The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
J N Ullom - One of the best experts on this subject based on the ideXlab platform.
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review of superconducting transition edge sensors for x Ray and Gamma Ray spectroscopy
Superconductor Science and Technology, 2015Co-Authors: J N Ullom, D A BennettAbstract:We present a review of emerging x-Ray and Gamma-Ray Spectrometers based on arRays of superconducting transition-edge sensors (TESs). Special attention will be given to recent progress in TES applications and in understanding TES physics.
D A Bennett - One of the best experts on this subject based on the ideXlab platform.
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review of superconducting transition edge sensors for x Ray and Gamma Ray spectroscopy
Superconductor Science and Technology, 2015Co-Authors: J N Ullom, D A BennettAbstract:We present a review of emerging x-Ray and Gamma-Ray Spectrometers based on arRays of superconducting transition-edge sensors (TESs). Special attention will be given to recent progress in TES applications and in understanding TES physics.
Y Nemirovsky - One of the best experts on this subject based on the ideXlab platform.
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statistical modeling of the spectral performance of a two dimensional arRay of Gamma Ray Spectrometers
Journal of Applied Physics, 2002Co-Authors: M Ifraimov, A Ludwig, Y NemirovskyAbstract:We develop a statistical model for the calculation of the spectral performance of two-dimensional (2D) arRay of Gamma-Ray Spectrometers. We consider a nonuniform field in the device, determined by the geometrical design of the anodes. The induced charge is calculated by solving the Poisson’s equation with the appropriate boundary conditions. Furthermore, the presented model simultaneously considers a random point of photon absorption and a random drift length for each carrier, taking into account the effect of multiple trapping and detrapping. The model developed in this article enables the optimal geometrical design of the 2D arRay of anodes according to the electrical properties of the given semiconductor material, in order to achieve optimal results for the spectral performances. The model consists of three parts. The first is the calculation of the potential at each point of a three-dimensional (3D) map of the device. The second is the calculation of the charge induced on the anode by a point charge p...
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spectroscopic evaluation of n type cdznte Gamma Ray Spectrometers
Journal of Electronic Materials, 2000Co-Authors: Y Nemirovsky, G Asa, J Gorelik, A PeyserAbstract:This work focuses on the evaluation of the spectroscopic performance of n-type CdZnTe Gamma-Ray Spectrometers, grown by a modified horizontal Bridgman Technique developed at IMARAD Imaging Systems Ltd. Two types of devices are studied: (i) detector arRays grown and produced by IMARAD and employing ohmic indium contacts and (ii) detectors and arRays fabricated at Technion in crystals provided by IMARAD, employing different types of contacts. Alpha particle spectroscopy as well as Gamma-Ray spectroscopy is used to evaluate and characterize the energy resolution of Gamma-Ray Spectrometers fabricated on n-type CdZnTe grown by a modified horizontal Bridgman and doped with indium. The electron and hole mobility lifetime products of the n-type CdZnTe material grown by IMARAD are estimated by measuring the dependence of charge collection efficiency upon the bias voltage, using a calibrated multichannel analyzer. The measured results indicate that the average electron and hole mobility-lifetime products are, respectively, of the order of μnτn=(1–2)·10−3 cm2/V and μpτp=6·10−6 cm2/V. The measured energy resolution of 122 keV photons is −(5–6)% when the source is not collimated and is reduced to −4.5% when the source is collimated. These results are obtained with ohmic cathode as well as with a rectifying cathode. A statistical model for the calculation of the pulse height spectra as a function of photon energy, electron and hole mobility-lifetime products and applied electric field, which has been recently reported in Applied Physical Letters, is used to determine the role of incomplete charge collection in the spectral performance of the n-type CdZnTe Spectrometers. The comparison between the measured and modeled results indicates that the dark noise, cross talk and non-uniformity are the main limiting factors of the spectral performance of the n-type Spectrometers rather than incomplete charge collection. The good spectroscopic performance of the arRays under study is attributed to an adequate hole mobility lifetime for the geometry of the pixilated arRays. The study indicates that the n-type CdZnTe Spectrometers are useful for a wide range of imaging applications.
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statistical modeling of pulse height spectrum of Gamma Ray Spectrometers limited by incomplete charge collection
Applied Physics Letters, 1999Co-Authors: Y NemirovskyAbstract:This letter presents an analytic approach to the calculation of the pulse height spectrum, using a statistical model, which simultaneously considers a random point of photon absorption (i.e., nonuniform absorption) and a random drift time for each carrier. The pulse height spectrum of Gamma-Ray Spectrometers is calculated as a function of photon energy, electron and hole mobility-lifetime products and applied electric field. For Spectrometers with a uniform electric field the pulse height spectrum is obtained by a single numerical integration of an analytical expression.
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statistical modeling of charge collection in semiconductor Gamma Ray Spectrometers
Journal of Applied Physics, 1999Co-Authors: Y NemirovskyAbstract:Charge collection efficiency and the variance of the collected charge of semiconductor Gamma-Ray Spectrometers are analytically modeled for the case of a uniform electric field. The model is based on a rigorous statistical approach. In contrast to previously reported models for the variance of the collected charge, the present statistical model simultaneously takes into account a random point of photon absorption (i.e., a nonuniform absorption) and a random drift time for each generated carrier. Analytical expressions are obtained for the variance of the collected charge as a function of photon energy, applied bias voltage, electron and hole mobility-lifetime products, and the direction of irradiation. Since at present the performance of high-Z room-temperature Spectrometers is mainly limited by the charge transport properties of the semiconductors, it is interesting to calculate the limit for the expected resolution. The statistical model presented here yields physical insight and determines quantitatively the expected spectrometer resolution as a function of the semiconductor transport parameters and device parameters, as well as the radiation parameters. Several limiting cases are calculated and discussed. The methodology presented here, which is based on conditional probabilities, can be extended to Spectrometers with nonuniform fields.
S E Labov - One of the best experts on this subject based on the ideXlab platform.
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Design of a multichannel ultra-high-resolution superconducting Gamma-Ray spectrometer
Hard X-Ray and Gamma-Ray Detector Physics VI, 2004Co-Authors: Stephan Friedrich, S Terracol, Troy W Barbee, T Niedermayr, Toshiyuki Miyazaki, Owen B. Drury, Z. A. Ali, M. Cunningham, J.d. Batteux, S E LabovAbstract:Superconducting Gamma-Ray microcalorimeters operated at temperatures around ~0.1 K offer an order of magnitude improvement in energy resolution over conventional high-purity Germanium Spectrometers. The calorimeters consist of a ~1 mm3 superconducting or insulating absorber and a sensitive thermistor, which are weakly coupled to a cold bath. Gamma-Ray capture increases the absorber temperature in proportion to the Gamma-Ray energy, this is measured by the thermistor, and both subsequently cool back down to the base temperature through the weak link. We are developing ultra-high-resolution Gamma-Ray Spectrometers based on Sn absorbers and superconducting Mo/Cu multilayer thermistors for nuclear non-proliferation applications. They have achieved an energy resolution between 60 and 90 eV for Gamma-Rays up to 100 keV. We also build two-stage adiabatic demagnetization refrigerators for user-friendly detector operation at 0.1 K. We present recent results on the performance of single pixel Gamma-Ray Spectrometers, and discuss the design of a large detector arRay for increased sensitivity.
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Gamma Ray Spectrometers using superconducting transition edge sensors with external active feedback bias
IEEE Transactions on Applied Superconductivity, 2001Co-Authors: Daniel Chow, M L Van Den Berg, A Loshak, Matthias Frank, Troy W Barbee, S E LabovAbstract:We are developing X-Ray and Gamma-Ray Spectrometers with high absorption efficiency and high energy-resolution for X-Ray and Gamma-Ray spectroscopy. They are microcalorimeters consisting of a bulk Sn absorber coupled to a Mo/Cu multilayer superconducting transition edge sensor (TES). We have operated these microcalorimeters with an external active feedback bias to linearize the detector response, improve the count rate performance, and extend the detection energy range. We measured an energy resolution of 120 eV FWHM for 60 keV incident Gamma-Rays with no degradation of resolution from active bias. We present X-Ray and Gamma-Ray results and operation of this detector design in both bias modes.
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Gamma Ray Spectrometers using superconducting transition edge sensors with external active feedback bias
Applied Superconductivity Conference 2000 Virginia Beach VA (US) 09 17 2000--09 22 2000, 2000Co-Authors: Daniel Chow, M L Van Den Berg, A Loshak, Matthias Frank, Troy W Barbee, S E LabovAbstract:The authors are developing x-Ray and Gamma-Ray Spectrometers with high absorption efficiency and high energy-resolution for x-Ray and Gamma-Ray spectroscopy. They are microcalorimeters consisting of a bulk Sn absorber coupled to a Mo/Cu multilayer superconducting transition edge sensor (TES). The authors have measured an energy resolution of 70 eV FWHM for 60 keV incident Gamma-Rays using electrothermal feedback. They have also operated these microcalorimeters with an external active feedback bias to linearize the detector response, improve the count rate performance, and extend the detection energy range. They present x-Ray and Gamma-Ray results operation of this detector design in both bias modes.
S Friedrich - One of the best experts on this subject based on the ideXlab platform.
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ultrahigh energy resolution Gamma Ray Spectrometers for precision measurements of uranium enrichment
Presented at: MARC VII (Methods & Applications of Radioanalytical Chemistry) Kona HI United States Apr 03 - Apr 07 2006, 2006Co-Authors: S Ali, I D Hau, T R Niedermayr, S FriedrichAbstract:Superconducting Gamma-Ray detectors offer an order of magnitude higher energy resolution than conventional high-purity germanium detectors. This can significantly increase the precision of non-destructive isotope analysis for nuclear samples where line overlap affects the errors of the measurement. We have developed Gamma-detectors based on superconducting molybdenum-copper sensors and bulk tin absorbers for nuclear science and national security applications. They have, depending on design, an energy resolution between {approx}50 and {approx}150 eV FWHM at {approx}100 keV. Here we apply this detector technology to the measurement of uranium isotope ratios, and discuss the trade-offs between energy resolution and quantum efficiency involved in detector design.
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the dynamic range of ultra high resolution cryogenic Gamma Ray Spectrometers
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2006Co-Authors: S Ali, S Terracol, O B Drury, S FriedrichAbstract:Abstract We are developing high-resolution cryogenic Gamma-Ray Spectrometers for nuclear science and non-proliferation applications. The Gamma-Ray detectors are composed of a bulk superconducting Sn foil absorber attached to a multilayer Mo/Cu transition-edge sensor (TES). The energy resolution of a detector with a 1×1×0.25 mm 3 Sn absorber is 50–90 eV FWHM for γ-Rays up to 100 keV, and it decreases for larger absorbers. Here, we present the detector performance for different absorber volumes, and discuss the trade-offs between energy resolution and dynamic range.
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the dynamic range of ultra high resolution cryogenic Gamma Ray Spectrometers
Presented at: Low Temperature Detectors (LTD) 11 Tokyo Japan Jul 31 - Aug 05 2005, 2005Co-Authors: S Ali, S Terracol, O B Drury, S FriedrichAbstract:We are developing high-resolution cryogenic Gamma-Ray Spectrometers for nuclear science and non-proliferation applications. The Gamma-Ray detectors are composed of a bulk superconducting Sn foil absorber attached to multilayer Mo/Cu transition-edge sensors (TES). The energy resolution achieved with a 1 x 1 x 0.25 mm{sup 3} Sn absorber is 50 -90eV for {Gamma}-Rays up to 100 keV and it decreases for large absorber sizes. We discuss the trade-offs between energy resolution and dynamic range, as well as development of TES arRays for higher count rates and better sensitivity.
