, operates efficiently at relatively low applied bias, 200 V; while detectors with high electron trapping, (??)e?5×10-3 cm2/V, required relative high voltage: as high as 1000 V for 5 mm thick detectors. Similarly 10 mm thick detectors can be operated at as low as 500 V. Moreover, both charge collection efficiency (CCE) and energy resolution(ER) were found to follow the same trend.

Awadalla, S. A.; Al-Grafi, M.; Iniewski, K.

2014-11-01

409

Superconductor IR detector research  

NASA Astrophysics Data System (ADS)

A development status report is presented for efforts in the testing and characterization of high temperature superconducting thin films (HTSTFs) in the role of IR detectors. While none of the HTSTFs thus far tested was specifically formulated to serve in an IR sensing capacity, the results obtained have confirmed the ability of the test apparatus devised to obtain accurate, reliable, and repeatable detector performance data. The initial HTSTF tests were conducted on BaCuO films sputtered on strontium titanate substrates. Chips made from the films were 5 x 5 mm and approximately 2 microns thick.

Meuser, L. H.; Thiede, D. A.; McDonald, P.; Garcia, J.

1989-10-01

410

Radiation Detectors and Art  

NASA Astrophysics Data System (ADS)

The use of radiation detectors in the analysis of art objects represents a very special application in a true interdisciplinary field. Radiation detectors employed in this field detect, e.g., x-rays, ?-rays, ? particles, and protons. Analyzed materials range from stones, metals, over porcelain to paintings. The available nondestructive and noninvasive analytical methods cover a broad range of techniques. Hence, for the sake of brevity, this chapter will concentrate on few techniques: Proton Induced X-ray Emission (PIXE) and Proton Induced ?-ray Emission (PIGE).

Denker, Andrea

411

Gaseous Radiation Detectors  

NASA Astrophysics Data System (ADS)

1. Introduction; 2. Electromagnetic interactions of charged particles with matter; 3. Interactions of photons and neutrons with matter; 4. Drift and diffusion of charges in gases; 5. Collisional excitations and charge multiplication in uniform fields; 6. Parallel plate counters; 7. Proportional counters; 8. Multiwire proportional chambers; 9. Drift chambers; 10. Time projection chambers; 11. Multitube arrays; 12. Resistive plate chambers; 13. Micro-pattern gas detectors; 14. Cherenkov ring imaging; 15. Miscellaneous detectors and applications; 16. Time degeneracy and aging; Further reading; References; Index.

Sauli, Fabio

2014-06-01

412

Cosmic ray detectors  

NASA Technical Reports Server (NTRS)

Work on the MSFC emulsion laboratory microscopes in which mechanical modifications previously made were verified is reviewed, as is a design study of a large area hybrid electronic/emulsion chamber balloon flight detector system. This design is built upon the experience obtained with the highly successful MSFC/UAH hybrid instrument flown by the JACEE consortium. The design included overall system design and specification, design and fabrication of a prototype large light diffusion for Cerenkov charge detector or scintillator, design of a multiwire proportional counter array and design of the gondola or flight support system.

Gregory, John C.

1987-01-01

413

Glow discharge detector  

DOEpatents

A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured.

Koo, Jackson C. (San Ramon, CA); Yu, Conrad M. (Antioch, CA)

2002-01-01

414

Neutron detectors comprising ultra-thin layers of boron powder  

DOEpatents

High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material having a thickness of from about 50 nm to about 250 nm and comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

Wang, Zhehul; Morris, Christopher

2013-07-23

415

Silicon planar technology for single-photon optical detectors  

Microsoft Academic Search

Design and fabrication of single photon avalanche detector (SPAD) in planar technology is reported. Device design and critical issues in the technology are discussed. Experimental test procedures are described for dark-counting rate, afterpulsing probability, photon timing resolution, and quantum detection efficiency. Low-noise detectors are obtained, with dark counting rates down to 10 c\\/s for devices with 10 ?m diameter, down

Emilio Sciacca; Andrea C. Giudice; Delfo Sanfilippo; Franco Zappa; Salvatore Lombardo; Rosario Consentino; C. Di Franco; M. Ghioni; G. Fallica; G. Bonanno; S. Cova; E. Rimini

2003-01-01

416

Photon counting detectors for Fabry-Perot interferometers  

NASA Technical Reports Server (NTRS)

Sealed channel plate photomultipliers with multiple discrete anodes for use as photon counting detectors in the image plane of Fabry-Perot interferometers are described. The influence of design and construction on performance of completed devices is discussed. Effects on spatial resolution, lifetime, and counting efficiency are described. It is shown that devices can be optimized for particular applications. The results should be generally applicable to resistive anode and wedge and strip anode types of sealed detectors.

Darlington, E. H.; Haviland, J. R.

1989-01-01

417

Modeling charge-sharing effects in pixellated CZT detectors  

Microsoft Academic Search

While charge-sharing in pixellated CdZnTe (CZT) room temperature radiation detectors has been studied numerically and experimentally in the last 5-10 years, there are no analytical models that will guide the optimization of CZT detector operations and enable efficient use of the correction algorithms. In this paper, we propose a new analytical model to provide an effective framework to study these

Kris Iniewski; Henry Chen; Glenn Bindley; Irfan Kuvvetli; C. Budtz-Jorgensen

2007-01-01

418

Trap influence on the performance of gallium arsenide radiation detectors  

SciTech Connect

Ohmic contacts play an important role in the performance of LEC gallium arsenide particle detectors since they possibly control the injection of charge carriers. Contact characteristics have been compared and related to electrically active defects induced during contact preparation and to the detector efficiency. The electric field distribution has also been analyzed. Spectroscopic investigations have put into evidence that the contact fabrication process significantly influences the trap density whilst it does not change their signatures.

Castaldini, A.; Cavallini, A.; Polenta, L. [Univ. of Bologna (Italy); Canali, C.; Nava, F. [Univ. of Modena (Italy); Papa, C. del [Univ. of Udine (Italy). Dept. of Physics

1996-12-31

419

Near room temperature X-ray and Gamma ray spectroscopic detectors for future space experiments  

E-print Network

New generation Cadmium Telluride (CZT & CdTe) solid state detectors can provide high quantum efficiency with reasonably good energy resolution and can operate at near room temperature; an unique advantage for space experiments. We present here results of our study of small diode detectors as well as large area pixel detectors. Our study is aimed at developing near room temperature hard X-ray spectroscopy detectors for ASTROSAT and other future Indian space science missions.We have studied a Si-PIN detector in the energy range 5 - 60 keV and CZT & CdTe Schottky diode detectors in the energy region 10 - 1330 keV. We have studied large area (64 cm$^2$) CZT pixel detectors with pixel size close to the small CZT detector. We have studied individual pixels as well as CZT detector as a whole (summed over all the 1024 pixels). The energy resolution behaviour of the large area CZT detector is similar to that of small diode detectors in the low energy region. The change in operating temperature from room temperature ~20 to ~70$ degree C drastically affects both the energy resolutionas well as the peak area due to a sharp rise in the thermal noise.These results suggest that the cooling of detector system will provide better energy resolution as well as detection efficiency.

J. S. Yadav; S. Savitri; J. P. Malkar

2005-07-07

420

Detector and Telescope Development for ProtoEXIST and Fine Beam Measurements of Spectral Response of CZT Detectors  

E-print Network

We outline our plan to develop ProtoEXIST, a balloon-borne prototype experiment for the Energetic X-ray Imaging Survey Telescope (EXIST) for the Black Hole Finder Probe. EXIST will consist of multiple wide-field hard X-ray coded-aperture telescopes. The current design of the EXIST mission employs two types of telescope systems: high energy telescopes (HETs) using CZT detectors, and low energy telescopes (LETs) using Si detectors. With ProtoEXIST, we will develop and demonstrate the technologies required for the EXIST HETs. As part of our development efforts, we also present recent laboratory measurements of the spectral response and efficiency variation of imaging CZT detectors on a fine scale (~0.5 mm). The preliminary results confirm the need for multi-pixel readouts and small inter-pixel gaps to achieve uniform spectral response and high detection efficiency across detectors.

J. Hong; A. Copete; J. E. Grindlay; S. V. Vadawale; W. W. Craig; F. Harrison; W. R. Cook; N. Gehrels

2005-09-26

421

The Upgraded D0 detector  

SciTech Connect

The D0 experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to D0.

Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, D.L.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahmed, S.N.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G.A.; Anastasoaie, M.; Andeen, T.; Anderson, J.T.; Anderson, S.; /Buenos Aires U. /Rio de Janeiro, CBPF /Sao Paulo, IFT /Alberta U./Simon Fraser U. /York U., Canada /McGill U. /Beijing, Inst. High Energy Phys. /Hefei, CUST /Andes U., Bogota /Charles U. /Prague, Tech. U. /Prague, Inst. Phys. /San Francisco deQuito U. /Clermont-Ferrand U. /LPSC, Grenoble /Marseille, CPPM /Orsay, LAL /Paris U., VI-VII /DAPNIA, Saclay /Strasbourg, IReS; ,

2005-07-01

422

Experimental Characterization of Space Charge in IZIP Detectors  

NASA Astrophysics Data System (ADS)

Interleaved ionization electrode geometries offer the possibility of efficient rejection of near-surface events. The CDMS collaboration has implemented this interleaved approach for the charge and phonon readout for our germanium detectors. During a recent engineering run with negligible ambient radiation, the detectors were found to lose ionization stability more quickly than expected. This paper summarizes studies done in order to determine the underlying cause of the instability, as well as possible running modes that maintain stability without unacceptable loss of livetime. Additionally, first results are shown for the new version IZIP mask which attempts to improve the overall stability of the detectors.

Doughty, T.; Pyle, M.; Mirabolfathi, N.; Serfass, B.; Kamaev, O.; Hertel, S.; Leman, S. W.; Brink, P.; Cabrera, B.; Sadoulet, B.

2012-06-01

423

Detector driver systems and photometric estimates for RIMAS  

NASA Astrophysics Data System (ADS)

The Rapid infrared IMAger-Spectrometer (RIMAS) is a rapid gamma-ray burst afterglow instrument that will provide photometric and spectroscopic coverage of the Y, J, H, and K bands. RIMAS separates light into two optical arms, YJ and HK, which allows for simultaneous coverage in two photometric bands. RIMAS utilizes two 2048 x 2048 pixel Teledyne HgCdTe (HAWAII-2RG) detectors along with a Spitzer Legacy Indium- Antimonide (InSb) guiding detector in spectroscopic mode to position and keep the source on the slit. We describe the software and hardware development for the detector driver and acquisition systems. The HAWAII- 2RG detectors simultaneously acquire images using Astronomical Research Cameras, Inc. driver, timing, and processing boards with two C++ wrappers running assembly code. The InSb detector clocking and acquisition system runs on a National Instruments cRIO-9074 with a Labview user interface and clocks written in an easily alterable ASCII file. We report the read noise, linearity, and dynamic range of our guide detector. Finally, we present RIMAS's estimated instrument efficiency in photometric imaging mode (for all three detectors) and expected limiting magnitudes. Our efficiency calculations include atmospheric transmission models, filter models, telescope components, and optics components for each optical arm.

Toy, Vicki L.; Kutyrev, Alexander S.; Lyness, Eric I.; Muench, Marius; Robinson, Frederick D.; Lotkin, Gennadiy N.; Capone, John I.; Veilleux, Sylvain; Moseley, Samuel H.; Gehrels, Neil A.; Vogel, Stuart N.

2014-07-01

424

Veto Detectors for the Micro-Modular Neutron Array  

NASA Astrophysics Data System (ADS)

Current neutron detectors at the National Superconducting Cyclotron Laboratory have a detection efficiency of ten percent for single neutron hits and one percent for double neutron hits. The Modular Neutron Array (MoNA), a large-area neutron detector consisting of 144 individual plastic scintillator modules, will have detection efficiencies of seventy percent for single neutron hits and nearly fifty percent for double neutron hits. MoNA will measure the energy of neutrons by time-of-flight relative to a start detector and the position by the time difference of the signals between both ends. Tests were conducted on a small subset of MoNA, ?MoNA, that consisted of eight MoNA detector bars. Two veto detectors placed in front of ?MoNA were used in these first test experiments where neutrons and charged particles were produced from high-energy ^36Ar and ^8Li beams. The veto detectors discriminated between neutrons and charged particles that hit the array following a reaction of the beam. The veto detectors were very thin, so most neutrons passed through them and into the modules without losing energy. However, the charged particles were easily identifiable when they passed through the veto paddles, allowing the differentiation between actual neutron events and background events of charged particles.

Lu, Yao; Baumann, Thomas; Thoennessen, Michael; Tryggestad, Erik; Evanger, Melanie; Luther, Bryan; Rajabali, Mustafa; Turner, Ramsey

2002-10-01

425

nGEM fast neutron detectors for beam diagnostics  

NASA Astrophysics Data System (ADS)

Fast neutron detectors with a sub-millimetric space resolution are required in order to qualify neutron beams in applications related to magnetically-controlled nuclear fusion plasmas and to spallation sources. A nGEM detector has been developed for the CNESM diagnostic system of the SPIDER NBI prototype for ITER and as beam monitor for fast neutrons lines at spallation sources. The nGEM is a triple GEM gaseous detector equipped with polypropylene and polyethylene layers used to convert fast neutrons into recoil protons through the elastic scattering process. This paper describes the results obtained by testing a nGEM detector at the ISIS spallation source on the VESUVIO beam line. Beam profiles (?x=14.35 mm, ?y=15.75 mm), nGEM counting efficiency (around 10-4 for 3 MeVdetector stability (?4.5%) and the effect of filtering the beam with different type of materials were successfully measured. The x beam profile was compared to the one measured by a single crystal diamond detector. Finally, the efficiency of the detector was simulated exploiting the GEANT4 tool.

Croci, G.; Claps, G.; Cavenago, M.; Dalla Palma, M.; Grosso, G.; Murtas, F.; Pasqualotto, R.; Perelli Cippo, E.; Pietropaolo, A.; Rebai, M.; Tardocchi, M.; Tollin, M.; Gorini, G.

2013-08-01

426

Detector assembly with a diamond detector for recording neutrons  

Microsoft Academic Search

The BDPN-1K detector assembly for neutron radiation comprises the detector and a preamplifier connected by a 10-m-long cable. The detector can be disassembled. Before the sensitive surface of the diamond there is placed a cover with a converter disk cemented to it; this disk is a UâOâ layer applied to an aluminum foil. Since the detector can be disassembled, the

A. E. Luchanskii; S. S. Martynov; V. S. Khrunov; V. A. Chekhlaev

1988-01-01

427

Fast Detector Simulation Using Lelaps, Detector Descriptions in GODL  

E-print Network

Lelaps is a fast detector simulation program which reads StdHep generator files and produces SIO or LCIO output files. It swims particles through detectors taking into account magnetic fields, multiple scattering and dE/dx energy loss. It simulates parameterized showers in EM and hadronic calorimeters and supports gamma conversions and decays. In addition to three built-in detector configurations, detector descriptions can also be read from files in the new GODL file format.

Langeveld, W

2005-01-01

428

Fast Detector Simulation Using Lelaps, Detector Descriptions in GODL  

SciTech Connect

Lelaps is a fast detector simulation program which reads StdHep generator files and produces SIO or LCIO output files. It swims particles through detectors taking into account magnetic fields, multiple scattering and dE/dx energy loss. It simulates parameterized showers in EM and hadronic calorimeters and supports gamma conversions and decays. In addition to three built-in detector configurations, detector descriptions can also be read from files in the new GODL file format.

Langeveld, Willy; /SLAC

2005-07-06

429

Photovoltaic radiation detector element  

DOEpatents

A radiation detector element is formed of a body of semiconductor material, a coating on the body which forms a photovoltaic junction therewith, and a current collector consisting of narrow metallic strips, the aforesaid coating having an opening therein in the edge of which closely approaches but is spaced from the current collector strips.

Agouridis, D.C.

1980-12-17

430

Sensitive hydrogen leak detector  

DOEpatents

A sensitive hydrogen leak detector system is described which uses passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor. 1 fig.

Myneni, G.R.

1999-08-03