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Sample records for hpge detector efficiencies

  1. A software for simulation of efficiency of HPGe detectors

    NASA Astrophysics Data System (ADS)

    Khiem, L. H.; Trong, T. D.

    2015-05-01

    Computer software named GE_EFF for calculation of detection efficiency of High Purity Ge detectors recently developed by us is presented. A Monte-Carlo method has been used for simulation. The software has been written in Visual Basic language. The calculated efficiencies for our detectors are in agreement with the measured values using a standard γ-ray sources. The software has been used at our laboratory of Institute of Physics for gamma radiation measurements.

  2. A software package using a mesh-grid method for simulating HPGe detector efficiencies

    SciTech Connect

    Gritzo, Russell E; Jackman, Kevin R; Biegalski, Steven R

    2009-01-01

    Traditional ways of determining the absolute full-energy peak efficiencies of high-purity germanium (HPGe) detectors are often time consuming, cost prohibitive, or not feasible. A software package, KMESS (Kevin's Mesh Efficiency Simulator Software), was developed to assist in predicting these efficiencies. It uses a semiempirical mesh-grid method and works for arbitrary source shapes and counting geometries. The model assumes that any gamma-ray source shape can be treated as a large enough collection of point sources. The code is readily adaptable, has a web-based graphical front-end. and could easily be coupled to a 3D scanner. As will be shown. this software can estimate absolute full-energy peak efficiencies with good accuracy in reasonable computation times. It has applications to the field of gamma-ray spectroscopy because it is a quick and accurate way to assist in performing quantitative analyses using HPGe detectors.

  3. Coincidence corrected efficiency calibration of Compton-suppressed HPGe detectors

    SciTech Connect

    Aucott, T.

    2015-04-20

    The authors present a reliable method to calibrate the full-energy efficiency and the coincidence correction factors using a commonly-available mixed source gamma standard. This is accomplished by measuring the peak areas from both summing and non-summing decay schemes and simultaneously fitting both the full-energy efficiency, as well as the total efficiency, as functions of energy. By using known decay schemes, these functions can then be used to provide correction factors for other nuclides not included in the calibration standard.

  4. Evaluation of ANGLE(R), a code for calculating HPGe detector efficiencies

    SciTech Connect

    Homan, Victoria M

    2010-10-25

    This paper evaluates the ANGLE(reg sign) software package, an advanced efficiency calibration software for high purity germanium detectors that is distributed by ORTEC(reg sign). ANGLE(reg sign) uses a semi-empirical approach, by way of the efficiency transfer method, based on the calculated effective solid angle. This approach would have an advantage over the traditional relative and stochastic methods by decreasing the chances for systematic errors and reducing sensitivity to uncertainties in detector parameters. For experimental confirmation, a closed-end coaxial HPGe detector was used with sample geometries frequently encountered at the Los Alamos National Laboratory. The results obtained were sufficient for detector-source configurations which included intercepting layers of plexiglass and carbon graphite, but somewhat insufficient for bare source configurations.

  5. Validation of an efficiency calibration procedure for a coaxial n-type and a well-type HPGe detector used for the measurement of environmental radioactivity

    NASA Astrophysics Data System (ADS)

    Morera-Gómez, Yasser; Cartas-Aguila, Héctor A.; Alonso-Hernández, Carlos M.; Nuñez-Duartes, Carlos

    2016-05-01

    To obtain reliable measurements of the environmental radionuclide activity using HPGe (High Purity Germanium) detectors, the knowledge of the absolute peak efficiency is required. This work presents a practical procedure for efficiency calibration of a coaxial n-type and a well-type HPGe detector using experimental and Monte Carlo simulations methods. The method was performed in an energy range from 40 to 1460 keV and it can be used for both, solid and liquid environmental samples. The calibration was initially verified measuring several reference materials provided by the IAEA (International Atomic Energy Agency). Finally, through the participation in two Proficiency Tests organized by IAEA for the members of the ALMERA network (Analytical Laboratories for the Measurement of Environmental Radioactivity) the validity of the developed procedure was confirmed. The validation also showed that measurement of 226Ra should be conducted using coaxial n-type HPGe detector in order to minimize the true coincidence summing effect.

  6. Monte Carlo calculations of the HPGe detector efficiency for radioactivity measurement of large volume environmental samples.

    PubMed

    Azbouche, Ahmed; Belgaid, Mohamed; Mazrou, Hakim

    2015-08-01

    A fully detailed Monte Carlo geometrical model of a High Purity Germanium detector with a (152)Eu source, packed in Marinelli beaker, was developed for routine analysis of large volume environmental samples. Then, the model parameters, in particular, the dead layer thickness were adjusted thanks to a specific irradiation configuration together with a fine-tuning procedure. Thereafter, the calculated efficiencies were compared to the measured ones for standard samples containing (152)Eu source filled in both grass and resin matrices packed in Marinelli beaker. From this comparison, a good agreement between experiment and Monte Carlo calculation results was obtained highlighting thereby the consistency of the geometrical computational model proposed in this work. Finally, the computational model was applied successfully to determine the (137)Cs distribution in soil matrix. From this application, instructive results were achieved highlighting, in particular, the erosion and accumulation zone of the studied site.

  7. Monte Carlo analysis of the influence of germanium dead layer thickness on the HPGe gamma detector experimental efficiency measured by use of extended sources.

    PubMed

    Chham, E; García, F Piñero; El Bardouni, T; Ferro-García, M Angeles; Azahra, M; Benaalilou, K; Krikiz, M; Elyaakoubi, H; El Bakkali, J; Kaddour, M

    2014-09-22

    We have carried out a study to figure out the influence of crystal inactive-layer thickness on gamma spectra measured by an HPGe detector. The thickness of this dead layer (DL) is not known (no information about it was delivered by the manufacturer) due to the existence of a transition zone where photons are increasingly absorbed. To perform this analyses a virtual model of a Canberra HPGe detector was produced with the aid of MCNPX 2.7 code. The main objective of this work is to produce an optimal modeling for our GPGe detector. To this end, the study included the analysis of the total inactive germanium layer thickness and the active volume that are needed in order to obtain the smallest discrepancy between calculated and experimental efficiencies. Calculations and measurements were performed for all of the radionuclides included in a standard calibration gamma cocktail solution. Different geometry sources were used: a Marinelli and two other new sources represented as S(1) and S(2). The former was used for the determination of the active volume, whereas the two latter were used for the determination of the face and lateral DL, respectively. The model was validated by comparing calculated and experimental full energy peak efficiencies in the 50-1900keV energy range. the results show that the insertion of the DL parameter in the modeling is absolutely essential to reproduce the experimental results, and that the thickness of this DL varies from one position to the other on the detector surface.

  8. Monte Carlo calculation of the efficiency calibration curve and coincidence-summing corrections in low-level gamma-ray spectrometry using well-type HPGe detectors

    PubMed

    Laborie; Le Petit G; Abt; Girard

    2000-07-01

    Well-type high-purity germanium (HPGe) detectors are well suited to the analysis of small amounts of environmental samples, as they can combine both low background and high detection efficiency. A low-background well-type detector is installed in the Modane underground Laboratory. In the well geometry, coincidence-summing effects are high and make the construction of the full energy peak efficiency curve a difficult task with an usual calibration standard, especially in the high energy range. Using the GEANT code and taking into account a detailed description of the detector and the source, efficiency curves have been modelled for several filling heights of the vial. With a special routine taking into account the decay schemes of the radionuclides, corrections for coincidence-summing effects that occur when measuring samples containing 238U, 232Th or 134Cs have been computed. The results are found to be in good agreement with the experimental data. It is shown that triple coincidences effect on counting losses accounts for 7-15% of pair coincidences effect in the case of 604 and 796 keV lines of 134Cs.

  9. Initial Field Measurements with the Multisensor Airborne Radiation Survey (MARS) High Purity Germanium (HPGe) Detector Array

    SciTech Connect

    Fast, James E.; Bonebrake, Christopher A.; Dorow, Kevin E.; Glasgow, Brian D.; Jensen, Jeffrey L.; Morris, Scott J.; Orrell, John L.; Pitts, W. Karl; Rohrer, John S.; Todd, Lindsay C.

    2010-06-29

    Abstract: The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gamma ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications. This paper reports on results from initial field measurements conducted in a truck and on two different boats.

  10. Application of PHOTON simulation software on calibration of HPGe detectors

    NASA Astrophysics Data System (ADS)

    Nikolic, J.; Puzovic, J.; Todorovic, D.; Rajacic, M.

    2015-11-01

    One of the major difficulties in gamma spectrometry of voluminous environmental samples is the efficiency calibration of the detectors used for the measurement. The direct measurement of different calibration sources, containing isolated γ-ray emitters within the energy range of interest, and subsequent fitting to a parametric function, is the most accurate and at the same time most complicated and time consuming method of efficiency calibration. Many other methods are developed in time, some of them using Monte Carlo simulation. One of such methods is a dedicated and user-friendly program PHOTON, developed to simulate the passage of photons through different media with different geometries. This program was used for efficiency calibration of three HPGe detectors, readily used in Laboratory for Environment and Radiation Protection of the Institute for Nuclear Sciences Vinca, Belgrade, Serbia. The simulation produced the spectral response of the detectors for fixed energy and for different sample geometries and matrices. Thus obtained efficiencies were compared to the values obtained by the measurement of the secondary reference materials and to the results obtained by GEANT4 simulation, in order to establish whether the simulated values agree with the experimental ones. To further analyze the results, a realistic measurement of the materials provided by the IAEA within different interlaboratory proficiency tests, was performed. The activities obtained using simulated efficiencies were compared to the reference values provided by the organizer. A good agreement in the mid energy section of the spectrum was obtained, while for low energies the lack of some parameters in the simulation libraries proved to produce unacceptable discrepancies.

  11. New approach to calculate the true-coincidence effect of HpGe detector

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    The corrections for true-coincidence effects in HpGe detector are important, especially at low source-to-detector distances. This work established an approach to calculate the true-coincidence effects experimentally for HpGe detectors of type Canberra GC3018 and Ortec GEM25-76-XLB-C, which are in operation at neutron activation analysis lab in Malaysian Nuclear Agency (NM). The correction for true-coincidence effects was performed close to detector at distances 2 and 5 cm using 57Co, 60Co, 133Ba and 137Cs as standard point sources. The correction factors were ranged between 0.93-1.10 at 2 cm and 0.97-1.00 at 5 cm for Canberra HpGe detector; whereas for Ortec HpGe detector ranged between 0.92-1.13 and 0.95-100 at 2 and 5 cm respectively. The change in efficiency calibration curve of the detector at 2 and 5 cm after correction was found to be less than 1%. Moreover, the polynomial parameters functions were simulated through a computer program, MATLAB in order to find an accurate fit to the experimental data points.

  12. A repair station for HpGe detectors

    NASA Astrophysics Data System (ADS)

    Shearman, Robert; Lister, Christopher; Mitchell, A. J.; Copp, Patrick; Jepeal, Steven; Chowdhury, Partha

    2013-10-01

    Hyper-pure Germanium detectors (HpGe) offer the highest energy resolution for gamma-ray nuclear spectroscopy (about 1.5 keV @ 1 MeV), and are used in all the world's leading detector arrays such as GammaSphere, AGATA and GRETINA. The detector crystals are operated in cryostats at 100 K to reduce thermal noise. To maintain low leakage current and low operating temperatures, cryostat hygiene is very important. Detectors must be regularly maintained by using a high-vacuum, oil-free annealing station. At elevated temperatures above 373 K the process of pumping and baking can also anneal away neutron damage to the detector crystals. This poster will show the design and building of a new HpGe repair station at U. Mass Lowell, and make comparisons of results obtained from this new station to the Gammasphere annealing factory at Argonne. This research is funded by the DOE National Nuclear Safety Administration and the Office of Science.

  13. Pulse shape analysis and position determination in segmented HPGe detectors: The AGATA detector library

    NASA Astrophysics Data System (ADS)

    Bruyneel, B.; Birkenbach, B.; Reiter, P.

    2016-03-01

    The AGATA Detector Library (ADL) was developed for the calculation of signals from highly segmented large volume high-purity germanium (HPGe) detectors. ADL basis sets comprise a huge amount of calculated position-dependent detector pulse shapes. A basis set is needed for Pulse Shape Analysis (PSA). By means of PSA the interaction position of a γ-ray inside the active detector volume is determined. Theoretical concepts of the calculations are introduced and cover the relevant aspects of signal formation in HPGe. The approximations and the realization of the computer code with its input parameters are explained in detail. ADL is a versatile and modular computer code; new detectors can be implemented in this library. Measured position resolutions of the AGATA detectors based on ADL are discussed.

  14. Optimization of Compton-suppression and summing schemes for the TIGRESS HPGe detector array

    NASA Astrophysics Data System (ADS)

    Schumaker, M. A.; Svensson, C. E.; Andreoiu, C.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Boston, A. J.; Chakrawarthy, R. S.; Churchman, R.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Jones, B.; Maharaj, R.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Scraggs, H. C.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.

    2007-04-01

    Methods of optimizing the performance of an array of Compton-suppressed, segmented HPGe clover detectors have been developed which rely on the physical position sensitivity of both the HPGe crystals and the Compton-suppression shields. These relatively simple analysis procedures promise to improve the precision of experiments with the TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS). Suppression schemes will improve the efficiency and peak-to-total ratio of TIGRESS for high γ-ray multiplicity events by taking advantage of the 20-fold segmentation of the Compton-suppression shields, while the use of different summing schemes will improve results for a wide range of experimental conditions. The benefits of these methods are compared for many γ-ray energies and multiplicities using a GEANT4 simulation, and the optimal physical configuration of the TIGRESS array under each set of conditions is determined.

  15. Measured and simulated performance of Compton-suppressed TIGRESS HPGe clover detectors

    NASA Astrophysics Data System (ADS)

    Schumaker, M. A.; Hackman, G.; Pearson, C. J.; Svensson, C. E.; Andreoiu, C.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Boston, A. J.; Chakrawarthy, R. S.; Churchman, R.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Jones, B.; Maharaj, R.; Morton, A. C.; Phillips, A. A.; Sarazin, F.; Scraggs, H. C.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.

    2007-01-01

    Tests of the performance of a 32-fold segmented HPGe clover detector coupled to a 20-fold segmented Compton-suppression shield, which form a prototype element of the TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS), have been made. Peak-to-total ratios and relative efficiencies have been measured for a variety of γ-ray energies. These measurements were used to validate a GEANT4 simulation of the TIGRESS detectors, which was then used to create a simulation of the full 12-detector array. Predictions of the expected performance of TIGRESS are presented. These predictions indicate that TIGRESS will be capable, for single 1 MeV γ rays, of absolute detection efficiencies of 17% and 9.4%, and peak-to-total ratios of 54% and 61% for the "high-efficiency" and "optimized peak-to-total" configurations of the array, respectively.

  16. RESEARCH NOTE FROM COLLABORATION: NNLC: non-negative least chi-square minimization and application to HPGe detectors

    NASA Astrophysics Data System (ADS)

    Désesquelles, P.; Ha, T. M. H.; Korichi, A.; LeBlanc, F.; Petrache, C. M.; AGATA Collaboration

    2009-03-01

    A new method is proposed for the problem of solving chi-square minimization with a positive solution. This method is embodied in an evolution of the popular NNLS algorithm. Its efficiency with respect to residue minimization is illustrated by the improvement it permits on the location of gamma-interactions inside an AGATA HPGe detector.

  17. MSE/SSE discrimination methods of the PC-HPGe detector

    NASA Astrophysics Data System (ADS)

    Lu, Zi-Feng; Li, Yu-Lan; Li, Jin; Yue, Qian; Li, Yuan-Jing

    2012-09-01

    Having advantages of low capacitance and low energy threshold, the PC-HPGe (Point-Contact High Purity Germanium) detector has found its application in the direct detection of WIMP(Weak Interaction Massive Particle) in CDEX (China Darkmatter Experiment). The MSE (Multi-Site Event) and SSE(Single-Site Event) discrimination methods of the PC-HPGe detector are introduced in this article, including their physical basis, the electronics system and the algorithms to implement them. Behaviors of the PC-HPGe detector are studied intensively through this research and finally the experimental results of the LE discrimination method are presented.

  18. Design, fabrication and performance optimization of bi-polar blocking planar HPGe radiation detector

    NASA Astrophysics Data System (ADS)

    Khizar, Muhammad; Wang, Guojian; Mei, Dongming

    2013-03-01

    A prototype planar radiation detector is designed, fabricated and characterized using bi-polar contact deposited on high purity single crystal germanium (HPGe). Performances of planar and semi-planar detectors are carried out for their low background counting and high absolute efficiency for high-energy photons applications. For this study, 40mm ? 15mm (diameter to vertical height) p-type HPGe samples with dislocation density EPD <3000 cm-2 are taken from HPGe ingots grown by Czochralski method. After a successful mechanical preparation, and standard cleaning and polishing procedure, samples are chemically etched by using a mixture of highly concentrated acids HF:HNO3 (1:4) in order to remove the surface oxides. A bi-polar blocking layer of amorphous germanium (a-Ge) is deposited on both the samples using low temperature RF sputtering plasma in a pre-mix precursor of H2 (15%) and Ar. For this, an optimized dose of the plasma power and chamber pressure is used for a controlled low temperature. The process was completed with the evaporation of Ohmic contacts using electron beam evaporator. This is worth noticing that special care is introduced during the handling of these samples, especially for the bi-polar blocking and metal contact layers deposition. Finally, the fabricated detectors are characterized at 77K temperature. In this paper, we show the results from the first prototype detector made of home grown crystals at USD. This work is supported by DOE grant DE-FG02-10ER46709 and the state of South Dakota.

  19. Efficiency transfer using the GEANT4 code of CERN for HPGe gamma spectrometry.

    PubMed

    Chagren, S; Ben Tekaya, M; Reguigui, N; Gharbi, F

    2016-01-01

    In this work we apply the GEANT4 code of CERN to calculate the peak efficiency in High Pure Germanium (HPGe) gamma spectrometry using three different procedures. The first is a direct calculation. The second corresponds to the usual case of efficiency transfer between two different configurations at constant emission energy assuming a reference point detection configuration and the third, a new procedure, consists on the transfer of the peak efficiency between two detection configurations emitting the gamma ray in different energies assuming a "virtual" reference point detection configuration. No pre-optimization of the detector geometrical characteristics was performed before the transfer to test the ability of the efficiency transfer to reduce the effect of the ignorance on their real magnitude on the quality of the transferred efficiency. The obtained and measured efficiencies were found in good agreement for the two investigated methods of efficiency transfer. The obtained agreement proves that Monte Carlo method and especially the GEANT4 code constitute an efficient tool to obtain accurate detection efficiency values. The second investigated efficiency transfer procedure is useful to calibrate the HPGe gamma detector for any emission energy value for a voluminous source using one point source detection efficiency emitting in a different energy as a reference efficiency. The calculations preformed in this work were applied to the measurement exercise of the EUROMET428 project. A measurement exercise where an evaluation of the full energy peak efficiencies in the energy range 60-2000 keV for a typical coaxial p-type HpGe detector and several types of source configuration: point sources located at various distances from the detector and a cylindrical box containing three matrices was performed. PMID:26623928

  20. Efficiency transfer using the GEANT4 code of CERN for HPGe gamma spectrometry.

    PubMed

    Chagren, S; Ben Tekaya, M; Reguigui, N; Gharbi, F

    2016-01-01

    In this work we apply the GEANT4 code of CERN to calculate the peak efficiency in High Pure Germanium (HPGe) gamma spectrometry using three different procedures. The first is a direct calculation. The second corresponds to the usual case of efficiency transfer between two different configurations at constant emission energy assuming a reference point detection configuration and the third, a new procedure, consists on the transfer of the peak efficiency between two detection configurations emitting the gamma ray in different energies assuming a "virtual" reference point detection configuration. No pre-optimization of the detector geometrical characteristics was performed before the transfer to test the ability of the efficiency transfer to reduce the effect of the ignorance on their real magnitude on the quality of the transferred efficiency. The obtained and measured efficiencies were found in good agreement for the two investigated methods of efficiency transfer. The obtained agreement proves that Monte Carlo method and especially the GEANT4 code constitute an efficient tool to obtain accurate detection efficiency values. The second investigated efficiency transfer procedure is useful to calibrate the HPGe gamma detector for any emission energy value for a voluminous source using one point source detection efficiency emitting in a different energy as a reference efficiency. The calculations preformed in this work were applied to the measurement exercise of the EUROMET428 project. A measurement exercise where an evaluation of the full energy peak efficiencies in the energy range 60-2000 keV for a typical coaxial p-type HpGe detector and several types of source configuration: point sources located at various distances from the detector and a cylindrical box containing three matrices was performed.

  1. Calculation of Coincidence Summing Correction Factors for an HPGe detector using GEANT4.

    PubMed

    Giubrone, G; Ortiz, J; Gallardo, S; Martorell, S; Bas, M C

    2016-07-01

    The aim of this paper was to calculate the True Coincidence Summing Correction Factors (TSCFs) for an HPGe coaxial detector in order to correct the summing effect as a result of the presence of (88)Y and (60)Co in a multigamma source used to obtain a calibration efficiency curve. Results were obtained for three volumetric sources using the Monte Carlo toolkit, GEANT4. The first part of this paper deals with modeling the detector in order to obtain a simulated full energy peak efficiency curve. A quantitative comparison between the measured and simulated values was made across the entire energy range under study. The True Summing Correction Factors were calculated for (88)Y and (60)Co using the full peak efficiencies obtained with GEANT4. This methodology was subsequently applied to (134)Cs, and presented a complex decay scheme. PMID:27085040

  2. HPGe detectors long time behaviour in high-resolution γ spectrometry

    NASA Astrophysics Data System (ADS)

    Sajo-Bohus, L.; Rosso, D.; Sajo Castelli, A. M.; Napoli, D. R.; Fioretto, E.; Menegazzo, R.; Barros, H.; Ur, C. A.; Palacios, D.; Liendo, J.

    2011-08-01

    A large set of data on long term performance of n-type HPGe detectors used in GASP, EUROBALL and CLARA γ spectrometers, as well as environmental measurements have been collected over two decades. In this paper a detailed statistical analysis of this data is given and detector long term behaviour is provided to the scientific community. We include failure, failure mode, repair frequency, repair outcome and its influence in the energy efficiency and energy resolution. A remarkable result is that the life span distribution is exponential. A detector's failure is a memory-less process, where a previous failure does not influence the upcoming one. Repaired spectrometers result in high reliability with deep implications in the management of large scale high-resolution gamma spectrometry related projects. Findings show that on average, detectors initial counting efficiency is slightly lower (∼2%) than that reported by the manufacturers and the repair process (including annealing) does not affect significantly the energy efficiency, even after a long period of use. Repaired detector energy resolution statistics show that the probability, that a repaired detector will be at least as good as it was originally, is more than 3/4.

  3. HPGe well-type detectors for neutron activation measurements on the Frascati Tokamak Upgrade tokamak

    SciTech Connect

    Bertalot, L.; Damiani, M.; Esposito, B.; Lagamba, L.; Podda, S.; Batistoni, P.; De Felice, P.; Biagini, R.

    1997-01-01

    We describe an improvement of the neutron activation system in operation on the Frascati Tokamak Upgrade (FTU) tokamak for the measurement of the total neutron yield. A HPGe well-type detector (200 cm{sup 3} active volume) is used to detect the photoemission from neutron activated samples ({sup 115m}In336.2 keV {gamma} rays from DD neutrons on indium for FTU). Due to their high geometrical efficiency, HPGe well-type detectors are particularly suited to the FTU low-level activity measurements. A particular effort has been devoted to the calibration of the measuring system. In particular, a multi-{gamma} calibration source (59{endash}1332 keV energy range) with a density of 7.31 g/cm{sup 3} consisting of a stack of indium foils has been prepared. This assures that the shape and volume of the calibration source are the same as those of the samples used in the actual measurements. The full-energy-peak efficiency at the {sup 115m}In336.2 keV line is 0.197 with an overall uncertainty of 2{percent} (1{sigma}). For a better characterization of the detector response as a function of the sample density, a further calibration source with the same geometry has been prepared in a gel aqueous solution (density {approximately}1 g/cm{sup 3}). The calibration curves for the well-type detector at the two different density values are compared. {copyright} {ital 1997 American Institute of Physics.}

  4. FRAM isotopic analysis of uranium in thick-walled containers using high energy gamma rays and planar HPGe detectors.

    SciTech Connect

    Sampson, Thomas E.; Hypes, P. A.; Vo, Duc T.

    2002-01-01

    We describe the use of the Los Alamos FRAM isotopic analysis software to make the first reported measurements on thick-walled UF{sub 6} cylinders using small planar HPGe detectors of the type in common use at the IAEA. Heretofore, planar detector isotopic analysis measurements on uranium have used the 100-keV region and can be defeated by 10 mm of steel absorber. The analysis of planar detector measurements through 13-16 mm of steel shows that FRAM can successfully carry out these measurements and analysis in the 120-1024 keV energy range, a range previously thought to be the sole province of more efficient coaxial detectors. This paper describes the measurement conditions and results and also compares the results to other FRAM measurements with coaxial HPGe detectors. The technique of gamma-ray isotopic analysis of arbitrary samples is desirable for measuring the isotopic composition of uranium in UF{sub 6} cylinders because it does not require calibration with standards or knowledge of the cylinder wall thickness. The International Atomic Energy Agency (IAEA) uses the MGAU (Multi Group Analysis Uranium) uranium isotopic analysis software with planar high purity germanium (HPGe) detectors to measure the isotopic composition of uranium. Measurements on UF{sub 6} cylinders with 13-16-mm thick steel walls are usually unsuccessful because of the strong absorption of the 89-100 keV gamma rays and x-rays that MGAU requires for the measurement. This paper describes the use of the Los Alamos FRAM isotopic analysis software to make these measurements on UF{sub 6} cylinders. Uranium measurements with FRAM typically cover the energy range from 120-1001 keV and can easily be made through the walls of UF{sub 6} cylinders. While these measurements are usually performed with efficient coaxial HPGe detectors, this paper reports the first successful measurements using small planar HPGe detectors of the type in common use at the IAEA.

  5. Compton imager based on a single planar segmented HPGe detector

    NASA Astrophysics Data System (ADS)

    Khaplanov, A.; Pettersson, J.; Cederwall, B.

    2007-10-01

    A collimator-free Compton imaging system has been developed based on a single high-purity germanium detector and used to generate images of radioactive sources emitting γ rays. The detector has a planar crystal with one pixellated contact with a total of 25 segments. Pulse shape analysis has been applied to achieve a 3D-position sensitivity of the detector. The first imaging results from this detector are presented, based on the reconstruction of events where a γ ray is fully absorbed after scattering between adjacent segments.

  6. Position sensitivity of the first SmartPET HPGe detector

    NASA Astrophysics Data System (ADS)

    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

    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.

  7. Optimized digital filtering techniques for radiation detection with HPGe detectors

    NASA Astrophysics Data System (ADS)

    Salathe, Marco; Kihm, Thomas

    2016-02-01

    This paper describes state-of-the-art digital filtering techniques that are part of GEANA, an automatic data analysis software used for the GERDA experiment. The discussed filters include a novel, nonlinear correction method for ballistic deficits, which is combined with one of three shaping filters: a pseudo-Gaussian, a modified trapezoidal, or a modified cusp filter. The performance of the filters is demonstrated with a 762 g Broad Energy Germanium (BEGe) detector, produced by Canberra, that measures γ-ray lines from radioactive sources in an energy range between 59.5 and 2614.5 keV. At 1332.5 keV, together with the ballistic deficit correction method, all filters produce a comparable energy resolution of ~1.61 keV FWHM. This value is superior to those measured by the manufacturer and those found in publications with detectors of a similar design and mass. At 59.5 keV, the modified cusp filter without a ballistic deficit correction produced the best result, with an energy resolution of 0.46 keV. It is observed that the loss in resolution by using a constant shaping time over the entire energy range is small when using the ballistic deficit correction method.

  8. Alpha Backgrounds for HPGe Detectors in Neutrinoless Double-Beta Decay Experiments

    SciTech Connect

    Johnson, R. A.; Burritt, T. H.; Elliott, S. R.; Gehman, V. M.; Guiseppe, V.E.; Wilkerson, J. F.

    2012-01-01

    The Majorana Experiment will use arrays of enriched HPGe detectors to search for the neutrinoless double-beta decay of 76Ge. Such a decay, if found, would show lepton-number violation and confirm the Majorana nature of the neutrino. Searches for such rare events are hindered by obscuring backgrounds which must be understood and mitigated as much as possible. A potentially important background contribution to this and other double-beta decay experiments could come from decays of alpha-emitting isotopes in the 232Th and 238U decay chains on or near the surfaces of the detectors. An alpha particle emitted external to an HPGe crystal can lose energy before entering the active region of the detector, either in some external-bulk material or within the dead region of the crystal. The measured energy of the event will only correspond to a partial amount of the total kinetic energy of the alpha and might obscure the signal from neutrinoless double-beta decay. A test stand was built and measurements were performed to quantitatively assess this background. We present results from these measurements and compare them to simulations using Geant4. These results are then used to measure the alpha backgrounds in an underground detector in situ. We also make estimates of surface contamination tolerances for double-beta decay experiments using solid-state detectors.

  9. Fabrication and performance tests of a segmented p-type HPGe detector

    NASA Astrophysics Data System (ADS)

    King, George S.; Avignone, Frank T.; Cox, Christopher E.; Hossbach, Todd W.; Jennings, Wayne; Reeves, James H.

    2008-10-01

    A p-type semi-coaxial HPGe detector has been segmented by cutting, with a diamond saw, and etching four circumferential grooves through the Li-diffused dead layer. The degree of segmentation was tested using a well-collimated low-energy gamma-ray source. An analysis cut that rejected events depositing energy in more than one segment was applied to an energy interval of 2038±5 keV, the region of interest ( Q ββ) for 76Ge 0 νββ decay experiments. This segmentation cut resulted in a reduction of the Compton continuum of 59%.

  10. Half-life measurements of lutetium-176 using underground HPGe-detectors.

    PubMed

    Hult, Mikael; Vidmar, Tim; Rosengård, Ulf; Marissens, Gerd; Lutter, Guillaume; Sahin, Namik

    2014-05-01

    The half-life of (176)Lu was determined by measuring the (176)Lu activity in metallic lutetium foils. Three different HPGe-detectors located 225 m underground were employed for the study. Measurements using the sum-peak method were performed and resulted in an average massic activity of (52.61±0.36) Bq g(-1). The foils were of natural isotopic abundance so using the massic activity and the value of the natural isotopic abundance of (2.59±0.01)%, a half-life of (3.722±0.029)×10(10)a could be calculated.

  11. Cosmic-ray-induced background intercomparison with actively shielded HPGe detectors at underground locations

    NASA Astrophysics Data System (ADS)

    Szücs, T.; Bemmerer, D.; Reinhardt, T. P.; Schmidt, K.; Takács, M. P.; Wagner, A.; Wagner, L.; Weinberger, D.; Zuber, K.

    2015-03-01

    The main background above 3MeV for in-beam nuclear astrophysics studies with -ray detectors is caused by cosmic-ray-induced secondaries. The two commonly used suppression methods, active and passive shielding, against this kind of background were formerly considered only as alternatives in nuclear astrophysics experiments. In this work the study of the effects of active shielding against cosmic-ray-induced events at a medium deep location is performed. Background spectra were recorded with two actively shielded HPGe detectors. The experiment was located at 148m below the surface of the Earth in the Reiche Zeche mine in Freiberg, Germany. The results are compared to data with the same detectors at the Earth's surface, and at depths of 45m and 1400m, respectively.

  12. Surface passivation effects on the performance of p-planar HPGe radiation detector

    NASA Astrophysics Data System (ADS)

    Khizar, Muhammad; Wang, Guojian; Mei, Dongming

    2013-03-01

    Surface passivation of HPGe detectors are always critical to reduce or eliminate the surface effects responsible for limiting both the leakage current and breakdown voltages of these devices. Among the critical part of any HPGe detector is the intrinsic surface, where the full bias voltage is applied at 77K. Typically, in order to make these surfaces electrically passive, and to avoid surface leakage currents, a thick layer of SiO2 is deposited by using different high temperature dry/wet deposition techniques. However, surface passivation using such techniques can result modifying the electric field, by compromising the charge collection in the volume near the contact surfaces. Another option is the amorphous germanium (a-Ge), which acts as a passivant as well as bi-polar blocking contacts. In this study, we have designed a controlled experiment to use Ge oxidation contact as a passivation layer by testing the electrical behavior of the crystal after each oxidation treatment. For this, a high quality a-Ge layer (~ 100 nm to 150 nm) is deposited at 1.5x106 torr using low temperature RF plasma sputtering deposition technique. Among the key characteristics of the deposited passivation layer includes the depositions rates, the precursors (pre-mixed (H2 ~ 15% and Ar) flow rates, plasma power, chamber pressure, and target to-substrate distance. We show the results from our study using home grown HPGe crystals at USD. This work is supported by DOE grant DE-FG02-10ER46709 and the state of South Dakota.

  13. True coincidence summing corrections for an extended energy range HPGe detector

    SciTech Connect

    Venegas-Argumedo, Y.; Montero-Cabrera, M. E.

    2015-07-23

    True coincidence summing (TCS) effect for natural radioactive families of U-238 and Th-232 represents a problem when an environmental sample with a close source-detector geometry measurement is performed. By using a certified multi-nuclide standard source to calibrate an energy extended range (XtRa) HPGe detector, it is possible to obtain an intensity spectrum slightly affected by the TCS effect with energies from 46 to 1836 keV. In this work, the equations and some other considerations required to calculate the TCS correction factor for isotopes of natural radioactive chains are described. It is projected a validation of the calibration, performed with the IAEA-CU-2006-03 samples (soil and water)

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

    PubMed

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

    2014-11-01

    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

  15. Identifying and quantifying short-lived fission products from thermal fission of HEU using portable HPGe detectors

    SciTech Connect

    Pierson, Bruce D.; Finn, Erin C.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Kephart, Rosara F.; Metz, Lori A.

    2013-03-01

    Due to the emerging potential for trafficking of special nuclear material, research programs are investigating current capabilities of commercially available portable gamma ray detection systems. Presented in this paper are the results of three different portable high-purity germanium (HPGe) detectors used to identify short-lived fission products generated from thermal neutron interrogation of small samples of highly enriched uranium. Samples were irradiated at the Washington State University (WSU) Nuclear Radiation Center’s 1MW TRIGA reactor. The three portable, HPGe detectors used were the ORTEC MicroDetective, the ORTEC Detective, and the Canberra Falcon. Canberra’s GENIE-2000 software was used to analyze the spectral data collected from each detector. Ultimately, these three portable detectors were able to identify a large range of fission products showing potential for material discrimination.

  16. Determination of HPGe peak efficiency for voluminous gamma-ray sources by using an effective solid angle method.

    PubMed

    Kang, M Y; Sun, G M; Kim, Junhyuck; Choi, H D

    2016-10-01

    A code called EXVol has been developed to obtain the absolute peak efficiency for an extended or voluminous γ-ray source. The method is based on the concept of effective solid angles. Several efficiency curves that have been determined semi-empirically for voluminous sources are compared with the experimental values based on certified reference volume sources. To study the geometric and matrix effects, standard γ-ray sources of several media, volumes and shapes were measured using HPGe detectors with three different efficiencies. For the n-type detector of 32% relative efficiency, the relative deviations are less than ±10%; this performance is similar to that of existing programs for similar purposes. The EXVol code is able to calculate the detection efficiency within approximately five minutes or less. Systematic errors based on EXVol input parameters, which are mainly due to the inherent uncertainty in the detector's characteristic dimensions provided by the vendor, are studied to obtain more accurate specifications of the detectors.

  17. Determination of HPGe peak efficiency for voluminous gamma-ray sources by using an effective solid angle method.

    PubMed

    Kang, M Y; Sun, G M; Kim, Junhyuck; Choi, H D

    2016-10-01

    A code called EXVol has been developed to obtain the absolute peak efficiency for an extended or voluminous γ-ray source. The method is based on the concept of effective solid angles. Several efficiency curves that have been determined semi-empirically for voluminous sources are compared with the experimental values based on certified reference volume sources. To study the geometric and matrix effects, standard γ-ray sources of several media, volumes and shapes were measured using HPGe detectors with three different efficiencies. For the n-type detector of 32% relative efficiency, the relative deviations are less than ±10%; this performance is similar to that of existing programs for similar purposes. The EXVol code is able to calculate the detection efficiency within approximately five minutes or less. Systematic errors based on EXVol input parameters, which are mainly due to the inherent uncertainty in the detector's characteristic dimensions provided by the vendor, are studied to obtain more accurate specifications of the detectors. PMID:27501137

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

    PubMed

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

    2013-11-01

    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.

  19. Neutron capture gamma-ray data and calculations for HPGe detector-based applications

    NASA Astrophysics Data System (ADS)

    McNabb, Dennis P.; Firestone, Richard B.

    2004-10-01

    Recently an IAEA Coordinated Research Project published an evaluation of thermal neutron capture gamma-ray cross sections, measured to 1-5% uncertainty, for over 80 elements [1] and produced the Evaluated Gamma-ray Activation File (EGAF) [2] containing nearly 35,000 primary and secondary gamma-rays is available from the IAEA Nuclear Data Section. We have begun an effort to model the quasi-continuum gamma-ray cascade following neutron capture using the approach outlined by Becvar et al. [3] while constraining the calculation to reproduce the measured cross sections deexciting low-lying levels. Our goal is to provide complete neutron capture gamma ray data in ENDF formatted files to use as accurate event generators for high-resolution HPGe detector based applications. The results will be benchmarked to experimental spectroscopic data and compared with existing gamma-decay widths and level densities. [1] Database of Prompt Gamma Rays from Slow Neutron Capture for Elemental Analysis, IAEA-TECDOC-DRAFT (December, 2003); http://www-nds.iaea.org/pgaa/tecdoc.pdf. [2] Evaluated Gamma-ray Activation File maintained by the International Atomic Energy Agency; http://www-nds.iaea.org/pgaa/. [3] F. Becvar, Nucl Instr. Meth. A417, 434 (1998).

  20. Double {beta} experiments with the help of scintillation and HPGe detectors at Gran Sasso

    SciTech Connect

    Barabash, A.; Konovalov, S. I.; Umatov, V. I.; Belli, P.; D'Angelo, S.; Di Marco, A.; Bernabei, R.; Boiko, R. S.; Chernyak, D. M.; Danevich, F. A.; Kobychev, V. V.; Kropivyansky, B. N.; Kudovbenko, V. M.; Nagorny, S. S.; Podviyanuk, R. B.; Polischuk, O. G.; Tretyak, V. I.; Vyshnevskyi, I. M.; Yurchenko, S. S.; Brudanin, V. B.; and others

    2011-12-16

    A search for double beta decay of {sup 64,70}Zn, {sup 180,186}W was carried out by using low background ZnWO{sub 4} crystal scintillators, while a CeCl{sub 3} scintillation detector was applied to investigate 2{beta} processes in {sup 136,138,142}Ce. A search for 2{beta} decay of {sup 96,104}Ru, {sup 156,158}Dy, {sup 190,198}Pt and study of 2{nu}2{beta} decay of {sup 100}Mo to the first excited 0{sup +} level of {sup 100}Ru were realized by ultra-low background HPGe {gamma} spectrometry. Moreover, CdWO{sub 4} crystal scintillators from enriched {sup 106}Cd and {sup 116}Cd isotopes were developed to search for 2{beta} decay of {sup 106}Cd and {sup 116}Cd. Finally, experiments aimed to investigate {sup 96,104}Ru and {sup 116}Cd are in progress and a new phase of the experiment to search for 2{beta} processes in {sup 106}Cd is in preparation.

  1. Measurement of real and imaginary form factors of silver atom using a high resolution HPGe detector.

    PubMed

    Krishnananda; Niranjana, K M; Badiger, N M

    2013-01-01

    The real and imaginary form factors of silver atom have been determined by using EDXRF method. The K x-ray photons in the energy range from 8.62 keV to 52.18 keV are generated by sending 59.56 keV gamma photons from ^{241}Am radioactive source on various targets. These K x-ray photons are transmitted through silver foils of suitable thickness. The incident and transmitted K x-ray photon intensities have been measured with a high resolution HPGe detector which is coupled to 16K MCA. The photoelectric cross sections at different K x-ray energies have been determined by measuring the intensities of the incident and transmitted x-ray photons. From these photoelectric cross section values, the imaginary form factors and the real form factors have been determined at various photon energies. Measured imaginary and real form factor values have been compared with theoretical values predicted by XCOM [23] and FFAST [24].

  2. Uncertainty in HPGe detector calibrations for in situ gamma-ray spectrometry.

    PubMed

    Boson, Jonas; Johansson, Lennart; Ramebäck, Henrik; Agren, Göran

    2009-06-01

    Semi-empirical methods are often used for efficiency calibrations of in situ gamma-ray spectrometry measurements with high-purity germanium detectors. The intrinsic detector efficiency is experimentally determined for different photon energies and angles of incidence, and a suitable expression for the efficiency is fitted to empirical data. In this work, the combined standard uncertainty of such an efficiency function for two detectors was assessed. The uncertainties in individual efficiency measurements were found to be about 1.9 and 3.1% (with a coverage factor k = 1, i.e. with a confidence interval of about 68%) for the two detectors. The main contributions to these uncertainties were found to originate from uncertainties in source-to-detector distance, source activity and full-energy peak count rate. The standard uncertainties of the fitted functions were found to be somewhat higher than the uncertainty of individual data points, i.e. 5.2 and 8.1% (k = 1). With the introduction of a new expression for the detector efficiency, these uncertainties were reduced to 3.7 and 4.2%, i.e. with up to a factor of two. Note that this work only addresses the uncertainty in the determination of intrinsic detector efficiency. PMID:19429646

  3. Validation of Monte Carlo model of HPGe detector for field-station measurement of airborne radioactivity

    NASA Astrophysics Data System (ADS)

    Šolc, J.; Kovář, P.; Dryák, P.

    2016-03-01

    A Monte Carlo (MC) model of a mechanically-cooled High Purity Germanium detection system IDM-200-V™ manufactured by ORTEC® was created, optimized and validated within the scope of the Joint Research Project ENV57 ``Metrology for radiological early warning networks in Europe''. The validation was performed for a planar source homogeneously distributed on a filter placed on top of the detector end cap and for point sources positioned farther from the detector by comparing simulated full-energy peak (FEP) detection efficiencies with the ones measured with two or three different pieces of the IDM detector. True coincidence summing correction factors were applied to the measured FEP efficiencies. Relative differences of FEP efficiencies laid within 8% that is fully satisfactory for the intended use of the detectors as instruments for airborne radioactivity measurement in field-stations. The validated MC model of the IDM-200-V™ detector is now available for further MC calculations planned in the ENV57 project.

  4. Evaluation of Monte Carlo-based calibrations of HPGe detectors for in situ gamma-ray spectrometry.

    PubMed

    Boson, Jonas; Plamboeck, Agneta H; Ramebäck, Henrik; Agren, Göran; Johansson, Lennart

    2009-11-01

    The aim of this work was to evaluate the use of Monte Carlo-based calibrations for in situ gamma-ray spectrometry. We have performed in situ measurements at five different sites in Sweden using HPGe detectors to determine ground deposition activity levels of (137)Cs from the 1986 Chernobyl accident. Monte Carlo-calculated efficiency calibration factors were compared with corresponding values calculated using a more traditional semi-empirical method. In addition, results for the activity ground deposition were also compared with activity densities found in soil samples. In order to facilitate meaningful comparisons between the different types of results, the combined standard uncertainty of in situ measurements was assessed for both calibration methods. Good agreement, both between the two calibration methods, and between in situ measurements and soil samples, was found at all five sites. Uncertainties in in situ measurements for the given measurement conditions, about 20 years after the fallout occurred, were found to be in the range 15-20% (with a coverage factor k=1, i.e. with a confidence interval of about 68%). PMID:19604609

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  6. Determination of LaBr3(Ce) internal background using a HPGe detector and Monte Carlo simulations.

    PubMed

    Camp, Anna; Vargas, Arturo; Fernández-Varea, José M

    2016-03-01

    The presence of (138)La and (227)Ac impurities in LaBr3(Ce) scintillator crystals is a drawback for their use in environmental radiation monitoring. A method is presented to evaluate the internal (138)La activity. Firstly, an experimental set-up is prepared with the LaBr3(Ce) crystal acting as the radiation source and an HPGe detector that acquires the photon spectrum. Then, the internal background spectrum is simulated with a modified version of the PENELOPE/penEasy Monte Carlo code. The simulated spectra agree with measurements conducted at ultra-low-background facilities. PMID:26688364

  7. Low background HPGe spectrometer in investigations of 2β decay

    SciTech Connect

    Rukhadze, Ekaterina [Institute of Experimental and Applied Physics, CTU in Prague, Horska 3a Collaboration: OBELIX Collaboration; TGV Collaboration; SuperNEMO Collaboration; and others

    2013-08-08

    The low background high sensitive HPGe spectrometer called OBELIX is briefly described. The calibration measurements using {sup 152}Eu, {sup 133}Ba and La{sub 2}O{sub 3} sources in different geometries, the obtained efficiency curves for OBELIX HPGe detector, the results of measurements of radioactivity of the NEMO-3 sources ({sup 100}Mo, {sup 150}Nd) as well as future plans for OBELIX detector (e.g. 0νEC/EC decay of {sup 106}Cd) are presented.

  8. Towards a deep characterization of a 64-fold-pixelated position sensitive detector for a new {gamma}-scanning system of HPGe segmented detectors

    SciTech Connect

    Hernandez-Prieto, A.; Quintana, B.

    2011-07-01

    Characterization of the electrical response of the HPGe segmented detectors is one of the current goals for the Nuclear Physics community in order to perform {gamma}-ray tracking or even imaging with these detectors. For this purpose, scanning devices have to be developed to achieve the signal-position association with the highest precision. In this laboratory, a new scanning system, SALSA (Salamanca Lyso-based Scanning Array), consisting on a high spatial resolution {gamma} camera, is a under development. In this work the whole scanning system is presented and first results for the characterization of the {gamma} camera are shown. (authors)

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

    PubMed

    Slaninka, Alojz; Slávik, Ondrej; Necas, Vladimír

    2010-01-01

    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.

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

    PubMed

    Slaninka, Alojz; Slávik, Ondrej; Necas, Vladimír

    2010-01-01

    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

  11. Study of the response of an ORTEC GMX45 HPGe detector with a multi-radionuclide volume source using Monte Carlo simulations.

    PubMed

    Saraiva, A; Oliveira, C; Reis, M; Portugal, L; Paiva, I; Cruz, C

    2016-07-01

    A model of an n-type ORTEC GMX45 HPGe detector was created using the MCNPX and the MCNP-CP codes. In order to validate the model, experimental efficiency was compared with the Monte Carlo simulations results. The reference source is a NIST traceable multi-gamma volume source in a water-equivalent epoxy resin matrix (1.15gcm(-3) density) containing several radionuclides: (210)Pb, (241)Am, (137)Cs and (60)Co in a cylinder shape container. Two distances of source bottom to end cap front surface of the detector have been considered. The efficiency for the nearest distance is higher than for longer distance. The relative difference between the measured and the simulated full-energy peak efficiency is less than 4.0% except for the 46.5keV energy peak of (210)Pb for the longer distance (6.5%) allowing to consider the model validated. In the absence of adequate standard calibration sources, efficiency and efficiency transfer factors for geometry deviations and matrix effects can be accurately computed by using Monte Carlo methods even if true coincidence could occur as is the case when the (60)Co radioisotope is present in the source.

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

    NASA Astrophysics Data System (ADS)

    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.; Ciemała, 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

    2013-03-01

    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,nγ)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.

  13. Study of accuracy in the position determination with SALSA, a γ-scanning system for the characterization of segmented HPGe detectors

    NASA Astrophysics Data System (ADS)

    Hernandez-Prieto, A.; Quintana, B.; Martìn, S.; Domingo-Pardo, C.

    2016-07-01

    Accurate characterization of the electric response of segmented high-purity germanium (HPGe) detectors as a function of the interaction position is one of the current goals of the Nuclear Physics community seeking to perform γ-ray tracking or even imaging with these detectors. For this purpose, scanning devices must be developed to achieve the signal-position association with the highest precision. With a view to studying the accuracy achieved with SALSA, the SAlamanca Lyso-based Scanning Array, here we report a detailed study on the uncertainty sources and their effect in the position determination inside the HPGe detector to be scanned. The optimization performed on the design of SALSA, aimed at minimizing the effect of the uncertainty sources, afforded an intrinsic uncertainty of ∼2 mm for large coaxial detectors and ∼1 mm for planar ones.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  15. High efficiency photoionization detector

    DOEpatents

    Anderson, D.F.

    1984-01-31

    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.

  16. High efficiency photoionization detector

    DOEpatents

    Anderson, David F.

    1984-01-01

    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.

  17. Wilcoxon signed-rank-based technique for the pulse-shape analysis of HPGe detectors

    NASA Astrophysics Data System (ADS)

    Martín, S.; Quintana, B.; Barrientos, D.

    2016-07-01

    The characterization of the electric response of segmented-contact high-purity germanium detectors requires scanning systems capable of accurately associating each pulse with the position of the interaction that generated it. This process requires an algorithm sensitive to changes above the electronic noise in the pulse shapes produced at different positions, depending on the resolution of the Ge crystal. In this work, a pulse-shape comparison technique based on the Wilcoxon signed-rank test has been developed. It provides a method to distinguish pulses coming from different interaction points in the germanium crystal. Therefore, this technique is a necessary step for building a reliable pulse-shape database that can be used later for the determination of the position of interaction for γ-ray tracking spectrometry devices such as AGATA, GRETA or GERDA. The method was validated by comparison with a χ2 test using simulated and experimental pulses corresponding to a Broad Energy germanium detector (BEGe).

  18. A Multi-Contact, Low Capacitance HPGe Detector for High Rate Gamma Spectroscopy

    SciTech Connect

    Cox, Christopher

    2014-12-04

    The detection, identification and non-destructive assay of special nuclear materials and nuclear fission by-products are critically important activities in support of nuclear non-proliferation programs. Both national and international nuclear safeguard agencies recognize that current accounting methods for spent nuclear fuel are inadequate from a safeguards perspective. Radiation detection and analysis by gamma-ray spectroscopy is a key tool in this field, but no instrument exists that can deliver the required performance (energy resolution and detection sensitivity) in the presence of very high background count rates encountered in the nuclear safeguards arena. The work of this project addresses this critical need by developing a unique gamma-ray detector based on high purity germanium that has the previously unachievable property of operating in the 1 million counts-per-second range while achieving state-of-the-art energy resolution necessary to identify and analyze the isotopes of interest. The technical approach was to design and fabricate a germanium detector with multiple segmented electrodes coupled to multi-channel high rate spectroscopy electronics. Dividing the germanium detector’s signal electrode into smaller sections offers two advantages; firstly, the energy resolution of the detector is potentially improved, and secondly, the detector is able to operate at higher count rates. The design challenges included the following; determining the optimum electrode configuration to meet the stringent energy resolution and count rate requirements; determining the electronic noise (and therefore energy resolution) of the completed system after multiple signals are recombined; designing the germanium crystal housing and vacuum cryostat; and customizing electronics to perform the signal recombination function in real time. In this phase I work, commercial off-the-shelf electrostatic modeling software was used to develop the segmented germanium crystal geometry

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

    SciTech Connect

    Solodov, Alexander A

    2008-01-01

    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.

  20. Orthogonal strip HPGe planar SmartPET detectors in Compton configuration

    NASA Astrophysics Data System (ADS)

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

    2007-10-01

    The evolution of Germanium detector technology over the last decade has lead to the possibility that they can be employed in medical and security imaging. The potential of excellent energy resolution coupled with good position information that Germanium affords removes the necessity for mechanical collimators that would be required in a conventional gamma camera system. By removing this constraint, the overall dose to the patient can be reduced or the throughput of the system can be increased. An additional benefit of excellent energy resolution is that tight gates can be placed on energies from either a multi-lined gamma source or from multi-nuclide sources increasing the number of sources that can be used in medical imaging. In terms of security imaging, segmented Germanium gives directionality and excellent spectroscopic information.

  1. Subspace Detectors: Efficient Implementation

    SciTech Connect

    Harris, D B; Paik, T

    2006-07-26

    computed efficiently for continuous multichannel seismic data. The speed of the calculation is significant as it may become desirable to deploy subspace detectors numbering in the thousands. One application contemplated for these detectors is as screens against signals from repeating sources such as mines or aftershocks of large earthquakes. With many tens of stations and potentially hundreds of sources to screen, efficient implementations are desirable. Speed, of course, can be achieved by procuring faster computers or special-purpose hardware. The approach we examine here is the development of two efficient algorithms that can make the calculations run faster on any machine. In the first section, we describe the subspace detector as we use it for the detection of repeating seismic events, defining terms and the parameterization used in succeeding sections. This section also reviews how the correlation computations central to the matched filter and subspace detectors can be implemented as a collection of convolution operations. Convolution algorithms using fast Fourier transforms, such as the overlap-add and overlap-save methods, have long been known as efficient implementations of discrete-time finite-impulse-response filters [e.g. Oppenheim and Schafer, 1975]. These may be extended in a straightforward manner to implement multichannel correlation detectors. In the second section, we describe how multichannel data can be multiplexed to compute the required convolutions with a single pair of FFT operations instead of a pair for each channel. This approach increases speed approximately twofold. Seismic data, almost invariably, are oversampled. This characteristic provides an opportunity for increased efficiency by decimating the data prior to performing the correlation calculations. In the third section, we describe a bandpass transformation of the data that allows a more aggressive decimation of the data without significant loss of fidelity in the correlation calculation

  2. Experimental Determination of the HPGe Spectrometer Efficiency Calibration Curves for Various Sample Geometry for Gamma Energy from 50 keV to 2000 keV

    SciTech Connect

    Saat, Ahmad; Hamzah, Zaini; Yusop, Mohammad Fariz; Zainal, Muhd Amiruddin

    2010-07-07

    Detection efficiency of a gamma-ray spectrometry system is dependent upon among others, energy, sample and detector geometry, volume and density of the samples. In the present study the efficiency calibration curves of newly acquired (August 2008) HPGe gamma-ray spectrometry system was carried out for four sample container geometries, namely Marinelli beaker, disc, cylindrical beaker and vial, normally used for activity determination of gamma-ray from environmental samples. Calibration standards were prepared by using known amount of analytical grade uranium trioxide ore, homogenized in plain flour into the respective containers. The ore produces gamma-rays of energy ranging from 53 keV to 1001 keV. Analytical grade potassium chloride were prepared to determine detection efficiency of 1460 keV gamma-ray emitted by potassium isotope K-40. Plots of detection efficiency against gamma-ray energy for the four sample geometries were found to fit smoothly to a general form of {epsilon} = A{Epsilon}{sup a}+B{Epsilon}{sup b}, where {epsilon} is efficiency, {Epsilon} is energy in keV, A, B, a and b are constants that are dependent on the sample geometries. All calibration curves showed the presence of a ''knee'' at about 180 keV. Comparison between the four geometries showed that the efficiency of Marinelli beaker is higher than cylindrical beaker and vial, while cylindrical disk showed the lowest.

  3. Comparison Of NaI And HPGe Minimum Detectable Activities

    SciTech Connect

    Bailey, Paul

    2002-11-30

    The Minimum Detectable Activity of a 76 mm by 76 mm (3" by 3") sodium iodide (NaI) crystal and 18 %, 42 % and 68 % efficient HPGe detectors were calculated and compared for gamma-ray spectrometry with count times in the range of 1 second to 15 minutes. All cases were for in situ measurements with a surface distribution source and a detector height of 1 meter. The radionuclides considered were 137Cs and 60Co.

  4. Applying a low energy HPGe detector gamma ray spectrometric technique for the evaluation of Pu/Am ratio in biological samples.

    PubMed

    Singh, I S; Mishra, Lokpati; Yadav, J R; Nadar, M Y; Rao, D D; Pradeepkumar, K S

    2015-10-01

    The estimation of Pu/(241)Am ratio in the biological samples is an important input for the assessment of internal dose received by the workers. The radiochemical separation of Pu isotopes and (241)Am in a sample followed by alpha spectrometry is a widely used technique for the determination of Pu/(241)Am ratio. However, this method is time consuming and many times quick estimation is required. In this work, Pu/(241)Am ratio in the biological sample was estimated with HPGe detector based measurements using gamma/X-rays emitted by these radionuclides. These results were compared with those obtained from alpha spectroscopy of sample after radiochemical analysis and found to be in good agreement. PMID:26141295

  5. Search for double beta processes in {sup 106}Cd with enriched {sup 106}CdWO{sub 4} crystal scintillator in coincidence with four crystals HPGe detector

    SciTech Connect

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

    2015-10-28

    A radiopure cadmium tungstate crystal scintillator, enriched in {sup 106}Cd ({sup 106}CdWO{sub 4}), was used to search for double beta decay processes in {sup 106}Cd in coincidence with an ultra-low background set-up containing four high purity germanium (HPGe) detectors in a single cryostat. The experiment has been completed after 13085 h of data taking. New improved limits on most of the double beta processes in {sup 106}Cd have been set on the level of 10{sup 20}−10{sup 21} yr. Tn particular, the half-life limit on the two neutrino electron capture with positron emission, T{sub 1/2} ≥ 1.8 × 10{sup 21} yr, reached the region of theoretical predictions.

  6. Experimentally determined vs. Monte Carlo simulated peak-to-valley ratios for a well-characterised n-type HPGe detector.

    PubMed

    Ostlund, Karl; Samuelsson, Christer; Rääf, Christopher L

    2014-10-23

    Measurements and simulations to investigate the contributing factors to the peak-to-valley (PTV) ratio have been both experimentally determined as well as Monte Carlo simulated for a well-characterised HPGe n-type detector together with a Cs-137 gamma source encapsulated in thin polystyrene. Measurements were carried out in a low-background gamma counting facility at Lund University. The results of the PTV ratio have been compared to distinguish what components or variables in the setup that significantly influence the ratio. In addition to manufacture specifications, the detector components have been examined using planar X-ray, source scanning and computer tomography in order to determine and verify component dimensions when necessary. In spite of these efforts a discrepancy of approximately 25% for thin absorbers in the PTV ratio between measurements and calculations is observed. However, this discrepancy becomes less significant for larger absorbing layers of copper (>1mm). This indicates that it would be difficult to achieve a field calibration for in-situ gamma spectrometry using the PTV ratio that could position a Cs-137 source in soil depth shallower than corresponding 1mm layer of copper. The results also showed that when building a detector in simulations part by part, the inner dead layer, and the contact pin are of great importance for the accuracy of the PTV ratio simulations. PMID:25464184

  7. Fast Neutron Sensitivity with HPGe

    SciTech Connect

    Seifert, Allen; Hensley, Walter K.; Siciliano, Edward R.; Pitts, W. K.

    2008-01-22

    In addition to being excellent gamma-ray detectors, germanium detectors are also sensitive to fast neutrons. Incident neutrons undergo inelastic scattering {Ge(n,n')Ge*} off germanium nuclei and the resulting excited states emit gamma rays or conversion electrons. The response of a standard 140% high-purity germanium (HPGe) detector with a bismuth germanate (BGO) anti-coincidence shield was measured for several neutron sources to characterize the ability of the HPGe detector to detect fast neutrons. For a sensitivity calculation performed using the characteristic fast neutron response peak that occurs at 692 keV, the 140% germanium detector system exhibited a sensitivity of ~175 counts / kg of WGPumetal in 1000 seconds at a source-detector distance of 1 meter with 4 in. of lead shielding between source and detector. Theoretical work also indicates that it might be possible to use the shape of the fast-neutron inelastic scattering signatures (specifically, the end-point energy of the long high energy tail of the resulting asymmetric peak) to gain additional information about the energy distribution of the incident neutron spectrum. However, the experimentally observed end-point energies appear to be almost identical for each of the fast neutron sources counted. Detailed MCNP calculations show that the neutron energy distributions impingent on the detector for these sources are very similar in this experimental configuration, due to neutron scattering in a lead shield (placed between the neutron source and HPGe detector to reduce the gamma ray flux), the BGO anti-coincidence detector, and the concrete floor.

  8. Tests of HPGe- and scintillation-based backpack γ-radiation survey systems.

    PubMed

    Nilsson, Jonas M C; Östlund, Karl; Söderberg, Joakim; Mattsson, Sören; Rääf, Christopher

    2014-09-01

    The performance of three different backpack-mounted γ-radiation survey systems has been investigated. The systems are based on a LaBr3:Ce detector and a NaI(Tl) detector both with active volume dimensions of 76.2 mm in diameter and 76.2 mm length and a 123% relative efficiency HPGe detector. The detection limits of the systems were tested in a controlled outdoor environment in Sweden, followed by field tests of the HPGe- and LaBr3:Ce-based systems at the site of a radioactive waste repository in Georgia (in the Caucasus region of Eurasia). The results showed that the high efficiency HPGe detector performed significantly better than similar sized LaBr3:Ce and NaI(Tl) detectors, however, the HPGe detector was significantly heavier than the other systems. The use of different analysis methods revealed that creating maps of the survey area was the best method for offline analysis of survey data collected from a large area. Using off-site personnel for analysis of the data proved to be beneficial.

  9. Characterization of HPGe gamma spectrometric detectors systems for Instrumental Neutron Activation Analysis (INAA) at the Colombian Geological Survey

    NASA Astrophysics Data System (ADS)

    Sierra, O.; Parrado, G.; Cañón, Y.; Porras, A.; Alonso, D.; Herrera, D. C.; Peña, M.; Orozco, J.

    2016-07-01

    This paper presents the progress made by the Neutron Activation Analysis (NAA) laboratory at the Colombian Geological Survey (SGC in its Spanish acronym), towards the characterization of its gamma spectrometric systems for Instrumental Neutron Activation Analysis (INAA), with the aim of introducing corrections to the measurements by variations in sample geometry. Characterization includes the empirical determination of the interaction point of gamma radiation inside the Germanium crystal, through the application of a linear model and the use of a fast Monte Carlo N-Particle (MCNP) software to estimate correction factors for differences in counting efficiency that arise from variations in sample density between samples and standards.

  10. Efficient scalable solid-state neutron detector.

    PubMed

    Moses, Daniel

    2015-06-01

    We report on scalable solid-state neutron detector system that is specifically designed to yield high thermal neutron detection sensitivity. The basic detector unit in this system is made of a (6)Li foil coupled to two crystalline silicon diodes. The theoretical intrinsic efficiency of a detector-unit is 23.8% and that of detector element comprising a stack of five detector-units is 60%. Based on the measured performance of this detector-unit, the performance of a detector system comprising a planar array of detector elements, scaled to encompass effective area of 0.43 m(2), is estimated to yield the minimum absolute efficiency required of radiological portal monitors used in homeland security. PMID:26133869

  11. Efficient scalable solid-state neutron detector

    SciTech Connect

    Moses, Daniel

    2015-06-15

    We report on scalable solid-state neutron detector system that is specifically designed to yield high thermal neutron detection sensitivity. The basic detector unit in this system is made of a {sup 6}Li foil coupled to two crystalline silicon diodes. The theoretical intrinsic efficiency of a detector-unit is 23.8% and that of detector element comprising a stack of five detector-units is 60%. Based on the measured performance of this detector-unit, the performance of a detector system comprising a planar array of detector elements, scaled to encompass effective area of 0.43 m{sup 2}, is estimated to yield the minimum absolute efficiency required of radiological portal monitors used in homeland security.

  12. Efficient scalable solid-state neutron detector

    NASA Astrophysics Data System (ADS)

    Moses, Daniel

    2015-06-01

    We report on scalable solid-state neutron detector system that is specifically designed to yield high thermal neutron detection sensitivity. The basic detector unit in this system is made of a 6Li foil coupled to two crystalline silicon diodes. The theoretical intrinsic efficiency of a detector-unit is 23.8% and that of detector element comprising a stack of five detector-units is 60%. Based on the measured performance of this detector-unit, the performance of a detector system comprising a planar array of detector elements, scaled to encompass effective area of 0.43 m2, is estimated to yield the minimum absolute efficiency required of radiological portal monitors used in homeland security.

  13. Highly efficient charged particle veto detector CUP

    NASA Astrophysics Data System (ADS)

    Palacz, M.; Nyberg, J.; Bednarczyk, P.; Dworski, J.; Górska, M.; Iwanicki, J.; Kapusta, M.; Kownacki, J.; Kulczycka, E.; Lagergren, K.; Moszyński, M.; Pieńkowski, L.; Stolarz, A.; Wolski, D.; Ziębliński, M.

    2005-09-01

    A novel, highly efficient, plastic scintillator detector has been constructed. The primary application of the detector is to act as a veto device in heavy-ion-induced fusion-evaporation reactions, in which the structure of proton-rich nuclides is investigated by γ-ray spectroscopy methods. The detector rejects events in which light charged particles, like protons and α particles, are emitted in the evaporation process, facilitating selection of reaction channels associated with emission of only neutrons. The detector was used in a EUROBALL experiment, with achieved efficiencies of 80% and 63% for protons and α particles, respectively. The design of the detector, its performance and limitations are discussed.

  14. Simulation of background reduction and Compton suppression in a low-background HPGe spectrometer at a surface laboratory

    NASA Astrophysics Data System (ADS)

    Niu, Shun-Li; Cai, Xiao; Wu, Zhen-Zhong; Liu, Yi; Xie, Yu-Guang; Yu, Bo-Xiang; Wang, Zhi-Gang; Fang, Jian; Sun, Xi-Lei; Sun, Li-Jun; Liu, Ying-Biao; Gao, Long; Zhang, Xuan; Zhao, Hang; Zhou, Li; Lü, Jun-Guang; Hu, Tao

    2015-08-01

    High-purity germanium (HPGe) detectors are well suited to analyse the radioactivity of samples. In order to reduce the environmental background for an ultra-low background HPGe spectrometer, low-activity lead and oxygen free copper are installed outside the probe to shield from gamma radiation, with an outer plastic scintillator to veto cosmic rays, and an anti-Compton detector to improve the peak-to-Compton ratio. Using Geant4 tools and taking into account a detailed description of the detector, we optimize the sizes of these detectors to reach the design requirements. A set of experimental data from an existing HPGe spectrometer was used to compare with the simulation. For the future low-background HPGe detector simulation, considering different thicknesses of BGO crystals and anti-coincidence efficiency, the simulation results show that the optimal BGO thickness is 5.5 cm, and the peak-to-Compton ratio of 40K is raised to 1000 when the anti-coincidence efficiency is 0.85. In 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 (50 keV-2.8 MeV), which is about 10-5 of the environmental background.

  15. Optimization of statistical methods for HpGe gamma-ray spectrometer used in wide count rate ranges

    NASA Astrophysics Data System (ADS)

    Gervino, G.; Mana, G.; Palmisano, C.

    2016-07-01

    The need to perform γ-ray measurements with HpGe detectors is a common technique in many fields such as nuclear physics, radiochemistry, nuclear medicine and neutron activation analysis. The use of HpGe detectors is chosen in situations where isotope identification is needed because of their excellent resolution. Our challenge is to obtain the "best" spectroscopy data possible in every measurement situation. "Best" is a combination of statistical (number of counts) and spectral quality (peak, width and position) over a wide range of counting rates. In this framework, we applied Bayesian methods and the Ellipsoidal Nested Sampling (a multidimensional integration technique) to study the most likely distribution for the shape of HpGe spectra. In treating these experiments, the prior information suggests to model the likelihood function with a product of Poisson distributions. We present the efforts that have been done in order to optimize the statistical methods to HpGe detector outputs with the aim to evaluate to a better order of precision the detector efficiency, the absolute measured activity and the spectra background. Reaching a more precise knowledge of statistical and systematic uncertainties for the measured physical observables is the final goal of this research project.

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

    SciTech Connect

    LaBrecque, J.J.; Preiss, I.L.

    1984-01-01

    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 material from Morro do Ferro to determine elemental compositions (including barium and rare-earth elements) and its relationship to the mobilization of thorium from the deposit using a Co-57 radioisotope source. The objective of this work was to develop an analytical method to determine barium and rare-earth element present in Venezuelan lateritic material from Cerro Impacto. We have employed a method before, employing a Si(Li) detector, but due to the low detection efficiencies in the rare-earth K-lines region (about 30 KeV - 40 KeV), we have decided to study the improvement in sensitivities and detection limits using an hyperpure germanium detector.

  17. An Efficient Ant-Based Edge Detector

    NASA Astrophysics Data System (ADS)

    Aydın, Doğan

    An efficient ant-based edge detector is presented. It is based on the distribution of ants on an image, ants try to find possible edges by using a state transition function based on 5x5 edge structures. Visual comparisons show that the proposed method gives finer details and thinner edges at lesser computational times when compared to earlier ant-based approaches. When compared to standard edge detectors, it shows robustness to Gaussian and Salt & Pepper noise and provides finer details than others with same parameter set in both clear and noisy images.

  18. Evaluation of the neutron background in an HPGe target for WIMP direct detection when using a reactor neutrino detector as a neutron veto system

    SciTech Connect

    Ji, Xiangpan; Xu, Ye Lin, Junsong; Feng, Yulong; Li, Haolin

    2013-11-15

    A direct WIMP (weakly interacting massive particle) detector with a neutron veto system is designed to better reject neutrons. The experimental configuration is studied in this paper involves 984 Ge modules placed inside a reactor-neutrino detector. The neutrino detector is used as a neutron veto device. The neutron background for the experimental design is estimated using the Geant4 simulation. The results show that the neutron background can decrease to O(0.01) events per year per tonne of high-purity germanium and it can be ignored in comparison with electron recoils.

  19. Obelix, a new low-background HPGe at Modane Underground Laboratory

    NASA Astrophysics Data System (ADS)

    Loaiza, P.; Brudanin, V.; Piquemal, F.; Rukhadze, E.; Rukhadze, N.; Stekl, I.; Warot, G.; Zampaolo, M.

    2015-08-01

    An ultra-low background coaxial HPGe detector for gamma-ray spectrometry with a relative efficiency of 160%, corresponding to a 600 cm3 Ge crystal, was installed at the Laboratoire Souterrain de Modane, France (4800 m.w.e). To reduce the instrinsic detector background, all parts involved in the detector cryostat were selected for their low radioactivity contamination. A shielding, composed of an inner layer of roman lead and an external layer of regular lead was installed, together with a system to reduce the Rn level inside the sample chamber. The shielding was designed to allow the measurement of Marinelli-shaped samples. We present the constructional details which lead to a remarkable low detector background of 73 cts/kg.d in [40, 3000] keV. Measured samples showed that sensitivities about 100 μBq/kg in 226Ra and 228Th are reached for samples of some kg and 30 days of lifetime.

  20. Quantum Efficient Detectors for Use in Absolute Calibration

    NASA Technical Reports Server (NTRS)

    Faust, Jessica; Eastwood, Michael; Pavri, Betina; Raney, James

    1998-01-01

    The trap or quantum efficient detector has a quantum efficiency of greater than 0.98 for the region from 450 to 900 nm. The region of flattest response is from 600 to 900 nm. The QED consists of three windowless Hamamatsu silicon detectors. The QED was mounted below AVIRIS to monitor the Spectralon panel for changes in radiance during radiometric calibration. The next step is to permanently mount the detector to AVIRIS and monitor the overall radiance of scenes along with calibration.

  1. High efficiency neutron sensitive amorphous silicon pixel detectors

    SciTech Connect

    Mireshghi, A.; Cho, G.; Drewery, J.S.; Hong, W.S.; Jing, T.; Lee, H.; Kaplan, S.N.; Perez-Mendez, V.

    1993-11-01

    A multi-layer a-Si:H based thermal neutron detector was designed, fabricated and simulated by Monte Carlo method. The detector consists of two PECVD deposited a-Si:H pin detectors interfaced with coated layers of Gd, as a thermal neutron converter. Simulation results indicate that a detector consisting of 2 Gd films with thicknesses of 2 and 4 {mu}m, sandwiched properly with two layers of sufficiently thick ({approximately}30{mu}m) amorphous silicon diodes, has the optimum parameters. The detectors have an intrinsic efficiency of about 42% at a threshold setting of 7000 electrons, with an expected average signal size of {approximately}12000 electrons which is well above the noise. This efficiency will be further increased to nearly 63%, if we use Gd with 50% enrichment in {sup 157}Gd. We can fabricate position sensitive detectors with spatial resolution of 300 {mu}m with gamma sensitivity of {approximately}1 {times} 10{sup {minus}5}. These detectors are highly radiation resistant and are good candidates for use in various application, where high efficiency, high resolution, gamma insensitive position sensitive neutron detectors are needed.

  2. Hit efficiency study of CMS prototype forward pixel detectors

    SciTech Connect

    Kim, Dongwook; /Johns Hopkins U.

    2006-01-01

    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.

  3. Efficiency and Gamma Sensitivity of a Lithium Glass Neutron Detector

    NASA Astrophysics Data System (ADS)

    Wallace, Adam; Rees, Lawrence; Czirr, Bart; Hoggan, Margarita

    2010-10-01

    Neutron detectors are used in national security applications for detecting potential radioactive material entering the country. Due to the shortage of Helium-3 for neutron detectors, Lithium-6 glass scintillators could be a good material for a replacement detector. Lithium-6 has a large neutron capture cross section, which gives high neutron detection rates. Our detector is based on the fact that neutrons are captured by Lithium-6 which rapidly decays into an alpha particle and triton. Those particles induce scintillation in the glass scintillator and are detected in a photomultiplier tube. The orientation of the plastic and Lithium-6 glass changes the efficiency of the detector. Monte Carlo for Neutral Particles (MCNP) calculations have shown that increasing amounts of plastic provide more efficient neutron detection and that placing a layer of glass in the front of the detector is the ideal configuration. Homeland Security requires that a replacement for Helium-3 detectors must have low gamma sensitivity and high neutron detection efficiency. We are measuring the absolute gamma sensitivity of various arrangements of glass and plastic scintillator. Our goal is to meet the Department of Homeland Security requirement for gamma sensitivity of one part in 10,000.

  4. High efficiency proportional neutron detector with solid liner internal structures

    DOEpatents

    Kisner, Roger Allen; Holcomb, David Eugene; Brown, Gilbert M.

    2014-08-05

    A tube-style neutron detector, a panel-style neutron detector incorporating a plurality of tube-style neutron detectors, and a panel-style neutron detector including a plurality of anode wires are provided. A plurality of channels is provided in a neutron detector such that each channel has an inner surface of a coating layer including a neutron-absorbing material. A wire anode is provided at end of each channel so that electrons generated by a charged daughter particle generated by a neutron are collected to detect a neutron-matter interaction. Moderator units can be incorporated into a neutron detector to provide improved detection efficiencies and/or to determine neutron energy spectrum. Gas-based proportional response from the neutron detectors can be employed for special nuclear material (SNM) detection. This neutron detector can provide similar performance to .sup.3He-based detectors without requiring .sup.3He and without containing toxic, flammable, or high-pressure materials.

  5. Realization of highly efficient hexagonal boron nitride neutron detectors

    NASA Astrophysics Data System (ADS)

    Maity, A.; Doan, T. C.; Li, J.; Lin, J. Y.; Jiang, H. X.

    2016-08-01

    We report the achievement of highly efficient 10B enriched hexagonal boron nitride (h-10BN) direct conversion neutron detectors. These detectors were realized from freestanding 4-in. diameter h-10BN wafers 43 μm in thickness obtained from epitaxy growth and subsequent mechanical separation from sapphire substrates. Both sides of the film were subjected to ohmic contact deposition to form a simple vertical "photoconductor-type" detector. Transport measurements revealed excellent vertical transport properties including high electrical resistivity (>1013 Ω cm) and mobility-lifetime (μτ) products. A much larger μτ product for holes compared to that of electrons along the c-axis of h-BN was observed, implying that holes (electrons) behave like majority (minority) carriers in undoped h-BN. Exposure to thermal neutrons from a californium-252 (252Cf) source moderated by a high density polyethylene moderator reveals that 43 μm h-10BN detectors possess 51.4% detection efficiency at a bias voltage of 400 V, which is the highest reported efficiency for any semiconductor-based neutron detector. The results point to the possibility of obtaining highly efficient, compact solid-state neutron detectors with high gamma rejection and low manufacturing and maintenance costs.

  6. Effects of detector efficiency mismatch on security of quantum cryptosystems

    SciTech Connect

    Makarov, Vadim; Anisimov, Andrey; Skaar, Johannes

    2006-08-15

    We suggest a type of attack on quantum cryptosystems that exploits variations in detector efficiency as a function of a control parameter accessible to an eavesdropper. With gated single-photon detectors, this control parameter can be the timing of the incoming pulse. When the eavesdropper sends short pulses using the appropriate timing so that the two gated detectors in Bob's setup have different efficiencies, the security of quantum key distribution can be compromised. Specifically, we show for the Bennett-Brassard 1984 (BB84) protocol that if the efficiency mismatch between 0 and 1 detectors for some value of the control parameter gets large enough (roughly 15:1 or larger), Eve can construct a successful faked-states attack causing a quantum bit error rate lower than 11%. We also derive a general security bound as a function of the detector sensitivity mismatch for the BB84 protocol. Experimental data for two different detectors are presented, and protection measures against this attack are discussed.

  7. Investigations of 2β decay of 106Cd and 58Ni with HPGe spectrometer OBELIX

    NASA Astrophysics Data System (ADS)

    Rukhadze, E.; Brudanin, V.; Fajt, L.; Hodák, R.; Klimenko, A.; Kochetov, O.; Loaiza, P.; Piquemal, F.; Rozov, S.; Rukhadze, N.; Shitov, Yu.; Špavorová, M.; Štekl, I.; Yakushev, E.; Zampaolo, M.

    2015-08-01

    Investigations of double beta decay processes to excited states of daughter nuclei were performed at the Modane underground laboratory (LSM, France, 4800 m w.e.) using the high sensitivity spectrometer OBELIX [1], which is a common activity of JINR Dubna, IEAP CTU in Prague and LSM. The spectrometer is based on the HPGe detector with the sensitive volume of 600 cm3 and relative efficiency of 160%. Investigation of resonant neutrino-less double electron capture of 106Cd was performed with ˜23.2 g of 106Cd (enrichment of 99.57%) during ˜17 days. The experiment with natural Ni (˜21.7 kg of mass) was also carried out during ˜47 days. The preliminary experimental limits for 0νEC/EC resonant decay to the excited states of 106Pd and different modes of β β decay 58Ni are presented.

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

    SciTech Connect

    Winn, W.G.

    1999-07-28

    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.

  9. Isotopic Analysis of Spent Nuclear Fuel with an Ultra-High Rate HPGe Spectrometer

    SciTech Connect

    Fast, James E.; Glasgow, Brian D.; Rodriguez, Douglas C.; VanDevender, Brent A.; Wood, Lynn S.

    2014-06-06

    A longstanding challenge is the assay of spent nuclear fuel (SNF). Determining the isotopic content of SNF requires gamma-ray spectroscopy. PNNL has developed new digital filtering and analysis techniques to produce an ultra high-rate gamma-ray spectrometer from a standard coaxial high-purity germanium (HPGe) crystal. This ~40% efficient detector has been operated for SNF measurements at a throughput of about 400k gamma-ray counts per second (kcps) at an input rate of 1.3 Mcps. Optimized filtering algorithms preserve the spectroscopic capability of the system even at these high rates. This talk will present the results of a SNF measurement with aged SNF pellets at PNNL’s Radiochemical Processing Laboratory, first results with a FPGA front end processor capable of processing the data in real time, and the development path toward a multi-element system to assay fuel assemblies.

  10. Testing the Ge detectors for the MAJORANA DEMONSTRATOR

    SciTech Connect

    Xu, W.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y. -D.; Christofferson, C. D.; Combs, D. C.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G.; Poon, A. W.P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G.H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Yakushev, E.; Young, A. R.; Yu, C. -H.; Yumatov, V.

    2015-03-24

    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 decay. It is crucial for the experiment to understand the performance of the HPGe crystals. A variety of crystal properties are being investigated, including basic properties such as energy resolution, efficiency, uniformity, capacitance, leakage current and crystal axis orientation, as well as more sophisticated properties, e.g. pulse shapes and dead layer and transition layer distributions. In this talk, we will present our measurements that characterize the HPGe crystals. We will also discuss the our simulation package for the detector characterization setup, and show that additional information can be extracted from data-simulation comparisons.

  11. Testing the Ge detectors for the MAJORANA DEMONSTRATOR

    DOE PAGES

    Xu, W.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; et al

    2015-03-24

    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 decay. It is crucial for the experiment to understand the performance of the HPGe crystals. A variety of crystal properties are being investigated, including basic properties such as energy resolution, efficiency, uniformity, capacitance, leakage current and crystal axis orientation, as well as more sophisticated properties, e.g. pulse shapes and dead layer and transition layer distributions. In this talk, we will present our measurements that characterize the HPGe crystals. We will also discuss the ourmore » simulation package for the detector characterization setup, and show that additional information can be extracted from data-simulation comparisons.« less

  12. Obelix, a new low-background HPGe at Modane Underground Laboratory

    SciTech Connect

    Loaiza, P.; Piquemal, F.; Warot, G.; Zampaolo, M.

    2015-08-17

    An ultra-low background coaxial HPGe detector for gamma-ray spectrometry with a relative efficiency of 160%, corresponding to a 600 cm{sup 3} Ge crystal, was installed at the Laboratoire Souterrain de Modane, France (4800 m.w.e). To reduce the instrinsic detector background, all parts involved in the detector cryostat were selected for their low radioactivity contamination. A shielding, composed of an inner layer of roman lead and an external layer of regular lead was installed, together with a system to reduce the Rn level inside the sample chamber. The shielding was designed to allow the measurement of Marinelli-shaped samples. We present the constructional details which lead to a remarkable low detector background of 73 cts/kg·d in [40, 3000] keV. Measured samples showed that sensitivities about 100 μBq/kg in {sup 226}Ra and {sup 228}Th are reached for samples of some kg and 30 days of lifetime.

  13. Improved photon counting efficiency calibration using superconducting single photon detectors

    NASA Astrophysics Data System (ADS)

    Gan, Haiyong; Xu, Nan; Li, Jianwei; Sun, Ruoduan; Feng, Guojin; Wang, Yanfei; Ma, Chong; Lin, Yandong; Zhang, Labao; Kang, Lin; Chen, Jian; Wu, Peiheng

    2015-10-01

    The quantum efficiency of photon counters can be measured with standard uncertainty below 1% level using correlated photon pairs generated through spontaneous parametric down-conversion process. Normally a laser in UV, blue or green wavelength range with sufficient photon energy is applied to produce energy and momentum conserved photon pairs in two channels with desired wavelengths for calibration. One channel is used as the heralding trigger, and the other is used for the calibration of the detector under test. A superconducting nanowire single photon detector with advantages such as high photon counting speed (<20 MHz), low dark count rate (<50 counts per second), and wideband responsivity (UV to near infrared) is used as the trigger detector, enabling correlated photons calibration capabilities into shortwave visible range. For a 355nm single longitudinal mode pump laser, when a superconducting nanowire single photon detector is used as the trigger detector at 1064nm and 1560nm in the near infrared range, the photon counting efficiency calibration capabilities can be realized at 532nm and 460nm. The quantum efficiency measurement on photon counters such as photomultiplier tubes and avalanche photodiodes can be then further extended in a wide wavelength range (e.g. 400-1000nm) using a flat spectral photon flux source to meet the calibration demands in cutting edge low light applications such as time resolved fluorescence and nonlinear optical spectroscopy, super resolution microscopy, deep space observation, and so on.

  14. Direct determination of the hit locations from experimental HPGe pulses

    NASA Astrophysics Data System (ADS)

    Désesquelles, P.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Dimmock, M. R.; Lazarus, I. H.; Ljungvall, J.; Nelson, L.; Nga, D.-T.; Nolan, P. J.; Rigby, S. V.; Simpson, J.; Van-Oanh, N.-T.

    2013-11-01

    The gamma-tracking technique optimises the determination of the energy and emission angle of gamma-rays detected by modern segmented HPGe detectors. This entails the determination, using the delivered pulse shapes, of the interaction points of the gamma-ray within the crystal. The direct method presented here allows the localisation of the hits using only a large sample of pulses detected in the actual operating conditions. No external crystal scanning system or pulse shape simulation code is needed. In order to validate this method, it is applied to sets of pulses obtained using the University of Liverpool scanning system. The hit locations are determined by the method with good precision.

  15. Measurement of Compton scattering in phantoms by germanium detectors

    SciTech Connect

    Zasadny, K.R.; Koral, K.F. . Medical Center); Floyd, C.E. Jr.; Jaszczak, R.J. . Dept. of Radiology)

    1990-04-01

    Quantitative Anger-camera tomography requires correction for Compton scattering. The Anger camera spectral-fitting technique can measure scatter fractions at designated positions in an image allowing for correction. To permit verification of those measurements for {sup 131}I, the authors have determined scatter fractions with a high-purity germanium (HPGe) detector and various phantom configurations. The scatter fraction values for {sup 99m}Tc were also measured and are compared to results from Monte Carlo simulation. The phantom consisted of a 22.2 cm diameter {times} 18.6 cm high cylinder filled with water and a 6 cm diameter water-filled sphere placed at various locations inside the cylinder. Radioisotope is added to either the sphere or the cylinder. The source is collimated by an Anger camera collimator and the active area of the HPGe detector is defined by a 0.6 cm diameter hole in a lead shielding mask. Corrections include accounting for the HPGe detector efficiency as a function of gamma-ray energy, the finite energy resolution of detector and the HPGe detector energy resolution compared to that for a NaI(Tl) Anger camera.

  16. Resonant infrared detector with substantially unit quantum efficiency

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    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.

  17. Implementation of a Portable HPGe for Field Contamination Assay.

    PubMed

    Hayes, Robert Bruce

    2016-06-01

    Using MCNP to construct a detector model based initially on x-ray images of a portable high purity germanium (HPGe) detector followed by normalizing covering material values to also agree with check source responses, a validation of the model was attained. By calibrating the detector parameters using large count spectra, rigorous reproducibility is attained for high activity measurements but does not prevent deviations from normality in error distributions at the very low count events where spectral peaks are not always identifiable. The resulting model was created to allow operational assay of contamination over large areal distributions that could not otherwise be measured, such as the exhaust shaft at the Waste Isolation Pilot Plant (WIPP). Results indicate that contamination levels of activity in the exhaust shaft can be assayed to within a factor of 2. Detection limits are evaluated to be well below the contamination levels, which would constitute a legal environmental release if unfiltered ventilation of the underground facility were used.

  18. Determination of the Quantum Efficiency of a Light Detector

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2008-01-01

    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…

  19. High-efficiency neutron detectors and methods of making same

    DOEpatents

    McGregor, Douglas S.; Klann, Raymond

    2007-01-16

    Neutron detectors, advanced detector process techniques and advanced compound film designs have greatly increased neutron-detection efficiency. One embodiment of the detectors utilizes a semiconductor wafer with a matrix of spaced cavities filled with one or more types of neutron reactive material such as 10B or 6LiF. The cavities are etched into both the front and back surfaces of the device such that the cavities from one side surround the cavities from the other side. The cavities may be etched via holes or etched slots or trenches. In another embodiment, the cavities are different-sized and the smaller cavities extend into the wafer from the lower surfaces of the larger cavities. In a third embodiment, multiple layers of different neutron-responsive material are formed on one or more sides of the wafer. The new devices operate at room temperature, are compact, rugged, and reliable in design.

  20. Efficiency and spatial resolution of the CASCADE thermal neutron detector

    NASA Astrophysics Data System (ADS)

    Köhli, M.; Allmendinger, F.; Häußler, W.; Schröder, T.; Klein, M.; Meven, M.; Schmidt, U.

    2016-08-01

    We report on the CASCADE project - a detection system, which has been designed for the purposes of neutron Spin Echo spectroscopy and which is continuously further developed and adapted to various applications. It features 2D spatially resolved detection of thermal neutrons at high rates. The CASCADE detector is composed of a stack of solid 10B coated Gas Electron Multiplier foils, which serve both as a neutron converter and as an amplifier for the primary ionization deposited in the standard counting gas environment. This multi-layer setup efficiently increases the detection efficiency and by extracting the signal of the charge traversing the stack the conversion layer can be identified allowing a precise determination of the time-of-flight. The spatial resolution is found by optical contrast determination to be σ =(1.39 ± 0.05) mm and by divergence corrected aperture measurements σ =(1.454 ± 0.007) mm , which is in agreement with the simulated detector model. Furthermore this enabled to investigate and describe the non-Gaussian resolution function. At the HEiDi diffractometer the absolute detection efficiency has been studied. At 0.6 Å for the 6 layer detector, which is currently part of the RESEDA spectrometer, an efficiency of 7.8% has been measured, which by means of Monte Carlo simulations translates to (21.0±1.5)% for thermal neutrons at 1.8 Å and (46.9±3.3)% at 5.4 Å.

  1. Investigation of the quantum efficiency of optical heterodyne detectors

    NASA Technical Reports Server (NTRS)

    Batchman, T. E.

    1984-01-01

    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.

  2. Roadmap for High Efficiency Solid-State Neutron Detectors

    SciTech Connect

    Nikolic, R; Cheung, C; Reinhardt, C; Wang, T

    2005-07-12

    Solid-state thermal neutron detectors are generally fabricated in a planar configuration by coating a layer of neutron-to-alpha converter material onto a semiconductor. The as-created alpha particles in the material are expected to impinge the semiconductor and create electron-hole pairs which provide the electrical signal. These devices are limited in efficiency to a range near (2-5%)/cm{sup 2} due to the conflicting thickness requirements of the converter layer. In this case, the layer is required to be thick enough to capture the incoming neutron flux while at the same time adequately thin to allow the alpha particles to reach the semiconductor. A three dimensional matrix structure has great potential to satisfy these two requirements in one device. Such structures can be realized by using PIN diode pillar elements to extend in the third dimension with the converter material filling the rest of the matrix. Our strategy to fabricate this structure is based on both ''top-down'' and ''bottom-up'' approaches. The ''top down'' approach employs high-density plasma etching techniques, while the ''bottom up'' approach draws on the growth of nanowires by chemical vapor deposition. From our simulations for structures with pillar diameters from 2 {micro}m down to 100 nm, the detector efficiency is expected to increase with a decrease in pillar size. Moreover, in the optimized configuration, the detector efficiency could be higher than 75%/cm{sup 2}. Finally, the road map for the relationship between detector diameter and efficiency will be outlined.

  3. Data encoding efficiency in pixel detector readout with charge information

    NASA Astrophysics Data System (ADS)

    Garcia-Sciveres, Maurice; Wang, Xinkang

    2016-04-01

    The average minimum number of bits needed for lossless readout of a pixel detector is calculated, in the regime of interest for particle physics where only a small fraction of pixels have a non-zero value per frame. This permits a systematic comparison of the readout efficiency of different encoding implementations. The calculation is compared to the number of bits used by the FE-I4 pixel readout chip of the ATLAS experiment.

  4. Germanium Detectors in Homeland Security at PNNL

    SciTech Connect

    Stave, Sean C.

    2015-05-01

    Neutron and gamma-ray detection is used for non-proliferation and national security applications. While lower energy resolution detectors such as NaI(Tl) have their place, high purity germanium (HPGe) also has a role to play. A detection with HPGe is often a characterization due to the very high energy resolution. However, HPGe crystals remain small and expensive leaving arrays of smaller crystals as an excellent solution. PNNL has developed two similar HPGe arrays for two very different applications. One array, the Multisensor Aerial Radiation Survey (MARS) detector is a fieldable array that has been tested on trucks, boats, and helicopters. The CASCADES HPGe array is an array designed to assay samples in a low background environment. The history of HPGe arrays at PNNL and the development of MARS and CASCADES will be detailed in this paper along with some of the other applications of HPGe at PNNL.

  5. Germanium detectors in homeland security at PNNL

    DOE PAGES

    Stave, S.

    2015-05-01

    Neutron and gamma-ray detection is used for non-proliferation and national security applications. While lower energy resolution detectors such as NaI(Tl) have their place, high purity germanium (HPGe) also has a role to play. A detection with HPGe is often a characterization due to the very high energy resolution. However, HPGe crystals remain small and expensive leaving arrays of smaller crystals as an excellent solution. PNNL has developed two similar HPGe arrays for two very different applications. One array, the Multisensor Aerial Radiation Survey (MARS) detector is a fieldable array that has been tested on trucks, boats, and helicopters. The CASCADESmore » HPGe array is an array designed to assay samples in a low background environment. The history of HPGe arrays at PNNL and the development of MARS and CASCADES will be detailed in this paper along with some of the other applications of HPGe at PNNL.« less

  6. Germanium detectors in homeland security at PNNL

    SciTech Connect

    Stave, S.

    2015-05-01

    Neutron and gamma-ray detection is used for non-proliferation and national security applications. While lower energy resolution detectors such as NaI(Tl) have their place, high purity germanium (HPGe) also has a role to play. A detection with HPGe is often a characterization due to the very high energy resolution. However, HPGe crystals remain small and expensive leaving arrays of smaller crystals as an excellent solution. PNNL has developed two similar HPGe arrays for two very different applications. One array, the Multisensor Aerial Radiation Survey (MARS) detector is a fieldable array that has been tested on trucks, boats, and helicopters. The CASCADES HPGe array is an array designed to assay samples in a low background environment. The history of HPGe arrays at PNNL and the development of MARS and CASCADES will be detailed in this paper along with some of the other applications of HPGe at PNNL.

  7. Investigations of 2β decay of {sup 106}Cd and {sup 58}Ni with HPGe spectrometer OBELIX

    SciTech Connect

    Rukhadze, E.; Fajt, L.; Hodák, R.; Špavorová, M.; Štekl, I.; Loaiza, P.

    2015-08-17

    Investigations of double beta decay processes to excited states of daughter nuclei were performed at the Modane underground laboratory (LSM, France, 4800 m w.e.) using the high sensitivity spectrometer OBELIX [1], which is a common activity of JINR Dubna, IEAP CTU in Prague and LSM. The spectrometer is based on the HPGe detector with the sensitive volume of 600 cm{sup 3} and relative efficiency of 160%. Investigation of resonant neutrino-less double electron capture of {sup 106}Cd was performed with ∼23.2 g of {sup 106}Cd (enrichment of 99.57%) during ∼17 days. The experiment with natural Ni (∼21.7 kg of mass) was also carried out during ∼47 days. The preliminary experimental limits for 0νEC/EC resonant decay to the excited states of {sup 106}Pd and different modes of β β decay {sup 58}Ni are presented.

  8. An efficient circle detector not relying on edge detection

    NASA Astrophysics Data System (ADS)

    Cai, Jia; Huang, Panfeng; Chen, Lu; Zhang, Bin

    2016-06-01

    Accurate and efficient detection of circular modules fixed on non-cooperative target is a key technology for Tethered Space Robot. This paper presents an efficient circle detector based on region-growing of gradient and histogram distribution of Euclidean distance. Region-growing of gradient is applied to generate arc support regions from single point. And the corresponding square fitting areas are defined to accelerate the detection and decrease storage. A histogram is then used to count frequency of the distances that participates in the accumulator and the parameters of each circle are acquired. Finally, a verification strategy of circular integrity is designed to test the detection results. We have tested our algorithm on 35 images dealing with kinds of circles and ellipses. Experimental results demonstrate that our method is able to detect circular objects under occlusion, image noises and moderate shape deformations with a good precision.

  9. Position-Dependent Local Detection Efficiency in a Nanowire Superconducting Single-Photon Detector.

    PubMed

    Renema, J J; Wang, Q; Gaudio, R; Komen, I; op 't Hoog, K; Sahin, D; Schilling, A; van Exter, M P; Fiore, A; Engel, A; de Dood, M J A

    2015-07-01

    We probe the local detection efficiency in a nanowire superconducting single-photon detector along the cross-section of the wire with a far subwavelength resolution. We experimentally find a strong variation in the local detection efficiency of the device. We demonstrate that this effect explains previously observed variations in NbN detector efficiency as a function of device geometry. PMID:26087352

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

    NASA Astrophysics Data System (ADS)

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

    1997-01-01

    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.

  11. An efficient repeating signal detector to investigate earthquake swarms

    NASA Astrophysics Data System (ADS)

    Skoumal, Robert J.; Brudzinski, Michael R.; Currie, Brian S.

    2016-08-01

    Repetitive earthquake swarms have been recognized as key signatures in fluid injection induced seismicity, precursors to volcanic eruptions, and slow slip events preceding megathrust earthquakes. We investigate earthquake swarms by developing a Repeating Signal Detector (RSD), a computationally efficient algorithm utilizing agglomerative clustering to identify similar waveforms buried in years of seismic recordings using a single seismometer. Instead of relying on existing earthquake catalogs of larger earthquakes, RSD identifies characteristic repetitive waveforms by rapidly identifying signals of interest above a low signal-to-noise ratio and then grouping based on spectral and time domain characteristics, resulting in dramatically shorter processing time than more exhaustive autocorrelation approaches. We investigate seismicity in four regions using RSD: (1) volcanic seismicity at Mammoth Mountain, California, (2) subduction-related seismicity in Oaxaca, Mexico, (3) induced seismicity in Central Alberta, Canada, and (4) induced seismicity in Harrison County, Ohio. In each case, RSD detects a similar or larger number of earthquakes than existing catalogs created using more time intensive methods. In Harrison County, RSD identifies 18 seismic sequences that correlate temporally and spatially to separate hydraulic fracturing operations, 15 of which were previously unreported. RSD utilizes a single seismometer for earthquake detection which enables seismicity to be quickly identified in poorly instrumented regions at the expense of relying on another method to locate the new detections. Due to the smaller computation overhead and success at distances up to ~50 km, RSD is well suited for real-time detection of low-magnitude earthquake swarms with permanent regional networks.

  12. Efficiency of antiscatter grids for flat-detector CT

    NASA Astrophysics Data System (ADS)

    Kyriakou, Yiannis; Kalender, Willi

    2007-10-01

    Flat-panel detector CT (FD-CT) scanners offer large volume coverage, but as a consequence are more susceptible to scatter artifacts than standard clinical CT scanners with smaller cone angles. FD-CT scanners can employ antiscatter grids as a scatter rejection technique. We evaluated three standard fluoroscopic antiscatter grids for two different field sizes with respect to scatter suppression efficiency and image quality improvement. The evaluations included simulations and measurements. Regarding the simulation a hybrid model combining deterministic and Monte Carlo (MC) calculations was used combined with an analytical calculation of grid transmission. The scatter-to-primary ratio (SPR) was measured using an adapted collimator technique in order to validate our simulations. The SPR obtained by simulations and measurements with and without antiscatter grids were in agreement typically within 10%. The employment of a grid does not generally provide a significant improvement of the signal-to-noise ratio (SNR). Antiscatter grids led to a significant reduction of cupping artifacts in all cases. There is a trade-off between the SNR and the reduction of the scatter intensity described by the signal-to-noise improvement factor (SNRif). For low- or medium-scatter conditions the increase in noise caused by the reduced primary transmission through the grid has to be compensated by a higher exposure. For high scatter conditions SNRif is significantly greater than 1; i.e. a decrease of dose of up to 50% can be reached.

  13. DESIGN OF A THERMOSIPHON FOR COOLING LOW-BACKGROUND HPGE ARRAYS

    SciTech Connect

    Aguayo Navarrete, Estanislao; Fast, James E.; Reid, Douglas J.

    2012-11-26

    ABSTRACT A two-phase nitrogen thermosiphon was developed for the new generation of low-background high-purity germanium (HPGe) arrays. The cooling system for these arrays has to be able to handle the heat load (>20 W) presented by a large detector mass while meeting stringent requirements necessary for low-background systems. The HPGe detector modules should operate as close to liquid nitrogen temperature (<80K) as possible to provide adequate operating conditions for a full range of HPGe impurity concentrations. In addition, exceptional temperature stability (<1 K) is needed to reduce electronic gain shifts due to changes in the front-end electronics operating temperature. In order to meet the background requirements of state-of-the-art systems these arrays are enclosed in passive lead and copper shielding up to 1 m thick. In this paper we present a cooling system for low-background experiments that complies with these stringent geometrical restrictions. Active cooling was integrated via a horizontal thermosiphon that can be fabricated using ultra-pure electroformed copper. It was charged with nitrogen to 434 kPa (63 PSIA) at 292 K, which provided a fill ratio of 10%. The results showed that the thermosiphon can effectively remove in excess of 25 W of heat load.

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

    PubMed

    Radu, Daniela; Stanga, Doru; Sima, Octavian

    2009-09-01

    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.

  15. Detection efficiency evaluation for a large area neutron sensitive microchannel plate detector

    NASA Astrophysics Data System (ADS)

    Wang, Yi-ming; Tian, Yang; Yang, Yi-gang; Liu, Ren; Pan, Jing-sheng; Wang, Xue-wu; Zhang, Zhi

    2016-09-01

    In this paper, the detection efficiency of a large area neutron sensitive microchannel plate detector has been evaluated. A 6LiF/ZnS scintillator detector 65 mm in diameter and 0.32 mm in thickness, with product code, EJ426HD2, produced by Eljen Technology, was employed as the benchmark detector. The TOF spectra of these two detectors were simultaneously measured and the energy spectra were then deduced to calculate the detection efficiency curve of the nMCP detector. Tests show the detection efficiency@25.3 meV thermal neutrons is 34% for this nMCP detector. Supported by National Natural Science Foundation of China (11375095, 11175098)

  16. A precise method to determine the activity of a weak neutron source using a germanium detector.

    PubMed

    Duke, M J M; Hallin, A L; Krauss, C B; Mekarski, P; Sibley, L

    2016-10-01

    A standard high purity germanium (HPGe) detector was used to determine the previously unknown neutron activity of a weak americium-beryllium (AmBe) neutron source. γ rays were created through (27)Al(n,n'), (27)Al(n,γ) and (1)H(n,γ) reactions induced by the neutrons on aluminum and acrylic disks, respectively. These γ rays were measured using the HPGe detector. Given the unorthodox experimental arrangement, a Monte Carlo simulation was developed to model the efficiency of the detector system to determine the neutron activity from the measured γ rays. The activity of our neutron source was determined to be 307.4±5.0n/s and is consistent for the different neutron-induced γ rays.

  17. A precise method to determine the activity of a weak neutron source using a germanium detector.

    PubMed

    Duke, M J M; Hallin, A L; Krauss, C B; Mekarski, P; Sibley, L

    2016-10-01

    A standard high purity germanium (HPGe) detector was used to determine the previously unknown neutron activity of a weak americium-beryllium (AmBe) neutron source. γ rays were created through (27)Al(n,n'), (27)Al(n,γ) and (1)H(n,γ) reactions induced by the neutrons on aluminum and acrylic disks, respectively. These γ rays were measured using the HPGe detector. Given the unorthodox experimental arrangement, a Monte Carlo simulation was developed to model the efficiency of the detector system to determine the neutron activity from the measured γ rays. The activity of our neutron source was determined to be 307.4±5.0n/s and is consistent for the different neutron-induced γ rays. PMID:27474906

  18. Validation of efficiency transfer for Marinelli geometries.

    PubMed

    Ferreux, Laurent; Pierre, Sylvie; Thanh, Tran Thien; Lépy, Marie-Christine

    2013-11-01

    In the framework of environmental measurements by gamma-ray spectrometry, some laboratories need to characterize samples in geometries for which a calibration is not directly available. A possibility is to use an efficiency transfer code, e.g., ETNA. However, validation for large volume sources, such as Marinelli geometries, is needed. With this aim in mind, ETNA is compared, initially to a Monte Carlo simulation (PENELOPE) and subsequently to experimental data obtained with a high-purity germanium detector (HPGe).

  19. Development of A Self Biased High Efficiency Solid-State Neutron Detector for MPACT Applications

    SciTech Connect

    Danon, Yaron; Bhat, Ishwara; Jian-Qiang Lu, James

    2013-09-03

    Neutron detection is an important aspect of materials protection, accounting, and control for transmutation (MPACT). Currently He-3 filled thermal neutron detectors are utilized in many applications; these detectors require high-voltage bias for operation, which complicates the system when multiple detectors are used. In addition, due to recent increase in homeland security activity and the nuclear renaissance, there is a shortage of He-3, and these detectors become more expensive. Instead, cheap solid-state detectors that can be mass produced like any other computer chips will be developed. The new detector does not require a bias for operation, has low gamma sensitivity, and a fast response. The detection system is based on a honeycomb-like silicon device, which is filled with B-10 as the neutron converter; while a silicon p-n diode (i.e., solar cell type device) formed on the thin silicon wall of the honeycomb structure detects the energetic charged particles emitted from the B-10 conversion layer. Such a detector has ~40% calculated thermal neutron detection efficiency with an overall detector thickness of about 200 ?m. Stacking of these devices allows over 90% thermal neutron detection efficiency. The goal of the proposed research is to develop a high-efficiency, low-noise, self-powered solid-state neutron detector system based on the promising results of the existing research program. A prototype of this solid-state neutron detector system with sufficient detector size (up to 8-inch diam., but still portable and inexpensive) and integrated with interface electronics (e.g., preamplifier) will be designed, fabricated, and tested as a coincidence counter for MPACT applications. All fabrications proposed are based on silicon-compatible processing; thus, an extremely cheap detector system could be massively produced like any other silicon chips. Such detectors will revolutionize current neutron detection systems by providing a solid-state alternative to

  20. Full Range MGA Plutonium Isotopic Analysis using Single Ge Detector

    SciTech Connect

    Buckley, W.M.; Wang, T.F.; Friensehner, A.; Kreek, S.A.; Lanier, R.G.; Parker, W.E.; Ruhter, W.; Twomey, T.; Martinez, D.; Keyser, R.; Sangsingkeow, P.

    2000-06-26

    The Gamma-Ray multi-group analysis code MGA developed at Lawrence Livermore National Laboratory has been widely used in the area of gamma-ray non-destructive plutonium assay. This plutonium isotopic analysis code de-convolutes the complicated, 100-keV x-ray and gamma-ray region to obtain the ratio of Pu isotopes. Calibration of the detector efficiency is not required, but is determined intrinsically from the measured spectra. The code can either analyze low-energy gamma-ray spectrum taken using a high-resolution HPGe detector for energies below 300 keV, or analyze the low-energy spectrum combined with a high-energy spectrum (up to 1 MeV) in the two-detector analysis mode. In the latter case, the use of two detectors has been mandated by the conflicting requirements: excellent resolution at low energies (characteristic of small planar detectors) with good high-energy efficiency (characteristic of coaxial detectors). Usually, a high-energy spectrum taken using a coaxial Ge detector will not provide sufficient energy resolution for 100-keV plutonium isotopic analysis, while the small planar used at low energies has inadequate high-energy efficiency. An optimized-geometry ORTEC HPGe detector has been developed which combines good energy resolution at 100 keV combined with acceptable high-energy ({approx} 1 MeV) efficiency in a single detector. It has been used to gather spectra of both low- and high-energy regions of plutonium spectra simultaneously, for analysis by MGA in the two-detector mode. Five Pu gamma-ray calibration standard sources were used in this study of this special detector.

  1. Non-streaming high-efficiency perforated semiconductor neutron detectors, methods of making same and measuring wand and detector modules utilizing same

    DOEpatents

    McGregor, Douglas S.; Shultis, John K.; Rice, Blake B.; McNeil, Walter J.; Solomon, Clell J.; Patterson, Eric L.; Bellinger, Steven L.

    2010-12-21

    Non-streaming high-efficiency perforated semiconductor neutron detectors, method of making same and measuring wands and detector modules utilizing same are disclosed. The detectors have improved mechanical structure, flattened angular detector responses, and reduced leakage current. A plurality of such detectors can be assembled into imaging arrays, and can be used for neutron radiography, remote neutron sensing, cold neutron imaging, SNM monitoring, and various other applications.

  2. Energy resolution and efficiency of phonon-mediated kinetic inductance detectors for light detection

    NASA Astrophysics Data System (ADS)

    Cardani, L.; Colantoni, I.; Cruciani, A.; Di Domizio, S.; Vignati, M.; Bellini, F.; Casali, N.; Castellano, M. G.; Coppolecchia, A.; Cosmelli, C.; Tomei, C.

    2015-08-01

    The development of sensitive cryogenic light detectors is of primary interest for bolometric experiments searching for rare events like dark matter interactions or neutrino-less double beta decay. Thanks to their good energy resolution and the natural multiplexed read-out, Kinetic Inductance Detectors (KIDs) are particularly suitable for this purpose. To efficiently couple KIDs-based light detectors to the large crystals used by the most advanced bolometric detectors, active surfaces of several cm2 are needed. For this reason, we are developing phonon-mediated detectors. In this paper, we present the results obtained with a prototype consisting of four 40 nm thick aluminum resonators patterned on a 2 × 2 cm2 silicon chip, and calibrated with optical pulses and X-rays. The detector features a noise resolution σE = 154 ± 7 eV and an (18 ± 2)% efficiency.

  3. SmartPET: Applying HPGe and pulse shape analysis to small-animal PET

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

    The SmartPET project is the development of a prototype small-animal imaging system based on the use of Hyperpure Germanium (HPGe) detectors. The use of digital electronics and application of Pulse Shape Analysis (PSA) techniques provide fine spatial resolution, while the excellent intrinsic energy resolution of HPGe detectors makes the system ideal for multi-nuclide imaging. As a result, the SmartPET system has the potential to function as a dual modality imager, operating as a dual-head Positron Emission Tomography (PET) camera or in a Compton Camera configuration for Single Photon Emission Computed Tomography (SPECT) imaging. In this paper, we discuss how the use of simple PSA techniques greatly improves the position sensitivity of the detector yielding improved spatial resolution in reconstructed images. The PSA methods presented have been validated by comparison to data from high-precision scanning of the detectors. Results from this analysis are presented along with initial images from the SmartPET system, which demonstrates the impact of these techniques on PET images.

  4. True coincidence summing correction and mathematical efficiency modeling of a well detector

    NASA Astrophysics Data System (ADS)

    Jäderström, H.; Mueller, W. F.; Atrashkevich, V.; Adekola, A. S.

    2015-06-01

    True coincidence summing (TCS) occurs when two or more photons are emitted from the same decay of a radioactive nuclide and are detected within the resolving time of the gamma ray detector. TCS changes the net peak areas of the affected full energy peaks in the spectrum and the nuclide activity is rendered inaccurate if no correction is performed. TCS is independent of the count rate, but it is strongly dependent on the peak and total efficiency, as well as the characteristics of a given nuclear decay. The TCS effects are very prominent for well detectors because of the high efficiencies, and make accounting for TCS a necessity. For CANBERRA's recently released Small Anode Germanium (SAGe) well detector, an extension to CANBERRA's mathematical efficiency calibration method (In Situ Object Calibration Software or ISOCS, and Laboratory SOurceless Calibration Software or LabSOCS) has been developed that allows for calculation of peak and total efficiencies for SAGe well detectors. The extension also makes it possible to calculate TCS corrections for well detectors using the standard algorithm provided with CANBERRAS's Spectroscopy software Genie 2000. The peak and total efficiencies from ISOCS/LabSOCS have been compared to MCNP with agreements within 3% for peak efficiencies and 10% for total efficiencies for energies above 30 keV. A sample containing Ra-226 daughters has been measured within the well and analyzed with and without TCS correction and applying the correction factor shows significant improvement of the activity determination for the energy range 46-2447 keV. The implementation of ISOCS/LabSOCS for well detectors offers a powerful tool for efficiency calibration for these detectors. The automated algorithm to correct for TCS effects in well detectors makes nuclide specific calibration unnecessary and offers flexibility in carrying out gamma spectral analysis.

  5. Evaluation of the efficiency curve of a Cadmiun Telluride detector for low-energy photon spectrometry.

    PubMed

    Correia, Amanda Ribeiro; Iwahara, Akira; da Cruz, Paulo Alberto Lima; da Silva, Carlos José; Tauhata, Luiz; Poledna, Roberto; da Silva, Ronaldo Lins; de Queiroz Filho, Pedro Pacheco; Lopes, Ricardo Tadeu

    2016-10-01

    The performance of a Cadmiun Telluride (CdTe) detector for low energy photon spectrometry was evaluated. Collected data were analyzed using the basic software package available with the CdTe detector system and the COLEGRAM code developed for photopeak deconvolution at LNHB/France. Several calibrated point sources were used to determine the energy versus efficiency curve. The efficiency curve was used in the determination of main X-ray intensities of (153)Sm and (177)Lu.

  6. Evaluation of the efficiency curve of a Cadmiun Telluride detector for low-energy photon spectrometry.

    PubMed

    Correia, Amanda Ribeiro; Iwahara, Akira; da Cruz, Paulo Alberto Lima; da Silva, Carlos José; Tauhata, Luiz; Poledna, Roberto; da Silva, Ronaldo Lins; de Queiroz Filho, Pedro Pacheco; Lopes, Ricardo Tadeu

    2016-10-01

    The performance of a Cadmiun Telluride (CdTe) detector for low energy photon spectrometry was evaluated. Collected data were analyzed using the basic software package available with the CdTe detector system and the COLEGRAM code developed for photopeak deconvolution at LNHB/France. Several calibrated point sources were used to determine the energy versus efficiency curve. The efficiency curve was used in the determination of main X-ray intensities of (153)Sm and (177)Lu. PMID:27544313

  7. Development of a high-count-rate neutron detector with position sensitivity and high efficiency

    SciTech Connect

    Nelson, R.; Sandoval, J.

    1996-10-01

    While the neutron scattering community is bombarded with hints of new technologies that may deliver detectors with high-count-rate capability, high efficiency, gamma-ray insensitivity, and high resolution across large areas, only the time-tested, gas-filled {sup 3}He and scintillation detectors are in widespread use. Future spallation sources with higher fluxes simply must exploit some of the advanced detector schemes that are as yet unproved as production systems. Technologies indicating promise as neutron detectors include pixel arrays of amorphous silicon, silicon microstrips, microstrips with gas, and new scintillation materials. This project sought to study the competing neutron detector technologies and determine which or what combination will lead to a production detector system well suited for use at a high-intensity neutron scattering source.

  8. Performance of SEM scintillation detector evaluated by modulation transfer function and detective quantum efficiency function.

    PubMed

    Bok, Jan; Schauer, Petr

    2014-01-01

    In the paper, the SEM detector is evaluated by the modulation transfer function (MTF) which expresses the detector's influence on the SEM image contrast. This is a novel approach, since the MTF was used previously to describe only the area imaging detectors, or whole imaging systems. The measurement technique and calculation of the MTF for the SEM detector are presented. In addition, the measurement and calculation of the detective quantum efficiency (DQE) as a function of the spatial frequency for the SEM detector are described. In this technique, the time modulated e-beam is used in order to create well-defined input signal for the detector. The MTF and DQE measurements are demonstrated on the Everhart-Thornley scintillation detector. This detector was alternated using the YAG:Ce, YAP:Ce, and CRY18 single-crystal scintillators. The presented MTF and DQE characteristics show good imaging properties of the detectors with the YAP:Ce or CRY18 scintillator, especially for a specific type of the e-beam scan. The results demonstrate the great benefit of the description of SEM detectors using the MTF and DQE. In addition, point-by-point and continual-sweep e-beam scans in SEM were discussed and their influence on the image quality was revealed using the MTF. PMID:24323770

  9. Performance of SEM scintillation detector evaluated by modulation transfer function and detective quantum efficiency function.

    PubMed

    Bok, Jan; Schauer, Petr

    2014-01-01

    In the paper, the SEM detector is evaluated by the modulation transfer function (MTF) which expresses the detector's influence on the SEM image contrast. This is a novel approach, since the MTF was used previously to describe only the area imaging detectors, or whole imaging systems. The measurement technique and calculation of the MTF for the SEM detector are presented. In addition, the measurement and calculation of the detective quantum efficiency (DQE) as a function of the spatial frequency for the SEM detector are described. In this technique, the time modulated e-beam is used in order to create well-defined input signal for the detector. The MTF and DQE measurements are demonstrated on the Everhart-Thornley scintillation detector. This detector was alternated using the YAG:Ce, YAP:Ce, and CRY18 single-crystal scintillators. The presented MTF and DQE characteristics show good imaging properties of the detectors with the YAP:Ce or CRY18 scintillator, especially for a specific type of the e-beam scan. The results demonstrate the great benefit of the description of SEM detectors using the MTF and DQE. In addition, point-by-point and continual-sweep e-beam scans in SEM were discussed and their influence on the image quality was revealed using the MTF.

  10. Development of an underground HPGe array facility for ultra low radioactivity measurements

    SciTech Connect

    Sala, E.; Kang, W. G.; Kim, Y. D.; Lee, M. H.; Leonard, D. S.; Hahn, I. S.; Kim, G. W.; Park, S. Y.

    2015-08-17

    Low Level Counting techniques using low background facilities are continuously under development to increase the possible sensitivity needed for rare physics events experiments. The CUP (Center for Underground Physics) group of IBS is developing, in collaboration with Canberra, a ultra low background instrument composed of two arrays facing each other with 7 HPGe detectors each. The low radioactive background of each detector has been evaluated and improved by the material selection of the detector components. Samples of all the building materials have been provided by the manufacturer and the contaminations had been measured using an optimized low background 100% HPGe with a dedicated shielding. The evaluation of the intrinsic background has been performed using MonteCarlo simulations and considering the contribution of each material with the measured contamination. To further reduce the background, the instrument will be placed in the new underground laboratory at YangYang exploiting the 700m mountain coverage and radon-free air supplying system. The array has been designed to perform various Ultra Low background measurements; the sensitivity we are expecting will allow not only low level measurements of Ra and Th contaminations in Copper or other usually pure materials, but also the search for rare decays. In particular some possible candidates and configurations to detect the 0νECEC (for example {sup 106}Cd and {sup 156}Dy) and rare β decays ({sup 96}Zr, {sup 180m}Ta , etc ) are under study.

  11. Development of an underground HPGe array facility for ultra low radioactivity measurements

    NASA Astrophysics Data System (ADS)

    Sala, E.; Hahn, I. S.; Kang, W. G.; Kim, G. W.; Kim, Y. D.; Lee, M. H.; Leonard, D. S.; Park, S. Y.

    2015-08-01

    Low Level Counting techniques using low background facilities are continuously under development to increase the possible sensitivity needed for rare physics events experiments. The CUP (Center for Underground Physics) group of IBS is developing, in collaboration with Canberra, a ultra low background instrument composed of two arrays facing each other with 7 HPGe detectors each. The low radioactive background of each detector has been evaluated and improved by the material selection of the detector components. Samples of all the building materials have been provided by the manufacturer and the contaminations had been measured using an optimized low background 100% HPGe with a dedicated shielding. The evaluation of the intrinsic background has been performed using MonteCarlo simulations and considering the contribution of each material with the measured contamination. To further reduce the background, the instrument will be placed in the new underground laboratory at YangYang exploiting the 700m mountain coverage and radon-free air supplying system. The array has been designed to perform various Ultra Low background measurements; the sensitivity we are expecting will allow not only low level measurements of Ra and Th contaminations in Copper or other usually pure materials, but also the search for rare decays. In particular some possible candidates and configurations to detect the 0νECEC (for example 106Cd and 156Dy) and rare β decays (96Zr, 180mTa , etc ) are under study.

  12. Evaluation of HPGe spectrometric devices in monitoring the level of radioactive contamination in metallurgical industry

    NASA Astrophysics Data System (ADS)

    Petrucci, A.; Arnold, D.; Burda, O.; De Felice, P.; Garcia-Toraño, E.; Mejuto, M.; Peyres, V.; Šolc, J.; Vodenik, B.

    2015-10-01

    This paper presents the results of the tests of High Purity Germanium (HPGe) based gamma spectrometers employed for radioactivity control carried out on a daily basis in steel factories. This new application of this type of detector is part of the Joint Research Project (JRP) MetroMETAL supported by the European Metrology Research Programme (EMRP). The final purpose of the project was the improvement and standardisation of the measurement methods and systems for the control of radioactivity of recycled metal scraps at the beginning of the working process and for the certification of the absence of any radioactive contamination above the clearance levels (IAEA-TECDOC-8S5) in final steel products, Clearance levels for radionuclides in solid materials: application of exemption principles). Two prototypes based on HPGe detectors were designed and assembled to suit the needs of steel mills which had been examined previously. The evaluation of the two prototypes, carried out at three steel factories with standard sources of 60Co, 137Cs, 192Ir, 226Ra and 241Am in three different matrices (slag, fume dust and cast steel) and with samples provided on-site by the factories, was successful. The measurements proved the superiority of the prototypes over the scintillation detectors now commonly used regarding energy resolution and multi-nuclide identification capability. The detection limits were assessed and are presented as well.

  13. 2E1 Ar(17+) decay and conventional radioactive sources to determine efficiency of semiconductor detectors.

    PubMed

    Lamour, Emily; Prigent, Christophe; Eberhardt, Benjamin; Rozet, Jean Pierre; Vernhet, Dominique

    2009-02-01

    Although reliable models may predict the detection efficiency of semiconductor detectors, measurements are needed to check the parameters supplied by the manufacturers, namely, the thicknesses of dead layer, beryllium window, and crystal active area. The efficiency of three silicon detectors has been precisely investigated in their entire photon energy range of detection. In the zero to a few keV range, we developed a new method based on the detection of the 2E1 decay of the metastable Ar(17+) 2s-->1s transition. Very good theoretical knowledge of the energetic distribution of the 2E1 decay mode enables precise characterization of the absorbing layers in front of the detectors. In the high-energy range (>10 keV), the detector crystal thickness plays a major role in the detection efficiency and has been determined using a (241)Am source.

  14. Note: Fast neutron efficiency in CR-39 nuclear track detectors

    SciTech Connect

    Cavallaro, S.

    2015-03-15

    CR-39 samples are commonly employed for fast neutron detection in fusion reactors and in inertial confinement fusion experiments. The literature reported efficiencies are strongly depending on experimental conditions and, in some cases, highly dispersed. The present note analyses the dependence of efficiency as a function of various parameters and experimental conditions in both the radiator-assisted and the stand-alone CR-39 configurations. Comparisons of literature experimental data with Monte Carlo calculations and optimized efficiency values are shown and discussed.

  15. Note: fast neutron efficiency in CR-39 nuclear track detectors.

    PubMed

    Cavallaro, S

    2015-03-01

    CR-39 samples are commonly employed for fast neutron detection in fusion reactors and in inertial confinement fusion experiments. The literature reported efficiencies are strongly depending on experimental conditions and, in some cases, highly dispersed. The present note analyses the dependence of efficiency as a function of various parameters and experimental conditions in both the radiator-assisted and the stand-alone CR-39 configurations. Comparisons of literature experimental data with Monte Carlo calculations and optimized efficiency values are shown and discussed.

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

    NASA Astrophysics Data System (ADS)

    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

    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 2.5μm 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 2.5μm.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.

  17. Detectors

    DOEpatents

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

    2002-01-01

    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.

  18. Efficient data transmission from silicon wafer strip detectors

    SciTech Connect

    Cooke, B.J.; Lackner, K.S.; Palounek, A.P.T.; Sharp, D.H.; Winter, L.; Ziock, H.J.

    1991-12-31

    An architecture for on-wafer processing is proposed for central silicon-strip tracker systems as they are currently designed for high energy physics experiments at the SSC, and for heavy ion experiments at RHIC. The data compression achievable with on-wafer processing would make it possible to transmit all data generated to the outside of the detector system. A set of data which completely describes the state of the wafer for low occupancy events and which contains important statistical information for more complex events can be transmitted immediately. This information could be used in early trigger decisions. Additional data packages which complete the description of the state of the wafer vary in size and are sent through a second channel. By buffering this channel the required bandwidth can be kept far below the peak data rates which occur in rate but interesting events. 18 refs.

  19. Efficiency of Moderated Neutron Lithium Glass Detectors Using Monte Carlo Techniques

    NASA Astrophysics Data System (ADS)

    James, Brian

    2011-10-01

    Due to national security concerns over the smuggling of special nuclear materials and the small supply of He-3 for use in neutron detectors, there is a great need for a new kind of neutron detector. Using Monte Carlo techniques I have been studying the use of lithium glass in varying configurations for neutron detectors. My research has included the effects of using a detector with two thin sheets of lithium at varying distances apart. I have also researched the effects of varying amounts of shielding a californium source with varying amounts of water. This is important since shielding would likely be used to make nuclear material more difficult to detect. The addition of one sheet of lithium-6 glass on the front surface of the detector significantly improves the efficiency for the detection of neutrons from a moderated fission source.

  20. Efficiency of TTAC's ORTEC IDM

    SciTech Connect

    Livesay, Jake; Combs, Jason C; Margrave, Timothy E; Miller, Ian J

    2012-08-01

    ORNL's Technical Testing and Analysis Center (TTAC) acquired a High Purity Germanium Detector (HPGe) from ORTEC - a variant called an Interchangeable Detection Module (IDM). This detector has excellent energy resolution as well as high intrinsic efficiency. The purpose of this report is to detail the determination of the efficiency curve of the IDM, so future measurements can quantify the (otherwise unknown) activity of sources. Without such a curve, the activity cannot be directly reported by use of the IDM alone - a separate device such as an ion chamber would be required. This builds upon the capability of TTAC. The method for determining the energy-dependent intrinsic efficiency is laid-out in this report. It's noteworthy that this basic technique can be applied to any spectroscopic radiation detector, independent of the specific type (e.g. NaI, CzT, ClYC).

  1. Quantum efficiency of a double quantum dot microwave photon detector

    NASA Astrophysics Data System (ADS)

    Wong, Clement; Vavilov, Maxim

    Motivated by recent interest in implementing circuit quantum electrodynamics with semiconducting quantum dots, we study charge transfer through a double quantum dot (DQD) capacitively coupled to a superconducting cavity subject to a microwave field. We analyze the DQD current response using input-output theory and determine the optimal parameter regime for complete absorption of radiation and efficient conversion of microwave photons to electric current. For experimentally available DQD systems, we show that the cavity-coupled DQD operates as a photon-to-charge converter with quantum efficiencies up to 80% C.W. acknowledges support by the Intelligence Community Postdoctoral Research Fellowship Program.

  2. Quantum efficiency performances of the NIR European Large Format Array detectors tested at ESTEC

    NASA Astrophysics Data System (ADS)

    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.

    2015-10-01

    Publisher's Note: This paper, originally published on 10/12/2015, was replaced with a corrected/revised version on 10/23/2015. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance. The Payload Technology Validation Section (SRE-FV) at ESTEC has the goal to validate new technology for future or on-going mission. In this framework, a test set up to characterize the quantum efficiency of near-infrared (NIR) detectors has been created. In the context of the NIR European Large Format Array ("LFA"), 3 deliverables detectors coming from SELEX-UK/ATC (UK) on one side, and CEA/LETI- CEA/IRFU-SOFRADIR (FR) on the other side were characterized. The quantum efficiency of an HAWAII-2RG detector from Teledyne was as well measured. The capability to compare on the same setup detectors from different manufacturers is a unique asset for the future mission preparation office. This publication will present the quantum efficiency results of a HAWAII-2RG detector from Teledyne with a 2.5um cut off compared to the LFA European detectors prototypes developed independently by SELEX-UK/ATC (UK) on one side, and CEA/LETI- CEA/IRFU-SOFRADIR (FR) on the other side.

  3. Characteristics of GRIFFIN high-purity germanium clover detectors

    NASA Astrophysics Data System (ADS)

    Rizwan, U.; Garnsworthy, A. B.; Andreoiu, C.; Ball, G. C.; Chester, A.; Domingo, T.; Dunlop, R.; Hackman, G.; Rand, E. T.; Smith, J. K.; Starosta, K.; Svensson, C. E.; Voss, P.; Williams, J.

    2016-06-01

    The Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei, GRIFFIN, is a new experimental facility for radioactive decay studies at the TRIUMF-ISAC laboratory. The performance of the 16 high-purity germanium (HPGe) clover detectors that will make up the GRIFFIN spectrometer is reported. The energy resolution, efficiency, timing resolution, crosstalk and preamplifier properties of each crystal were measured using a combination of analog and digital data acquisition techniques. The absolute efficiency and add-back factors are determined for the energy range of 80-3450 keV. The detectors show excellent performance with an average over all 64 crystals of a FWHM energy resolution of 1.89(6) keV and relative efficiency with respect to a 3 in . × 3 in . NaI detector of 41(1)% at 1.3 MeV.

  4. Bell inequalities violated using detectors of low efficiency

    NASA Astrophysics Data System (ADS)

    Pál, Károly F.; Vértesi, Tamás

    2015-11-01

    We define a family of binary-outcome n -party m ≤n settings per party Bell inequalities whose members require the least detection efficiency for their violation among all known inequalities of the same type. This gives upper bounds for the minimum value of the critical efficiency—below which no violation is possible—achievable for such inequalities. For m =2 , our family reduces to the one given by Larsson and Semitecolos in 2001 [Phys. Rev. A 63, 022117 (2001), 10.1103/PhysRevA.63.022117]. For m >2 , a gap remains between these bounds and the best lower bounds. The violating state near the threshold efficiency always approaches a product state of n qubits.

  5. Practical attacks on decoy-state quantum-key-distribution systems with detector efficiency mismatch

    NASA Astrophysics Data System (ADS)

    Fei, Yangyang; Gao, Ming; Wang, Weilong; Li, Chaobo; Ma, Zhi

    2015-05-01

    To the active-basis-choice decoy-state quantum-key-distribution systems with detector efficiency mismatch, we present a modified attack strategy, which is based on the faked states attack, with quantum nondemolition measurement ability to restress the threat of detector efficiency mismatch. Considering that perfect quantum nondemolition measurement ability doesn't exist in real life, we also propose a practical attack strategy using photon number resolving detectors. Theoretical analysis and numerical simulation results show that, without changing the channel, our attack strategies are serious threats to decoy-state quantum-key-distribution systems. The eavesdropper may get some information about the secret key without causing any alarms. Besides, the lower bound of detector efficiency mismatch to run our modified faked states attack successfully with perfect quantum nondemolition measurement ability is also given out, which provides the producers of quantum-key-distribution systems with a reference and can be treated as the approximate secure bound of detector efficiency mismatch in decoy-state quantum-key-distribution systems.

  6. Fabrication process development for high-purity germanium radiation detectors with amorphous semiconductor contacts

    NASA Astrophysics Data System (ADS)

    Looker, Quinn

    High-purity germanium (HPGe) radiation detectors are well established as a valuable tool in nuclear science, astrophysics, and nuclear security applications. HPGe detectors excel in gamma-ray spectroscopy, offering excellent energy resolution with large detector sizes for high radiation detection efficiency. Although a robust fabrication process has been developed, improvement is needed, especially in developing electrical contact and surface passivation technology for position-sensitive detectors. A systematic study is needed to understand how the detector fabrication process impacts detector performance and reliability. In order to provide position sensitivity, the electrical contacts are segmented to form multiple electrodes. This segmentation creates new challenges in the fabrication process and warrants consideration of additional detector effects related to the segmentation. A key area of development is the creation of the electrical contacts in a way that enables reliable operation, provides low electronic noise, and allows fine segmentation of electrodes, giving position sensitivity for radiation interactions in the detector. Amorphous semiconductor contacts have great potential to facilitate new HPGe detector designs by providing a thin, high-resistivity surface coating that is the basis for electrical contacts that block both electrons and holes and can easily be finely segmented. Additionally, amorphous semiconductor coatings form a suitable passivation layer to protect the HPGe crystal surface from contamination. This versatility allows a simple fabrication process for fully passivated, finely segmented detectors. However, the fabrication process for detectors with amorphous semiconductors is not as highly developed as for conventional technologies. The amorphous semiconductor layer properties can vary widely based on how they are created and these can translate into varying performance of HPGe detectors with these contacts. Some key challenges include

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

    SciTech Connect

    Rukhadze, Ekaterina [Institute of Experimental and Applied Physics, CTU in Prague, Horska 3a Collaboration: OBELIX Collaboration; SuperNEMO Collaboration

    2013-12-30

    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 2ν2β{sup −} decay of {sup 100}Mo to the 0{sup +} (1130 keV) and 2{sup +} (540 keV) excited states as well as future plans for OBELIX detector are given.

  8. Low-cost fabrication of high efficiency solid-state neutron detectors

    NASA Astrophysics Data System (ADS)

    Wu, Jia-Woei; Huang, Kuan-Chih; Weltz, Adam; English, Erik; Hella, Mona M.; Dahal, Rajendra; Lu, James J.-Q.; Danon, Yaron; Bhat, Ishwara B.

    2016-05-01

    The development of high-efficiency solid state thermal neutron detectors at low cost is critical for a wide range of civilian and defense applications. The use of present neutron detector system for personal radiation detection is limited by the cost, size, weight and power requirements. Chip scale solid state neutron detectors based on silicon technology would provide significant benefits in terms of cost, volume, and allow for wafer level integration with charge preamplifiers and readout electronics. In this paper, anisotropic wet etching of (110) silicon wafers was used to replace deep reactive ion etching (DRIE) to produce microstructured neutron detectors with lower cost and compatibility with mass production. Deep trenches were etched by 30 wt% KOH at 85°C with a highest etch ratio of (110) to (111). A trench-microstructure thermal neutron detector described by the aforementioned processes was fabricated and characterized. The detector—which has a continuous p+-n junction diode—was filled with enriched boron (99% of 10B) as a neutron converter material. The device showed a leakage current of ~ 6.7 × 10-6 A/cm2 at -1V and thermal neutron detection efficiency of ~16.3%. The detector uses custom built charge pre-amplifier, a shaping amplifier, and an analogto- digital converter (ADC) for data acquisition.

  9. Energy resolution and efficiency of phonon-mediated kinetic inductance detectors for light detection

    SciTech Connect

    Cardani, L.; Colantoni, I.; Coppolecchia, A.; Cruciani, A.; Vignati, M.; Bellini, F.; Casali, N.; Cosmelli, C.; Di Domizio, S.; Castellano, M. G.; Tomei, C.

    2015-08-31

    The development of sensitive cryogenic light detectors is of primary interest for bolometric experiments searching for rare events like dark matter interactions or neutrino-less double beta decay. Thanks to their good energy resolution and the natural multiplexed read-out, Kinetic Inductance Detectors (KIDs) are particularly suitable for this purpose. To efficiently couple KIDs-based light detectors to the large crystals used by the most advanced bolometric detectors, active surfaces of several cm{sup 2} are needed. For this reason, we are developing phonon-mediated detectors. In this paper, we present the results obtained with a prototype consisting of four 40 nm thick aluminum resonators patterned on a 2 × 2 cm{sup 2} silicon chip, and calibrated with optical pulses and X-rays. The detector features a noise resolution σ{sub E} = 154 ± 7 eV and an (18 ± 2)% efficiency.

  10. Investigation of the Charge Collection Efficiency of CdMnTe Radiation Detectors

    SciTech Connect

    Bolotnikov A.; Rafiei, R.; Boardman, D.; Sarbutt, A.; Prokopovich, A.; Kim, K.; Reinhard, M.I.; James, R.B.

    2012-06-01

    This paper presents the growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe) crystals grown by the vertical Bridgman technique. The 10 x 10 x 1.9 mm{sup 3} samples have been fabricated, and the charge collection properties of the CdMnTe detectors have been measured. Alpha-particle spectroscopy measurements have yielded an average charge collection efficiency approaching 100%. Ion beam induced charge (IBIC) measurements have been performed by raster scanning focused 5.5 MeV {sup 4}He beams onto the detectors. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of Te inclusions within the detector bulk, and the reduction in charge collection efficiency in their locality has been quantified. It has been shown that the role of Te inclusions in degrading charge collection is reduced with increasing values of bias voltage. IBIC measurements for a range of low biases have highlighted the evolution of the charge collection uniformity across the detectors.

  11. Thicker, more efficient superconducting strip-line detectors for high throughput macromolecules analysis

    SciTech Connect

    Casaburi, A.; Ejrnaes, M.; Cristiano, R.; Zen, N.; Ohkubo, M.; Pagano, S.

    2011-01-10

    Fast detectors with large area are required in time-of-flight mass spectrometers for high throughput analysis of biological molecules. We fabricated and characterized subnanosecond 1x1 mm{sup 2} NbN superconducting strip-line detectors. The influence of the strip-line thickness on the temporal characteristics and efficiency of the detector for the impacts of keV accelerated molecules is investigated. We find that the increase of thickness improves both efficiency and response time. In the thicker sample we achieved a rise time of 380 ps, a fall time of 1.38 ns, and a higher count rate. The physics involved in this behavior is investigated.

  12. Development of a low-mass and high-efficiency charged-particle detector

    NASA Astrophysics Data System (ADS)

    Naito, D.; Maeda, Y.; Kawasaki, N.; Masuda, T.; Nanjo, H.; Nomura, T.; Sasaki, M.; Sasao, N.; Seki, S.; Shiomi, K.; Tajima, Y.

    2016-02-01

    We have developed a low-mass and high-efficiency charged-particle detector for an experimental study of the rare decay K_L rArr π ^0 ν bar {ν }. The detector is important for suppressing the background with charged particles to the level below the signal branching ratio predicted by the Standard Model (O(10^{-11})). The detector consists of two layers of 3 mm thick plastic scintillators with embedded wavelength-shifting fibers and multi-pixel photon counters for the readout. We manufactured the counter and evaluated the performance in terms of light yield, timing resolution, and efficiency. With this design, we achieved an inefficiency per layer against penetrating charged particles of less than 1.5 × 10^{-5}, which satisfies the requirement of the KOTO experiment determined from simulation studies.

  13. A highly efficient neutron time-of-flight detector for inertial confinement fusion experiments

    NASA Astrophysics Data System (ADS)

    Izumi, N.; Yamaguchi, K.; Yamagajo, T.; Nakano, T.; Kasai, T.; Urano, T.; Azechi, H.; Nakai, S.; Iida, T.

    1999-01-01

    We have developed the highly efficient neutron detector system MANDALA for the inertial-confinement-fusion experiment. The MANDALA system consists of 842 elements plastic scintillation detectors and data acquisition electronics. The detection level is the yield of 1.2×105 for 2.5 MeV and 1×105 for 14.1 MeV neutrons (with 100 detected hits). We have calibrated the intrinsic detection efficiencies of the detector elements using a neutron generator facility. Timing calibration and integrity test of the system were also carried out with a 60Co γ ray source. MANDALA system was applied to the implosion experiments at the GEKKO XII laser facility. The integrity test was carried out by implosion experiments.

  14. Theoretical determination of the neuron detection efficiency of plastic track detectors. I. Theoretical model

    NASA Astrophysics Data System (ADS)

    Pretzsch, Gunter

    A theoretical model to determine the neutron detection efficiency of organic solid state nuclear track detectors without external radiator is described. The model involves the following calculation steps: production of heavy charged particles within the detector volume, characterization of the charged particles by appropriate physical quantities, application of suitable registration criteria, formation of etch pits. The etch pits formed are described by means of a distribution function which is doubly differential in both diameter and depth of the etch pits. The distribution function serves as the input value for the calculation of the detection efficiency. The detection efficiency is defined as the measured effect per neutron fluence. Hence it depends on the evaluation technique considered. The calculation of the distribution function is carried out for cellulose triacetate. The determination of the concrete detection efficiency using the light microscope and light transmission measurements as the evaluation technique will be described in further publications.

  15. Monte-Carlo calculations of Ge detector escape-peak efficiencies

    NASA Technical Reports Server (NTRS)

    Owens, Alan; Gehrels, Neil; Pascarelle, Sebastian M.; Teegarden, Bonnard J.

    1991-01-01

    The authors present calculated first and second escape peak efficiencies for a variety of n-type coaxial Ge detectors using the Monte Carlo method. The results are given for right-circular cylindrical geometries of size ranging from 3-cm diameter x 3-cm thick to 8-cm diameter x 8-cm thick. For completeness, the intrinsic interaction and photopeak efficiencies for energies ranging from 20 keV to 20 MeV are listed. The calculations have been tested against experimental measurement and found to be in agreement to within the quoted errors (typically 10 percent). It is found that the ratio of the second escape peak efficiency to the first escape peak efficiency, R, is approximately independent of energy for small detector volumes but has a weak power law energy dependence for large volumes. It is shown that R also varies as an inverse power law of the active volume.

  16. High quantum-efficiency photon-number-resolving detector for photonic on-chip information processing.

    PubMed

    Calkins, Brice; Mennea, Paolo L; Lita, Adriana E; Metcalf, Benjamin J; Kolthammer, W Steven; Lamas-Linares, Antia; Spring, Justin B; Humphreys, Peter C; Mirin, Richard P; Gates, James C; Smith, Peter G R; Walmsley, Ian A; Gerrits, Thomas; Nam, Sae Woo

    2013-09-23

    The integrated optical circuit is a promising architecture for the realization of complex quantum optical states and information networks. One element that is required for many of these applications is a high-efficiency photon detector capable of photon-number discrimination. We present an integrated photonic system in the telecom band at 1550 nm based on UV-written silica-on-silicon waveguides and modified transition-edge sensors capable of number resolution and over 40 % efficiency. Exploiting the mode transmission failure of these devices, we multiplex three detectors in series to demonstrate a combined 79 % ± 2 % detection efficiency with a single pass, and 88 % ± 3 % at the operating wavelength of an on-chip terminal reflection grating. Furthermore, our optical measurements clearly demonstrate no significant unexplained loss in this system due to scattering or reflections. This waveguide and detector design therefore allows the placement of number-resolving single-photon detectors of predictable efficiency at arbitrary locations within a photonic circuit - a capability that offers great potential for many quantum optical applications. PMID:24104153

  17. High-efficiency quantum-nondemolition single-photon-number-resolving detector

    SciTech Connect

    Munro, W.J.; Nemoto, Kae; Beausoleil, R.G.; Spiller, T.P.

    2005-03-01

    We discuss an approach to the problem of creating a photon-number-resolving detector using the giant Kerr nonlinearities available in electromagnetically induced transparency. Our scheme can implement a photon-number quantum-nondemolition measurement with high efficiency ({approx}99%) using fewer than 1600 atoms embedded in a dielectric waveguide.

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

    PubMed

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

    2014-07-01

    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

  19. Waveguide integrated superconducting single-photon detectors with high internal quantum efficiency at telecom wavelengths

    PubMed Central

    Kahl, Oliver; Ferrari, Simone; Kovalyuk, Vadim; Goltsman, Gregory N.; Korneev, Alexander; Pernice, Wolfram H. P.

    2015-01-01

    Superconducting nanowire single-photon detectors (SNSPDs) provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, compatibility with an integrated optical platform is a crucial requirement for applications in emerging quantum photonic technologies. Here we present SNSPDs embedded in nanophotonic integrated circuits which achieve internal quantum efficiencies close to unity at 1550 nm wavelength. This allows for the SNSPDs to be operated at bias currents far below the critical current where unwanted dark count events reach milli-Hz levels while on-chip detection efficiencies above 70% are maintained. The measured dark count rates correspond to noise-equivalent powers in the 10−19 W/Hz−1/2 range and the timing jitter is as low as 35 ps. Our detectors are fully scalable and interface directly with waveguide-based optical platforms. PMID:26061283

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

    SciTech Connect

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

    2015-03-02

    We experimentally investigate the effect of a magnetic field on photon detection in superconducting single-photon detectors (SSPDs). 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 interchangeable, 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 photon counts, and also shows that no enhancement of the intrinsic detection efficiency of a straight SSPD wire is achievable in a magnetic field.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    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 energy range. In this work we present and discuss spectra from a CdTe semiconductor detector covering the energy region from Cu (K α1 = 8.047 keV) to U (K α1 = 98.439 keV). Pure thick samples were irradiated with proton beams at the ITN 3.0 MV Tandetron accelerator in the High Resolution High Energy PIXE set-up. Results and the application to the study of a Portuguese Ossa Morena region Dark Stone sample are presented in this work.

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

    DOEpatents

    Rowland, Mark S.; Howard, Douglas E.; Wong, James L.; Jessup, James L.; Bianchini, Greg M.; Miller, Wayne O.

    2007-10-23

    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.

  3. Comparison of two HPGe counting system used in activation studies for nuclear astrophysics

    SciTech Connect

    Szücs, T.; Kiss, G. G.; Fülöp, Zs.

    2014-05-09

    The activation method is a widely used technique to measure charged-particle induced cross sections for astrophys-ical applications. This two step technique is used for example to measure alpha-induced cross sections in γ-process related studies. The first step – in which a target is irradiated with a proton/alpha beam – is followed by the determination of the produced activity. Especially in p-process related studies in the heavier mass range, the produced radioactive nuclei decays mainly with electron-capture, resulting intense x-rays. The activity of the reaction products hence can be determine via the counting of these x-rays, and not only by counting the usually much weaker γ-rays. In this paper we compare the minimum detectable activity (MDA) of two High Purity Germanium (HPGe) detectors used for x- and γ-ray counting in activation experiments.

  4. An efficient, movable single-particle detector for use in cryogenic ultra-high vacuum environments

    SciTech Connect

    Spruck, Kaija; Becker, Arno; Fellenberger, Florian; Grieser, Manfred; Hahn, Robert von; Klinkhamer, Vincent; Vogel, Stephen; Wolf, Andreas; Krantz, Claude; Novotný, Oldřich; Schippers, Stefan

    2015-02-15

    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 für Kernphysik (Max Planck Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics, can operate at ambient temperatures down to ∼10 K and consist fully of ultra-high vacuum compatible, high-temperature bakeable, and non-magnetic materials. The set-up is designed to meet the technical demands of MPIK’s Cryogenic Storage Ring. 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.

  5. An efficient, movable single-particle detector for use in cryogenic ultra-high vacuum environments.

    PubMed

    Spruck, Kaija; Becker, Arno; Fellenberger, Florian; Grieser, Manfred; von Hahn, Robert; Klinkhamer, Vincent; Novotný, Oldřich; Schippers, Stefan; Vogel, Stephen; Wolf, Andreas; Krantz, Claude

    2015-02-01

    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 für Kernphysik (Max Planck Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics, can operate at ambient temperatures down to ∼10 K and consist fully of ultra-high vacuum compatible, high-temperature bakeable, and non-magnetic materials. The set-up is designed to meet the technical demands of MPIK's Cryogenic Storage Ring. 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.

  6. Comparison of methods for assessing geometric efficiency on multi-detector CT scanners.

    PubMed

    Berris, Theocharis; Perisinakis, Kostas; Papadakis, Antonios E; Damilakis, John

    2013-05-01

    The aim of the current study was to compare the film method against the method based on a new CT slice detector in assessing geometric efficiency (GE) of x-ray beams utilized by a multi-detector CT (MDCT) scanner. Measurements of GE were performed using radiographic films and a solid state CT slice detector for all beam qualities, collimations and focal spot sizes available on an MDCT scanner. Repeatability of GE measurements was assessed. The radiographic film and the solid state detector methods were compared to each other in regard to efficacy in measuring free-in-air GE. The values of GE determined using the radiographic film method were found to range between 48.5% and 90.6%. Differences between values obtained with the radiographic film method and corresponding values obtained with the solid state detector were less than 10% exceeding 5% for only one case. Both methods show that wide beams have higher GE values compared to thin ones. The use of large instead of small focal spot was found to deteriorate GE values by up to 23.1%. Beam quality did not seem to influence GE of the various collimations. When thin beam collimations are employed, a considerable amount of the radiation is wasted for non-imaging purposes. Both film and solid state probe methods are capable of measuring GE of thin as well as wide collimations. The solid state detector is the easiest to use, however its usefulness is reduced by the fact that it cannot measure dose profiles of beam collimations available for step-and-shoot mode of operation.

  7. Note: Determining the detection efficiency of excited neutral atoms by a microchannel plate detector

    SciTech Connect

    Berry, Ben; Zohrabi, M.; Hayes, D.; Ablikim, U.; Jochim, Bethany; Severt, T.; Carnes, K. D.; Ben-Itzhak, I.

    2015-04-15

    We present a method for determining the detection efficiency of neutral atoms relative to keV ions. Excited D* atoms are produced by D{sub 2} fragmentation in a strong laser field. The fragments are detected by a micro-channel plate detector either directly as neutrals or as keV ions following field ionization and acceleration by a static electric field. Moreover, we propose a new mechanism by which neutrals are detected. We show that the ratio of the yield of neutrals and ions can be related to the relative detection efficiency of these species.

  8. Optical adapters to improve the collection efficiency of the Multi-Anode Photo-Multipliers detectors

    NASA Astrophysics Data System (ADS)

    Gambicorti, L.; Mazzinghi, P.; Pace, E.

    2006-11-01

    Aim of this work is to describe the optical system developed, with ray-tracing simulations, to improve the collection efficiency of Multi-Anode Photo-Multipliers (MAPMTs) detectors from Hamamatsu corp., used in nuclear, cosmic-rays and neutrino physics experiments. These optical collectors have imaging and filtering capability. Such characteristics allow to improve the collection efficiency of detectors, focusing all photons inside the sensitive area, and also to improve the signal-to-noise ratio by limiting the wave lengths band to the region of interest. These filtering properties allow to avoid background photons from nearby spectral regions and they are studied to minimize the wavelength shifting in comparison with the increasing of the incident angle. The spectrum of transmissivity have been realized with high transparency in wavelength range of interest and with a sharp cutoff outside. In this work, the application on different typologies of PMT have been studied. Particularly, the collection efficiency of the 64-channel PMT was improved from 45% to 75% using our optical adapters. On an electrostatic-focusing PMT, with an efficiency of 74%, the application of our innovative solutions have enhanced this efficiency exceeding 90%, including the band pass filter and keeping the mass below 25 g. First prototypes have been fabricated.

  9. Detective quantum efficiency of photon-counting x-ray detectors

    SciTech Connect

    Tanguay, Jesse; Yun, Seungman; Kim, Ho Kyung; Cunningham, Ian A.

    2015-01-15

    Purpose: Single-photon-counting (SPC) x-ray imaging has the potential to improve image quality and enable novel energy-dependent imaging methods. Similar to conventional detectors, optimizing image SPC quality will require systems that produce the highest possible detective quantum efficiency (DQE). This paper builds on the cascaded-systems analysis (CSA) framework to develop a comprehensive description of the DQE of SPC detectors that implement adaptive binning. Methods: The DQE of SPC systems can be described using the CSA approach by propagating the probability density function (PDF) of the number of image-forming quanta through simple quantum processes. New relationships are developed to describe PDF transfer through serial and parallel cascades to accommodate scatter reabsorption. Results are applied to hypothetical silicon and selenium-based flat-panel SPC detectors including the effects of reabsorption of characteristic/scatter photons from photoelectric and Compton interactions, stochastic conversion of x-ray energy to secondary quanta, depth-dependent charge collection, and electronic noise. Results are compared with a Monte Carlo study. Results: Depth-dependent collection efficiency can result in substantial broadening of photopeaks that in turn may result in reduced DQE at lower x-ray energies (20–45 keV). Double-counting interaction events caused by reabsorption of characteristic/scatter photons may result in falsely inflated image signal-to-noise ratio and potential overestimation of the DQE. Conclusions: The CSA approach is extended to describe signal and noise propagation through photoelectric and Compton interactions in SPC detectors, including the effects of escape and reabsorption of emission/scatter photons. High-performance SPC systems can be achieved but only for certain combinations of secondary conversion gain, depth-dependent collection efficiency, electronic noise, and reabsorption characteristics.

  10. Detective quantum efficiency: a standard test to ensure optimal detector performance and low patient exposures

    NASA Astrophysics Data System (ADS)

    Escartin, Terenz R.; Nano, Tomi F.; Cunningham, Ian A.

    2016-03-01

    The detective quantum efficiency (DQE), expressed as a function of spatial frequency, describes the ability of an x-ray detector to produce high signal-to-noise ratio (SNR) images. While regulatory and scientific communities have used the DQE as a primary metric for optimizing detector design, the DQE is rarely used by end users to ensure high system performance is maintained. Of concern is that image quality varies across different systems for the same exposures with no current measures available to describe system performance. Therefore, here we conducted an initial DQE measurement survey of clinical x-ray systems using a DQE-testing instrument to identify their range of performance. Following laboratory validation, experiments revealed that the DQE of five different systems under the same exposure level (8.0 μGy) ranged from 0.36 to 0.75 at low spatial frequencies, and 0.02 to 0.4 at high spatial frequencies (3.5 cycles/mm). Furthermore, the DQE dropped substantially with decreasing detector exposure by a factor of up to 1.5x in the lowest spatial frequency, and a factor of 10x at 3.5 cycles/mm due to the effect of detector readout noise. It is concluded that DQE specifications in purchasing decisions, combined with periodic DQE testing, are important factors to ensure patients receive the health benefits of high-quality images for low x-ray exposures.

  11. Simulations for Light Collection Efficiency (Jlab Hall C 12 GeV Kaon Aerogel Detector)

    NASA Astrophysics Data System (ADS)

    Rothgeb, Laura

    2011-10-01

    Studying the additional flavor degree of freedom in charged kaon production allows for an unexampled insight into the transition from hadronic to partonic degrees of freedom in exclusive processes and specifically the reaction mechanism underlying strangeness production. This unique opportunity has gone greatly unexplored, however, because of the challenges posed by the experimental factors. One of these challenges is determining a method of separation for kaons from pion and proton backgrounds at high momenta. The simplest and most cost-effective solution is the implementation of a kaon aerogel Cherenkov detector. At the Catholic University of America, we are building such a detector for use in the 12GeV Hall C Super High Momentum Spectrometer at Jefferson Lab. The detector will use photo multiplier tubes to collect the Cherenkov radiation given off by the aerogel and convert that signal into analyzable data that will be used to determine the form factor of the kaon, which will yield a greater understanding of the internal structure of the proton. In this presentation I will present the results from the simulations carried out to optimize the aerogel coverage and study the effect of light guides on the efficiency of the detector. Supported in part by NSF grants PHY 1019521 and 1039446.

  12. A Mechanically-Cooled, Highly-Portable, HPGe-Based, Coded-Aperture Gamma-Ray Imager

    SciTech Connect

    Ziock, Klaus-Peter; Boehnen, Chris Bensing; Hayward, Jason P; Raffo-Caiado, Ana Claudia

    2010-01-01

    Coded-aperture gamma-ray imaging is a mature technology that is capable of providing accurate and quantitative images of nuclear materials. Although it is potentially of high value to the safeguards and arms-control communities, it has yet to be fully embraced by those communities. One reason for this is the limited choice, high-cost, and low efficiency of commercial instruments; while instruments made by research organizations are frequently large and / or unsuitable for field work. In this paper we present the results of a project that mates the coded-aperture imaging approach with the latest in commercially-available, position-sensitive, High Purity Germanium (HPGe) detec-tors. The instrument replaces a laboratory prototype that, was unsuitable for other than demonstra-tions. The original instrument, and the cart on which it is mounted to provide mobility and pointing capabilities, has a footprint of ~ 2/3 m x 2 m, weighs ~ 100 Kg, and requires cryogen refills every few days. In contrast, the new instrument is tripod mounted, weighs of order 25 Kg, operates with a laptop computer, and is mechanically cooled. The instrument is being used in a program that is ex-ploring the use of combined radiation and laser scanner imaging. The former provides information on the presence, location, and type of nuclear materials while the latter provides design verification information. To align the gamma-ray images with the laser scanner data, the Ge imager is fitted and aligned to a visible-light stereo imaging unit. This unit generates a locus of 3D points that can be matched to the precise laser scanner data. With this approach, the two instruments can be used completely independently at a facility, and yet the data can be accurately overlaid based on the very structures that are being measured.

  13. Design of a polarization-insensitive superconducting nanowire single photon detector with high detection efficiency

    NASA Astrophysics Data System (ADS)

    Zheng, Fan; Xu, Ruiying; Zhu, Guanghao; Jin, Biaobing; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng

    2016-03-01

    Superconducting nanowire single photon detectors (SNSPDs) deliver superior performance over their competitors in the near-infrared regime. However, these detectors have an intrinsic polarization dependence on the incident wave because of their one-dimensional meander structure. In this paper, we propose an approach to eliminate the polarization sensitivity of SNSPDs by using near-field optics to increase the absorption of SNSPDs under transverse magnetic (TM) illumination. In addition, an optical cavity is added to our SNSPD to obtain nearly perfect absorption of the incident wave. Numerical simulations show that the maximum absorption of a designed SNSPD can reach 96% at 1550 nm, and indicate that the absorption difference between transverse electric (TE) and TM polarization is less than 0.5% across a wavelength window of 300 nm. Our work provides the first demonstration of the possibility of designing a polarization-insensitive and highly efficient SNSPD without performing device symmetry improvements.

  14. Adaptation of Crystal Ball and TAPS Detectors for Efficient Data Acquisition at MAMI

    NASA Astrophysics Data System (ADS)

    Asercion, Joseph

    2010-11-01

    To prepare the experimental apparatus at MAMI for the next set real photon experiments, the Crystal Ball and Two Armed Photon Spectrometer (TAPS) detector systems needed to be optimized for better performance. The Crystal Ball and TAPS particle detectors at MAMI employs object-oriented data acquisition architecture based on the C++ language as well as CERN's ROOT library. This system, utilized by the A2 collaboration at the institute, has been adequate for past experiments; however, it has recently proven to be more and more unstable. To alleviate this problem, the data acquisition software was rewritten as a more cohesive architecture, allowing for greater flexibility in experimental parameters and a decrease in instability. In addition to restructuring the software system, new Gas Electron Multipliers (GEMs) were investigated for use with the Crystal Ball as signal amplification devices using generated voltage signals to test feedback efficiency. These modifications are necessary to provide improved signal detection and data acquisition in future experiments.

  15. Design of a polarization-insensitive superconducting nanowire single photon detector with high detection efficiency.

    PubMed

    Zheng, Fan; Xu, Ruiying; Zhu, Guanghao; Jin, Biaobing; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng

    2016-01-01

    Superconducting nanowire single photon detectors (SNSPDs) deliver superior performance over their competitors in the near-infrared regime. However, these detectors have an intrinsic polarization dependence on the incident wave because of their one-dimensional meander structure. In this paper, we propose an approach to eliminate the polarization sensitivity of SNSPDs by using near-field optics to increase the absorption of SNSPDs under transverse magnetic (TM) illumination. In addition, an optical cavity is added to our SNSPD to obtain nearly perfect absorption of the incident wave. Numerical simulations show that the maximum absorption of a designed SNSPD can reach 96% at 1550 nm, and indicate that the absorption difference between transverse electric (TE) and TM polarization is less than 0.5% across a wavelength window of 300 nm. Our work provides the first demonstration of the possibility of designing a polarization-insensitive and highly efficient SNSPD without performing device symmetry improvements. PMID:26948672

  16. Testing Random-Detector-Efficiency Countermeasure in a Commercial System Reveals a Breakable Unrealistic Assumption

    NASA Astrophysics Data System (ADS)

    Huang, Anqi; Sajeed, Shihan; Chaiwongkhot, Poompong; Soucarros, Mathilde; Legre, Matthieu; Makarov, Vadim

    2016-11-01

    In the last decade, efforts have been made to reconcile theoretical security with realistic imperfect implementations of quantum key distribution (QKD). Implementable countermeasures are proposed to patch the discovered loopholes. However, certain countermeasures are not as robust as would be expected. In this paper, we present a concrete example of ID Quantique's random-detector-efficiency countermeasure against detector blinding attacks. As a third-party tester, we have found that the first industrial implementation of this countermeasure is effective against the original blinding attack, but not immune to a modified blinding attack. Then, we implement and test a later full version of this countermeasure containing a security proof [C. C. W. Lim et al., IEEE Journal of Selected Topics in Quantum Electronics, 21, 6601305 (2015)]. We find that it is still vulnerable against the modified blinding attack, because an assumption about hardware characteristics on which the proof relies fails in practice.

  17. Design of a polarization-insensitive superconducting nanowire single photon detector with high detection efficiency

    PubMed Central

    Zheng, Fan; Xu, Ruiying; Zhu, Guanghao; Jin, Biaobing; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng

    2016-01-01

    Superconducting nanowire single photon detectors (SNSPDs) deliver superior performance over their competitors in the near-infrared regime. However, these detectors have an intrinsic polarization dependence on the incident wave because of their one-dimensional meander structure. In this paper, we propose an approach to eliminate the polarization sensitivity of SNSPDs by using near-field optics to increase the absorption of SNSPDs under transverse magnetic (TM) illumination. In addition, an optical cavity is added to our SNSPD to obtain nearly perfect absorption of the incident wave. Numerical simulations show that the maximum absorption of a designed SNSPD can reach 96% at 1550 nm, and indicate that the absorption difference between transverse electric (TE) and TM polarization is less than 0.5% across a wavelength window of 300 nm. Our work provides the first demonstration of the possibility of designing a polarization-insensitive and highly efficient SNSPD without performing device symmetry improvements. PMID:26948672

  18. Monte Carlo simulation of gamma-ray interactions in an over-square high-purity germanium detector for in-vivo measurements

    NASA Astrophysics Data System (ADS)

    Saizu, Mirela Angela

    2016-09-01

    The developments of high-purity germanium detectors match very well the requirements of the in-vivo human body measurements regarding the gamma energy ranges of the radionuclides intended to be measured, the shape of the extended radioactive sources, and the measurement geometries. The Whole Body Counter (WBC) from IFIN-HH is based on an “over-square” high-purity germanium detector (HPGe) to perform accurate measurements of the incorporated radionuclides emitting X and gamma rays in the energy range of 10 keV-1500 keV, under conditions of good shielding, suitable collimation, and calibration. As an alternative to the experimental efficiency calibration method consisting of using reference calibration sources with gamma energy lines that cover all the considered energy range, it is proposed to use the Monte Carlo method for the efficiency calibration of the WBC using the radiation transport code MCNP5. The HPGe detector was modelled and the gamma energy lines of 241Am, 57Co, 133Ba, 137Cs, 60Co, and 152Eu were simulated in order to obtain the virtual efficiency calibration curve of the WBC. The Monte Carlo method was validated by comparing the simulated results with the experimental measurements using point-like sources. For their optimum matching, the impact of the variation of the front dead layer thickness and of the detector photon absorbing layers materials on the HPGe detector efficiency was studied, and the detector’s model was refined. In order to perform the WBC efficiency calibration for realistic people monitoring, more numerical calculations were generated simulating extended sources of specific shape according to the standard man characteristics.

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

    PubMed Central

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

    2012-01-01

    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

  20. Estimation of extrinsic detection efficiency using intrinsic detection sensitivity of the commercial single photon detector

    NASA Astrophysics Data System (ADS)

    Hammura, Kiyotaka; Xu, Xiulai; Brossard, Frederic; Williams, David

    2009-03-01

    The detection efficiency (DE) of the commercial single-photon-receiver based on InGaAs gate-mode avalanche photodiode is estimated using the detection sensitivity (DS). 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.

  1. Potential of combining iterative reconstruction with noise efficient detector design: aggressive dose reduction in head CT

    PubMed Central

    Bender, B; Schabel, C; Fenchel, M; Ernemann, U; Korn, A

    2015-01-01

    Objective: With further increase of CT numbers and their dominant contribution to medical exposure, there is a recent quest for more effective dose control. While reintroduction of iterative reconstruction (IR) has proved its potential in many applications, a novel focus is placed on more noise efficient detectors. Our purpose was to assess the potential of IR in combination with an integrated circuit detector (ICD) for aggressive dose reduction in head CT. Methods: Non-contrast low-dose head CT [190 mAs; weighted volume CT dose index (CTDIvol), 33.2 mGy] was performed in 50 consecutive patients, using a new noise efficient detector and IR. Images were assessed in terms of quantitative and qualitative image quality and compared with standard dose acquisitions (320 mAs; CTDIvol, 59.7 mGy) using a conventional detector and filtered back projection. Results: By combining ICD and IR in low-dose examinations, the signal to noise was improved by about 13% above the baseline level in the standard-dose control group. Both, contrast-to-noise ratio (2.02 ± 0.6 vs 1.88 ± 0.4; p = 0.18) and objective measurements of image sharpness (695 ± 84 vs 705 ± 151 change in Hounsfield units per pixel; p = 0.79) were fully preserved in the low-dose group. Likewise, there was no significant difference in the grading of several subjective image quality parameters when both noise-reducing strategies were used in low-dose examinations. Conclusion: Combination of noise efficient detector with IR allows for meaningful dose reduction in head CT without compromise of standard image quality. Advances in knowledge: Our study demonstrates the feasibility of almost 50% dose reduction in head CT dose (1.1 mSv per scan) through combination of novel dose-reducing strategies. PMID:25827204

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

    PubMed

    Broda, R; Jeczmieniowski, A

    2004-01-01

    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.

  3. Low energy response of the NICER detectors and "threshold efficiency" effect

    NASA Astrophysics Data System (ADS)

    Prigozhin, Gregory; Doty, John; LaMarr, Beverly; Malonis, Andrew; Remillard, Ronald A.; Scholze, Frank; Laubis, Christian; Krumrey, Michael

    2016-04-01

    The Neutron Star Interior Composition ExploreR (NICER) is an instrument that is planned to be installed on the International Space Station in 2016 to study time-resolved spectra of the rapidly changing celestial ojects. The focal plane of the instrument consists of 56 Silicon Drift Detectors (SDDs). Signal from each SDD is fed to shaping amplifiers and triggering circuits that determine both amplitude and time of arrival for each "event".Zero crossing timing circuit is used in order to suppress energy dependent "time walk". That is done with a chain producing a derivative of the shaped signal, and the same chain detects threshold crossings marking the arrival of an X-ray photon. Higher noise of the differentiated signal leads to a somewhat extended band of signal amplitudes close to the threshold value, for which detection efficiency is less than 100%. Detection efficiency in this area affects the low energy portion of the detector response, and is very well described by an error function. We will present accurate measurements of this effect, show the consequences for the instrument quantum efficiency and the shape of the response function and will describe the calibration procedures that would allow selection of optimal threshold values for each observation.

  4. Pixelated detectors and improved efficiency for magnetic imaging in STEM differential phase contrast.

    PubMed

    Krajnak, Matus; McGrouther, Damien; Maneuski, Dzmitry; Shea, Val O'; McVitie, Stephen

    2016-06-01

    The application of differential phase contrast imaging to the study of polycrystalline magnetic thin films and nanostructures has been hampered by the strong diffraction contrast resulting from the granular structure of the materials. In this paper we demonstrate how a pixelated detector has been used to detect the bright field disk in aberration corrected scanning transmission electron microscopy (STEM) and subsequent processing of the acquired data allows efficient enhancement of the magnetic contrast in the resulting images. Initial results from a charged coupled device (CCD) camera demonstrate the highly efficient nature of this improvement over previous methods. Further hardware development with the use of a direct radiation detector, the Medipix3, also shows the possibilities where the reduction in collection time is more than an order of magnitude compared to the CCD. We show that this allows subpixel measurement of the beam deflection due to the magnetic induction. While the detection and processing is data intensive we have demonstrated highly efficient DPC imaging whereby pixel by pixel interpretation of the induction variation is realised with great potential for nanomagnetic imaging. PMID:27085170

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

    SciTech Connect

    Dickens, J.K.

    1991-01-01

    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.

  6. GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra

    SciTech Connect

    Winn, W.G.

    1999-07-28

    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.

  7. Ultra-low noise mechanically cooled germanium detector

    NASA Astrophysics Data System (ADS)

    Barton, P.; Amman, M.; Martin, R.; Vetter, K.

    2016-03-01

    Low capacitance, large volume, high purity germanium (HPGe) radiation detectors have been successfully employed in low-background physics experiments. However, some physical processes may not be detectable with existing detectors whose energy thresholds are limited by electronic noise. In this paper, methods are presented which can lower the electronic noise of these detectors. Through ultra-low vibration mechanical cooling and wire bonding of a CMOS charge sensitive preamplifier to a sub-pF p-type point contact HPGe detector, we demonstrate electronic noise levels below 40 eV-FWHM.

  8. Minimum length Pb/SCIN detector for efficient cosmic ray identification

    NASA Technical Reports Server (NTRS)

    Snyder, H. David

    1989-01-01

    A study was made of the performance of a minimal length cosmic ray shower detector that would be light enough for space flight and would provide efficient identification of positions and protons. Cosmic ray positions are mainly produced in the decay chain of: Pion yields Muon yields Positron and they provide a measure of the matter density traversed by primary protons. Present positron flux measurements are consistent with the Leaky Box and Halo models for sources of cosmic rays. Abundant protons in the space environment are a significant source of background that would wash out the positron signal. Protons and positrons produced very distictive showers of particles when they enter matter; many studies have been published on their behavior on large calorimeter detectors. The challenge is to determine the minimal material necessary (minimal calorimeter depth) for positive particles identification. The primary instrument for the investigation is the Monte Carlo code GEANT, a library of programs from CERN that can be used to model experimental geometry, detector responses and particle interaction processes. The use of the Monte Carlo approach is crucial since statistical fluctuations in shower shape are significant. Studies conducted during the 1988 summer program showed that straightforward approaches to the problem achieved 85 to 90 percent correct identification, but left a residue of 10 to 15 percent misidentified particles. This percentage improved to a few percent when multiple shower-cut criteria were applied to the data. This summer, the same study was extended to employ several physical and statistical methods of identifying response of the calorimeter and the efficiency of the optimal shower cuts to off-normal incidence particle was determined.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    SciTech Connect

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

    2008-06-24

    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.

  11. Maximizing the quantum efficiency of microchannel plate detectors - The collection of photoelectrons from the interchannel web using an electric field

    NASA Technical Reports Server (NTRS)

    Taylor, R. C.; Hettrick, M. C.; Malina, R. F.

    1983-01-01

    High quantum efficiency and two-dimensional imaging capabilities make the microchannel plate (MCP) a suitable detector for a sky survey instrument. The Extreme Ultraviolet Explorer satellite, to be launched in 1987, will use MCP detectors. A feature which limits MCP efficiency is related to the walls of individual channels. The walls are of finite thickness and thus form an interchannel web. Under normal circumstances, this web does not contribute to the detector's quantum efficiency. Panitz and Foesch (1976) have found that in the case of a bombardment with ions, electrons were ejected from the electrode material coating the web. By applying a small electric field, the electrons were returned to the MCP surface where they were detected. The present investigation is concerned with the enhancement of quantum efficiencies in the case of extreme UV wavelengths. Attention is given to a model and a computer simulation which quantitatively reproduce the experimental results.

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

    SciTech Connect

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

    2013-12-02

    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 β-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 sp{sup 3}-carbon layer around the graphitic electrodes, evidenced by micro-Raman imaging, by means of a numerical model of the charge transport near the electrodes.

  13. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry

    NASA Astrophysics Data System (ADS)

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R.; Chess, Jordan; McMorran, Benjamin J.; Czarnik, Cory; Rose, Harald H.; Ercius, Peter

    2016-02-01

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.

  14. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry.

    PubMed

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R; Chess, Jordan; McMorran, Benjamin J; Czarnik, Cory; Rose, Harald H; Ercius, Peter

    2016-01-01

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals. PMID:26923483

  15. 4D STEM: High efficiency phase contrast imaging using a fast pixelated detector

    NASA Astrophysics Data System (ADS)

    Yang, H.; Jones, L.; Ryll, H.; Simson, M.; Soltau, H.; Kondo, Y.; Sagawa, R.; Banba, H.; MacLaren, I.; Nellist, P. D.

    2015-10-01

    Phase contrast imaging is widely used for imaging beam sensitive and weak phase objects in electron microscopy. In this work we demonstrate the achievement of high efficient phase contrast imaging in STEM using the pnCCD, a fast direct electron pixelated detector, which records the diffraction patterns at every probe position with a speed of 1000 to 4000 frames per second, forming a 4D STEM dataset simultaneously with the incoherent Z-contrast imaging. Ptychographic phase reconstruction has been applied and the obtained complex transmission function reveals the phase of the specimen. The results using GaN and Ti, Nd- doped BiFeO3 show that this imaging mode is especially powerful for imaging light elements in the presence of much heavier elements.

  16. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry

    PubMed Central

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R.; Chess, Jordan; McMorran, Benjamin J.; Czarnik, Cory; Rose, Harald H.; Ercius, Peter

    2016-01-01

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals. PMID:26923483

  17. High efficiency photon counting detectors for the FAUST Spacelab far ultraviolet astronomy payload

    NASA Technical Reports Server (NTRS)

    Siegmund, O. H. W.; Lampton, M.; Bixler, J.; Vallerga, J.; Bowyer, S.

    1987-01-01

    The performances of sealed tube microchannel-plate position sensitive detectors having transmission CsI photocathodes or opaque CsI photocathodes are compared. These devices were developed for the FAUST Spacelab payload to accomplish imaging surveys in the band between 1300 A and 1800 A. It is demonstrated that photocathode quantum efficiencies in excess of 40 percent at 1216 A have been achieved with the transmission and the opaque CsI photocathodes. The effect of the photoelectron trajectory on the spatial resolution is assessed. Spatial resolution of less than 70 microns FWHM has been obtained and is maintained up to event rates of 50,000/sec. Background rates of 0.55 events sq cm per sec have been achieved and low distortion (less than 1 percent) imaging has been demonstrated.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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 β-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.

  19. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry.

    PubMed

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R; Chess, Jordan; McMorran, Benjamin J; Czarnik, Cory; Rose, Harald H; Ercius, Peter

    2016-02-29

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.

  20. Efficiency calibration and minimum detectable activity concentration of a real-time UAV airborne sensor system with two gamma spectrometers.

    PubMed

    Tang, Xiao-Bin; Meng, Jia; Wang, Peng; Cao, Ye; Huang, Xi; Wen, Liang-Sheng; Chen, Da

    2016-04-01

    A small-sized UAV (NH-UAV) airborne system with two gamma spectrometers (LaBr3 detector and HPGe detector) was developed to monitor activity concentration in serious nuclear accidents, such as the Fukushima nuclear accident. The efficiency calibration and determination of minimum detectable activity concentration (MDAC) of the specific system were studied by MC simulations at different flight altitudes, different horizontal distances from the detection position to the source term center and different source term sizes. Both air and ground radiation were considered in the models. The results obtained may provide instructive suggestions for in-situ radioactivity measurements of NH-UAV.

  1. Efficiency calibration and minimum detectable activity concentration of a real-time UAV airborne sensor system with two gamma spectrometers.

    PubMed

    Tang, Xiao-Bin; Meng, Jia; Wang, Peng; Cao, Ye; Huang, Xi; Wen, Liang-Sheng; Chen, Da

    2016-04-01

    A small-sized UAV (NH-UAV) airborne system with two gamma spectrometers (LaBr3 detector and HPGe detector) was developed to monitor activity concentration in serious nuclear accidents, such as the Fukushima nuclear accident. The efficiency calibration and determination of minimum detectable activity concentration (MDAC) of the specific system were studied by MC simulations at different flight altitudes, different horizontal distances from the detection position to the source term center and different source term sizes. Both air and ground radiation were considered in the models. The results obtained may provide instructive suggestions for in-situ radioactivity measurements of NH-UAV. PMID:26773821

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

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    SciTech Connect

    CUI,Y.

    2007-05-01

    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.

  4. Large-sensitive-area superconducting nanowire single-photon detector at 850 nm with high detection efficiency.

    PubMed

    Li, Hao; Zhang, Lu; You, Lixing; Yang, Xiaoyan; Zhang, Weijun; Liu, Xiaoyu; Chen, Sijing; Wang, Zhen; Xie, Xiaoming

    2015-06-29

    Satellite-ground quantum communication requires single-photon detectors of 850-nm wavelength with both high detection efficiency and large sensitive area. We developed superconducting nanowire single-photon detectors (SNSPDs) on one-dimensional photonic crystals, which acted as optical cavities to enhance the optical absorption, with a sensitive-area diameter of 50 μm. The fabricated multimode fiber coupled NbN SNSPDs exhibited a maximum system detection efficiency (DE) of up to 82% and a DE of 78% at a dark count rate of 100 Hz at 850-nm wavelength as well as a system jitter of 105 ps. PMID:26191739

  5. Quantum efficiency measurement of the Transiting Exoplanet Survey Satellite (TESS) CCD detectors

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, A.; Villasenor, J.; Thayer, C.; Kissel, S.; Ricker, G.; Seager, S.; Lyle, R.; Deline, A.; Morgan, E.; Sauerwein, T.; Vanderspek, R.

    2016-07-01

    Very precise on-ground characterization and calibration of TESS CCD detectors will significantly assist in the analysis of the science data from the mission. An accurate optical test bench with very high photometric stability has been developed to perform precise measurements of the absolute quantum efficiency. The setup consists of a vacuum dewar with a single MIT Lincoln Lab CCID-80 device mounted on a cold plate with the calibrated reference photodiode mounted next to the CCD. A very stable laser-driven light source is integrated with a closed-loop intensity stabilization unit to control variations of the light source down to a few parts-per-million when averaged over 60 s. Light from the stabilization unit enters a 20 inch integrating sphere. The output light from the sphere produces near-uniform illumination on the cold CCD and on the calibrated reference photodiode inside the dewar. The ratio of the CCD and photodiode signals provides the absolute quantum efficiency measurement. The design, key features, error analysis, and results from the test campaign are presented.

  6. Charged Particle Induced Radiation damage of Germanium Detectors in Space: Two Mars Observer Gamma-Ray Detectors

    NASA Technical Reports Server (NTRS)

    Bruekner, J.; Koenen, M.; Evans, L. G.; Starr, R.; Bailey, S. H.; Boynton W. V.

    1997-01-01

    The Mars Observer Gamma-Ray Spectrometer (MO GRS) was designed to measure gamma-rays emitted by the Martian surface. This gamma-ray emission is induced by energetic cosmic-ray particles penetrating the Martian surface and producing many secondary particles and gamma rays. The MO GRS consisted of an high-purity germanium (HPGe) detector with a passive cooler. Since radiation damage due to permanent bombardment of energetic cosmic ray particles (with energies up to several GeV) was expected for the MO GRS HPGe crystal, studies on radiation damage effects of HPGe crystals were carried on earth. One of the HPGe crystals (paradoxically called FLIGHT) was similar to the MO GRS crystal. Both detectors, MO GRS and FLIGHT, contained closed-end coaxial n-type HPGe crystals and had the same geometrical dimensions (5.6 x 5.6 cm). Many other parameters, such as HV and operation temperature, differed in space and on earth, which made it somewhat difficult to directly compare the performance of both detector systems. But among other detectors, detector FLIGHT provided many useful data to better understand radiation damage effects.

  7. (HP)Ge Measurement of spectra for diagnostic X-ray beams.

    PubMed

    Nogueira, M S; Mota, H C; Campos, L L

    2004-01-01

    The X-ray spectra applied in diagnostic radiology to the energy range between 50 and 125 kVp, were experimentally determined using a high-purity germanium detector, (HP)Ge, coupled to a multichannel analyser. A simple stripping procedure was implemented, according to that described by Seelentag and Panzer, to correct the pulse height distribution and then to determine the photon spectra. The measurements were performed for those conditions where the X-ray beam is transmitted through Pb filters 0.2-0.7 mm thick. It was necessary to estimate the effective dose in the same way that it is done for radiology diagnosis room shielding projects. The spectra were also determined to the X-ray qualities recommended by the IEC for primary diagnostic X-ray and for X-ray beams attenuated by aluminium filters 2.5-42.5 mm thick. The spectra obtained were compared with data derived from the literature presenting good agreement. PMID:15367779

  8. Hand-Held Gamma-Ray Spectrometer Based on High-Efficiency Frisch-Ring Cdznte Detectors

    SciTech Connect

    Cui, Y.; Bolotnikov, A; Camarda, G; Hossain, A; James, R; DeGeronimo, G; Fried, J; O'Connor, P; Kargar, A; et. al.

    2008-01-01

    Frisch-ring CdZnTe detectors have demonstrated both good energy resolution, <1% FWHM at 662 keV, and good efficiency in detecting gamma rays, highlighting the strong potential of CdZnTe materials for such applications. We are designing a hand-held gamma-ray spectrometer based on Frisch-ring detectors at Brookhaven National Laboratory. It employs an 8 times 8 CdZnTe detector array to achieve a high volume of 19.2 cm3, so greatly improving detection efficiency. By using the front-end application-specific integrated circuits (ASICs) developed at BNL, this spectrometer has a small profile and high energy-resolution. It includes a signal processing circuit, digitization and storage circuits, a high-voltage module, and a universal serial bus (USB) interface. In this paper, we detail the system's structure and report the results of our tests with it.

  9. HST/WFC3 UVIS Detector: Dark, Charge Transfer Efficiency, and Point Spread Function Calibrations

    NASA Astrophysics Data System (ADS)

    Bourque, Matthew; Anderson, Jay; Baggett, Sylvia; Bowers, Ariel; MacKenty, John W.; Sahu, Kailash C.

    2015-08-01

    Wide Field Camera 3 (WFC3) is a fourth-generation imaging instrument on board the Hubble Space Telescope (HST) that was installed during Servicing Mission 4 in May 2009. As one of two channels available on WFC3, the UVIS detector is comprised of two e2v CCDs and is sensitive to ultraviolet and visible light. Here we provide updates to the characterization and monitoring of the UVIS performance and stability. We present the long-term growth of the dark current and the hot pixel population, as well as the evolution of Charge Transfer Efficiency (CTE). We also discuss updates to the UVIS dark calibration products, which are used to correct for dark current in science images. We examine the impacts of CTE losses and outline some techniques to mitigate CTE effects during and after observation by use of post-flash and pixel-based CTE corrections. Finally, we summarize an investigation of WFC3/UVIS Point Spread Functions (PSFs) and their potential use for characterizing the focus of the instrument.

  10. Intrinsic detection efficiency of superconducting nanowire single photon detector in the modified hot spot model

    NASA Astrophysics Data System (ADS)

    Zotova, A. N.; Vodolazov, D. Yu

    2014-12-01

    We theoretically study the dependence of the intrinsic detection efficiency (IDE) of a superconducting nanowire single photon detector on the applied current, I, and magnetic field, H. We find that the current, at which the resistive state appears in the superconducting film, depends on the position of the hot spot (a region with suppressed superconductivity around the place where the photon has been absorbed) with respect to the edges of the film. This circumstance leads to inevitable smooth dependence IDE(I) when IDE ˜ 0.05-1, even for a homogenous straight superconducting film and in the absence of fluctuations. For IDE ≲ 0.05, a much sharper current dependence comes from the fluctuation-assisted vortex entry to the hot spot, which is located near the edge of the film. We find that a weak magnetic field strongly affects IDE when the photon detection is connected with fluctuation-assisted vortex entry to the hot spot (IDE \\ll 1), and it weakly affects IDE when the photon detection is connected with the current-induced vortex nucleation in the film with the hot spot (IDE ˜ 0.05-1).

  11. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry

    DOE PAGES

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R.; Chess, Jordan; McMorran, Benjamin J.; Czarnik, Cory; Rose, Harald H.; Ercius, Peter

    2016-02-29

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, makingmore » it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Ultimately, simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.« less

  12. Efficient phase contrast imaging in STEM using a pixelated detector. Part 1: experimental demonstration at atomic resolution.

    PubMed

    Pennycook, Timothy J; Lupini, Andrew R; Yang, Hao; Murfitt, Matthew F; Jones, Lewys; Nellist, Peter D

    2015-04-01

    We demonstrate a method to achieve high efficiency phase contrast imaging in aberration corrected scanning transmission electron microscopy (STEM) with a pixelated detector. The pixelated detector is used to record the Ronchigram as a function of probe position which is then analyzed with ptychography. Ptychography has previously been used to provide super-resolution beyond the diffraction limit of the optics, alongside numerically correcting for spherical aberration. Here we rely on a hardware aberration corrector to eliminate aberrations, but use the pixelated detector data set to utilize the largest possible volume of Fourier space to create high efficiency phase contrast images. The use of ptychography to diagnose the effects of chromatic aberration is also demonstrated. Finally, the four dimensional dataset is used to compare different bright field detector configurations from the same scan for a sample of bilayer graphene. Our method of high efficiency ptychography produces the clearest images, while annular bright field produces almost no contrast for an in-focus aberration-corrected probe.

  13. Efficient phase contrast imaging in STEM using a pixelated detector. Part 1: Experimental demonstration at atomic resolution

    DOE PAGES

    Pennycook, Timothy J.; Lupini, Andrew R.; Yang, Hao; Murfitt, Matthew F.; Jones, Lewys; Nellist, Peter D.

    2014-10-15

    In this paper, we demonstrate a method to achieve high efficiency phase contrast imaging in aberration corrected scanning transmission electron microscopy (STEM) with a pixelated detector. The pixelated detector is used to record the Ronchigram as a function of probe position which is then analyzed with ptychography. Ptychography has previously been used to provide super-resolution beyond the diffraction limit of the optics, alongside numerically correcting for spherical aberration. Here we rely on a hardware aberration corrector to eliminate aberrations, but use the pixelated detector data set to utilize the largest possible volume of Fourier space to create high efficiency phasemore » contrast images. The use of ptychography to diagnose the effects of chromatic aberration is also demonstrated. In conclusion, the four dimensional dataset is used to compare different bright field detector configurations from the same scan for a sample of bilayer graphene. Our method of high efficiency ptychography produces the clearest images, while annular bright field produces almost no contrast for an in-focus aberration-corrected probe.« less

  14. Efficient phase contrast imaging in STEM using a pixelated detector. Part 1: Experimental demonstration at atomic resolution

    SciTech Connect

    Pennycook, Timothy J.; Lupini, Andrew R.; Yang, Hao; Murfitt, Matthew F.; Jones, Lewys; Nellist, Peter D.

    2014-10-15

    In this paper, we demonstrate a method to achieve high efficiency phase contrast imaging in aberration corrected scanning transmission electron microscopy (STEM) with a pixelated detector. The pixelated detector is used to record the Ronchigram as a function of probe position which is then analyzed with ptychography. Ptychography has previously been used to provide super-resolution beyond the diffraction limit of the optics, alongside numerically correcting for spherical aberration. Here we rely on a hardware aberration corrector to eliminate aberrations, but use the pixelated detector data set to utilize the largest possible volume of Fourier space to create high efficiency phase contrast images. The use of ptychography to diagnose the effects of chromatic aberration is also demonstrated. In conclusion, the four dimensional dataset is used to compare different bright field detector configurations from the same scan for a sample of bilayer graphene. Our method of high efficiency ptychography produces the clearest images, while annular bright field produces almost no contrast for an in-focus aberration-corrected probe.

  15. Development of a new method for measurement of neutron detector efficiency up to 20 MeV

    SciTech Connect

    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.

    2014-09-03

    A new approach to neutron detector efficiency 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 based on the 252Cf results. The 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. Furthermore, 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.

  16. Development of a new method for measurement of neutron detector efficiency up to 20 MeV

    DOE PAGES

    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.

    2014-09-03

    A new approach to neutron detector efficiency 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 based on the 252Cf results. The 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. Furthermore, the laboratory energies for the neutrons at the paired energies differmore » 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.« less

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

    NASA Astrophysics Data System (ADS)

    Gopal, Arun

    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

  18. Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources.

    PubMed

    Yalcin, S; Gurler, O; Kaynak, G; Gundogdu, O

    2007-10-01

    This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature.

  19. Calculation of the absolute detection efficiency of a moderated /sup 235/U neutron detector on the Tokamak Fusion Test Reactor

    SciTech Connect

    Ku, L.P.; Hendel, H.W.; Liew, S.L.

    1989-02-01

    Neutron transport simulations have been carried out to calculate the absolute detection efficiency of a moderated /sup 235/U neutron detector which is used on the TFTR as a part of the primary fission detector diagnostic system for measuring fusion power yields. Transport simulations provide a means by which the effects of variations in various shielding and geometrical parameters can be explored. These effects are difficult to study in calibration experiments. The calculational model, benchmarked against measurements, can be used to complement future detector calibrations, when the high level of radioactivity resulting from machine operation may severely restrict access to the tokamak. We present a coupled forward-adjoint algorithm, employing both the deterministic and Monte Carlo sampling methods, to model the neutron transport in the complex tokamak and detector geometries. Sensitivities of the detector response to the major and minor radii, and angular anisotropy of the neutron emission are discussed. A semi-empirical model based on matching the calculational results with a small set of experiments produces good agreement (+-15%) for a wide range of source energies and geometries. 20 refs., 6 figs., 4 tabs.

  20. An Efficient Acoustic Density Estimation Method with Human Detectors Applied to Gibbons in Cambodia

    PubMed Central

    Kidney, Darren; Rawson, Benjamin M.; Borchers, David L.; Stevenson, Ben C.; Marques, Tiago A.; Thomas, Len

    2016-01-01

    Some animal species are hard to see but easy to hear. Standard visual methods for estimating population density for such species are often ineffective or inefficient, but methods based on passive acoustics show more promise. We develop spatially explicit capture-recapture (SECR) methods for territorial vocalising species, in which humans act as an acoustic detector array. We use SECR and estimated bearing data from a single-occasion acoustic survey of a gibbon population in northeastern Cambodia to estimate the density of calling groups. The properties of the estimator are assessed using a simulation study, in which a variety of survey designs are also investigated. We then present a new form of the SECR likelihood for multi-occasion data which accounts for the stochastic availability of animals. In the context of gibbon surveys this allows model-based estimation of the proportion of groups that produce territorial vocalisations on a given day, thereby enabling the density of groups, instead of the density of calling groups, to be estimated. We illustrate the performance of this new estimator by simulation. We show that it is possible to estimate density reliably from human acoustic detections of visually cryptic species using SECR methods. For gibbon surveys we also show that incorporating observers’ estimates of bearings to detected groups substantially improves estimator performance. Using the new form of the SECR likelihood we demonstrate that estimates of availability, in addition to population density and detection function parameters, can be obtained from multi-occasion data, and that the detection function parameters are not confounded with the availability parameter. This acoustic SECR method provides a means of obtaining reliable density estimates for territorial vocalising species. It is also efficient in terms of data requirements since since it only requires routine survey data. We anticipate that the low-tech field requirements will make this method

  1. Characterisation of a Si(Li) orthogonal-strip detector

    NASA Astrophysics Data System (ADS)

    Harkness, L. J.; Judson, D. S.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Nolan, P. J.; Sweeney, A.; Beau, J.; Lampert, M.; Pirard, B.; Zuvic, M.

    2013-10-01

    A Compton camera composed of an orthogonal-strip Si(Li) detector and an orthogonal-strip HPGe SmartPET detector is under investigation at the University of Liverpool. To optimise the performance of the system, it is essential to quantify the response of the detectors to gamma irradiation. Such measurements have previously been reported for the SmartPET detector and in this work we report on the experimental characterisation of the Si(Li) detector. Precision scans of the detector have been performed using a finely collimated 241Am gamma-ray source to determine the uniformity and charge collection properties of the detector.

  2. Integrated four-channel all-fiber up-conversion single-photon-detector with adjustable efficiency and dark count

    NASA Astrophysics Data System (ADS)

    Zheng, Ming-Yang; Shentu, Guo-Liang; Ma, Fei; Zhou, Fei; Zhang, Hai-Ting; Dai, Yun-Qi; Xie, Xiuping; Zhang, Qiang; Pan, Jian-Wei

    2016-09-01

    Up-conversion single photon detector (UCSPD) has been widely used in many research fields including quantum key distribution, lidar, optical time domain reflectrometry, and deep space communication. For the first time in laboratory, we have developed an integrated four-channel all-fiber UCSPD which can work in both free-running and gate modes. This compact module can satisfy different experimental demands with adjustable detection efficiency and dark count. We have characterized the key parameters of the UCSPD system.

  3. Novel processing and properties of high efficiency superconducting infrared bolometric detectors

    NASA Astrophysics Data System (ADS)

    Moxey, Donovan E.

    1998-12-01

    The work in this dissertation involves the design, fabrication, and analysis of superconducting infrared bolometric detectors. These bolometers have been made from superconducting YBasb2Cusb3Osb{7-delta} (YBCO) deposited on silicon (100) substrates utilizing a buffer layer of yttria stabilized zirconia (YSZ). Thin films of undoped and silver(Ag) doped YBCO, as well as stacked layers of undoped/Ag-doped YBCO have been deposited by pulsed laser deposition (PLD). The microstructure and materials properties of these films have been studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and secondary ion mass spectroscopy (SIMS). The electrical and transport properties of these films have been investigated using four-point resistance versus temperature measurements. The results of the investigations of the materials and electrical properties of these films show that they are of high quality, and exhibit superconducting characteristics that are conducive for bolometer device applications. For the first time superconducting bolometric detectors have been fabricated using a novel photolithographic and anti-reflective coating (ARC) process. This fabrication process can be used to fabricate any type of device structure that utilizes superconducting YBCO. The use of an anti-reflective coating simplifies the overall device fabrication process and allows this process to be easily integrated with conventional silicon device processing steps. The anti-reflective coating serves as a barrier to moisture and other contaminants that react with YBCO, as well as act as an absorption medium that improves the optical collection efficiency of the device. Optical analysis of these three bolometer device structures has been carried out using a helium neon (HeNe; lambda = 632.8nm) laser. At a bias of 1mA, and chopping frequency of 100Hz; we have measured photoresponse as a function of device temperature, calculated responsivity, and

  4. Development of a portable instrument for automated measurements of the detective quantum efficiency of x-ray detectors

    NASA Astrophysics Data System (ADS)

    Cunningham, I. A.; Lazarev, S.; Sattarivand, M.; Jankovic, N. D.

    2007-03-01

    The scientific community has generally adopted use of the modulation transfer function (MTF) and detective quantum efficiency (DQE) as primary measures of performance of radiographic detectors. However, measurement of these parameters is generally restricted to experts in laboratory environments due to the required x-ray physics knowledge, specialized instrumentation and computational analyses. We have developed a prototype instrument that automates both the physical measurement and subsequent image analysis to determine the MTF, noise power spectrum (NPS) and DQE of radiographic and mammographic systems. The instrument is placed in the x-ray path directly in front of the detector. A series of images are acquired, saved in "raw" DICOM format and then used to determine the MTF (using the slanted-edge method) and NPS. The number of incident quanta is calculated from measurements of the incident exposure including corrections for air temperature and pressure and ionization chamber spectral response. The primary sources of error are backscatter from the detector and scatter generated within the instrument. These have been minimized to achieve an incident exposure measurement within 2% of a calibrated electrometer and chamber in free space. The MTF and DQE of a commercial CsI-based flat-panel detector were measured over a range of incident exposures from 20 uR to 20 mR per image. Results agreed with both our own laboratory measurements and previously published measurements performed elsewhere with a similar detector within 2% for the MTF and 5% for the DQE. A complete DQE analysis of a clinical digital flat-panel detector is completed in 30 minutes and requires no system modifications.

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

    NASA Astrophysics Data System (ADS)

    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.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Bryngemark, L.; Buanes, T.; Buat, Q.; Bucci, F.; Buchholz, P.; Buckingham, R. M.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Buehrer, F.; Bugge, L.; Bugge, M. K.; Bulekov, O.; Bundock, A. C.; Burckhart, H.; Burdin, S.; Burghgrave, B.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, V.; Bussey, P.; Buszello, C. P.; Butler, B.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Byszewski, M.; Urbán, S. Cabrera; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L. P.; Calvet, D.; Calvet, S.; Toro, R. Camacho; Camarda, S.; Cameron, D.; Caminada, L. M.; Armadans, R. Caminal; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Cantero, J.; Cantrill, R.; Cao, T.; Garrido, M. D. M. Capeans; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Cardarelli, R.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, A. A.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Castaneda-Miranda, E.; Castelli, A.; Gimenez, V. Castillo; Castro, N. F.; Catastini, P.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Cattani, G.; Caughron, S.; Cavaliere, V.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerio, B.; Cerny, K.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chalupkova, I.; Chan, K.; Chang, P.; Chapleau, B.; Chapman, J. D.; Charfeddine, D.; Charlton, D. G.; Chau, C. C.; Barajas, C. A. Chavez; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, L.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, Y.; Cheplakov, A.; Moursli, R. Cherkaoui El; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiefari, G.; Childers, J. T.; Chilingarov, A.; Chiodini, G.; Chisholm, A. S.; Chislett, R. T.; Chitan, A.; Chizhov, M. V.; Chouridou, S.; Chow, B. K. B.; Christidi, I. A.; Chromek-Burckhart, D.; Chu, M. L.; Chudoba, J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Ciftci, R.; Cinca, D.; Cindro, V.; Ciocio, A.; Cirkovic, P.; Citron, Z. H.; Citterio, M.; Ciubancan, M.; Clark, A.; Clark, P. J.; Clarke, R. N.; Cleland, W.; Clemens, J. C.; Clement, B.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Cogan, J. G.; Coggeshall, J.; Cole, B.; Cole, S.; Colijn, A. P.; Collins-Tooth, C.; Collot, J.; Colombo, T.; Colon, G.; Compostella, G.; Muiño, P. Conde; Coniavitis, E.; Conidi, M. C.; Connell, S. H.; Connelly, I. A.; Consonni, S. M.; Consorti, V.; Constantinescu, S.; Conta, C.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cooper-Smith, N. J.; Copic, K.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Côté, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Ortuzar, M. Crispin; Cristinziani, M.; Crosetti, G.; Cuciuc, C.-M.; Cuenca Almenar, C.; Donszelmann, T. Cuhadar; Cummings, J.; Curatolo, M.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; Czyczula, Z.; D'Auria, S.; D'Onofrio, M.; De Sousa, M. J. Da Cunha Sargedas; Da Via, C.; Dabrowski, W.; Dafinca, A.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Daniells, A. C.; Hoffmann, M. Dano; Dao, V.; Darbo, G.; Darlea, G. L.; Darmora, S.; Dassoulas, J. A.; Davey, W.; David, C.; Davidek, T.; Davies, E.; Davies, M.; Davignon, O.; Davison, A. R.; Davison, P.; Davygora, Y.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; De Castro, S.; De Cecco, S.; de Graat, J.; De Groot, N.; de Jong, P.; De La Taille, C.; De la Torre, H.; De Lorenzi, F.; De Nooij, L.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; De Zorzi, G.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dechenaux, B.; Dedovich, D. V.; Degenhardt, J.; Deigaard, I.; Del Peso, J.; Del Prete, T.; Deliot, F.; Delitzsch, C. M.; Deliyergiyev, M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delsart, P. A.; Deluca, C.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Ciaccio, A. Di; Di Ciaccio, L.; Domenico, A. Di; Donato, C. Di; Girolamo, A. Di; Girolamo, B. Di; Mattia, A. Di; Micco, B. Di; Nardo, R. Di; Simone, A. Di; Sipio, R. Di; Valentino, D. Di; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Dietzsch, T. A.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dionisi, C.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Vale, M. A. B. do; Wemans, A. Do Valle; Doan, T. K. O.; Dobos, D.; Dobson, E.; Doglioni, C.; Doherty, T.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dos Anjos, A.; Dova, M. T.; Doyle, A. T.; Dris, M.; Dubbert, J.; Dube, S.; Dubreuil, E.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Dudziak, F.; Duflot, L.; Duguid, L.; Dührssen, M.; Dunford, M.; Duran Yildiz, H.; Düren, M.; Durglishvili, A.; Dwuznik, M.; Dyndal, M.; Ebke, J.; Edson, W.; Edwards, N. C.; Ehrenfeld, W.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Engelmann, R.; Erdmann, J.; Ereditato, A.; Eriksson, D.; Ernis, G.; Ernst, J.; Ernst, M.; Ernwein, J.; Errede, D.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Favareto, A.; Fayard, L.; Federic, P.; Fedin, O. L.; Fedorko, W.; Fehling-Kaschek, M.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Perez, S. Fernandez; Fernando, W.; Ferrag, S.; Ferrando, J.; Ferrara, V.; Ferrari, A.; Ferrari, P.; Ferrari, R.; de Lima, D. E. Ferreira; Ferrer, A.; Ferrere, D.; Ferretti, C.; Parodi, A. Ferretto; Fiascaris, M.; Fiedler, F.; Filipčič, A.; Filipuzzi, M.; Filthaut, F.; Fincke-Keeler, M.; Finelli, K. D.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, J.; Fisher, M. J.; Fisher, W. C.; Fitzgerald, E. A.; Flechl, M.; Fleck, I.; Fleischmann, P.; Fleischmann, S.; Fletcher, G. T.; Fletcher, G.; Flick, T.; Floderus, A.; Castillo, L. R. Flores; Bustos, A. C. Florez; Flowerdew, M. J.; Formica, A.; Forti, A.; Fortin, D.; Fournier, D.; Fox, H.; Fracchia, S.; Francavilla, P.; Franchini, M.; Franchino, S.; Francis, D.; Franklin, M.; Franz, S.; Fraternali, M.; French, S. T.; Friedrich, C.; Friedrich, F.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Torregrosa, E. Fullana; Fulsom, B. G.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gabrielli, A.; Gadatsch, S.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Galea, C.; Galhardo, B.; Gallas, E. J.; Gallo, V.; Gallop, B. J.; Gallus, P.; Galster, G.; Gan, K. K.; Gandrajula, R. P.; Gao, J.; Gao, Y. S.; Walls, F. M. Garay; Garberson, F.; García, C.; Navarro, J. E. García; Garcia-Sciveres, M.; Gardner, R. W.; Garelli, N.; Garonne, V.; Gatti, C.; Gaudio, G.; Gaur, B.; Gauthier, L.; Gauzzi, P.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gazis, E. N.; Ge, P.; Gecse, Z.; Gee, C. N. P.; Geerts, D. A. A.; Geich-Gimbel, Ch.; Gellerstedt, K.; Gemme, C.; Gemmell, A.; Genest, M. H.; Gentile, S.; George, M.; George, S.; Gerbaudo, D.; Gershon, A.; Ghazlane, H.; Ghodbane, N.; Giacobbe, B.; Giagu, S.; Giangiobbe, V.; Giannetti, P.; Gianotti, F.; Gibbard, B.; Gibson, S. M.; Gilchriese, M.; Gillam, T. P. S.; Gillberg, D.; Gilles, G.; Gingrich, D. M.; Giokaris, N.; Giordani, M. P.; Giordano, R.; Giorgi, F. M.; Giraud, P. F.; Giugni, D.; Giuliani, C.; Giulini, M.; Gjelsten, B. K.; Gkialas, I.; Gladilin, L. K.; Glasman, C.; Glatzer, J.; Glaysher, P. C. F.; Glazov, A.; Glonti, G. L.; Goblirsch-Kolb, M.; Goddard, J. R.; Godfrey, J.; Godlewski, J.; Goeringer, C.; Goldfarb, S.; Golling, T.; Golubkov, D.; Gomes, A.; Fajardo, L. S. Gomez; Gonçalo, R.; Costa, J. Goncalves Pinto Firmino Da; Gonella, L.; de la Hoz, S. González; Parra, G. Gonzalez; Silva, M. L. Gonzalez; Gonzalez-Sevilla, S.; Goossens, L.; Gorbounov, P. A.; Gordon, H. A.; Gorelov, I.; Gorfine, G.; Gorini, B.; Gorini, E.; Gorišek, A.; Gornicki, E.; Goshaw, A. T.; Gössling, C.; Gostkin, M. I.; Gouighri, M.; Goujdami, D.; Goulette, M. P.; Goussiou, A. G.; Goy, C.; Gozpinar, S.; Grabas, H. M. X.; Graber, L.; Grabowska-Bold, I.; Grafström, P.; Grahn, K.-J.; Gramling, J.; Gramstad, E.; Grancagnolo, F.; Grancagnolo, S.; Grassi, V.; Gratchev, V.; Gray, H. M.; Graziani, E.; Grebenyuk, O. G.; Greenwood, Z. D.; Gregersen, K.; Gregor, I. M.; Grenier, P.; Griffiths, J.; Grigalashvili, N.; Grillo, A. A.; Grimm, K.; Grinstein, S.; Gris, Ph.; Grishkevich, Y. V.; Grivaz, J.-F.; Grohs, J. P.; Grohsjean, A.; Gross, E.; Grosse-Knetter, J.; Grossi, G. C.; Groth-Jensen, J.; Grout, Z. J.; Grybel, K.; Guan, L.; Guescini, F.; Guest, D.; Gueta, O.; Guicheney, C.; Guido, E.; Guillemin, T.; Guindon, S.; Gul, U.; Gumpert, C.; Gunther, J.; Guo, J.; Gupta, S.; Gutierrez, P.; Gutierrez Ortiz, N. G.; Gutschow, C.; Guttman, N.; Guyot, C.; Gwenlan, C.; Gwilliam, C. B.; Haas, A.; Haber, C.; Hadavand, H. K.; Haddad, N.; Haefner, P.; Hageboeck, S.; Hajduk, Z.; Hakobyan, H.; Haleem, M.; Hall, D.; Halladjian, G.; Hamacher, K.; Hamal, P.; Hamano, K.; Hamer, M.; Hamilton, A.; Hamilton, S.; Hamnett, P. G.; Han, L.; Hanagaki, K.; Hanawa, K.; Hance, M.; Hanke, P.; Hansen, J. B.; Hansen, J. D.; Hansen, P. H.; Hara, K.; Hard, A. S.; Harenberg, T.; Harkusha, S.; Harper, D.; Harrington, R. D.; Harris, O. M.; Harrison, P. F.; Hartjes, F.; Harvey, A.; Hasegawa, S.; Hasegawa, Y.; Hasib, A.; Hassani, S.; Haug, S.; Hauschild, M.; Hauser, R.; Havranek, M.; Hawkes, C. M.; Hawkings, R. J.; Hawkins, A. D.; Hayashi, T.; Hayden, D.; Hays, C. P.; Hayward, H. S.; Haywood, S. J.; Head, S. J.; Heck, T.; Hedberg, V.; Heelan, L.; Heim, S.; Heim, T.; Heinemann, B.; Heinrich, L.; Heisterkamp, S.; Hejbal, J.; Helary, L.; Heller, C.; Heller, M.; Hellman, S.; Hellmich, D.; Helsens, C.; Henderson, J.; Henderson, R. C. W.; Hengler, C.; Henrichs, A.; Henriques Correia, A. M.; Henrot-Versille, S.; Hensel, C.; Herbert, G. H.; Jiménez, Y. Hernández; Herrberg-Schubert, R.; Herten, G.; Hertenberger, R.; Hervas, L.; Hesketh, G. G.; Hessey, N. P.; Hickling, R.; Higón-Rodriguez, E.; Hill, J. C.; Hiller, K. H.; Hillert, S.; Hillier, S. J.; Hinchliffe, I.; Hines, E.; Hirose, M.; Hirschbuehl, D.; Hobbs, J.; Hod, N.; Hodgkinson, M. C.; Hodgson, P.; Hoecker, A.; Hoeferkamp, M. R.; Hoffman, J.; Hoffmann, D.; Hofmann, J. I.; Hohlfeld, M.; Holmes, T. R.; Hong, T. M.; Hooft van Huysduynen, L.; Hostachy, J.-Y.; Hou, S.; Hoummada, A.; Howard, J.; Howarth, J.; Hrabovsky, M.; Hristova, I.; Hrivnac, J.; Hryn'ova, T.; Hsu, P. J.; Hsu, S.-C.; Hu, D.; Hu, X.; Huang, Y.; Hubacek, Z.; Hubaut, F.; Huegging, F.; Huffman, T. B.; Hughes, E. W.; Hughes, G.; Huhtinen, M.; Hülsing, T. A.; Hurwitz, M.; Huseynov, N.; Huston, J.; Huth, J.; Iacobucci, G.; Iakovidis, G.; Ibragimov, I.; Iconomidou-Fayard, L.; Idarraga, J.; Ideal, E.; Iengo, P.; Igonkina, O.; Iizawa, T.; Ikegami, Y.; Ikematsu, K.; Ikeno, M.; Iliadis, D.; Ilic, N.; Inamaru, Y.; Ince, T.; Ioannou, P.; Iodice, M.; Iordanidou, K.; Ippolito, V.; Quiles, A. Irles; Isaksson, C.; Ishino, M.; Ishitsuka, M.; Ishmukhametov, R.; Issever, C.; Istin, S.; Iturbe Ponce, J. M.; Ivashin, A. V.; Iwanski, W.; Iwasaki, H.; Izen, J. M.; Izzo, V.; Jackson, B.; Jackson, J. N.; Jackson, M.; Jackson, P.; Jaekel, M. R.; Jain, V.; Jakobs, K.; Jakobsen, S.; Jakoubek, T.; Jakubek, J.; Jamin, D. O.; Jana, D. K.; Jansen, E.; Jansen, H.; Janssen, J.; Janus, M.; Jarlskog, G.; Javůrek, T.; Jeanty, L.; Jeng, G.-Y.; Jennens, D.; Jenni, P.; Jentzsch, J.; Jeske, C.; Jézéquel, S.; Ji, H.; Ji, W.; Jia, J.; Jiang, Y.; Jimenez Belenguer, M.; Jin, S.; Jinaru, A.; Jinnouchi, O.; Joergensen, M. D.; Johansson, K. E.; Johansson, P.; Johns, K. A.; Jon-And, K.; Jones, G.; Jones, R. W. L.; Jones, T. J.; Jongmanns, J.; Jorge, P. M.; Joshi, K. D.; Jovicevic, J.; Ju, X.; Jung, C. A.; Jungst, R. M.; Jussel, P.; Juste Rozas, A.; Kaci, M.; Kaczmarska, A.; Kado, M.; Kagan, H.; Kagan, M.; Kajomovitz, E.; Kama, S.; Kanaya, N.; Kaneda, M.; Kaneti, S.; Kanno, T.; Kantserov, V. A.; Kanzaki, J.; Kaplan, B.; Kapliy, A.; Kar, D.; Karakostas, K.; Karastathis, N.; Karnevskiy, M.; Karpov, S. N.; Karthik, K.; Kartvelishvili, V.; Karyukhin, A. N.; Kashif, L.; Kasieczka, G.; Kass, R. D.; Kastanas, A.; Kataoka, Y.; Katre, A.; Katzy, J.; Kaushik, V.; Kawagoe, K.; Kawamoto, T.; Kawamura, G.; Kazama, S.; Kazanin, V. F.; Kazarinov, M. Y.; Keeler, R.; Keener, P. T.; Kehoe, R.; Keil, M.; Keller, J. S.; Keoshkerian, H.; Kepka, O.; Kerševan, B. P.; Kersten, S.; Kessoku, K.; Keung, J.; Khalil-zada, F.; Khandanyan, H.; Khanov, A.; Khodinov, A.; Khomich, A.; Khoo, T. J.; Khoriauli, G.; Khoroshilov, A.; Khovanskiy, V.; Khramov, E.; Khubua, J.; Kim, H. 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M.; Sellers, G.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Serre, T.; Seuster, R.; Severini, H.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L. Y.; Shank, J. T.; Shao, Q. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Sherwood, P.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shiyakova, M.; Shmeleva, A.; Shochet, M. J.; Short, D.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Shushkevich, S.; Sicho, P.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silbert, O.; Silva, J.; Silver, Y.; Silverstein, D.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simoniello, R.; Simonyan, M.; Sinervo, P.; Sinev, N. B.; Sipica, V.; Siragusa, G.; Sircar, A.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinnari, L. A.; Skottowe, H. P.; Skovpen, K. Yu.; Skubic, P.; Slater, M.; Slavicek, T.; Sliwa, K.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snidero, G.; Snow, J.; Snyder, S.; Sobie, R.; Socher, F.; Sodomka, J.; Soffer, A.; Soh, D. A.; Solans, C. A.; Solar, M.; Solc, J.; Soldatov, E. Yu.; Soldevila, U.; Camillocci, E. Solfaroli; Solodkov, A. A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Song, H. Y.; Soni, N.; Sood, A.; Sopko, V.; Sopko, B.; Sorin, V.; Sosebee, M.; Soualah, R.; Soueid, P.; Soukharev, A. M.; South, D.; Spagnolo, S.; Spanò, F.; Spearman, W. R.; Spighi, R.; Spigo, G.; Spousta, M.; Spreitzer, T.; Spurlock, B.; Denis, R. D. St.; Staerz, S.; Stahlman, J.; Stamen, R.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staszewski, R.; Stavina, P.; Steele, G.; Steinberg, P.; Stekl, I.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stern, S.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoerig, K.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Subramania, HS.; Subramaniam, R.; Succurro, A.; Sugaya, Y.; Suhr, C.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Susinno, G.; Sutton, M. R.; Suzuki, Y.; Svatos, M.; Swedish, S.; Swiatlowski, M.; Sykora, I.; Sykora, T.; Ta, D.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tam, J. Y. C.; Tamsett, M. C.; Tan, K. G.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanasijczuk, A. J.; Tani, K.; Tannoury, N.; Tapprogge, S.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, C.; Taylor, F. E.; Taylor, G. N.; Taylor, W.; Teischinger, F. A.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Ten Kate, H.; Teng, P. K.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Therhaag, J.; Theveneaux-Pelzer, T.; Thoma, S.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, E. N.; Thompson, P. D.; Thompson, P. D.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Thomson, M.; Thong, W. M.; Thun, R. P.; Tian, F.; Tibbetts, M. J.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tiouchichine, E.; Tipton, P.; Tisserant, S.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tollefson, K.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Topilin, N. D.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Tran, H. L.; Trefzger, T.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Triplett, N.; Trischuk, W.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; True, P.; Trzebinski, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tua, A.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Turk Cakir, I.; Turra, R.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Uchida, K.; Ueda, I.; Ueno, R.; Ughetto, M.; Ugland, M.; Uhlenbrock, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Urbaniec, D.; Urquijo, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Gallego, E. Valladolid; Vallecorsa, S.; Ferrer, J. A. Valls; Van Berg, R.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; Van Der Leeuw, R.; van der Ster, D.; Eldik, N. van; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vazeille, F.; Schroeder, T. Vazquez; Veatch, J.; Veloso, F.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigne, R.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Virzi, J.; Vitells, O.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vogel, A.; Vokac, P.; Volpi, G.; Volpi, M.; Schmitt, H. von der; Radziewski, H. von; Toerne, E. von; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Milosavljevic, M. Vranjes; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, W.; Wagner, P.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Walsh, B.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, X.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Warsinsky, M.; Washbrook, A.; Wasicki, C.; Watanabe, I.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weigell, P.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wendland, D.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wicke, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wijeratne, P. A.; Wildauer, A.; Wildt, M. A.; Wilkens, H. G.; Will, J. Z.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wilson, A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Wittig, T.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wright, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wulf, E.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xiao, M.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yamada, M.; Yamaguchi, H.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, U. K.; Yang, Y.; Yanush, S.; Yao, L.; Yao, W.-M.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yen, A. L.; Yildirim, E.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zaytsev, A.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zevi della Porta, G.; Zhang, D.; Zhang, F.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, X.; Zhang, Z.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, L.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Zinonos, Z.; Ziolkowski, M.; Zitoun, R.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zutshi, V.; Zwalinski, L.

    2014-07-01

    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.

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

    SciTech Connect

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

    2014-06-09

    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 μm × 10 μm 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.

  7. Quantum efficiencies of imaging detectors with alkali halide photocathodes. I - Microchannel plates with separate and integral CsI photocathodes

    NASA Technical Reports Server (NTRS)

    Carruthers, George R.

    1987-01-01

    Measurements and comparisons have been made of the quantum efficiencies of microchannel plate (MCP) detectors in the far-UV (below 2000-A) wavelength range using CsI photocathodes (a) deposited on the front surfaces of microchannel plates and (b) deposited on solid substrates as opaque photocathodes with the resulting photoelectrons input to microchannel plates. The efficiences were measured in both pulse-counting and photodiode modes of operation. Typical efficiencies are about 15 percent at 1216 A for a CsI-coated MCP compared with 65 percent for an opaque CsI photocathode MCP detector. Special processing has yielded an efficiency as high as 20 percent for a CsI-coated MCP. This may possibly be further improved by optimization of the tilt angle of the MCP channels relative to the front face of the MCP and incident radiation. However, at present there still remains a factor of at least 3 quantum efficiency advantage in the separate opaque CsI photocathode configuration.

  8. EFFICIENCY STUDY OF A LEGe DETECTOR SYSTEM FOR THE ASSESSMENT OF 241Am IN SKULL AT CIEMAT WHOLE BODY COUNTER.

    PubMed

    Pérez López, B; Navarro, J F; López Ponte, M A; Nogueira, P

    2016-09-01

    (241)Am incorporation due to an incident or chronic exposure causes an internal dose, which can be evaluated from the total activity of this isotope in the skeleton several months after the intake. For this purpose, it is necessary to perform in vivo measurements of this bone-seeker radionuclide in appropriate counting bone geometries with very low attenuation of surrounded tissue and to extrapolate to total activity in the skeleton (ICRP 89, Basic anatomical and physiological data for use in radiological protection: reference values. 2001. 265). The work here presented refers to direct measurements of americium in the Cohen skull phantom at the CIEMAT Whole Body Counter (WBC) using low-energy germanium (LEGe) detectors inside a shielding room. The main goal was to determinate the most adequate head counting geometry for the in vivo detection of americium in the bone. The calibration of the in vivo LEGe system was performed with four detectors with 2 cm of distance to Cohen phantom. Two geometries were measured, on junction of frontal to parietal bones and frontal bone. The efficiencies are very similar in both geometries, the preferred counting geometry is the most comfortable for the person, with the LEGe detectors in the highest part of the frontal bone, near the junction with the parietal bone, CIEMAT WBC participated in a skull intercomparison exercise organised by WG7 of EURADOS (European Radiation Dosimetry Group e.V.). Efficiencies using three different skull phantoms were obtained. Measurements were performed for different head counting positions, four of them in the plane of symmetry and others over the temporal bone. The detector was placed in parallel with the calibration phantom at a distance of 1 cm. The main gamma emission of (241)Am, 59.5 keV (36 %), was used for comparing efficiency values. The lower efficiency was obtained over the frontal and occipital bones. Measurement with one LEGe detector over the parietal bone is the most efficient. The

  9. High-Efficiency CdZnTe Position-Sensitive VFG Gamma-Ray Detectors for Safeguards Applications

    SciTech Connect

    Bolotnikov, Aleksey E.; James, Ralph B.; Cui, Y.; De Geronimo, G.; Vernon, E.; Camarda, G. S.; Hossain, A.; Yang, G.; Indusi, J.; Boyer, Brian

    2015-09-30

    The goal of this project is to incorporate a Cadmium-Zinc-Telluride (CdZnTe or CZT) detector (with 1% or better resolution) into a bench-top prototype for isotope identification and related safeguards applications. The bench-top system is based on a 2x2 array of 6x6x20 mm3 position-sensitive virtual Frisch-grid (VFG) CZT detectors. The key features of the array are that it allows for the use of average-grade CZT material with a moderate content of defects, and yet it provides high-energy resolution, 1% FWHM at 662 keV, large effective area, and low-power consumption. The development of this type of 3D detector and new instruments incorporating them is motivated by the high cost and low availability of large, > 1 cm3, CZT crystals suitable for making multi-pixel detectors with acceptable energy resolution and efficiency.

  10. High-efficiency superconducting nanowire single-photon detectors fabricated from MoSi thin-films

    NASA Astrophysics Data System (ADS)

    Verma, V. B.; Korzh, B.; Bussières, F.; Horansky, R. D.; Dyer, S. D.; Lita, A. E.; Vayshenker, I.; Marsili, F.; Shaw, M. D.; Zbinden, H.; Mirin, R. P.; Nam, S. W.

    2015-12-01

    We demonstrate high-efficiency superconducting nanowire single-photon detectors (SNSPDs) fabricated from MoSi thin-films. We measure a maximum system detection efficiency (SDE) of 87 +- 0.5 % at 1542 nm at a temperature of 0.7 K, with a jitter of 76 ps, maximum count rate approaching 10 MHz, and polarization dependence as low as 3.4 +- 0.7 % The SDE curves show saturation of the internal efficiency similar to WSi-based SNSPDs at temperatures as high as 2.3 K. We show that at similar cryogenic temperatures, MoSi SNSPDs achieve efficiencies comparable to WSi-based SNSPDs with nearly a factor of two reduction in jitter.

  11. Improvements in the Low Energy Collection Efficiency of Si(Li) X-ray Detectors

    SciTech Connect

    Cox,C.; Fischer, D.; Schwartz, W.; Song, Y.

    2005-01-01

    Soft X-ray beam-line applications are of fundamental importance to material research, and commonly employ high-resolution Si(Li) detectors for energy dispersive spectroscopy. However, the measurement of X-rays below 1 keV is compromised by absorption in the material layers in front of the active crystal and a dead layer at the crystal surface. Various Schottky barrier type contacts were investigated resulting in a 40% reduction of the dead-layer thickness and a factor of two increased sensitivity at carbon K{sub {alpha}} compared to the standard Si(Li) detector. Si(Li) detectors were tested on the U7A soft X-ray beam-line at the National Synchrotron Light Source and on a scanning electron microscope (SEM).

  12. 226Ra as a standard source for efficiency calibration of Ge(Li) detectors

    NASA Astrophysics Data System (ADS)

    Farouk, M. A.; Al-Soraya, A. M.

    1982-09-01

    The relative intensities of gamma-rays resulting from the decay of 226Ra in equilibrium with its short-lived daughters have been measured using two different high resolution Ge(Li) detectors. The accuracy of the measurements does not exceed 2.5%. The most intense components of gamma-rays from thin 226Ra are recommended for use as a calibration standard Ge(Li) detectors in the energy range from 186 keV to 3.050 MeV.

  13. Time-resolved singlet-oxygen luminescence detection with an efficient and practical semiconductor single-photon detector

    PubMed Central

    Boso, Gianluca; Ke, Damei; Korzh, Boris; Bouilloux, Jordan; Lange, Norbert; Zbinden, Hugo

    2015-01-01

    In clinical applications, such as PhotoDynamic Therapy, direct singlet-oxygen detection through its luminescence in the near-infrared range (1270 nm) has been a challenging task due to its low emission probability and the lack of suitable single-photon detectors. Here, we propose a practical setup based on a negative-feedback avalanche diode detector that is a viable alternative to the current state-of-the art for different clinical scenarios, especially where geometric collection efficiency is limited (e.g. fiber-based systems, confocal microscopy, scanning systems etc.). The proposed setup is characterized with Rose Bengal as a standard photosensitizer and it is used to measure the singlet-oxygen quantum yield of a new set of photosensitizers for site-selective photodynamic therapy. PMID:26819830

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

    SciTech Connect

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

    2014-02-24

    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 μs 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.

  15. Search for rare nuclear decays with HPGe detectors at the STELLA facility of the LNGS

    SciTech Connect

    Belli, P.; Di Marco, A.; Bernabei, R.; D'Angelo, S.; Cappella, F.; D'Angelo, A.; Incicchitti, A.; Cerulli, R.; Di Vacri, M. L.; Laubenstein, M.; Nisi, S.; Danevich, F. A.; Kobychev, V. V.; Poda, D. V.; Tretyak, V. I.; Kovtun, G. P.; Kovtun, N. G.; Shcherban, A. P.; Solopikhin, D. A.; Polischuk, O. G.; and others

    2013-12-30

    Results on the search for rare nuclear decays with the ultra low background facility STELLA at the LNGS using gamma ray spectrometry are presented. In particular, the best T{sub 1/2} limits were obtained for double beta processes in {sup 96}Ru and {sup 104}Ru. Several isotopes, which potentially decay through different 2β channels, including also possible resonant double electron captures, were investigated for the first time ({sup 156}Dy, {sup 158}Dy, {sup 184}Os, {sup 192}Os, {sup 190}Pt, {sup 198}Pt). Search for resonant absorption of solar {sup 7}Li axions in a LiF crystal gave the best limit for the mass of {sup 7}Li axions (< 8.6 keV). Rare alpha decay of {sup 190}Pt to the first excited level of {sup 186}Os(E{sub exc} = 137.2keV) was observed for the first time.

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

    PubMed

    Campbell, D L; Peterson, T E

    2014-11-21

    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.

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

    PubMed Central

    Campbell, DL; Peterson, TE

    2014-01-01

    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

  18. High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

    DOEpatents

    Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

    1989-02-07

    A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

  19. High-efficiency scintillation detector for combined detection of thermal and fast neutrons and gamma radiation

    DOEpatents

    Chiles, M.M.; Mihalczo, J.T.; Blakeman, E.D.

    1987-02-27

    A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation event count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

  20. High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

    DOEpatents

    Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

    1989-01-01

    A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

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

    PubMed

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

    2014-11-01

    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.

  2. Proton-induced radiation damage in germanium detectors

    SciTech Connect

    Bruckner, J.; Korfer, M.; Wanke, H. , Mainz ); Schroeder, A.N.F. ); Figes, D.; Dragovitsch, P. ); Englert, P.A.J. ); Starr, R.; Trombka, J.I. . Goddard Space Flight Center); Taylor, I. ); Drake, D.M.; Shunk, E.R. )

    1991-04-01

    High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 10{sub 8} protons cm{sup {minus}2} (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific as well as engineering data on detector performance were collected. During the incremental irradiation, the peak shape produced by the detectors showed a significant change from a Gaussian shape to a broad complex structure. After the irradiation all detectors were thoroughly characterized by measuring many parameters. To remove the accumulated radiation damage the detectors were stepwise annealed at temperatures T {le} 110{degrees}C while staying specially designed cryostats. This paper shows that n-type HPGe detectors can be used in charged particles environments as high-energy resolution devices until a certain level of radiation damage is accumulated and that the damage can be removed at moderate annealing temperatures and the detector returned to operating condition.

  3. Active noise canceling system for mechanically cooled germanium radiation detectors

    DOEpatents

    Nelson, Karl Einar; Burks, Morgan T

    2014-04-22

    A microphonics noise cancellation system and method for improving the energy resolution for mechanically cooled high-purity Germanium (HPGe) detector systems. A classical adaptive noise canceling digital processing system using an adaptive predictor is used in an MCA to attenuate the microphonics noise source making the system more deployable.

  4. High-efficiency superconducting nanowire single-photon detectors fabricated from MoSi thin-films.

    PubMed

    Verma, V B; Korzh, B; Bussières, F; Horansky, R D; Dyer, S D; Lita, A E; Vayshenker, I; Marsili, F; Shaw, M D; Zbinden, H; Mirin, R P; Nam, S W

    2015-12-28

    We report on MoSi SNSPDs which achieved high system detection efficiency (87.1 ± 0.5% at 1542 nm) at 0.7 K and we demonstrate that these detectors can also be operated with saturated internal efficiency at a temperature of 2.3 K in a Gifford-McMahon cryocooler. We measured a minimum system jitter of 76 ps, maximum count rate approaching 10 MHz, and polarization dependence as low as 3.3 ± 0.1%. The performance of MoSi SNSPDs at 2.3 K is similar to the performance of WSi SNSPDs at < 1 K. The higher operating temperature of MoSi SNSPDs makes these devices promising for widespread use due to the simpler and less expensive cryogenics required for their operation.

  5. Derivation of the sensitivity of a Geiger mode avalanche photodiode detector from a given efficiency for quantum key distribution experiments

    NASA Astrophysics Data System (ADS)

    Hammura, Kiyotaka; Williams, David

    2009-05-01

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

  6. High-efficiency WSi superconducting nanowire single-photon detectors operating at 2.5 K

    SciTech Connect

    Verma, V. B.; Horansky, R. D.; Lita, A. E.; Mirin, R. P.; Nam, S. W.; Korzh, B.; Bussières, F.; Zbinden, H.; Marsili, F.; Shaw, M. D.

    2014-09-22

    We investigate the operation of WSi superconducting nanowire single-photon detectors (SNSPDs) at 2.5 K, a temperature which is ∼70% of the superconducting transition temperature (T{sub C}) of 3.4 K. We demonstrate saturation of the system detection efficiency at 78 ± 2% at a wavelength of 1310 nm, with a jitter of 191 ps. We find that the jitter at 2.5 K is limited by the noise of the readout and can be improved through the use of cryogenic amplifiers. Operation of SNSPDs with high efficiency at temperatures very close to T{sub C} appears to be a unique property of amorphous WSi.

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    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.

  8. Automation of the Characterization of High Purity Germanium Detectors

    NASA Astrophysics Data System (ADS)

    Dugger, Charles ``Chip''

    2014-09-01

    Neutrinoless double beta decay is a rare hypothesized process that may yield valuable insight into the fundamental properties of the neutrino. Currently there are several experiments trying to observe this process, including the Majorana DEMONSTRAOR experiment, which uses high purity germanium (HPGe) detectors to generate and search for these events. Because the event happens internally, it is essential to have the lowest background possible. This is done through passive detector shielding, as well as event discrimination techniques that distinguish between multi-site events characteristic of gamma-radiation, and single-site events characteristic of neutrinoless double beta decay. Before fielding such an experiment, the radiation response of the detectors must be characterized. A robotic arm is being tested for future calibration of HPGe detectors. The arm will hold a source at locations relative to the crystal while data is acquired. Several radioactive sources of varying energy levels will be used to determine the characteristics of the crystal. In this poster, I will present our work with the robot, as well as the characterization of data we took with an underground HPGe detector at the WIPP facility in Carlsbad, NM (2013). Neutrinoless double beta decay is a rare hypothesized process that may yield valuable insight into the fundamental properties of the neutrino. Currently there are several experiments trying to observe this process, including the Majorana DEMONSTRAOR experiment, which uses high purity germanium (HPGe) detectors to generate and search for these events. Because the event happens internally, it is essential to have the lowest background possible. This is done through passive detector shielding, as well as event discrimination techniques that distinguish between multi-site events characteristic of gamma-radiation, and single-site events characteristic of neutrinoless double beta decay. Before fielding such an experiment, the radiation response of

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

    SciTech Connect

    Kachulis, Chris; /Yale U. /SLAC

    2011-06-22

    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

  10. Experimental investigation of the radiation shielding efficiency of a MCP detector in the radiation environment near Jupiter's moon Europa

    NASA Astrophysics Data System (ADS)

    Tulej, M.; Meyer, S.; Lüthi, M.; Lasi, D.; Galli, A.; Piazza, D.; Desorgher, L.; Reggiani, D.; Hajdas, W.; Karlsson, S.; Kalla, L.; Wurz, P.

    2016-09-01

    Neutral Ion Mass spectrometer (NIM) is one of the instruments in the Particle Environmental Package (PEP) designed for the JUICE mission of ESA to the Jupiter system. NIM, equipped with a sensitive MCP ion detector, will conduct detailed measurements of the chemical composition of Jovian icy moons exospheres. To achieve high sensitivity of the instrument, radiation effects due to the high radiation background (high-energy electrons and protons) around Jupiter have to be minimised. We investigate the performance of an Al-Ta-Al composite stack as a potential shielding against high-energy electrons. Experiments were performed at the PiM1 beam line of the High Intensity Proton Accelerator Facilities located at the Paul Scherrer Institute, Villigen, Switzerland. The facility delivers a particle beam containing e-, μ- and π- with momentum from 17.5 to 345 MeV/c (Hajdas et al., 2014). The measurements of the radiation environment generated during the interaction of primary particles with the Al-Ta-Al material were conducted with dedicated beam diagnostic methods and with the NIM MCP detector. In parallel, modelling studies using GEANT4 and GRAS suites were performed to identify products of the interaction and predict ultimate fluxes and particle rates at the MCP detector. Combination of experiment and modelling studies yields detailed characterisation of the radiation fields produced by the interaction of the incident e- with the shielding material in the range of the beam momentum from 17.5 to 345 MeV/c. We derived the effective MCP detection efficiency to primary and secondary radiation and effective shielding transmission coefficients to incident high-energy electron beam in the range of applied beam momenta. This study shows that the applied shielding attenuates efficiently high-energy electrons. Nevertheless, owing to nearly linear increase of the bremsstrahlung production rate with incident beam energy, above 130 MeV their detection rates measured by the MCP

  11. Photon detectors with high quantum efficiency at NUV range using a confinement of wavelength-shifted signals and optical couplers

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Hadaway, J.; Pakhomov, A.; Takizawa, Y.

    Near-UV wavelengths 300 - 400 nm have been in a death-valley for photon detectors due to very low quantum efficiencies QE in this range Conventional bi-alkali photocathodes of PMTs do not have QE better than 20-26 Much better photo-cathodes like GaAsP GaN and similar give better efficiencies but only at wavelengths 400nm and are severely plagued by very short lifetimes Avalanche Photo-diodes perform better at low temperatures but no better than 35 QE in the NUV region Silicon Photo-multipliers at Geiger mode SiPM with micro-pixels have high QEs 90 like CCD and CMOS as bare silicon but are severely plagued by very poor geometrical fill-factors 30 and their overallQMis limited to no better than 20 at NUV regime An optical interference-filter works as a half-mirror passing more than 90 of NUV lights 300-400 nm and reflect more than 90 of longer wavelength lights 400 nm UV photons after converted into blue-green lights by wavelength-shifter are reflected back and confined without much loss back into space A specific dichroic interference mirror with WLS was made by RIKEN Japan H Shimizu Y Takahashi Y Takizawa Patent pending 2000-399940 for this optical principle It also allows a better use of limited photo-sensitive micro-cells of SiPM overcoming the past serious problem of its very poor fill-factor As a result Half-mirror SiPM yields high final efficiency for NUV photons This new detector TRAPPER with optical couplers for SiPM or by GaAsP PMTs could be used for photon-hungry space experiments at NUV range TRAPPER

  12. Approaching the Ultimate Limits of Communication Efficiency with a Photon-Counting Detector

    NASA Technical Reports Server (NTRS)

    Erkmen, Baris; Moision, Bruce; Dolinar, Samuel J.; Birnbaum, Kevin M.; Divsalar, Dariush

    2012-01-01

    Coherent states achieve the Holevo capacity of a pure-loss channel when paired with an optimal measurement, but a physical realization of this measurement is as of yet unknown, and it is also likely to be of high complexity. In this paper, we focus on the photon-counting measurement and study the photon and dimensional efficiencies attainable with modulations over classical- and nonclassical-state alphabets. We first review the state-of-the-art coherent on-off-keying (OOK) with a photoncounting measurement, illustrating its asymptotic inefficiency relative to the Holevo limit. We show that a commonly made Poisson approximation in thermal noise leads to unbounded photon information efficiencies, violating the conjectured Holevo limit. We analyze two binary-modulation architectures that improve upon the dimensional versus photon efficiency tradeoff achievable with conventional OOK. We show that at high photon efficiency these architectures achieve an efficiency tradeoff that differs from the best possible tradeoff--determined by the Holevo capacity--by only a constant factor. The first architecture we analyze is a coherent-state transmitter that relies on feedback from the receiver to control the transmitted energy. The second architecture uses a single-photon number-state source.

  13. The detective quantum efficiency of photon-counting x-ray detectors using cascaded-systems analyses

    SciTech Connect

    Tanguay, Jesse; Yun, Seungman; Kim, Ho Kyung; Cunningham, Ian A.

    2013-04-15

    Purpose: Single-photon counting (SPC) x-ray imaging has the potential to improve image quality and enable new advanced energy-dependent methods. The purpose of this study is to extend cascaded-systems analyses (CSA) to the description of image quality and the detective quantum efficiency (DQE) of SPC systems. Methods: Point-process theory is used to develop a method of propagating the mean signal and Wiener noise-power spectrum through a thresholding stage (required to identify x-ray interaction events). The new transfer relationships are used to describe the zero-frequency DQE of a hypothetical SPC detector including the effects of stochastic conversion of incident photons to secondary quanta, secondary quantum sinks, additive noise, and threshold level. Theoretical results are compared with Monte Carlo calculations assuming the same detector model. Results: Under certain conditions, the CSA approach can be applied to SPC systems with the additional requirement of propagating the probability density function describing the total number of image-forming quanta through each stage of a cascaded model. Theoretical results including DQE show excellent agreement with Monte Carlo calculations under all conditions considered. Conclusions: Application of the CSA method shows that false counts due to additive electronic noise results in both a nonlinear image signal and increased image noise. There is a window of allowable threshold values to achieve a high DQE that depends on conversion gain, secondary quantum sinks, and additive noise.

  14. Spectral response of multi-element silicon detectors

    SciTech Connect

    Ludewigt, B.A.; Rossington, C.S.; Chapman, K.

    1997-04-01

    Multi-element silicon strip detectors, in conjunction with integrated circuit pulse-processing electronics, offer an attractive alternative to conventional lithium-drifted silicon Si(Li) and high purity germanium detectors (HPGe) for high count rate, low noise synchrotron x-ray fluorescence applications. One of the major differences between the segmented Si detectors and the commercially available single-element Si(Li) or HPGe detectors is that hundreds of elements can be fabricated on a single Si substrate using standard silicon processing technologies. The segmentation of the detector substrate into many small elements results in very low noise performance at or near, room temperature, and the count rate of the detector is increased many-fold due to the multiplication in the total number of detectors. Traditionally, a single channel of detector with electronics can handle {approximately}100 kHz count rates while maintaining good energy resolution; the segmented detectors can operate at greater than MHz count rates merely due to the multiplication in the number of channels. One of the most critical aspects in the development of the segmented detectors is characterizing the charge sharing and charge loss that occur between the individual detector strips, and determining how these affect the spectral response of the detectors.

  15. Neutron Damage in Mechanically-Cooled High-Purity Germanium Detectors for Field-Portable Prompt Gamma Neutron Activation Analysis (PGNAA) Systems

    SciTech Connect

    E.H. Seabury; C.J. Wharton; A.J. Caffrey; J.B. McCabe; C. DeW. Van Siclen

    2013-10-01

    Prompt Gamma Neutron Activation (PGNAA) systems require the use of a gamma-ray spectrometer to record the gamma-ray spectrum of an object under test and allow the determination of the object’s composition. Field-portable systems, such as Idaho National Laboratory’s PINS system, have used standard liquid-nitrogen-cooled high-purity germanium (HPGe) detectors to perform this function. These detectors have performed very well in the past, but the requirement of liquid-nitrogen cooling limits their use to areas where liquid nitrogen is readily available or produced on-site. Also, having a relatively large volume of liquid nitrogen close to the detector can impact some assessments, possibly leading to a false detection of explosives or other nitrogen-containing chemical. Use of a mechanically-cooled HPGe detector is therefore very attractive for PGNAA applications where nitrogen detection is critical or where liquid-nitrogen logistics are problematic. Mechanically-cooled HPGe detectors constructed from p-type germanium, such as Ortec’s trans-SPEC, have been commercially available for several years. In order to assess whether these detectors would be suitable for use in a fielded PGNAA system, Idaho National Laboratory (INL) has been performing a number of tests of the resistance of mechanically-cooled HPGe detectors to neutron damage. These detectors have been standard commercially-available p-type HPGe detectors as well as prototype n-type HPGe detectors. These tests compare the performance of these different detector types as a function of crystal temperature and incident neutron fluence on the crystal.

  16. Patient-dependent count-rate adaptive normalization for PET detector efficiency with delayed-window coincidence events.

    PubMed

    Niu, Xiaofeng; Ye, Hongwei; Xia, Ting; Asma, Evren; Winkler, Mark; Gagnon, Daniel; Wang, Wenli

    2015-07-01

    Quantitative PET imaging is widely used in clinical diagnosis in oncology and neuroimaging. Accurate normalization correction for the efficiency of each line-of- response is essential for accurate quantitative PET image reconstruction. In this paper, we propose a normalization calibration method by using the delayed-window coincidence events from the scanning phantom or patient. The proposed method could dramatically reduce the 'ring' artifacts caused by mismatched system count-rates between the calibration and phantom/patient datasets. Moreover, a modified algorithm for mean detector efficiency estimation is proposed, which could generate crystal efficiency maps with more uniform variance. Both phantom and real patient datasets are used for evaluation. The results show that the proposed method could lead to better uniformity in reconstructed images by removing ring artifacts, and more uniform axial variance profiles, especially around the axial edge slices of the scanner. The proposed method also has the potential benefit to simplify the normalization calibration procedure, since the calibration can be performed using the on-the-fly acquired delayed-window dataset. PMID:26086713

  17. Patient-dependent count-rate adaptive normalization for PET detector efficiency with delayed-window coincidence events

    NASA Astrophysics Data System (ADS)

    Niu, Xiaofeng; Ye, Hongwei; Xia, Ting; Asma, Evren; Winkler, Mark; Gagnon, Daniel; Wang, Wenli

    2015-07-01

    Quantitative PET imaging is widely used in clinical diagnosis in oncology and neuroimaging. Accurate normalization correction for the efficiency of each line-of- response is essential for accurate quantitative PET image reconstruction. In this paper, we propose a normalization calibration method by using the delayed-window coincidence events from the scanning phantom or patient. The proposed method could dramatically reduce the ‘ring’ artifacts caused by mismatched system count-rates between the calibration and phantom/patient datasets. Moreover, a modified algorithm for mean detector efficiency estimation is proposed, which could generate crystal efficiency maps with more uniform variance. Both phantom and real patient datasets are used for evaluation. The results show that the proposed method could lead to better uniformity in reconstructed images by removing ring artifacts, and more uniform axial variance profiles, especially around the axial edge slices of the scanner. The proposed method also has the potential benefit to simplify the normalization calibration procedure, since the calibration can be performed using the on-the-fly acquired delayed-window dataset.

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

    SciTech Connect

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

    2014-02-07

    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.

  19. Efficiency and rate capability studies of the time-of-flight detector for isochronous mass measurements of stored short-lived nuclei with the FRS-ESR facility

    NASA Astrophysics Data System (ADS)

    Kuzminchuk-Feuerstein, Natalia; Fabian, Benjamin; Diwisch, Marcel; Plaß, Wolfgang R.; Geissel, Hans; Ayet San Andrés, Samuel; Dickel, Timo; Knöbel, Ronja; Scheidenberger, Christoph; Sun, Baohua; Weick, Helmut

    2016-06-01

    A time-of-flight (TOF) detector is used for Isochronous Mass Spectrometry (IMS) with the projectile fragment separator FRS and the heavy-ion storage ring ESR. Exotic nuclei are spatially separated in flight with the FRS at about 70% of the speed of light and are injected into the ESR. The revolution times of the stored ions circulating in the ESR are measured with a thin transmission foil detector. When the ions penetrate the thin detector foil, secondary electrons (SEs) are emitted from the surface and provide the timing information in combination with microchannel plate (MCP) detectors. The isochronous transport of the SEs is performed by perpendicular superimposed electric and magnetic fields. The detection efficiency and the rate capability of the TOF detector have been studied in simulations and experiments. As a result the performance of the TOF detector has been improved substantially: (i) The SE collection efficiency was doubled by use of an optimized set of electric and magnetic field values; now SEs from almost the full area of the foil are transmitted to the MCP detectors. (ii) The rate capability of the TOF detector was improved by a factor of four by the use of MCPs with 5 μm pore size. (iii) With these MCPs and a carbon foil with a reduced thickness of 10 μg/cm2 the number of recorded revolutions in the ESR has been increased by nearly a factor of 10. The number of recorded revolutions determine the precision of the IMS experiments. Heavy-ion measurements were performed with neon ions at 322 MeV/u and uranium fission fragments at about 370 MeV/u. In addition, measurements with an alpha source were performed in the laboratory with a duplicate of the TOF detector.

  20. An efficient procedure for tomotherapy treatment plan verification using the on-board detector

    NASA Astrophysics Data System (ADS)

    Pisaturo, O.; Miéville, F.; Tercier, P.-A.; Allal, A. S.

    2015-02-01

    In this work, a fast and simple procedure for tomotherapy treatment plan verification using the on-board detector (OBD) has been developed. This procedure allows verification of plans with static and dynamic jaws (TomoEDGE). A convolution-based calculation model has been derived in order to link the leaf control sinogram from the treatment planning system to the data acquired by the OBD during a static couch procedure. The convolution kernel has been optimized using simple plans calculated in the Tomotherapy Cheese phantom. The optimal kernel has been found to be a lorentzian function, whose parameter Γ is 0.186 for the 1 cm jaw opening, 0.232 for the 2.5 cm jaw opening and 0.373 for the 5 cm jaw opening. The evaluation has been performed with a γ-index analysis. The dose criterion was 3% of the 95th percentile of the dose distribution and the distance-to-agreement criterion is 2 mm. In order to validate the procedure, it has been applied to around 50 clinical treatment plans, which had already been validated by the Delta4 phantom (Scandidos, Sweden). 96% of the tested plans have passed the criteria. Concerning the other 4%, significant discrepancies between the leaf pattern in the leaf control sinogram and the OBD data have been shown, which might be due to differences in the leaf open time. This corresponds also to a higher sensitivity of this method over the Delta4, adding the possibility of better monitoring the treatment delivery.

  1. Fabrication of multi-layered absorption structure for high quantum efficiency photon detectors

    SciTech Connect

    Fujii, Go; Fukuda, Daiji; Numata, Takayuki; Yoshizawa, Akio; Tsuchida, Hidemi; Fujino, Hidetoshi; Ishii, Hiroyuki; Itatani, Taro; Zama, Tatsuya; Inoue, Shuichiro

    2009-12-16

    We report on some efforts to improve a quantum efficiency of titanium-based optical superconducting transition edge sensors using the multi-layered absorption structure for maximizing photon absorption in the Ti layer. Using complex refractive index values of each film measured by a Spectroscopic Ellipsometry, we designed and optimized by a simulation code. An absorption measurement of fabricated structure was in good agreement with the design and was higher than 99% at optimized wavelength of 1550 nm.

  2. Results from the characterisation of Advanced GAmma Tracking Array prototype detectors and their consequences for the next-generation nuclear physics spectrometer

    NASA Astrophysics Data System (ADS)

    Dimmock, M. R.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Nelson, L.; Nolan, P.; Rigby, S.; Unsworth, C.; Lazarus, I.; Simpson, J.; Medina, P.; Parisel, C.; Santos, C.

    2007-09-01

    The Advanced GAmma Tracking Array (AGATA) is a European project that is aiming to construct a complete 4π High Purity Germanium (HPGe) gamma-ray spectrometer for nuclear structure studies at future Radioactive Ion Beam (RIB) Facilities. The proposed array will utilise digital electronics, Pulse Shape Analysis (PSA) and Gamma-Ray Tracking (GRT) algorithms, to overcome the limited efficiencies encountered by current Escape Suppressed Spectrometers (ESS), whilst maintaining the high Peak-to-Total ratio. Two AGATA symmetrical segmented Canberra Eurisys (CE) prototype HPGe detectors have been tested at the University of Liverpool. A highly collimated Cs-137 (662keV) beam was raster scanned across each detector and data were collected in both singles and coincidence modes. The charge sensitive preamplifier output pulse shapes from all 37 channels (one for each of the 36 segments and one for the centre contact) were digitised and stored for offline analysis. The shapes of the real charge and image charge pulses have been studied to give detailed information on the position dependent response of each detector. 1mm position sensitivity has been achieved with the parameterisation of average pulse shapes, calculated from data collected with each of the detectors. The coincidence data has also been utilised to validate the electric field simulation code Multi Geometry Simulation (MGS). The precisely determined 3D interaction positions allow the comparison of experimental pulse shapes from single site interactions with those generated by the simulation. It is intended that the validated software will be used to calculate a basis data set of pulse shapes for the array, from which any interaction site can be determined through a χ2 minimisation of the digitized pulse with linear combinations of basis pulseshapes. The results from this partial validation, along with those from the investigation into the position sensitivity of each detector are presented.

  3. Study on the novel neutron-to-proton convertor for improving the detection efficiency of a triple GEM based fast neutron detector

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Dong; Yang, He-Run; Ren, Zhong-Guo; Zhang, Jun-We; Yang, Lei; Zhang, Chun-Hui; Ha, Ri-Ba-La; An, Lü-Xing; Hu, Bi-Tao

    2015-02-01

    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 the Institute of Modern Physics (IMP) at Lanzhou in the present work. First, the developed triple GEM detector is tested by measuring its effective gain and energy resolution with 55Fe X-ray source to ensure that it has a good performance. The effective gain and obtained energy resolution is 5.0×104 and around 19.2%, respectively. Secondly, the novel multi-layered HDPE converter is coupled with the cathode of the triple GEM detector making it a high-efficiency fast neutron detector. Its effective neutron response is four times higher than that of the traditional single-layered conversion technique when the converter layer number is 38. Supported by National Natural Science Foundation of China (11135002, 11305232, 11175076)

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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.

  5. 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)

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

    2011-12-01

    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

  6. An investigation of HPGe gamma efficiency calibration software (ANGLE V.3) for applications in nuclear decommissioning.

    PubMed

    Bell, S J; Judge, S M; Regan, P H

    2012-12-01

    High resolution gamma spectrometry offers a rapid method to characterise waste materials on a decommissioning nuclear site. To meet regulatory requirements, measurements must be traceable to national standards, meaning that the spectrometers must be calibrated for a wide range of materials. Semi-empirical modelling software (such as ANGLE™) offers a convenient method to carry out such calibrations. This paper describes an assessment of the modelling software for use by a small laboratory based on a nuclear site. The results confirmed the need for accurate information on the detection construction if the calibration were to be accurate to within 10%. PMID:23041778

  7. High Throughput, High Yield Fabrication of High Quantum Efficiency Back-Illuminated Photon Counting, Far UV, UV, and Visible Detector Arrays

    NASA Technical Reports Server (NTRS)

    Nikzad, Shouleh; Hoenk, M. E.; Carver, A. G.; Jones, T. J.; Greer, F.; Hamden, E.; Goodsall, T.

    2013-01-01

    In this paper we discuss the high throughput end-to-end post fabrication processing of high performance delta-doped and superlattice-doped silicon imagers for UV, visible, and NIR applications. As an example, we present our results on far ultraviolet and ultraviolet quantum efficiency (QE) in a photon counting, detector array. We have improved the QE by nearly an order of magnitude over microchannel plates (MCPs) that are the state-of-the-art UV detectors for many NASA space missions as well as defense applications. These achievements are made possible by precision interface band engineering of Molecular Beam Epitaxy (MBE) and Atomic Layer Deposition (ALD).

  8. Gigahertz-gated InGaAs/InP single-photon detector with detection efficiency exceeding 55% at 1550 nm

    NASA Astrophysics Data System (ADS)

    Comandar, L. C.; Fröhlich, B.; Dynes, J. F.; Sharpe, A. W.; Lucamarini, M.; Yuan, Z. L.; Penty, R. V.; Shields, A. J.

    2015-02-01

    We report on a gated single-photon detector based on InGaAs/InP avalanche photodiodes (APDs) with a single-photon detection efficiency exceeding 55% at 1550 nm. Our detector is gated at 1 GHz and employs the self-differencing technique for gate transient suppression. It can operate nearly dead time free, except for the one clock cycle dead time intrinsic to self-differencing, and we demonstrate a count rate of 500 Mcps. We present a careful analysis of the optimal driving conditions of the APD measured with a dead time free detector characterization setup. It is found that a shortened gate width of 360 ps together with an increased driving signal amplitude and operation at higher temperatures leads to improved performance of the detector. We achieve an afterpulse probability of 7% at 50% detection efficiency with dead time free measurement and a record efficiency for InGaAs/InP APDs of 55% at an afterpulse probability of only 10.2% with a moderate dead time of 10 ns.

  9. Gigahertz-gated InGaAs/InP single-photon detector with detection efficiency exceeding 55% at 1550 nm

    SciTech Connect

    Comandar, L. C.; Fröhlich, B.; Dynes, J. F.; Sharpe, A. W.; Lucamarini, M.; Yuan, Z. L.; Shields, A. J.; Penty, R. V.

    2015-02-28

    We report on a gated single-photon detector based on InGaAs/InP avalanche photodiodes (APDs) with a single-photon detection efficiency exceeding 55% at 1550 nm. Our detector is gated at 1 GHz and employs the self-differencing technique for gate transient suppression. It can operate nearly dead time free, except for the one clock cycle dead time intrinsic to self-differencing, and we demonstrate a count rate of 500 Mcps. We present a careful analysis of the optimal driving conditions of the APD measured with a dead time free detector characterization setup. It is found that a shortened gate width of 360 ps together with an increased driving signal amplitude and operation at higher temperatures leads to improved performance of the detector. We achieve an afterpulse probability of 7% at 50% detection efficiency with dead time free measurement and a record efficiency for InGaAs/InP APDs of 55% at an afterpulse probability of only 10.2% with a moderate dead time of 10 ns.

  10. Charge-collection efficiency and long-term stability of single-crystal CVD diamond detector under different carrier-drift conditions

    NASA Astrophysics Data System (ADS)

    Sato, Yuki; Murakami, Hiroyuki; Shimaoka, Takehiro; Tsubota, Masakatsu; Kaneko, Junichi H.

    2016-04-01

    We investigate the performance of a charged-particle detector fabricated using single-crystal diamond grown by chemical vapor deposition. The detector identified four different 241Am α-particle energies (5.389, 5.443, 5.486, and 5.545 MeV) thanks to its superior energy resolution of 0.407 ± 0.004% for electron drift and 0.418 ± 0.004% for hole drift (full width at half maximum). The charge-collection efficiency inside the diamond crystal was above 97.0% for both electrons and holes. The diamond detector also exhibited no significant degradation in terms of pulse-height spectra and energy resolution during operation for more than 100 h under electron-drift conditions. In contrast, the pulse-height spectra obtained under hole-drift conditions deteriorated because of the polarization phenomenon.

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

    NASA Astrophysics Data System (ADS)

    Huang, Kuan-Chih; Dahal, Rajendra; Lu, James J.-Q.; Danon, Yaron; Bhat, Ishwara B.

    2013-04-01

    We report the continuous p-n junction formation in honeycomb structured Si diode by in situ boron deposition and diffusion process using low pressure chemical vapor deposition for solid-state thermal neutron detection applications. Optimized diffusion temperature of 800 °C was obtained by current density-voltage characteristics for fabricated p+-n diodes. A very low leakage current density of ˜2 × 10-8 A/cm2 at -1 V was measured for enriched boron filled honeycomb structured neutron detector with a continuous p+-n junction. The neutron detection efficiency for a Maxwellian spectrum incident on the face of the detector was measured under zero bias voltage to be ˜26%. These results are very encouraging for fabrication of large area solid-state neutron detector that could be a viable alternative to 3He tube based technology.

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

    SciTech Connect

    Yun, Seungman; Tanguay, Jesse; Cunningham, Ian A.; Kim, Ho Kyung

    2013-04-15

    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

  13. Neutrino Detectors: Challenges and Opportunities

    SciTech Connect

    Soler, F. J. P.

    2011-10-06

    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.

  14. Strategy of HPGe screening measurements in the SuperNEMO experiment

    SciTech Connect

    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 Collaboration: SuperNEMO Collaboration

    2013-08-08

    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}(0ν)>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.

  15. Semiconductor detectors for Compton imaging in nuclear medicine

    NASA Astrophysics Data System (ADS)

    Harkness, LJ; Judson, D. S.; Kennedy, H.; Sweeney, A.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Nolan, P. J.; Sampson, J. A.; Burrows, I.; Groves, J.; Headspith, J.; Lazarus, I. H.; Simpson, J.; Bimson, W. E.; Kemp, G. J.

    2012-01-01

    An investigation is underway at the University of Liverpool to assess the suitability of two position sensitive semiconductor detectors as components of a Compton camera for nuclear medical imaging. The ProSPECTus project aims to improve image quality, provide shorter data acquisition times and lower patient doses by replacing conventional Single Photon Emission Computed Tomography (SPECT) systems. These mechanically collimated systems are employed to locate a radioactive tracer that has been administered to a patient to study specifically targeted physiological processes. The ProSPECTus system will be composed of a Si(Li) detector and a High Purity Germanium (HPGe) detector, a configuration deemed optimum using a validated Geant4 simulation package. Characterising the response of the detectors to gamma irradiation is essential in maximising the sensitivity and image resolution of the system. To this end, the performance of the HPGe ProSPECTus detector and a suitable Si(Li) detector has been assessed at the University of Liverpool. The energy resolution of the detectors has been measured and a surface scan of the Si(Li) detector has been performed using a finely collimated 241Am gamma ray source. Results from the investigation will be presented.

  16. Photon detectors

    SciTech Connect

    Va`vra, J.

    1995-10-01

    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.

  17. Charge collection performance of a segmented planar high-purity germanium detector

    NASA Astrophysics Data System (ADS)

    Cooper, R. J.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Grint, A. N.; Harkness, L. J.; Nolan, P. J.; Oxley, D. C.; Scraggs, D. P.; Lazarus, I.; Simpson, J.; Dobson, J.

    2008-10-01

    High-precision scans of a segmented planar high-purity germanium (HPGe) detector have been performed with a range of finely collimated gamma ray beams allowing the response as a function of gamma ray interaction position to be quantified. This has allowed the development of parametric pulse shape analysis (PSA) techniques and algorithms for the correction of imperfections in performance. In this paper we report on the performance of this detector, designed for use in a positron emission tomography (PET) development system.

  18. Enhanced Detection Efficiency of Direct Conversion X-ray Detector Using Polyimide as Hole-Blocking Layer

    PubMed Central

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

    2013-01-01

    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/μm) 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 cm2/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

  19. Efficiency of the cross-correlation statistic for gravitational wave stochastic background signals with non-Gaussian noise and heterogeneous detector sensitivities

    NASA Astrophysics Data System (ADS)

    Martellini, Lionel; Regimbau, Tania

    2015-11-01

    Under standard assumptions including stationary and serially uncorrelated Gaussian gravitational wave stochastic background signal and noise distributions, as well as homogenous detector sensitivities, the standard cross-correlation detection statistic is known to be optimal in the sense of minimizing the probability of a false dismissal at a fixed value of the probability of a false alarm. The focus of this paper is to analyze the comparative efficiency of this statistic, vs a simple alternative statistic obtained by cross-correlating the squared measurements, in situations that deviate from such standard assumptions. We find that differences in detector sensitivities have a large impact on the comparative efficiency of the cross-correlation detection statistic, which is dominated by the alternative statistic when these differences reach 1 order of magnitude. This effect holds even when both the signal and noise distributions are Gaussian. While the presence of non-Gaussian signals has no material impact for reasonable parameter values, the relative inefficiency of the cross-correlation statistic is less prominent for fat-tailed noise distributions, but it is magnified in case noise distributions have skewness parameters of opposite signs. Our results suggest that introducing an alternative detection statistic can lead to noticeable sensitivity gains when noise distributions are possibly non-Gaussian and/or when detector sensitivities exhibit substantial differences, a situation that is expected to hold in joint detections from Advanced LIGO and Advanced Virgo, in particular in the early phases of development of the detectors, or in joint detections from Advanced LIGO and the Einstein Telescope.

  20. 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)

    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

    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.

  1. 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

    Tanaka, Y. T.; Yoshikawa, I.; Yoshioka, K.; Terasawa, T.; Saito, Y.; Mukai, T.

    2007-03-15

    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.

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

    PubMed

    Tanaka, Y T; Yoshikawa, I; Yoshioka, K; Terasawa, T; Saito, Y; Mukai, T

    2007-03-01

    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.

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

    SciTech Connect

    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.; and others

    2014-04-15

    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 × 10{sup 6} cm{sup −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.

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

    SciTech Connect

    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.

    2014-04-14

    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, the overlap of particle tracks leads to under-counting at typical processing conditions (5h 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.

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

    DOE PAGES

    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.; et al

    2014-04-14

    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, the overlap of particle tracks leads to under-counting at typical processing conditions (5h 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 detectionmore » 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.« less

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

    PubMed

    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

    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 × 10(6) 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. PMID:24784597

  7. Advanced UV Detectors and Detector Arrays

    NASA Technical Reports Server (NTRS)

    Pankove, Jacques I.; Torvik, John

    1998-01-01

    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.

  8. Investigation of quantum efficiency in mid-wave infrared (MWIR) InAs/GaSb type-II strained layer superlattice (T2SL) detectors

    NASA Astrophysics Data System (ADS)

    Acosta, Lilian; Klein, Brianna; Tian, Zhao-Bing; Frantz, Eric; Myers, Stephen; Gautam, Nutan; Schuler-Sandy, Ted; Plis, Elena; Krishna, Sanjay

    2014-02-01

    The objective of this study is to optimize the absorption in the active region of InAs/GaSb T2SL photodetectors for the realization of high-performance MWIR devices. Two sets of MWIR (λ100% cut-off ~ 5.5μm at 77K) T2SL detectors were realized; one set with varied detector absorber thickness, the other set with varied T2SL period. The T2SL material quality was evaluated on the basis of room temperature photoluminescence (RTPL) and the high-resolution X-ray diffraction (HRXRD) data. Then the device performance was compared using spectral response, dark current and responsivity measurements. Finally, quantum efficiency was calculated and employed as a metric for the definition of the optimal T2SL period and active region thickness. For the first part of the study, a homojunction pin architecture based on 8 monolayers (MLs) InAs/8MLs GaSb T2SL was used. The thickness of the non-intentionally doped absorber layers were 1.5μm, 2.5μm, and 3.5μm. For the second part of the study, unipolar barrier (pBiBn) devices were grown. The thickness of the absorber region and the T2SL constituent InAs layer thicknesses were kept the same (1.5 μm and 8 MLs, respectively) whereas the T2SL constituent GaSb thickness was varied as 6 MLs, 8 MLs, and 10 MLs. We have found that the pin detector with 2.5 μm thick absorber and the pBiBn detector with 8 ML InAs/ 8 ML GaSb T2SL composition are, within the scope of this study, optimal for the realization of MWIR single-element devices and FPAs with corresponding architectures.

  9. Ge well detector calibration by means of a trial and error procedure using the dead layers as a unique parameter in a Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Courtine, Fabien; Pilleyre, Thierry; Sanzelle, Serge; Miallier, Didier

    2008-11-01

    The project aimed at modelling an HPGe well detector in view to predict its photon-counting efficiency by means of the Monte Carlo simulation code GEANT4. Although a qualitative and quantitative description of the crystal and housing was available, uncertainties were associated to parameters controlling the detector response. This induced poor agreement between the efficiency calculated on the basis of nominal data and the actual efficiency experimentally measured with a 137Cs point source. It was then decided to improve the model, by parameterization of a trial and error method. The distribution of the dead layers was adopted as a unique parameter, in order to explore the possibilities and pertinence of this parameter. In the course of the work, it appeared necessary to introduce the possibility that the thickness of the dead layers was not uniform for a given surface. At the end of the process, the results allowed to conclude that the approach was able to give a model adapted to practical application with a satisfactory precision in the calculated efficiency. The pattern of the "dead layers" that was obtained is characterized by a variable thickness which seems to be physically relevant. It implicitly and partly accounts for effects that are not originated from actual dead layers, such as incomplete charge collection. But, such effects, which are uneasily accounted for, can, in a first approximation, be represented by "dead layers"; this is an advantage of the parameterization that was adopted.

  10. Neutron detector

    DOEpatents

    Stephan, Andrew C.; Jardret; Vincent D.

    2011-04-05

    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.

  11. Neutron detector

    SciTech Connect

    Stephan, Andrew C; Jardret, Vincent D

    2009-04-07

    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.

  12. Intelligent Detector Design

    SciTech Connect

    Graf, N.A.; /SLAC

    2012-06-11

    As the complexity and resolution of imaging detectors increases, the need for detailed simulation of the experimental setup also becomes more important. Designing the detectors requires efficient tools to simulate the detector response and reconstruct the events. We have developed efficient and flexible 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. 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.

  13. The effects of Doppler broadening and detector resolution on the performance of three-stage Compton cameras

    PubMed Central

    Mackin, Dennis; Polf, Jerimy; Peterson, Steve; Beddar, Sam

    2013-01-01

    Purpose: The authors investigated how the characteristics of the detectors used in a three-stage Compton camera (CC) affect the CC's ability to accurately measure the emission distribution and energy spectrum of prompt gammas (PG) emitted by nuclear de-excitations during proton therapy. The detector characteristics they studied included the material (high-purity germanium [HPGe] and cadmium zinc telluride [CZT]), Doppler broadening (DB), and resolution (lateral, depth, and energy). Methods: The authors simulated three-stage HPGe and CZT CCs of various configurations, detecting gammas from point sources with energies ranging from 0.511 to 7.12 MeV. They also simulated a proton pencil beam irradiating a tissue target to study how the detector characteristics affect the PG data measured by CCs in a clinical proton therapy setting. They used three figures of merit: the distance of closest approach (DCA) and the point of closest approach (PCA) between the measured and actual position of the PG emission origin, and the calculated energy resolution. Results: For CCs with HPGe detectors, DB caused the DCA to be greater than 3 mm for 14% of the 6.13 MeV gammas and 20% of the 0.511 MeV gammas. For CCs with CZT detectors, DB caused the DCA to be greater than 3 mm for 18% of the 6.13 MeV gammas and 25% of the 0.511 MeV gammas. The full width at half maximum (FWHM) of the PCA in the \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}\\hat z\\end{equation*} \\end{document}z^ direction for HPGe and CZT detectors ranged from 1.3 to 0.4 mm for gammas with incident energy ranging from 0.511 to 7.12 MeV. For CCs composed of HPGe detectors, the resolution of incident gamma energy calculated by the CC ranged from 6% to 1% for gammas with true incident energies from 0.511 to 7.12 Me

  14. The effects of Doppler broadening and detector resolution on the performance of three-stage Compton cameras

    SciTech Connect

    Mackin, Dennis; Polf, Jerimy; Peterson, Steve; Beddar, Sam

    2013-01-15

    Purpose: The authors investigated how the characteristics of the detectors used in a three-stage Compton camera (CC) affect the CC's ability to accurately measure the emission distribution and energy spectrum of prompt gammas (PG) emitted by nuclear de-excitations during proton therapy. The detector characteristics they studied included the material (high-purity germanium [HPGe] and cadmium zinc telluride [CZT]), Doppler broadening (DB), and resolution (lateral, depth, and energy). Methods: The authors simulated three-stage HPGe and CZT CCs of various configurations, detecting gammas from point sources with energies ranging from 0.511 to 7.12 MeV. They also simulated a proton pencil beam irradiating a tissue target to study how the detector characteristics affect the PG data measured by CCs in a clinical proton therapy setting. They used three figures of merit: the distance of closest approach (DCA) and the point of closest approach (PCA) between the measured and actual position of the PG emission origin, and the calculated energy resolution. Results: For CCs with HPGe detectors, DB caused the DCA to be greater than 3 mm for 14% of the 6.13 MeV gammas and 20% of the 0.511 MeV gammas. For CCs with CZT detectors, DB caused the DCA to be greater than 3 mm for 18% of the 6.13 MeV gammas and 25% of the 0.511 MeV gammas. The full width at half maximum (FWHM) of the PCA in the z-caret direction for HPGe and CZT detectors ranged from 1.3 to 0.4 mm for gammas with incident energy ranging from 0.511 to 7.12 MeV. For CCs composed of HPGe detectors, the resolution of incident gamma energy calculated by the CC ranged from 6% to 1% for gammas with true incident energies from 0.511 to 7.12 MeV. For CCs composed of CZT detectors, the resolution of gamma energy calculated by the CC ranged from 10% to 1% for gammas with true incident energies from 0.511 to 7.12 MeV. For HPGe and CZT CCs in which all detector effect were included, the DCA was less than 3 mm for 75% and 68% of the

  15. Effect of the wire width on the intrinsic detection efficiency of superconducting-nanowire single-photon detectors

    SciTech Connect

    Lusche, R. Semenov, A.; Ilin, K.; Siegel, M.; Korneeva, Y.; Trifonov, A.; Korneev, A.; Goltsman, G.; Vodolazov, D.; Hübers, H.-W.

    2014-07-28

    A thorough spectral study of the intrinsic single-photon detection efficiency in superconducting TaN and NbN nanowires with different widths has been performed. The experiment shows that the cut-off of the intrinsic detection efficiency at near-infrared wavelengths is most likely controlled by the local suppression of the barrier for vortex nucleation around the absorption site. Beyond the cut-off quasi-particle diffusion in combination with spontaneous, thermally activated vortex crossing explains the detection process. For both materials, the reciprocal cut-off wavelength scales linearly with the wire width where the scaling factor agrees with the hot-spot detection model.

  16. Mathematical efficiency calibration with uncertain source geometries using smart optimization

    SciTech Connect

    Menaa, N.; Mirolo, L.

    2011-07-01

    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)

  17. Power and area efficient 4-bit column-level ADC in a CMOS pixel sensor for the ILD vertex detector

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Morel, F.; Hu-Guo, Ch; Hu, Y.

    2013-01-01

    A 48 × 64 pixels prototype CMOS pixel sensor (CPS) integrated with 4-bit column-level, self triggered ADCs for the outer layers of the ILD vertex detector (VTX) was developed and fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. The pixel concept combines in-pixel amplification with a correlated double sampling (CDS) operation. The ADCs accommodating the pixel read out in a rolling shutter mode complete the conversion by performing a multi-bit/step approximation. The design was optimised for power saving at sampling frequency. The prototype sensor is currently at the stage of being started testing and evaluation. So what is described is based on post simulation results rather than test data. This 4-bit ADC dissipates, at a 3-V supply and 6.25-MS/s sampling rate, 486 μW in its inactive mode, which is by far the most frequent. This value rises to 714 μW in case of the active mode. Its footprint amounts to 35 × 545 μm2.

  18. Modeling of neutron spectrum in the gamma spectroscopy measurements with Ge-detectors

    NASA Astrophysics Data System (ADS)

    Knežević, D.; Jovančević, N.; Krmar, M.; Petrović, J.

    2016-10-01

    In this study, we present a novel approach for estimation of neutron spectra that are present during gamma spectroscopy measurements performed by a Ge detector. This method is based on the calculation of the neutron spectra by using an unfolding procedure, where the activity of the Ge isotopes, produced by the neutron reactions, and the available cross section data for those reactions are the input parameters. This new approach was tested by background gamma spectroscopy measurements with a HPGe detector. Obtained results show that this method can provide useful information about the neutron spectra at the position of the Ge detectors.

  19. A direct comparison of Ge and Si(Li) detectors in the 2--20 keV range

    SciTech Connect

    Rossington, C.S.; Giauque, R.D.; Jaklevic, J.M.

    1991-10-01

    The spectral response of high purity Ge (HPGe) and lithium-drifted Si (Si(Li)) surface barrier detectors of similar geometry has been measured over a range of x-ray energies under identical experimental conditions. Detector characteristics such as spectral background, escape peak intensity, entrance window absorption, and energy resolution are presented and compared. Although these characteristic have been discussed in the literature previously, this paper represents an attempt to consolidate the information by making comparisons under equivalent experimental conditions for the two types of detectors. A primary goal of the study is a comparison of the two types of detectors for use in x-ray fluorescence applications.

  20. Method for manufacturing solid-state thermal neutron detectors with simultaneous high thermal neutron detection efficiency (>50%) and neutron to gamma discrimination (>1.0E4)

    SciTech Connect

    Nikolic, Rebecca J.; Conway, Adam M.; Heineck, Daniel; Voss, Lars F.; Wang, Tzu Fang; Shao, Qinghui

    2013-10-15

    Methods for manufacturing solid-state thermal neutron detectors with simultaneous high thermal neutron detection efficiency (>50%) and neutron to gamma discrimination (>10.sup.4) are provided. A structure is provided that includes a p+ region on a first side of an intrinsic region and an n+ region on a second side of the intrinsic region. The thickness of the intrinsic region is minimized to achieve a desired gamma discrimination factor of at least 1.0E+04. Material is removed from one of the p+ region or the n+ region and into the intrinsic layer to produce pillars with open space between each pillar. The open space is filed with a neutron sensitive material. An electrode is placed in contact with the pillars and another electrode is placed in contact with the side that is opposite of the intrinsic layer with respect to the first electrode.

  1. Lower limits of spin detection efficiency for two-parameter two-qubit (TPTQ) states with non-ideal ferromagnetic detectors

    NASA Astrophysics Data System (ADS)

    Majd, Nayereh; Ghasemi, Zahra

    2016-10-01

    We have investigated a TPTQ state as an input state of a non-ideal ferromagnetic detectors. Minimal spin polarization required to demonstrate spin entanglement according to entanglement witness and CHSH inequality with respect to (w.r.t.) their two free parameters have been found, and we have numerically shown that the entanglement witness is less stringent than the direct tests of Bell's inequality in the form of CHSH in the entangled limits of its free parameters. In addition, the lower limits of spin detection efficiency fulfilling secure cryptographic key against eavesdropping have been derived. Finally, we have considered TPTQ state as an output of spin decoherence channel and the region of ballistic transmission time w.r.t. spin relaxation time and spin dephasing time has been found.

  2. Lower limits of spin detection efficiency for two-parameter two-qubit (TPTQ) states with non-ideal ferromagnetic detectors

    NASA Astrophysics Data System (ADS)

    Majd, Nayereh; Ghasemi, Zahra

    2016-07-01

    We have investigated a TPTQ state as an input state of a non-ideal ferromagnetic detectors. Minimal spin polarization required to demonstrate spin entanglement according to entanglement witness and CHSH inequality with respect to (w.r.t.) their two free parameters have been found, and we have numerically shown that the entanglement witness is less stringent than the direct tests of Bell's inequality in the form of CHSH in the entangled limits of its free parameters. In addition, the lower limits of spin detection efficiency fulfilling secure cryptographic key against eavesdropping have been derived. Finally, we have considered TPTQ state as an output of spin decoherence channel and the region of ballistic transmission time w.r.t. spin relaxation time and spin dephasing time has been found.

  3. A new experimental procedure for determination of photoelectric efficiency of a NaI(Tl) detector used for nuclear medicine liquid waste monitoring with traceability to a reference standard radionuclide calibrator.

    PubMed

    Ceccatelli, A; Campanella, F; Ciofetta, G; Marracino, F M; Cannatà, V

    2010-02-01

    To determine photopeak efficiency for (99m)Tc of the NaI(Tl) detector used for liquid waste monitoring at the Nuclear Medicine Unit of IRCCS Paediatric Hospital Bambino Gesù in Rome, a specific experimental procedure, with traceability to primary standards, was developed. Working with the Italian National Institute for Occupational Prevention and Safety, two different calibration source geometries were employed and the detector response dependence on geometry was investigated. The large percentage difference (almost 40%) between the two efficiency values obtained showed that geometrical effects cannot be neglected.

  4. Derivation of Sensitivity of a Geiger Mode Apds Detector from a Given Efficiency to Estimate Total Photon Counts

    NASA Astrophysics Data System (ADS)

    Hammura, Kiyotaka; Williams, David Arfon

    2009-06-01

    The detection sensitivity (DS) of the commercial single-photon-receiver based on InGaAs gatemode avalanche photodiode is estimated. Instalment of a digital-blanking-system (DBS) to reduce dark current makes the difference between DS and the detection efficiency (DE). By numerical simulations, it is found that the blanked number of light-pulses by DBS is as many as a quarter of all incident pulses for a specific operation condition. DS is estimated at 0.27, which is 35% larger than a given DE.

  5. Investigations of quantum efficiency in type-II InAs/GaSb very long wavelength infrared superlattice detectors

    NASA Astrophysics Data System (ADS)

    Li, Xiaochao; Jiang, Dongwei; Zhang, Yong; Liu, Gang; Wang, Dongbo; Yu, Qingjiang; Zhao, Liancheng

    2016-04-01

    In this paper, we have investigated the quantum efficiency (QE) of InAs/GaSb T2SL very long wavelength Infrared (VLWIR) photodetectors with 50% cutoff of 12.7 μm. Due to the small depletion width and similar absorption coefficient in the T2SL material system, the minority-carrier diffusion length was determined as the key element to improve the QE of VLWIR T2SL photodetectors. The minority-carrier diffusion length was estimated by a comparison of the experimental data with the Hovel model. Our result suggest that the short hole diffusion length (Lh ∼ 520 nm) and the large its ratio to the width of this region (xn/Lh) are considered against the photo-excited carrier collection in the T2SL photodetectors. In addition, the influence of surface recombination velocity (Sh) on the QE of the T2SL photodetectors is also studied. The change of QE with Sh is not so significant due to the relatively low absorption coefficient and short hole diffusion length in our photodetector.

  6. Multiple detectors "Influence Method".

    PubMed

    Rios, I J; Mayer, R E

    2016-05-01

    The "Influence Method" is conceived for the absolute determination of a nuclear particle flux in the absence of known detector efficiency and without the need to register coincidences of any kind. This method exploits the influence of the presence of one detector in the count rate of another detector, when they are placed one behind the other and define statistical estimators for the absolute number of incident particles and for the efficiency (Rios and Mayer, 2015a). Its detailed mathematical description was recently published (Rios and Mayer, 2015b) and its practical implementation in the measurement of a moderated neutron flux arising from an isotopic neutron source was exemplified in (Rios and Mayer, 2016). With the objective of further reducing the measurement uncertainties, in this article we extend the method for the case of multiple detectors placed one behind the other. The new estimators for the number of particles and the detection efficiency are herein derived.

  7. Multiple detectors "Influence Method".

    PubMed

    Rios, I J; Mayer, R E

    2016-05-01

    The "Influence Method" is conceived for the absolute determination of a nuclear particle flux in the absence of known detector efficiency and without the need to register coincidences of any kind. This method exploits the influence of the presence of one detector in the count rate of another detector, when they are placed one behind the other and define statistical estimators for the absolute number of incident particles and for the efficiency (Rios and Mayer, 2015a). Its detailed mathematical description was recently published (Rios and Mayer, 2015b) and its practical implementation in the measurement of a moderated neutron flux arising from an isotopic neutron source was exemplified in (Rios and Mayer, 2016). With the objective of further reducing the measurement uncertainties, in this article we extend the method for the case of multiple detectors placed one behind the other. The new estimators for the number of particles and the detection efficiency are herein derived. PMID:26943904

  8. Detective quantum efficiency for photon-counting hybrid pixel detectors in the tender X-ray domain: application to Medipix3RX.

    PubMed

    Rinkel, Jean; Magalhães, Debora; Wagner, Franz; Meneau, Florian; Cesar Vicentin, Flavio

    2016-01-01

    Synchrotron-radiation-based X-ray imaging techniques using tender X-rays are facing a growing demand, in particular to probe the K absorption edges of low-Z elements. Here, a mathematical model has been developed for estimating the detective quantum efficiency (DQE) at zero spatial frequency in the tender X-ray energy range for photon-counting detectors by taking into account the influence of electronic noise. The experiments were carried out with a Medipix3RX ASIC bump-bonded to a 300 µm silicon sensor at the Soft X-ray Spectroscopy beamline (D04A-SXS) of the Brazilian Synchrotron Light Laboratory (LNLS, Campinas, Brazil). The results show that Medipix3RX can be used to develop new imaging modalities in the tender X-ray range for energies down to 2 keV. The efficiency and optimal DQE depend on the energy and flux of the photons. The optimal DQE values were found in the 7.9-8.6 keV photon energy range. The DQE deterioration for higher energies due to the lower absorption efficiency of the sensor and for lower energies due to the electronic noise has been quantified. The DQE for 3 keV photons and 1 × 10(4) photons pixel(-1) s(-1) is similar to that obtained with 19 keV photons. Based on our model, the use of Medipix3RX could be extended down to 2 keV which is crucial for coming applications in imaging techniques at modern synchrotron sources. PMID:26698065

  9. Position sensitive solid state detectors

    NASA Astrophysics Data System (ADS)

    Schnatterly, S. E.; Husk, D.

    1986-05-01

    Solid state detectors have been used for years as high quantum efficiency detectors for visible light. In this paper the use of PDA and CCD, solid state detectors, in the X-ray region will be discussed. In particular examples of data in the soft X-ray region are presented. Finally the use of phosphor coatings to enhance the sensitivity of solid state detectors is described.

  10. The high-efficiency γ-ray spectroscopy setup γ3 at HIγS

    NASA Astrophysics Data System (ADS)

    Löher, B.; Derya, V.; Aumann, T.; Beller, J.; Cooper, N.; Duchêne, M.; Endres, J.; Fiori, E.; Isaak, J.; Kelley, J.; Knörzer, M.; Pietralla, N.; Romig, C.; Savran, D.; Scheck, M.; Scheit, H.; Silva, J.; Tonchev, A.; Tornow, W.; Weller, H.; Werner, V.; Zilges, A.

    2013-09-01

    The existing Nuclear Resonance Fluorescence (NRF) setup at the HIγS facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform γ-γ coincidence experiments. The new setup combines large volume LaBr3 : Ce detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient γ-ray spectroscopy setup with the mono-energetic high-intensity photon beam of HIγS provides a worldwide unique experimental facility to investigate the γ-decay pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus 32S at 8.125 MeV beam energy. The relative γ-decay branching ratio from the 1+ level at 8125.4 keV to the first excited 2+ state was determined to 15.7(3)%.

  11. Transmutation detectors

    NASA Astrophysics Data System (ADS)

    Viererbl, L.; Lahodová, Z.; Klupák, V.; Sus, F.; Kučera, J.; Kůs, P.; Marek, M.

    2011-03-01

    We have designed a new type of detectors, called transmutation detectors, which can be used primarily for neutron fluence measurement. The transmutation detector method differs from the commonly used activation detector method in evaluation of detector response after irradiation. Instead of radionuclide activity measurement using radiometric methods, the concentration of stable non-gaseous nuclides generated by transmutation in the detector is measured using analytical methods like mass spectrometry. Prospective elements and nuclear reactions for transmutation detectors are listed and initial experimental results are given. The transmutation detector method could be used primarily for long-term measurement of neutron fluence in fission nuclear reactors, but in principle it could be used for any type of radiation that can cause transmutation of nuclides in detectors. This method could also be used for measurement in accelerators or fusion reactors.

  12. 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

    Hussain, Nazim; /McGill U.

    2011-07-01

    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.

  13. HIgh Rate X-ray Fluorescence Detector

    SciTech Connect

    Grudberg, Peter Matthew

    2013-04-30

    The purpose of this project was to develop a compact, modular multi-channel x-ray detector with integrated electronics. This detector, based upon emerging silicon drift detector (SDD) technology, will be capable of high data rate operation superior to the current state of the art offered by high purity germanium (HPGe) detectors, without the need for liquid nitrogen. In addition, by integrating the processing electronics inside the detector housing, the detector performance will be much less affected by the typically noisy electrical environment of a synchrotron hutch, and will also be much more compact than current systems, which can include a detector involving a large LN2 dewar and multiple racks of electronics. The combined detector/processor system is designed to match or exceed the performance and features of currently available detector systems, at a lower cost and with more ease of use due to the small size of the detector. In addition, the detector system is designed to be modular, so a small system might just have one detector module, while a larger system can have many you can start with one detector module, and add more as needs grow and budget allows. The modular nature also serves to simplify repair. In large part, we were successful in achieving our goals. We did develop a very high performance, large area multi-channel SDD detector, packaged with all associated electronics, which is easy to use and requires minimal external support (a simple power supply module and a closed-loop water cooling system). However, we did fall short of some of our stated goals. We had intended to base the detector on modular, large-area detectors from Ketek GmbH in Munich, Germany; however, these were not available in a suitable time frame for this project, so we worked instead with pnDetector GmbH (also located in Munich). They were able to provide a front-end detector module with six 100 m^2 SDD detectors (two monolithic arrays of three elements each) along with

  14. Layered semiconductor neutron detectors

    DOEpatents

    Mao, Samuel S; Perry, Dale L

    2013-12-10

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  15. Characterisation of the SmartPET planar Germanium detectors

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

    Small Animal Reconstruction PET (SmartPET) is a project funded by the UK medical research council (MRC) to demonstrate proof of principle that Germanium can be utilised in Positron Emission Tomography (PET). The SmartPET demonstrator consists of two orthogonal strip High Purity Germanium (HPGe) planar detectors manufactured by ORTEC. The aim of the project is to produce images of an internal source with sub mm 3 spatial resolution. Before this image can be achieved the detectors have to be fully characterised to understand the response at any given location to a γ-ray interaction. This has been achieved by probing the two detectors at a number of specified points with collimated sources of various energies and strengths. A 1 mm diameter collimated beam of photons was raster scanned in 1 mm steps across the detector. Digital pulse shape data were recorded from all the detector channels and the performance of the detector for energy and position determination has been assessed. Data will be presented for the first SmartPET detector.

  16. Photon detectors with gaseous amplification

    SciTech Connect

    Va`vra, J.

    1996-08-01

    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.

  17. Smoke Detector

    NASA Technical Reports Server (NTRS)

    1979-01-01

    In the photo, Fire Chief Jay Stout of Safety Harbor, Florida, is explaining to young Richard Davis the workings of the Honeywell smoke and fire detector which probably saved Richard's life and that of his teen-age brother. Alerted by the detector's warning, the pair were able to escape their burning home. The detector in the Davis home was one of 1,500 installed in Safety Harbor residences in a cooperative program conducted by the city and Honeywell Inc.

  18. Direct Detectors for Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Clough, R. N.; Moldovan, G.; Kirkland, A. I.

    2014-06-01

    There is interest in improving the detectors used to capture images in transmission electron microscopy. Detectors with an improved modulation transfer function at high spatial frequencies allow for higher resolution in images at lower magnification, which leads to an increased effective field of view. Detectors with improved detective quantum efficiency are important for low dose applications. One way in which these performance enhancements can be achieved is through direct detection, where primary electrons are converted directly into suitable electrical signals by the detector rather than relying on an indirect electron to photon conversion before detection. In this paper we present the characterisation of detector performance for a number of different direct detection technologies, and compare these technologies to traditional indirect detectors. Overall our results show that direct detection enables a significant improvement in all aspects of detector performance.

  19. 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

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

    2014-04-01

    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.

  20. 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

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

    2014-04-01

    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

  1. Pocked surface neutron detector

    DOEpatents

    McGregor, Douglas; Klann, Raymond

    2003-04-08

    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.

  2. LEDs for Efficient Energy

    ERIC Educational Resources Information Center

    Guerin, David A.

    1978-01-01

    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)

  3. Optical Detectors

    NASA Astrophysics Data System (ADS)

    Goushcha, Alexander; Tabbert, Bernd

    Optical detectors are applied in all fields of human activities - from basic research to commercial applications in communication, automotive, medical imaging, homeland security, and other fields. The processes of light interaction with matter described in other chapters of this handbook form the basis for understanding the optical detectors physics and device properties.

  4. Optical Detectors

    NASA Astrophysics Data System (ADS)

    Tabbert, Bernd; Goushcha, Alexander

    Optical detectors are applied in all fields of human activities from basic research to commercial applications in communication, automotive, medical imaging, homeland security, and other fields. The processes of light interaction with matter described in other chapters of this handbook form the basis for understanding the optical detectors physics and device properties.

  5. An Efficient, FPGA-Based, Cluster Detection Algorithm Implementation for a Strip Detector Readout System in a Time Projection Chamber Polarimeter

    NASA Technical Reports Server (NTRS)

    Gregory, Kyle J.; Hill, Joanne E. (Editor); Black, J. Kevin; Baumgartner, Wayne H.; Jahoda, Keith

    2016-01-01

    A fundamental challenge in a spaceborne application of a gas-based Time Projection Chamber (TPC) for observation of X-ray polarization is handling the large amount of data collected. The TPC polarimeter described uses the APV-25 Application Specific Integrated Circuit (ASIC) to readout a strip detector. Two dimensional photoelectron track images are created with a time projection technique and used to determine the polarization of the incident X-rays. The detector produces a 128x30 pixel image per photon interaction with each pixel registering 12 bits of collected charge. This creates challenging requirements for data storage and downlink bandwidth with only a modest incidence of photons and can have a significant impact on the overall mission cost. An approach is described for locating and isolating the photoelectron track within the detector image, yielding a much smaller data product, typically between 8x8 pixels and 20x20 pixels. This approach is implemented using a Microsemi RT-ProASIC3-3000 Field-Programmable Gate Array (FPGA), clocked at 20 MHz and utilizing 10.7k logic gates (14% of FPGA), 20 Block RAMs (17% of FPGA), and no external RAM. Results will be presented, demonstrating successful photoelectron track cluster detection with minimal impact to detector dead-time.

  6. An efficient, FPGA-based, cluster detection algorithm implementation for a strip detector readout system in a Time Projection Chamber polarimeter

    NASA Astrophysics Data System (ADS)

    Gregory, Kyle J.; Hill, Joanne E.; Black, J. Kevin; Baumgartner, Wayne H.; Jahoda, Keith

    2016-05-01

    A fundamental challenge in a spaceborne application of a gas-based Time Projection Chamber (TPC) for observation of X-ray polarization is handling the large amount of data collected. The TPC polarimeter described uses the APV-25 Application Specific Integrated Circuit (ASIC) to readout a strip detector. Two dimensional photo- electron track images are created with a time projection technique and used to determine the polarization of the incident X-rays. The detector produces a 128x30 pixel image per photon interaction with each pixel registering 12 bits of collected charge. This creates challenging requirements for data storage and downlink bandwidth with only a modest incidence of photons and can have a significant impact on the overall mission cost. An approach is described for locating and isolating the photoelectron track within the detector image, yielding a much smaller data product, typically between 8x8 pixels and 20x20 pixels. This approach is implemented using a Microsemi RT-ProASIC3-3000 Field-Programmable Gate Array (FPGA), clocked at 20 MHz and utilizing 10.7k logic gates (14% of FPGA), 20 Block RAMs (17% of FPGA), and no external RAM. Results will be presented, demonstrating successful photoelectron track cluster detection with minimal impact to detector dead-time.

  7. Gaseous Detectors

    NASA Astrophysics Data System (ADS)

    Titov, Maxim

    Since long time, the compelling scientific goals of future high-energy physics experiments were a driving factor in the development of advanced detector technologies. A true innovation in detector instrumentation concepts came in 1968, with the development of a fully parallel readout for a large array of sensing elements - the Multi-Wire Proportional Chamber (MWPC), which earned Georges Charpak a Nobel prize in physics in 1992. Since that time radiation detection and imaging with fast gaseous detectors, capable of economically covering large detection volumes with low mass budget, have been playing an important role in many fields of physics. Advances in photolithography and microprocessing techniques in the chip industry during the past decade triggered a major transition in the field of gas detectors from wire structures to Micro-Pattern Gas Detector (MPGD) concepts, revolutionizing cell-size limitations for many gas detector applications. The high radiation resistance and excellent spatial and time resolution make them an invaluable tool to confront future detector challenges at the next generation of colliders. The design of the new micro-pattern devices appears suitable for industrial production. Novel structures where MPGDs are directly coupled to the CMOS pixel readout represent an exciting field allowing timing and charge measurements as well as precise spatial information in 3D. Originally developed for the high-energy physics, MPGD applications have expanded to nuclear physics, photon detection, astroparticle and neutrino physics, neutron detection, and medical imaging.

  8. PET detector modules based on novel detector technologies

    SciTech Connect

    Moses, W.W.; Derenzo, S.E.; Budinger, T.F.

    1994-05-01

    A successful PET detector module must identify 511 keV photons with: high efficiency (>85%), high spatial resolution (<5 mm fwhm), low cost (<$600 / in{sup 2}), low dead time (<4 {mu}s in{sup 2}), good timing resolution (<5 ns fwhm for conventional PET, <200 ps fwhm for time of flight), and good energy resolution (<100 keV fwhm), where these requirements are listed in decreasing order of importance. The ``high efficiency`` requirement also implies that the detector modules must pack together without inactive gaps. Several novel and emerging radiation detector technologies could improve the performance of PET detectors. Avalanche photodiodes, PIN photodiodes, metal channel dynode photomultiplier tubes, and new scintillators all have the potential to improve PET detectors significantly.

  9. Performance of A Compact Multi-crystal High-purity Germanium Detector Array for Measuring Coincident Gamma-ray Emissions

    SciTech Connect

    Howard, Chris; Daigle, Stephen; Buckner, Matt; Erikson, Luke E.; Runkle, Robert C.; Stave, Sean C.; Champagne, Art; Cooper, Andrew; Downen, Lori; Glasgow, Brian D.; Kelly, Keegan; Sallaska, Anne

    2015-02-18

    The Multi-sensor Airborne Radiation Survey (MARS) detector is a 14-crystal array of high-purity germanium (HPGe) detectors housed in a single cryostat. The array was used to measure the astrophysical S-factor for the 14N(p,γ)15O* reaction for several transition energies at an effective center of mass energy of 163 keV. Owing to the segmented nature of the MARS detector, the effect of gamma-ray summing was greatly reduced in comparison to past experiments which utilized large, single-crystal detectors. The new S-factor values agree within the uncertainties with the past measurements. Details of the analysis and detector performance will be presented.

  10. Performance of a compact multi-crystal high-purity germanium detector array for measuring coincident gamma-ray emissions

    NASA Astrophysics Data System (ADS)

    Howard, Chris; Daigle, Stephen; Buckner, Matt; Erikson, Luke E.; Runkle, Robert C.; Stave, Sean C.; Champagne, Arthur E.; Cooper, Andrew; Downen, Lori; Glasgow, Brian D.; Kelly, Keegan; Sallaska, Anne

    2015-05-01

    The Multi-sensor Airborne Radiation Survey (MARS) detector is a 14-crystal array of high-purity germanium (HPGe) detectors housed in a single cryostat. The array was used to measure the astrophysical S-factor for the 14N(p,γ)15O* reaction for several transition energies at an effective center-of-mass energy of 163 keV. Owing to the granular nature of the MARS detector, the effect of gamma-ray summing was greatly reduced in comparison to past experiments which utilized large, single-crystal detectors. The new S-factor values agree within their uncertainties with the past measurements. Details of the analysis and detector performance are presented.

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

    SciTech Connect

    Not Available

    2006-10-01

    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.

  12. MS Detectors

    SciTech Connect

    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

    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.

  13. Evaluation of the efficiency of radioactive decontamination for alkyd and epoxy-urethane coating systems

    NASA Astrophysics Data System (ADS)

    Jevremović, Milutin; Milošević, Bratislav; Lazarević, Nataša

    2010-01-01

    This article presents experimental results obtained by the investigation of the efficiency of radioactive decontamination of a metal surface with alkyd and epoxy-urethane coating systems, which are used for the painting of military equipment. During the evaluation of the efficiency of decontamination, the impact of contaminants on the coating was not examined but the amount of contaminants residual after decontamination was, and was determined by activity measurements of the surface. The samples for testing were painted aluminum plates contaminated by liquid solutions of radioactive isotopes 60Co, 133Ba, 152Eu and 241Am (A=12297.91 Bq/ml). Decontamination of contaminated samples was performed with 0.5% detergent solution on the basis of synthetic surfactants. The activity measurements of samples were conducted using gamma spectroscopy system with a high-resolution high-purity germanium (HPGe) detector of relative efficiency of 50% at 60Co (1.33 MeV). The degree of removal of the radioactivity on the samples was observed as an indicator of the efficiency of decontamination. A comparison of the results is presented in relation to the retention time of the contamination on the surface coating, which is an important factor for the efficiency of decontamination. The samples with an alkyd coating system showed better efficiency of decontamination than the samples with the epoxy-urethane coating system, although the coatings based on epoxy and urethane resin were superior in relation to the alkyd in terms of protection, decorative characteristics and chemical resistance. The difference in the efficiency of decontamination for the examined coatings increases almost linearly in relation to the retention time of the contaminants in the coating.

  14. Dedicated 4πβ (LS)-γ (HPGe) digital coincidence system based on synchronous high-speed multichannel data acquisition

    NASA Astrophysics Data System (ADS)

    Chen, Ji-Feng; Song, Ke-Zhu; Liu, Jia-Cheng

    2016-03-01

    A dedicated 4πβ (LS) -γ (HPGe) digital coincidence system with five acquisition channels has been developed. Three ADC acquisition channels with an acquisition resolution of 8 bits and acquisition rate of 1 GSPS are utilized to collect the signals from three PMTs which are used to detect β decay, and two acquisition channels with an acquisition resolution of 16 bits and acquisition rate of 50 MSPS are utilized to collect the signals from high-purity germanium (HPGe), which is used to detect γ decay. In order to increase the accuracy of the coincidence system, all five acquisition channels are synchronous within 500 ps. The data collected by the five acquisition channels will be transmitted to the host PC through a PCI bus and saved as a file. Off-line software is utilized for the 4πβ (LS) -γ (HPGe) coincidence and data analysis as needed in practical applications. Tests of the system show that system can record pulse signals from 4πβ (LS) -γ (HPGe) synchronously for further coincidence calculation and the highest coincidence rate of the system is 20 K/s, which is sufficient for most applications. Compared with traditional coincidence modules like MAC3, the digital coincidence system has a higher flexibility of coincidence algorithm. In addition, due to the use of ADC, the structure of the coincidence system is simplified. This paper introduces the design of the hardware, the synchronization method and the test results of this system. Supported by National Metrology Institute of China

  15. Spectrum correction algorithm for detectors in airborne radioactivity monitoring equipment NH-UAV based on a ratio processing method

    NASA Astrophysics Data System (ADS)

    Cao, Ye; Tang, Xiao-Bin; Wang, Peng; Meng, Jia; Huang, Xi; Wen, Liang-Sheng; Chen, Da

    2015-10-01

    The unmanned aerial vehicle (UAV) radiation monitoring method plays an important role in nuclear accidents emergency. In this research, a spectrum correction algorithm about the UAV airborne radioactivity monitoring equipment NH-UAV was studied to measure the radioactive nuclides within a small area in real time and in a fixed place. The simulation spectra of the high-purity germanium (HPGe) detector and the lanthanum bromide (LaBr3) detector in the equipment were obtained using the Monte Carlo technique. Spectrum correction coefficients were calculated after performing ratio processing techniques about the net peak areas between the double detectors on the detection spectrum of the LaBr3 detector according to the accuracy of the detection spectrum of the HPGe detector. The relationship between the spectrum correction coefficient and the size of the source term was also investigated. A good linear relation exists between the spectrum correction coefficient and the corresponding energy (R2=0.9765). The maximum relative deviation from the real condition reduced from 1.65 to 0.035. The spectrum correction method was verified as feasible.

  16. Lanthanum Bromide Detectors for Safeguards Measurements

    SciTech Connect

    Wright, J.

    2011-05-25

    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.

  17. Characterization of naturally occurring radioactive materials in Libyan oil pipe scale using a germanium detector and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Habib, A. S.; Shutt, A. L.; Regan, P. H.; Matthews, M. C.; Alsulaiti, H.; Bradley, D. A.

    2014-02-01

    Radioactive scale formation in various oil production facilities is acknowledged to pose a potential significant health and environmental issue. The presence of such an issue in Libyan oil fields was recognized as early as 1998. The naturally occurring radioactive materials (NORM) involved in this matter are radium isotopes (226Ra and 228Ra) and their decay products, precipitating into scales formed on the surfaces of production equipment. A field trip to a number of onshore Libyan oil fields has indicated the existence of elevated levels of specific activity in a number of locations in some of the more mature oil fields. In this study, oil scale samples collected from different parts of Libya have been characterized using gamma spectroscopy through use of a well shielded HPGe spectrometer. To avoid potential alpha-bearing dust inhalation and in accord with safe working practices at this University, the samples, contained in plastic bags and existing in different geometries, are not permitted to be opened. MCNP, a Monte Carlo simulation code, is being used to simulate the spectrometer and the scale samples in order to obtain the system absolute efficiency and then to calculate sample specific activities. The samples are assumed to have uniform densities and homogeneously distributed activity. Present results are compared to two extreme situations that were assumed in a previous study: (i) with the entire activity concentrated at a point on the sample surface proximal to the detector, simulating the sample lowest activity, and; (ii) with the entire activity concentrated at a point on the sample surface distal to the detector, simulating the sample highest activity.

  18. Ionization-based detectors for gas chromatography.

    PubMed

    Poole, Colin F

    2015-11-20

    The gas phase ionization detectors are the most widely used detectors for gas chromatography. The column and makeup gases commonly used in gas chromatography are near perfect insulators. This facilitates the detection of a minute number of charge carriers facilitating the use of ionization mechanisms of low efficiency while providing high sensitivity. The main ionization mechanism discussed in this report are combustion in a hydrogen diffusion flame (flame ionization detector), surface ionization in a plasma (thermionic ionization detector), photon ionization (photoionization detector and pulsed discharge helium ionization detector), attachment of thermal electrons (electron-capture detector), and ionization by collision with metastable helium species (helium ionization detector). The design, response characteristics, response mechanism, and suitability for fast gas chromatography are the main features summarized in this report. Mass spectrometric detection and atomic emission detection, which could be considered as ionization detectors of a more sophisticated and complex design, are not discussed in this report. PMID:25757823

  19. Ionization-based detectors for gas chromatography.

    PubMed

    Poole, Colin F

    2015-11-20

    The gas phase ionization detectors are the most widely used detectors for gas chromatography. The column and makeup gases commonly used in gas chromatography are near perfect insulators. This facilitates the detection of a minute number of charge carriers facilitating the use of ionization mechanisms of low efficiency while providing high sensitivity. The main ionization mechanism discussed in this report are combustion in a hydrogen diffusion flame (flame ionization detector), surface ionization in a plasma (thermionic ionization detector), photon ionization (photoionization detector and pulsed discharge helium ionization detector), attachment of thermal electrons (electron-capture detector), and ionization by collision with metastable helium species (helium ionization detector). The design, response characteristics, response mechanism, and suitability for fast gas chromatography are the main features summarized in this report. Mass spectrometric detection and atomic emission detection, which could be considered as ionization detectors of a more sophisticated and complex design, are not discussed in this report.

  20. Analysis of Cadmium Based Neutron Detector Configurations

    NASA Astrophysics Data System (ADS)

    James, Brian; Rees, Lawrence; Czirr, J. Bart

    2012-10-01

    Due to national security concerns pertaining to the smuggling of special nuclear materials and a small supply of He-3 for use in neutron detectors, there is currently a need for a new kind of neutron detector. Using Monte Carlo techniques I have studied the neutron capture efficiency of an array of cadmium wedge detectors in the presence of a californium source. By using varying numbers of wedges and comparing their capture ratios we will be better able to design future detectors.

  1. A multiparametric HPGe-NaI acquisition system for low gamma activity measurements of meteorites

    NASA Astrophysics Data System (ADS)

    Taricco, C.; Bhandari, N.; Colombetti, P.; Mariani, I.; Verma, N.; Vivaldo, G.

    The study of long-term solar activity variations in the past requires the use of radioisotopic data planetary reservoirs. At the Laboratory of Monte dei Cappuccini in Torino (IFSI-Torino, INAF) for many years we have been studying radioisotopes in meteorites, because their production, which is related to galactic cosmic ray flux in the heliosphere, is anticorrelated with the heliospheric magnetic field variations. We have developed very sensitive gamma detection techniques, in particular to measure 44Ti activity in meteorites; due to its half-life (t1/2=59.2 years), this radioisotope is an ideal index to reveal the imprint of solar activity variations on the centennial scale. Recently we have improved the spectrometer by a new multiparametric acquisition system, which allows to extract efficiently the 44Ti peak from the natural background.

  2. Nonequilibrium superconducting detectors

    NASA Astrophysics Data System (ADS)

    Cristiano, R.; Ejrnaes, M.; Esposito, E.; Lisitskyi, M. P.; Nappi, C.; Pagano, S.; Perez de Lara, D.

    2006-03-01

    Nonequilibrium superconducting detectors exploit the early stages of the energy down cascade which occur after the absorption of radiation. They operate on a short temporal scale ranging from few microseconds down to tens of picoseconds. In such a way they provide fast counting capability, high time discrimination and also, for some devices, energy sensitivity. Nonequilibrium superconducting detectors are developed for their use both in basic science and in practical applications for detection of single photons or single ionized macromolecules. In this paper we consider two devices: distributed readout imaging detectors (DROIDs) based on superconducting tunnel junctions (STJs), which are typically used for high-speed energy spectroscopy applications, and hot-electron superconductive detectors (HESDs), which are typically used as fast counters and time discriminators. Implementation of the DROID geometry to use a single superconductor is discussed. Progress in the fabrication technology of NbN nanostructured HESDs is presented. The two detectors share the high sensitivity that makes them able to efficiently detect even single photons down to infrared energy.

  3. Pyroelectric detectors

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    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.

  4. PHASE DETECTOR

    DOEpatents

    Kippenhan, D.O.

    1959-09-01

    A phase detector circuit is described for use at very high frequencies of the order of 50 megacycles. The detector circuit includes a pair of rectifiers inverted relative to each other. One voltage to be compared is applied to the two rectifiers in phase opposition and the other voltage to be compared is commonly applied to the two rectifiers. The two result:ng d-c voltages derived from the rectifiers are combined in phase opposition to produce a single d-c voltage having amplitude and polarity characteristics dependent upon the phase relation between the signals to be compared. Principal novelty resides in the employment of a half-wave transmission line to derive the phase opposing signals from the first voltage to be compared for application to the two rectifiers in place of the transformer commonly utilized for such purpose in phase detector circuits for operation at lower frequency.

  5. Hydrogen detector

    DOEpatents

    Kanegae, Naomichi; Ikemoto, Ichiro

    1980-01-01

    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.

  6. Microwave detector

    DOEpatents

    Meldner, Heiner W.; Cusson, Ronald Y.; Johnson, Ray M.

    1986-01-01

    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.

  7. Microwave detector

    DOEpatents

    Meldner, H.W.; Cusson, R.Y.; Johnson, R.M.

    1985-02-08

    A microwave detector is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite produces a magnetization field flux that links a B-dot loop. The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means 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.

  8. Silicon Detectors

    NASA Astrophysics Data System (ADS)

    Sadrozinski, Hartmut

    2014-03-01

    The use of silicon detectors has experienced an exponential growth in accelerator and space based experiments, similar to trends in the semiconductor industry as a whole, usually paraphrased as ``Moore's Law.'' Some of the essentials for this phenomenon will be presented, together with examples of the exciting science results which it enabled. With the establishment of a ``semiconductor culture'' in universities and laboratories around the world, an increased understanding of the sensors results in thinner, faster, more radiation-resistant detectors, spawning an amazing wealth of new technologies and applications, which will be the main subject of the presentation.

  9. Microwave detector

    SciTech Connect

    Meldner, H.W.; Cusson, R.Y.; Johnson, R.M.

    1986-12-02

    A detector is described for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations, the detector comprising: a B-dot loop linking the magnetic field of the microwave pulse; a biased ferrite, that produces a magnetization field flux that links the B-dot loop. The ferrite is positioned within the B-dot loop so that the magnetic field of the microwave pulse interacts with the ferrite and thereby participates in the formation of the magnetization field flux; and high-frequency insensitive means for measuring electric voltage or current induced in the B-dot loop.

  10. A study on radon absorption efficiencies of edible oils produced in India.

    PubMed

    Karunakara, N; Al-Azmi, Darwish

    2010-04-01

    A study on absorption of radon by different edible oils of plant origins produced and used in India was conducted in order to identify efficient radon-absorbing oils. A comparative study of radon absorption by edible oils of India with that of olive oil, which is known as a good absorber of radon, was also carried out. The study was performed by bubbling known concentrations of radon through the oil contained in a bottle and then evaluating the bubbled oil by gamma-ray spectrometry using an HPGe detector. The results show that oils such as coconut oil, gingelly oil (till oil), ground nut oil, mustard oil, sunflower oil, and saffola kardi oil are also good absorbers for radon, and among them coconut oil and gingelly oils are better absorbers than olive oil. The Henry's equilibrium constant (or the concentration factor), an indicator for the solubility of gas in liquids, was also measured for different types of oil by saturating a known volume of the oil with radon. The Henry's equilibrium constant varied in the range 7.32-8.22 for the Indian vegetable oils, and for olive oil it was found to be 7.88. The details of the experimental technique employed and results obtained are presented and discussed in this paper.

  11. Vertex detectors

    SciTech Connect

    Lueth, V.

    1992-07-01

    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.

  12. Biological Applications of Cryogenic Detectors

    SciTech Connect

    Friedrich, S

    2003-12-03

    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.

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

    SciTech Connect

    Aguayo, E.; Amman, M.; Avignone, F. T.; Barton, P. J.; Beene, James R; Bertrand Jr, Fred E; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y-D; Christofferson, C. D.; Collar, Juan I.; Combs, D. C.; Detwiler, J.A.; Doe, P. J.; Efremenko, Yuri; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J.E.; Fields, N.; Finnerty, P.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E.W.; Horton, M.; Howard, S.; Howe, M. 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.; Looker, Q.; Luke, P.N.; MacMullin, S.; Martin, R.D.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Orrell, John L.; Overman, N. R.; Perumpilly, G.; Phillips II, D. G.; et al.

    2013-01-01

    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.

  14. Resistor-less charge sensitive amplifier for semiconductor detectors

    NASA Astrophysics Data System (ADS)

    Pelczar, K.; Panas, K.; Zuzel, G.

    2016-11-01

    A new concept of a Charge Sensitive Amplifier without a high-value resistor in the feedback loop is presented. Basic spectroscopic parameters of the amplifier coupled to a coaxial High Purity Germanium detector (HPGe) are discussed. The amplifier signal input is realized with an n-channel J-FET transistor. The feedback capacitor is discharged continuously by the second, forward biased n-channel J-FET, driven by an RC low-pass filter. Both the analog-with a standard spectroscopy amplifier and a multi-channel analyzer-and the digital-by applying a Flash Analog to Digital Converter-signal readouts were tested. The achieved resolution in the analog and the digital readouts was 0.17% and 0.21%, respectively, at the Full Width at Half Maximum of the registered 60Co 1332.5 keV gamma line.

  15. Neutron detectors comprising boron powder

    SciTech Connect

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

    2013-05-21

    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.

  16. Requirements on high resolution detectors

    SciTech Connect

    Koch, A.

    1997-02-01

    For a number of microtomography applications X-ray detectors with a spatial resolution of 1 {mu}m are required. This high spatial resolution will influence and degrade other parameters of secondary importance like detective quantum efficiency (DQE), dynamic range, linearity and frame rate. This note summarizes the most important arguments, for and against those detector systems which could be considered. This article discusses the mutual dependencies between the various figures which characterize a detector, and tries to give some ideas on how to proceed in order to improve present technology.

  17. Charge-collection efficiency of single-crystal CVD diamond detector for low-energy charged particles with energies ranging from 100 keV to 2 MeV

    NASA Astrophysics Data System (ADS)

    Sato, Yuki; Murakami, Hiroyuki; Shimaoka, Takehiro; Tsubota, Masakatsu; Kaneko, Junichi H.

    2016-10-01

    The performance of a diamond detector created from a single-crystal diamond grown by chemical vapor deposition was studied for application in detecting charged particles having energies ranging from 100 keV to 2 MeV. Energy peaks of different low-energy ions were clearly observed. However, we observed that the pulse height for individual incident ions decreases with increasing atomic number of the ions. We estimated the charge collection efficiency of the generated charge carriers by the incident charged particles. The charge collection efficiencies are 97.0 ± 0.7% for 2 MeV helium-ions (He+). On the other hand, compared with that of He+, silicon-ions (Si+) and gold-ions (Au3+) show low charge collection efficiency: 70.6 ± 2.2% and 29.5 ± 4.2% for 2 MeV-Si+ and 2 MeV-Au3+, respectively. We also found that the charge collection efficiency decreases as the generated charge density inside the diamond crystal increases.

  18. The Watchman Detector Design

    NASA Astrophysics Data System (ADS)

    Dazeley, Steven

    2014-03-01

    The Watchman collaboration is proposing a kiloton scale antineutrino detector of reactor-based antineutrinos for non-proliferation purposes. As an added bonus the detector will also have the capability to search for evidence of sterile neutrino oscillation, super-nova antineutrinos and, in a second phase, measure the neutrino mass hierarchy. Despite that fact that KamLAND demonstrated the feasibility of kiloton scale, long distance antineutrino detection with liquid scintillator, similar detectors at the megaton scale remain problematic for environmental, cost and light attenuation reasons. Water, with gadolinium added for neutron sensitivity, may be the detection medium of choice if its efficiency can be shown to be competitive with scintillator. The goal of the Watchman project, therefore, is to demonstrate medium distance reactor antineutrino detection, and thus demonstrate the feasibility of moving to water-based megaton scale antineutrino detectors in the future. In this talk I will describe the scope of the experiment, the physics and engineering challenges involved, the proposed design and the predicted performance of the experimental non-proliferation and high-energy physics program. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344. Release number LLNL-ABS-648381.

  19. Angle detector

    NASA Technical Reports Server (NTRS)

    Parra, G. T. (Inventor)

    1978-01-01

    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.

  20. Flame Detector

    NASA Technical Reports Server (NTRS)

    1990-01-01

    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.

  1. Neutrino Detectors

    NASA Astrophysics Data System (ADS)

    von Feilitzsch, Franz; Lanfranchi, Jean-Côme; Wurm, Michael

    The neutrino was postulated by Wolfgang Pauli in the early 1930s, but could only be detected for the first time in the 1950s. Ever since scientists all around the world have worked on the detection and understanding of this particle which so scarcely interacts with matter. Depending on the origin and nature of the neutrino, various types of experiments have been developed and operated. In this entry, we will review neutrino detectors in terms of neutrino energy and associated detection technique as well as the scientific outcome of some selected examples. After a brief historical introduction, the detection of low-energy neutrinos originating from nuclear reactors or from the Earth is used to illustrate the principles and difficulties which are encountered in detecting neutrinos. In the context of solar neutrino spectroscopy, where the neutrino is used as a probe for astrophysics, three different types of neutrino detectors are presented - water Čerenkov, radiochemical, and liquid-scintillator detectors. Moving to higher neutrino energies, we discuss neutrinos produced by astrophysical sources and from accelerators. The entry concludes with an overview of a selection of future neutrino experiments and their scientific goals.

  2. Dust Detector

    NASA Technical Reports Server (NTRS)

    Kelley, M. C.

    2001-01-01

    We discuss a recent sounding rocket experiment which found charged dust in the Earth's tropical mesosphere. The dust detector was designed to measure small (5000 - 10000 amu.) charged dust particles, most likely of meteoric origin. A 5 km thick layer of positively charged dust was found at an altitude of 90 km, in the vicinity of an observed sporadic sodium layer and sporadic E layer. The observed dust was positively charged in the bulk of the dust layer, but was negatively charged near the bottom.

  3. Ion detector

    DOEpatents

    Tullis, Andrew M.

    1987-01-01

    An improved ion detector device of the ionization detection device chamber ype comprises an ionization chamber having a central electrode therein surrounded by a cylindrical electrode member within the chamber with a collar frictionally fitted around at least one of the electrodes. The collar has electrical contact means carried in an annular groove in an inner bore of the collar to contact the outer surface of the electrode to provide electrical contact between an external terminal and the electrode without the need to solder leads to the electrode.

  4. Analytical response function for planar Ge detectors

    NASA Astrophysics Data System (ADS)

    García-Alvarez, Juan A.; Maidana, Nora L.; Vanin, Vito R.; Fernández-Varea, José M.

    2016-04-01

    We model the response function (RF) of planar HPGe x-ray spectrometers for photon energies between around 10 keV and 100 keV. The RF is based on the proposal of Seltzer [1981. Nucl. Instrum. Methods 188, 133-151] and takes into account the full-energy absorption in the Ge active volume, the escape of Ge Kα and Kβ x-rays and the escape of photons after one Compton interaction. The relativistic impulse approximation is employed instead of the Klein-Nishina formula to describe incoherent photon scattering in the Ge crystal. We also incorporate a simple model for the continuous component of the spectrum produced by the escape of photo-electrons from the active volume. In our calculations we include external interaction contributions to the RF: (i) the incoherent scattering effects caused by the detector's Be window and (ii) the spectrum produced by photo-electrons emitted in the Ge dead layer that reach the active volume. The analytical RF model is compared with pulse-height spectra simulated using the PENELOPE Monte Carlo code.

  5. New class of neutron detectors

    SciTech Connect

    Czirr, J.B.

    1997-09-01

    An optimized neutron scattering instrument design must include all significant components, including the detector. For example, useful beam intensity is limited by detector dead time; detector pixel size determines the optimum beam diameter, sample size, and sample to detector distance; and detector efficiency vs. wavelength determines the available energy range. As an example of the next generation of detectors that could affect overall instrumentation design, we will describe a new scintillator material that is potentially superior to currently available scintillators. We have grown and tested several small, single crystal scintillators based upon the general class of cerium-activated lithium lanthanide borates. The outstanding characteristic of these materials is the high scintillation efficiency-as much as five times that of Li-glass scintillators. This increase in light output permits the practical use of the exothermic B (n, alpha) reaction for low energy neutron detection. This reaction provides a four-fold increase in capture cross section relative to the Li (n, alpha) reaction, and the intriguing possibility of demanding a charged-particle/gamma ray coincidence to reduce background detection rates. These new materials will be useful in the thermal and epithermal energy ran at reactors and pulsed neutron sources.

  6. Analysis of SMELS and reference materials for validation of the k0-based internal monostandard NAA method using in-situ detection efficiency

    NASA Astrophysics Data System (ADS)

    Acharya, R.; Swain, K. K.; Reddy, A. V. R.

    2010-10-01

    Three synthetic multielement standards (SMELS I, II and III) and two reference materials (RMs), SL-3 and Soil-7 of IAEA were analyzed for validation of the k0-based internal monostandard neutron activation analysis (IM-NAA) method utilizing in-situ relative detection efficiency. The internal monostandards used in SMELS and RMs were Au and Sc, respectively. The samples were irradiated in Apsara and Dhruva reactors, BARC and radioactive assay was carried out using a 40% relative efficiency HPGe detector coupled to an 8 k MCA. Concentrations of 23 elements were determined in both SMELS and RMs. In the case of RMs, concentrations of a few elements, whose certified values are not available, could also be determined. The % deviations for the elements determined in SMELS with respect to the assigned values and RMs with respect to certified values were within ±8%. The Z-score values at 95% confidence level for most of the elements in both the materials were within ±1.

  7. Signals induced by charge-trapping in EDELWEISS FID detectors: analytical modeling and applications

    NASA Astrophysics Data System (ADS)

    Arnaud, Q.; Armengaud, E.; Augier, C.; Benoît, A.; Bergé, L.; Billard, J.; Blümer, J.; de Boissière, T.; Broniatowski, A.; Camus, P.; Cazes, A.; Chapellier, M.; Charlieux, F.; Dumoulin, L.; Eitel, K.; Foerster, N.; Fourches, N.; Gascon, J.; Giuliani, A.; Gros, M.; Hehn, L.; Heuermann, G.; De Jésus, M.; Jin, Y.; Juillard, A.; Kleifges, M.; Kozlov, V.; Kraus, H.; Kéfélian, C.; Kudryavtsev, V. A.; Le-Sueur, H.; Marnieros, S.; Navick, X.-F.; Nones, C.; Olivieri, E.; Pari, P.; Paul, B.; Piro, M.-C.; Poda, D.; Queguiner, E.; Rozov, S.; Sanglard, V.; Schmidt, B.; Scorza, S.; Siebenborn, B.; Tcherniakhovski, D.; Vagneron, L.; Weber, M.; Yakushev, E.

    2016-10-01

    The EDELWEISS-III direct dark matter search experiment uses cryogenic HP-Ge detectors Fully covered with Inter-Digitized electrodes (FID). They are operated at low fields (< 1 V/cm), and as a consequence charge-carrier trapping significantly affects both the ionization and heat energy measurements. This paper describes an analytical model of the signals induced by trapped charges in FID detectors based on the Shockley-Ramo theorem. It is used to demonstrate that veto electrodes, initially designed for the sole purpose of surface event rejection, can be used to provide a sensitivity to the depth of the energy deposits, characterize the trapping in the crystals, perform heat and ionization energy corrections and improve the ionization baseline resolutions. These procedures are applied successfully to actual data.

  8. Flexible composite radiation detector

    DOEpatents

    Cooke, D. Wayne; Bennett, Bryan L.; Muenchausen, Ross E.; Wrobleski, Debra A.; Orler, Edward B.

    2006-12-05

    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.

  9. Oscillator detector

    SciTech Connect

    Potter, B.M.

    1980-05-13

    An alien liquid detector employs a monitoring element and an oscillatory electronic circuit for maintaining the temperature of the monitoring element substantially above ambient temperature. The output wave form, eg., frequency of oscillation or wave shape, of the oscillatory circuit depends upon the temperaturedependent electrical characteristic of the monitoring element. A predetermined change in the output waveform allows water to be discriminated from another liquid, eg., oil. Features of the invention employing two thermistors in two oscillatory circuits include positioning one thermistor for contact with water and the other thermistor above the oil-water interface to detect a layer of oil if present. Unique oscillatory circuit arrangements are shown that achieve effective thermistor action with an economy of parts and energizing power. These include an operational amplifier employed in an astable multivibrator circuit, a discrete transistor-powered tank circuit, and use of an integrated circuit chip.

  10. The X-ray response of CdZnTe detectors to be used as future spectroscopic detectors for X-ray astronomy

    NASA Astrophysics Data System (ADS)

    Kraft, S.; Bavdaz, M.; Castelletto, B.; Peacock, A.; Scholze, F.; Ulm, G.; Gagliardi, M.-A.; Nenonen, S.; Tuomi, T.; Juvonen, M.; Rantamäki, R.

    1998-12-01

    The next generation of X-ray astrophysics missions may well extend the energy range beyond the current limit of about 10keV studied by the existing X-ray Astrophysics space missions such as ASCA or future missions such as AXAF and XMM to be launched in the next few years. To address with a high degree of sensitivity the astrophysical problems associated with X-ray emission in the X-ray band from 0.2 to 100keV a significant extension of the capabilities of focusing X-ray optics and imaging broad band hard X-ray detectors will be required. Future missions such as INTEGRAL, BASIS and EXIST will make use of CdZnTe or CdTe detectors for imaging spectroscopy down to about 5keV with a spectral resolution between 3% and 7% at 100keV. This is about a factor of 10 away from what is theoretically possible and mainly caused by the poor crystal quality. In this paper experimental results on the study of the X-ray response of CdZnTe detectors are presented. The detector response to photons with energies between 1 and 5keV has been investigated using synchrotron radiation and a preliminary model to describe the detector response developed. The limitations on the energy resolution, due to incomplete charge collection and spatial non-uniformities, are presented based on the detailed mapping of the energy response of a detector exposed to highly monochromatised synchrotron radiation. At higher energies results have been obtained using a 241Am radioactive source and an electron cyclotron resonance source so as to establish the detector performance and overall response to medium- and higher-energy X-ray photons up to 60keV. Based on these results the performance of the detectors are compared with Si(Li) and HPGe solid-state detectors.

  11. Isotope identification software for Gamma spectra taken with CdZnTe detectors

    NASA Astrophysics Data System (ADS)

    Brutscher, J.; Arlt, R.; Czock, K. H.

    2001-02-01

    The identification of isotopes in a sample emitting gamma rays is a complex and difficult task particularly if the number of gamma lines is high, detector resolution and statistics are limited and little is known about the history of the sample. The better the resolution the easier this task can be accomplished. High-purity germanium detectors (HPGe) are in this respect the best choice, however, they are difficult to use under field conditions and in spent fuel ponds, since they require liquid nitrogen for cooling. NaI detectors do not require cooling, but have limitations in their resolution. For field applications, e.g., the verification of nuclear material, the use of CdZnTe detectors has advantages over NaI detectors since their resolution is much better. CdZnTe detectors, often exhibit asymmetric peak shapes, particularly at high energies making automated peak fitting methods and sophisticated isotope identification programs difficult to use. In this paper the design and use of a semi-automated isotope identification program is described. It is based on an interactive graphical method to find a simple solution to identifying various isotopes which may be present in a sample. The spectrum to be analyzed and an isotopic library containing a list of suspected isotopes is loaded. After selection of detector type , measurement geometry and starting values for the resolution, a peak search is performed. This can also determine the FWHM of the gamma peaks as function of energy. For each gamma peak found, the software suggests possible candidate isotopes to which the gamma peak may belong. The next, most decisive step to determine to which of the sometimes many choices of isotopes, a certain gamma line belongs to, is visual and interactive. Once one candidate's gamma line is marked, the program overlays the expected gamma peak pattern of this isotope with the measured one. Based on the presence or absence of certain lines in the spectrum (checked visually, aided by a

  12. Pillar Structured Thermal Neutron Detector

    SciTech Connect

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

    2008-06-10

    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.

  13. Neutron detector characterization for SCINTIA array

    SciTech Connect

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

    2011-07-01

    SCINTIA is a new detector array of organic scintillators under development at the Inst. for Reference Materials and Measurements (IRMM). The present design of SCINTIA includes NE213, p-terphenyl and Li glass neutron detectors positioned in a spherical configuration around the target. The properties of a novel p-terphenyl neutron detector to be used with SCINTIA have been investigated using photon sources and neutrons from a time tagged {sup 252}Cf(sf) source. 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. (authors)

  14. High precision thermal neutron detectors

    SciTech Connect

    Radeka, V.; Schaknowski, N.A.; Smith, G.C.; Yu, B.

    1994-12-31

    Two-dimensional position sensitive detectors are indispensable in neutron diffraction experiments for determination of molecular and crystal structures in biology, solid-state physics and polymer chemistry. Some performance characteristics of these detectors are elementary and obvious, such as the position resolution, number of resolution elements, neutron detection efficiency, counting rate and sensitivity to gamma-ray background. High performance detectors are distinguished by more subtle characteristics such as the stability of the response (efficiency) versus position, stability of the recorded neutron positions, dynamic range, blooming or halo effects. While relatively few of them are needed around the world, these high performance devices are sophisticated and fairly complex, their development requires very specialized efforts. In this context, we describe here a program of detector development, based on {sup 3}He filled proportional chambers, which has been underway for some years at the Brookhaven National Laboratory. Fundamental approaches and practical considerations are outlined that have resulted in a series of high performance detectors with the best known position resolution, position stability, uniformity of response and reliability over time, for devices of this type.

  15. Improved Scintillator Materials for Compact Electron Antineutrino Detectors

    SciTech Connect

    Dijkstra, Peter; Wortche, Heinrich J.; Browne, Wesley R.

    2011-04-27

    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.

  16. Detector requirements for space infrared astronomy

    NASA Technical Reports Server (NTRS)

    Wright, E. L.

    1986-01-01

    Requirements for background-limited (BLIP) detectors are discussed in terms of number of photons falling on each pixel, dark current, high detective quantum efficiencies, large numbers of pixels, and array size.

  17. Detector simulation needs for detector designers

    SciTech Connect

    Hanson, G.G.

    1987-11-01

    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.

  18. Fundamental properties of semiconductor materials, and material performance in detectors

    NASA Technical Reports Server (NTRS)

    Casper, K. J.

    1973-01-01

    Procedures for determining fundamental properties of semiconductor materials, their performance as radiation detectors, and their service life as such detectors are given. Relationships were established between the minority carrier lifetime in the bulk of the material and the charge collection efficiency of the detector.

  19. Spiral silicon drift detectors

    SciTech Connect

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

    1988-01-01

    An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs.

  20. Testing and Characterization of SuperCDMS Dark Matter Detectors

    SciTech Connect

    Shank, Benjamin

    2014-05-01

    The Cryogenic Dark Matter Search (SuperCDMS) relies on collection of phonons and charge carriers in semiconductors held at tens of milliKelvin as handles for detection of Weakly Interacting Massive Particles (WIMPs). This thesis begins with a brief overview of the direct dark matter search (Chapter 1) and SuperCDMS detectors (Chapter 2). In Chapter 3, a 3He evaporative refrigerator facility is described. Results from experiments performed in-house at Stanford to measure carrier transport in high-purity germanium (HPGe) crystals operated at sub-Kelvin temperatures are presented in Chapter 4. Finally, in Chapter 5 a new numerical model and a time-domain optimal filtering technique are presented, both developed for use with superconducting Transition Edge Sensors (TESs), that provide excellent event reconstruction for single particle interactions in detectors read out with superconducting W-TESs coupled to energy-collecting films of Al. This thesis is not intended to be read straight through. For those new to CDMS or dark matter searches, the first two chapters are meant to be a gentle introduction for experimentalists. They are by no means exhaustive. The remaining chapters each stand alone, with different audiences.

  1. A novel method for assessing position-sensitive detector performance

    SciTech Connect

    Clinthorne, N.H.; Rogers, W.L.; Shao, L.; Hero, A.O. III; Koral, K.F.

    1989-02-01

    A marked point process model of a position-sensitive detector is developed which includes the effects of detector efficiency, spatial response, energy response, and source statistics. The average mutual information between the incident distribution of ..gamma.. rays and the detector response is derived and used as a performance index for detector optimization. A brief example is presented which uses this figure-of-merit for optimization of light guide dimensions for a modular scintillation camera.

  2. PAU camera: detectors characterization

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

    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.

  3. Apfel's superheated drop detector

    NASA Astrophysics Data System (ADS)

    D'Errico, Francesco

    2001-05-01

    The introduction of new approaches for radiation dosimetry is rare. A similar breakthrough occurred in 1979, when Robert Apfel invented the superheated drop detector, a miniature relative of the bubble chamber. A fundamental in high-energy particle physics, the bubble chamber utilizes a liquid briefly brought to a transient, radiation-sensitive superheated state by reducing its pressure. Mass boiling of the liquid is prevented by cyclic pressurization, drastically limiting the detection efficiency. In Apfel's detector, the liquid is kept in a steady superheated state by fractionating it into droplets and dispersing them in an immiscible host fluid, a perfectly smooth and clean container. The approach extends the lifetime of the metastable droplets to the point that practical application in radiation dosimetry is possible. Bubble formation is measured from the volume of vapor or by detecting individual vaporizations acoustically. Various halocarbons are employed and this permits a wide range of applications. Moderately superheated halocarbons are used for neutron measurements, since they are only nucleated by energetic neutron recoil particles. Highly superheated halocarbons nucleate with much smaller energy deposition and are used to detect photons and electrons. This paper reviews the radiation physics of superheated emulsions and their manifold applications.

  4. Room temperature semiconductor detectors for safeguards measurements

    NASA Astrophysics Data System (ADS)

    Arlt, R.; Rundquist, D. E.

    A summary is given of the principal areas of application where CdTe detectors are presently used by the IAEA in nuclear material safeguards. Hemispheric detectors with a sensitive volume of about 20 mm 3 have their principal application in the verification of irradiated nuclear material. Larger volume hemispheric detectors are used for the verification of unirradiated material. Their availability, however, is still limited. Problems with the commercial supply of detectors and with ruggedizing the design of the miniature detection probes need to be solved. New results which are relevant for future applications are described. It has been shown that hemispheric detectors made of CdZnTe provide a resolution of 3-4% and a peak/Compton ratio larger than two for 137Cs. Large volume planar CdZnTe have been used in conjunction with pulse shape discrimination electronics. The detector efficiency, however, still remains below the values expected from their geometric dimensions. A new technique to achieve single charge collection in large volume CdZnTe detectors has been developed. Planar detectors with PIN structure and Peltier cooling have further improved. However, the problem of long term stability has not been solved yet. Silicon detectors are increasingly used in unattended radiation monitoring systems. They have a proven long term stability and can cover a signal range of 5-6 decades if used with fast pulse counting electronics.

  5. Waste Characterization Using Gamma Ray Spectrometry with Automated Efficiency Optimization - 13404

    SciTech Connect

    Bosko, A.; Venkataraman, R.; Bronson, F.L.; Ilie, G.; Russ, W.R.

    2013-07-01

    Gamma ray spectrometry using High Purity Germanium (HPGe) detectors is commonly employed in assaying radioactive waste streams from a variety of sources: nuclear power plants, Department of Energy (DOE) laboratories, medical facilities, decontamination and decommissioning activities etc. The radioactive material is typically packaged in boxes or drums (for e.g. B-25 boxes or 208 liter drums) and assayed to identify and quantify radionuclides. Depending on the origin of the waste stream, the radionuclides could be special nuclear materials (SNM), fission products, or activation products. Efficiency calibration of the measurement geometry is a critical step in the achieving accurate quantification of radionuclide content. Due to the large size of the waste items, it is impractical and expensive to manufacture gamma ray standard sources for performing a measurement based calibration. For well over a decade, mathematical efficiency methods such as those in Canberra's In Situ Object Counting System (ISOCS) have been successfully employed in the efficiency calibration of gamma based waste assay systems. In the traditional ISOCS based calibrations, the user provides input data such as the dimensions of the waste item, the average density and fill height of the matrix, and matrix composition. As in measurement based calibrations, the user typically defines a homogeneous matrix with a uniform distribution of radioactivity. Actual waste containers can be quite nonuniform, however. Such simplifying assumptions in the efficiency calibration could lead to a large Total Measurement Uncertainty (TMU), thus limiting the amount of waste that can be disposed of as intermediate or low activity level waste. To improve the accuracy of radionuclide quantification, and reduce the TMU, Canberra has developed the capability to optimize the efficiency calibration using the ISOCS method. The optimization is based on benchmarking the efficiency shape and magnitude to the data available in the

  6. SU-E-I-62: Assessing Radiation Dose Reduction and CT Image Optimization Through the Measurement and Analysis of the Detector Quantum Efficiency (DQE) of CT Images Using Different Beam Hardening Filters

    SciTech Connect

    Collier, J; Aldoohan, S; Gill, K

    2014-06-01

    Purpose: Reducing patient dose while maintaining (or even improving) image quality is one of the foremost goals in CT imaging. To this end, we consider the feasibility of optimizing CT scan protocols in conjunction with the application of different beam-hardening filtrations and assess this augmentation through noise-power spectrum (NPS) and detector quantum efficiency (DQE) analysis. Methods: American College of Radiology (ACR) and Catphan phantoms (The Phantom Laboratory) were scanned with a 64 slice CT scanner when additional filtration of thickness and composition (e.g., copper, nickel, tantalum, titanium, and tungsten) had been applied. A MATLAB-based code was employed to calculate the image of noise NPS. The Catphan Image Owl software suite was then used to compute the modulated transfer function (MTF) responses of the scanner. The DQE for each additional filter, including the inherent filtration, was then computed from these values. Finally, CT dose index (CTDIvol) values were obtained for each applied filtration through the use of a 100 mm pencil ionization chamber and CT dose phantom. Results: NPS, MTF, and DQE values were computed for each applied filtration and compared to the reference case of inherent beam-hardening filtration only. Results showed that the NPS values were reduced between 5 and 12% compared to inherent filtration case. Additionally, CTDIvol values were reduced between 15 and 27% depending on the composition of filtration applied. However, no noticeable changes in image contrast-to-noise ratios were noted. Conclusion: The reduction in the quanta noise section of the NPS profile found in this phantom-based study is encouraging. The reduction in both noise and dose through the application of beam-hardening filters is reflected in our phantom image quality. However, further investigation is needed to ascertain the applicability of this approach to reducing patient dose while maintaining diagnostically acceptable image qualities in a

  7. The TALE Tower Detector

    NASA Astrophysics Data System (ADS)

    Bergman, D. R.

    The TA Low Energy Extension will include a Tower FluorescenceDetector. Extensive air showers at the lowest usful energies for fluorescence detectors will in general be close to the detector. This requires viewing all elevation angles to be able to reconstruct showers. The TALE Tower Detector, operating in conjunction with other TALE detectors will view elevation angles up to above 70 degrees, with an azimuthal coverage of about 90 degrees. Results from a prototype mirror operated in conjunction with the HiRes detector will also be presented.

  8. GADRAS Detector Response Function.

    SciTech Connect

    Mitchell, Dean J.; Harding, Lee; Thoreson, Gregory G; Horne, Steven M.

    2014-11-01

    The Gamma Detector Response and Analysis Software (GADRAS) applies a Detector Response Function (DRF) to compute the output of gamma-ray and neutron detectors when they are exposed to radiation sources. The DRF is fundamental to the ability to perform forward calculations (i.e., computation of the response of a detector to a known source), as well as the ability to analyze spectra to deduce the types and quantities of radioactive material to which the detectors are exposed. This document describes how gamma-ray spectra are computed and the significance of response function parameters that define characteristics of particular detectors.

  9. The upgraded DØ detector

    NASA Astrophysics Data System (ADS)

    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.; Kalinin, A. M.; Kalk, J.; Kalmani, S. D.; Karmanov, D.; Kasper, J.; Katsanos, I.; Kau, D.; Kaur, R.; Ke, Z.; Kehoe, R.; Kermiche, S.; Kesisoglou, S.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. M.; Kim, H.; Kim, K. H.; Kim, T. J.; Kirsch, N.; Klima, B.; Klute, M.; Kohli, J. M.; Konrath, J.-P.; Komissarov, E. V.; Kopal, M.; Korablev, V. M.; Kostritski, A.; Kotcher, J.; Kothari, B.; Kotwal, A. V.; Koubarovsky, A.; Kozelov, A. V.; Kozminski, J.; Kryemadhi, A.; Kouznetsov, O.; Krane, J.; Kravchuk, N.; Krempetz, K.; Krider, J.; Krishnaswamy, M. R.; Krzywdzinski, S.; Kubantsev, M.; Kubinski, R.; Kuchinsky, N.; Kuleshov, S.; Kulik, Y.; Kumar, A.; Kunori, S.; Kupco, A.; Kurča, T.; Kvita, J.; Kuznetsov, V. E.; Kwarciany, R.; Lager, S.; Lahrichi, N.; Landsberg, G.; Larwill, M.; Laurens, P.; Lavigne, B.; Lazoflores, J.; Le Bihan, A.-C.; Le Meur, G.; Lebrun, P.; Lee, S. W.; Lee, W. M.; Leflat, A.; Leggett, C.; Lehner, F.; Leitner, R.; Leonidopoulos, C.; Leveque, J.; Lewis, P.; Li, J.; Li, Q. Z.; Li, X.; Lima, J. G. R.; Lincoln, D.; Lindenmeyer, C.; Linn, S. L.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Litmaath, M.; Lizarazo, J.; Lobo, L.; Lobodenko, A.; Lokajicek, M.; Lounis, A.; Love, P.; Lu, J.; Lubatti, H. J.; Lucotte, A.; Lueking, L.; Luo, C.; Lynker, M.; Lyon, A. L.; Machado, E.; Maciel, A. K. A.; Madaras, R. J.; Mättig, P.; Magass, C.; Magerkurth, A.; Magnan, A.-M.; Maity, M.; Makovec, N.; Mal, P. K.; Malbouisson, H. B.; Malik, S.; Malyshev, V. L.; Manakov, V.; Mao, H. S.; Maravin, Y.; Markley, D.; Markus, M.; Marshall, T.; Martens, M.; Martin, M.; Martin-Chassard, G.; Mattingly, S. E. K.; Matulik, M.; Mayorov, A. A.; McCarthy, R.; McCroskey, R.; McKenna, M.; McMahon, T.; Meder, D.; Melanson, H. L.; Melnitchouk, A.; Mendes, A.; Mendoza, D.; Mendoza, L.; Meng, X.; Merekov, Y. P.; Merkin, M.; Merritt, K. W.; Meyer, A.; Meyer, J.; Michaut, M.; Miao, C.; Miettinen, H.; Mihalcea, D.; Mikhailov, V.; Miller, D.; Mitrevski, J.; Mokhov, N.; Molina, J.; Mondal, N. K.; Montgomery, H. E.; Moore, R. W.; Moulik, T.; Muanza, G. S.; Mostafa, M.; Moua, S.; Mulders, M.; Mundim, L.; Mutaf, Y. D.; Nagaraj, P.; Nagy, E.; Naimuddin, M.; Nang, F.; Narain, M.; Narasimhan, V. S.; Narayanan, A.; Naumann, N. A.; Neal, H. A.; Negret, J. P.; Nelson, S.; Neuenschwander, R. T.; Neustroev, P.; Noeding, C.; Nomerotski, A.; Novaes, S. F.; Nozdrin, A.; Nunnemann, T.; Nurczyk, A.; Nurse, E.; O'Dell, V.; O'Neil, D. C.; Oguri, V.; Olis, D.; Oliveira, N.; Olivier, B.; Olsen, J.; Oshima, N.; Oshinowo, B. O.; Otero y Garzón, G. J.; Padley, P.; Papageorgiou, K.; Parashar, N.; Park, J.; Park, S. K.; Parsons, J.; Partridge, R.; Parua, N.; Patwa, A.; Pawloski, G.; Perea, P. M.; Perez, E.; Peters, O.; Pétroff, P.; Petteni, M.; Phaf, L.; Piegaia, R.; Pleier, M.-A.; Podesta-Lerma, P. L. M.; Podstavkov, V. M.; Pogorelov, Y.; Pol, M.-E.; Pompoš, A.; Polosov, P.; Pope, B. G.; Popkov, E.; Porokhovoy, S.; Prado da Silva, W. L.; Pritchard, W.; Prokhorov, I.; Prosper, H. B.; Protopopescu, S.; Przybycien, M. B.; Qian, J.; Quadt, A.; Quinn, B.; Ramberg, E.; Ramirez-Gomez, R.; Rani, K. J.; Ranjan, K.; Rao, M. V. S.; Rapidis, P. A.; Rapisarda, S.; Raskowski, J.; Ratoff, P. N.; Ray, R. E.; Reay, N. W.; Rechenmacher, R.; Reddy, L. V.; Regan, T.; Renardy, J.-F.; Reucroft, S.; Rha, J.; Ridel, M.; Rijssenbeek, M.; Ripp-Baudot, I.; Rizatdinova, F.; Robinson, S.; Rodrigues, R. F.; Roco, M.; Rotolo, C.; Royon, C.; Rubinov, P.; Ruchti, R.; Rucinski, R.; Rud, V. I.; Russakovich, N.; Russo, P.; Sabirov, B.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santoro, A.; Satyanarayana, B.; Savage, G.; Sawyer, L.; Scanlon, T.; Schaile, D.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schieferdecker, P.; Schmitt, C.; Schwanenberger, C.; Schukin, A. A.; Schwartzman, A.; Schwienhorst, R.; Sengupta, S.; Severini, H.; Shabalina, E.; Shamim, M.; Shankar, H. C.; Shary, V.; Shchukin, A. A.; Sheahan, P.; Shephard, W. D.; Shivpuri, R. K.; Shishkin, A. A.; Shpakov, D.; Shupe, M.; Sidwell, R. A.; Simak, V.; Sirotenko, V.; Skow, D.; Skubic, P.; Slattery, P.; Smith, D. E.; Smith, R. P.; Smolek, K.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Song, X.; Song, Y.; Sonnenschein, L.; Sopczak, A.; Sorín, V.; Sosebee, M.; Soustruznik, K.; Souza, M.; Spartana, N.; Spurlock, B.; Stanton, N. R.; Stark, J.; Steele, J.; Stefanik, A.; Steinberg, J.; Steinbrück, G.; Stevenson, K.; Stolin, V.; Stone, A.; Stoyanova, D. A.; Strandberg, J.; Strang, M. A.; Strauss, M.; Ströhmer, R.; Strom, D.; Strovink, M.; Stutte, L.; Sumowidagdo, S.; Sznajder, A.; Talby, M.; Tentindo-Repond, S.; Tamburello, P.; Taylor, W.; Telford, P.; Temple, J.; Terentyev, N.; Teterin, V.; Thomas, E.; Thompson, J.; Thooris, B.; Titov, M.; Toback, D.; Tokmenin, V. V.; Tolian, C.; Tomoto, M.; Tompkins, D.; Toole, T.; Torborg, J.; Touze, F.; Towers, S.; Trefzger, T.; Trincaz-Duvoid, S.; Trippe, T. G.; Tsybychev, D.; Tuchming, B.; Tully, C.; Turcot, A. S.; Tuts, P. M.; Utes, M.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Vachon, B.; van den Berg, P. J.; van Gemmeren, P.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vartapetian, A.; Vasilyev, I. A.; Vaupel, M.; Vaz, M.; Verdier, P.; Vertogradov, L. S.; Verzocchi, M.; Vigneault, M.; Villeneuve-Seguier, F.; Vishwanath, P. R.; Vlimant, J.-R.; Von Toerne, E.; Vorobyov, A.; Vreeswijk, M.; Vu Anh, T.; Vysotsky, V.; Wahl, H. D.; Walker, R.; Wallace, N.; Wang, L.; Wang, Z.-M.; Warchol, J.; Warsinsky, M.; Watts, G.; Wayne, M.; Weber, M.; Weerts, H.; Wegner, M.; Wermes, N.; Wetstein, M.; White, A.; White, V.; Whiteson, D.; Wicke, D.; Wijnen, T.; Wijngaarden, D. A.; Wilcer, N.; Willutzki, H.; Wilson, G. W.; Wimpenny, S. J.; Wittlin, J.; Wlodek, T.; Wobisch, M.; Womersley, J.; Wood, D. R.; Wyatt, T. R.; Wu, Z.; Xie, Y.; Xu, Q.; Xuan, N.; Yacoob, S.; Yamada, R.; Yan, M.; Yarema, R.; Yasuda, T.; Yatsunenko, Y. A.; Yen, Y.; Yip, K.; Yoo, H. D.; Yoffe, F.; Youn, S. W.; Yu, J.; Yurkewicz, A.; Zabi, A.; Zanabria, M.; Zatserklyaniy, A.; Zdrazil, M.; Zeitnitz, C.; Zhang, B.; Zhang, D.; Zhang, X.; Zhao, T.; Zhao, Z.; Zheng, H.; Zhou, B.; Zhou, B.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zieminski, A.; Zitoun, R.; Zmuda, T.; Zutshi, V.; Zviagintsev, S.; Zverev, E. G.; Zylberstejn, A.

    2006-09-01

    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.

  10. The MINOS detectors

    SciTech Connect

    Habig, A.; Grashorn, E.W.; /Minnesota U., Duluth

    2005-07-01

    The Main Injector Neutrino Oscillation Search (MINOS) experiment's primary goal is the precision measurement of the neutrino oscillation parameters in the atmospheric neutrino sector. This long-baseline experiment uses Fermilab's NuMI beam, measured with a Near Detector at Fermilab, and again 735 km later using a Far Detector in the Soudan Mine Underground Lab in northern Minnesota. The detectors are magnetized iron/scintillator calorimeters. The Far Detector has been operational for cosmic ray and atmospheric neutrino data from July of 2003, the Near Detector from September 2004, and the NuMI beam started in early 2005. This poster presents details of the two detectors.

  11. CR-39 detector compared with Kodalpha film type (LR115) in terms of radon concentration

    NASA Astrophysics Data System (ADS)

    Dwaikat, Nidal; Safarini, Ghassan; El-hasan, Mousa; Iida, Toshiyuki

    2007-05-01

    CR-39 detectors and Kodalpha film type (LR115) were compared in terms of radon radiation concentration. Thirteen CR-39 detectors with the same number of Kodalpha film type (LR115) were used in this study. The correlation factor between the radon concentrations, obtained by the two groups of detectors was found to be 0.99. Detector time efficiency (DTE) was calculated for both types of detectors. DTE of Kodalpha film is larger than that of CR-39 detector and this indicates that LR115 is more efficient and sensitive for radon radiation than CR-39 detector.

  12. Tin Can Radiation Detector.

    ERIC Educational Resources Information Center

    Crull, John L.

    1986-01-01

    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)

  13. Neutron-chamber detectors and applications

    SciTech Connect

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

    1990-01-01

    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.

  14. Low light level detectors for astronomy.

    PubMed

    Boyce, P B

    1977-10-14

    There is an almost bewildering variety of detectors being used for ground-based astronomical observations. Many of the detectors have advantages for particular projects. One-dimensional detectors are simple, yet suitable for spectroscopy. Other detectors offer high photometric precision and dimensional stability. Some are designed for observing only faint objects and some for bright ones. Sometimes the necessity of having a high quantum efficiency at a particular wavelength dictates the choice of detector. In reality the situation is even more chaotic. This review has not covered some of the exotic detectors that have been developed for x-ray and far-ultraviolet imaging from spacecraft. These detectors use devices such as resistive plates, multianode or crossed-wire microchannel plates, and so on. These devices have not yet seen extensive use in ground-based applications, and their future as visible light detectors remains uncertain. The reasons for the development of such a wide variety of detectors are clear. Commercially available devices are simply not capable of meeting the low light level and photometric performance capabilities needed for astronomical observations. The driving forces are the commercial and military applications for detectors, and with few exceptions there has not been sufficient funding available to mount a detector development program for astronomy. Therefore, astronomers have sought to adapt existing commercial devices to the particular problem at hand. The large number of individual efforts summarized in this review is the result. In the future, I expect the variety to diminish as one or two really good detectors become capable of performing well under the wide variety of observational conditions encountered in astronomy. Many people have proclaimed the ultimate detector to be just around the corner. This is yet to happen. However, I venture to speculate that low-noise, high-performance CCD detectors with a format of 500 by 500 or larger

  15. Segmented pyroelector detector

    DOEpatents

    Stotlar, S.C.; McLellan, E.J.

    1981-01-21

    A pyroelectric detector is described which has increased voltage output and improved responsivity over equivalent size detectors. The device comprises a plurality of edge-type pyroelectric detectors which have a length which is much greater than the width of the segments between the edge-type electrodes. External circuitry connects the pyroelectric detector segments in parallel to provide a single output which maintains 50 ohm impedance characteristics.

  16. Single-sided CZT strip detectors

    NASA Astrophysics Data System (ADS)

    Macri, John R.; Dönmez, Burçin; Widholm, Mark; Hamel, Louis-Andre; Julien, Manuel; Narita, Tomohiko; Ryan, James M.; McConnell, Mark L.

    2004-09-01

    We report progress in the study of thick CZT strip detectors for 3-d imaging and spectroscopy and discuss two approaches to device design. We present the spectroscopic, imaging, detection efficiency and response uniformity performance of prototype devices. Unlike double-sided strip detectors, these devices feature both row and column contacts implemented on the anode surface. This electron-only approach circumvents problems associated with poor hole transport in CZT that normally limit the thickness and energy range of double-sided strip detectors. These devices can achieve similar performance to pixel detectors. The work includes laboratory and simulation studies aimed at developing compact, efficient, detector modules for 0.05 to 1 MeV gamma radiation measurements. The low channel count strip detector approach can significantly reduce the complexity and power requirements of the readout electronics. This is particularly important in space-based coded aperture or Compton telescope instruments requiring large area, large volume detector arrays. Such arrays will be required for NASA's Black Hole Finder Probe (BHFP) and Advanced Compton Telescope (ACT).

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

    SciTech Connect

    Mori, T.; Izumi, T.; Ou, I.; Yano, T.; Sakuda, M.; Tamii, A.; Suzuki, T.; Yosoi, M.

    2012-11-12

    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.

  18. 7Li-induced reactions for fast-timing with LaBr3:Ce detectors

    NASA Astrophysics Data System (ADS)

    Mason, P. J. R.; Podolyàk, Zs.; Mǎrginean, N.; Regan, P. H.; Alexander, T.; Algora, A.; Alharbi, T.; Bowry, M.; Britton, R.; Bucurescu, D.; Bruce, A. M.; Bunce, M.; Cǎta-Danil, G.; Cǎta-Danil, I.; Cooper, N.; Deleanu, D.; Delion, D.; Filipescu, D.; Gelletly, W.; Glodariu, T.; Gheorghe, I.; Ghiťǎ, D.; Ilie, G.; Ivanova, D.; Kisyov, S.; Lalkovski, S.; Lica, R.; Liddick, S. N.; Mǎrginean, R.; Mihai, C.; Mulholland, K.; Negret, A.; Nita, C. R.; Rice, S.; Roberts, O. J.; Sava, T.; Smith, J. F.; Söderström, P.-A.; Stevenson, P. D.; Stroe, L.; Toma, S.; Townsley, C.; Werner, V.; Wilson, E.; Wood, R. T.; Zamfir, N. V.; Zhekova, M.

    2012-10-01

    7Li induced-reactions have been used with a 186W target to populate nuclei around A˜180-190 at the National Institute of Physics and Nuclear Engineering in Bucharest, Romania. An array of high-purity germanium (HPGe) and cerium-doped lanthanum bromide (LaBr3:Ce) detectors have been used to measure sub-nanosecond half-lives with fast-timing techniques. The yrast 2+ state in 190Os was measured to be t1/2 = 375(20)ps, in excellent agreement with the literature value. The previously unreported half-life of the 564-keV state in 189Ir has also been measured and a value of t1/2 = 540(100)ps ps obtained.

  19. Gamma ray detector shield

    DOEpatents

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

    1985-08-26

    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.

  20. LGB neutron detector

    NASA Astrophysics Data System (ADS)

    Quist, Nicole

    2012-10-01

    The double pulse signature of the Gadolinium Lithium Borate Cerium doped plastic detector suggests its effectiveness for analyzing neutrons while providing gamma ray insensitivity. To better understand this detector, a californium gamma/neutron time of flight facility was constructed in our lab. Reported here are efforts to understand the properties and applications of the LGB detector with regards to neutron spectroscopy.

  1. Tevatron Detector Upgrades

    SciTech Connect

    Lipton, Ronald

    2005-03-22

    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. We 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.

  2. Tevatron detector upgrades

    SciTech Connect

    Lipton, R.; /Fermilab

    2005-01-01

    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.

  3. NUV Detector Dark Monitor

    NASA Astrophysics Data System (ADS)

    Zheng, Wei

    2010-09-01

    Perform routine monitoring of MAMA detector dark current. The main purpose isto look for evidence of a change in the dark rates, both to track on-orbit timedependence and to check for a detector problem developing. The spatial distribution of dark rates on the detector and the effect of SAA will also be studied.

  4. NUV Detector Dark Monitor

    NASA Astrophysics Data System (ADS)

    Ely, Justin

    2013-10-01

    Perform routine monitoring of MAMA detector dark current. The main purpose isto look for evidence of a change in the dark rates, both to track on-orbit timedependence and to check for a detector problem developing. The spatial distribution of dark rates on the detector and the effect of SAA will also be studied.

  5. NUV Detector Dark Monitor

    NASA Astrophysics Data System (ADS)

    Ely, Justin

    2012-10-01

    Perform routine monitoring of MAMA detector dark current. The main purpose isto look for evidence of a change in the dark rates, both to track on-orbit timedependence and to check for a detector problem developing. The spatial distribution of dark rates on the detector and the effect of SAA will also be studied.

  6. NUV Detector Dark Monitor

    NASA Astrophysics Data System (ADS)

    Cox, Colin

    2011-10-01

    Perform routine monitoring of MAMA detector dark current. The main purpose isto look for evidence of a change in the dark rates, both to track on-orbit timedependence and to check for a detector problem developing. The spatial distribution of dark rates on the detector and the effect of SAA will also be studied.

  7. Single photon detector with high polarization sensitivity

    PubMed Central

    Guo, Qi; Li, Hao; You, LiXing; Zhang, WeiJun; Zhang, Lu; Wang, Zhen; Xie, XiaoMing; Qi, Ming

    2015-01-01

    Polarization is one of the key parameters of light. Most optical detectors are intensity detectors that are insensitive to the polarization of light. A superconducting nanowire single photon detector (SNSPD) is naturally sensitive to polarization due to its nanowire structure. Previous studies focused on producing a polarization-insensitive SNSPD. In this study, by adjusting the width and pitch of the nanowire, we systematically investigate the preparation of an SNSPD with high polarization sensitivity. Subsequently, an SNSPD with a system detection efficiency of 12% and a polarization extinction ratio of 22 was successfully prepared. PMID:25875225

  8. Large area liquid argon detectors for interrogation systems

    NASA Astrophysics Data System (ADS)

    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

    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.

  9. Large area liquid argon detectors for interrogation systems

    SciTech Connect

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

    2013-04-19

    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.

  10. Noise performance of the D0 layer 0 silicon detector

    SciTech Connect

    Johnson, M.; /Fermilab

    2006-11-01

    A new inner detector called Layer 0 has been added to the existing silicon detector for the DZero colliding beams experiment. This detector has an all carbon fiber support structure that employs thin copper clad Kapton sheets embedded in the surface of the carbon fiber structure to improve the grounding of the structure and a readout system that fully isolates the local detector ground from the rest of the detector. Initial measurements show efficiencies greater than 90% and 0.3 ADC count common mode contribution to the signal noise.

  11. Detector developments at DESY.

    PubMed

    Wunderer, Cornelia B; Allahgholi, Aschkan; Bayer, Matthias; Bianco, Laura; Correa, Jonathan; Delfs, Annette; Göttlicher, Peter; Hirsemann, Helmut; Jack, Stefanie; Klyuev, Alexander; Lange, Sabine; Marras, Alessandro; Niemann, Magdalena; Pithan, Florian; Reza, Salim; Sheviakov, Igor; Smoljanin, Sergej; Tennert, Maximilian; Trunk, Ulrich; Xia, Qingqing; Zhang, Jiaguo; Zimmer, Manfred; Das, Dipayan; Guerrini, Nicola; Marsh, Ben; Sedgwick, Iain; Turchetta, Renato; Cautero, Giuseppe; Giuressi, Dario; Menk, Ralf; Khromova, Anastasiya; Pinaroli, Giovanni; Stebel, Luigi; Marchal, Julien; Pedersen, Ulrik; Rees, Nick; Steadman, Paul; Sussmuth, Mark; Tartoni, Nicola; Yousef, Hazem; Hyun, HyoJung; Kim, KyungSook; Rah, Seungyu; Dinapoli, Roberto; Greiffenberg, Dominic; Mezza, Davide; Mozzanica, Aldo; Schmitt, Bernd; Shi, Xintian; Krueger, Hans; Klanner, Robert; Schwandt, Joem; Graafsma, Heinz

    2016-01-01

    With the increased brilliance of state-of-the-art synchrotron radiation sources and the advent of free-electron lasers (FELs) enabling revolutionary science with EUV to X-ray photons comes an urgent need for suitable photon imaging detectors. Requirements include high frame rates, very large dynamic range, single-photon sensitivity with low probability of false positives and (multi)-megapixels. At DESY, one ongoing development project - in collaboration with RAL/STFC, Elettra Sincrotrone Trieste, Diamond, and Pohang Accelerator Laboratory - is the CMOS-based soft X-ray imager PERCIVAL. PERCIVAL is a monolithic active-pixel sensor back-thinned to access its primary energy range of 250 eV to 1 keV with target efficiencies above 90%. According to preliminary specifications, the roughly 10 cm × 10 cm, 3.5k × 3.7k monolithic sensor will operate at frame rates up to 120 Hz (commensurate with most FELs) and use multiple gains within 27 µm pixels to measure 1 to ∼100000 (500 eV) simultaneously arriving photons. DESY is also leading the development of the AGIPD, a high-speed detector based on hybrid pixel technology intended for use at the European XFEL. This system is being developed in collaboration with PSI, University of Hamburg, and University of Bonn. The AGIPD allows single-pulse imaging at 4.5 MHz frame rate into a 352-frame buffer, with a dynamic range allowing single-photon detection and detection of more than 10000 photons at 12.4 keV in the same image. Modules of 65k pixels each are configured to make up (multi)megapixel cameras. This review describes the AGIPD and the PERCIVAL concepts and systems, including some recent results and a summary of their current status. It also gives a short overview over other FEL-relevant developments where the Photon Science Detector Group at DESY is involved. PMID:26698052

  12. High-energy detector

    DOEpatents

    Bolotnikov, Aleksey E.; Camarda, Giuseppe; Cui, Yonggang; James, Ralph B.

    2011-11-22

    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.

  13. Microstructured silicon neutron detectors for security applications

    NASA Astrophysics Data System (ADS)

    Esteban, S.; Fleta, C.; Guardiola, C.; Jumilla, C.; Pellegrini, G.; Quirion, D.; Rodriguez, J.; Lozano, M.

    2014-12-01

    In this paper we present the design and performance of a perforated thermal neutron silicon detector with a 6LiF neutron converter. This device was manufactured within the REWARD project workplace whose aim is to develop and enhance technologies for the detection of nuclear and radiological materials. The sensor perforated structure results in a higher efficiency than that obtained with an equivalent planar sensor. The detectors were tested in a thermal neutron beam at the nuclear reactor at the Instituto Superior Técnico in Lisbon and the intrinsic detection efficiency for thermal neutrons and the gamma sensitivity were obtained. The Geant4 Monte Carlo code was used to simulate the experimental conditions, i.e. thermal neutron beam and the whole detector geometry. An intrinsic thermal neutron detection efficiency of 8.6%±0.4% with a discrimination setting of 450 keV was measured.

  14. Neutron and X-ray Detectors

    SciTech Connect

    Carini, Gabriella; Denes, Peter; Gruener, Sol; Lessner, Elianne

    2012-08-01

    The Basic Energy Sciences (BES) X-ray and neutron user facilities attract more than 12,000 researchers each year to perform cutting-edge science at these state-of-the-art sources. While impressive breakthroughs in X-ray and neutron sources give us the powerful illumination needed to peer into the nano- to mesoscale world, a stumbling block continues to be the distinct lag in detector development, which is slowing progress toward data collection and analysis. Urgently needed detector improvements would reveal chemical composition and bonding in 3-D and in real time, allow researchers to watch “movies” of essential life processes as they happen, and make much more efficient use of every X-ray and neutron produced by the source The immense scientific potential that will come from better detectors has triggered worldwide activity in this area. Europe in particular has made impressive strides, outpacing the United States on several fronts. Maintaining a vital U.S. leadership in this key research endeavor will require targeted investments in detector R&D and infrastructure. To clarify the gap between detector development and source advances, and to identify opportunities to maximize the scientific impact of BES user facilities, a workshop on Neutron and X-ray Detectors was held August 1-3, 2012, in Gaithersburg, Maryland. Participants from universities, national laboratories, and commercial organizations from the United States and around the globe participated in plenary sessions, breakout groups, and joint open-discussion summary sessions. Sources have become immensely more powerful and are now brighter (more particles focused onto the sample per second) and more precise (higher spatial, spectral, and temporal resolution). To fully utilize these source advances, detectors must become faster, more efficient, and more discriminating. In supporting the mission of today’s cutting-edge neutron and X-ray sources, the workshop identified six detector research challenges

  15. Plastic neutron detectors.

    SciTech Connect

    Wilson, Tiffany M.S; King, Michael J.; Doty, F. Patrick

    2008-12-01

    This work demonstrated the feasibility and limitations of semiconducting {pi}-conjugated organic polymers for fast neutron detection via n-p elastic scattering. Charge collection in conjugated polymers in the family of substituted poly(p-phenylene vinylene)s (PPV) was evaluated using band-edge laser and proton beam ionization. These semiconducting materials can have high H/C ratio, wide bandgap, high resistivity and high dielectric strength, allowing high field operation with low leakage current and capacitance noise. The materials can also be solution cast, allowing possible low-cost radiation detector fabrication and scale-up. However, improvements in charge collection efficiency are necessary in order to achieve single particle detection with a reasonable sensitivity. The work examined processing variables, additives and environmental effects. Proton beam exposure was used to verify particle sensitivity and radiation hardness to a total exposure of approximately 1 MRAD. Conductivity exhibited sensitivity to temperature and humidity. The effects of molecular ordering were investigated in stretched films, and FTIR was used to quantify the order in films using the Hermans orientation function. The photoconductive response approximately doubled for stretch-aligned films with the stretch direction parallel to the electric field direction, when compared to as-cast films. The response was decreased when the stretch direction was orthogonal to the electric field. Stretch-aligned films also exhibited a significant sensitivity to the polarization of the laser excitation, whereas drop-cast films showed none, indicating improved mobility along the backbone, but poor {pi}-overlap in the orthogonal direction. Drop-cast composites of PPV with substituted fullerenes showed approximately a two order of magnitude increase in photoresponse, nearly independent of nanoparticle concentration. Interestingly, stretch-aligned composite films showed a substantial decrease in

  16. The ATLAS Detector Control System

    NASA Astrophysics Data System (ADS)

    Lantzsch, K.; Arfaoui, S.; Franz, S.; Gutzwiller, O.; Schlenker, S.; Tsarouchas, C. A.; Mindur, B.; Hartert, J.; Zimmermann, S.; Talyshev, A.; Oliveira Damazio, D.; Poblaguev, A.; Braun, H.; Hirschbuehl, D.; Kersten, S.; Martin, T.; Thompson, P. D.; Caforio, D.; Sbarra, C.; Hoffmann, D.; Nemecek, S.; Robichaud-Veronneau, A.; Wynne, B.; Banas, E.; Hajduk, Z.; Olszowska, J.; Stanecka, E.; Bindi, M.; Polini, A.; Deliyergiyev, M.; Mandic, I.; Ertel, E.; Marques Vinagre, F.; Ribeiro, G.; Santos, H. F.; Barillari, T.; Habring, J.; Huber, J.; Arabidze, G.; Boterenbrood, H.; Hart, R.; Iakovidis, G.; Karakostas, K.; Leontsinis, S.; Mountricha, E.; Ntekas, K.; Filimonov, V.; Khomutnikov, V.; Kovalenko, S.; Grassi, V.; Mitrevski, J.; Phillips, P.; Chekulaev, S.; D'Auria, S.; Nagai, K.; Tartarelli, G. F.; Aielli, G.; Marchese, F.; Lafarguette, P.; Brenner, R.

    2012-12-01

    The ATLAS experiment is one of the multi-purpose experiments at the Large Hadron Collider (LHC) at CERN, constructed to study elementary particle interactions in collisions of high-energy proton beams. Twelve different sub detectors as well as the common experimental infrastructure are controlled and monitored by the Detector Control System (DCS) using a highly distributed system of 140 server machines running the industrial SCADA product PVSS. Higher level control system layers allow for automatic control procedures, efficient error recognition and handling, manage the communication with external systems such as the LHC controls, and provide a synchronization mechanism with the ATLAS data acquisition system. Different databases are used to store the online parameters of the experiment, replicate a subset used for physics reconstruction, and store the configuration parameters of the systems. This contribution describes the computing architecture and software tools to handle this complex and highly interconnected control system.

  17. Optimization of a neutron detector design using adjoint transport simulation

    SciTech Connect

    Yi, C.; Manalo, K.; Huang, M.; Chin, M.; Edgar, C.; Applegate, S.; Sjoden, G.

    2012-07-01

    A synthetic aperture approach has been developed and investigated for Special Nuclear Materials (SNM) detection in vehicles passing a checkpoint at highway speeds. SNM is postulated to be stored in a moving vehicle and detector assemblies are placed on the road-side or in chambers embedded below the road surface. Neutron and gamma spectral awareness is important for the detector assembly design besides high efficiencies, so that different SNMs can be detected and identified with various possible shielding settings. The detector assembly design is composed of a CsI gamma-ray detector block and five neutron detector blocks, with peak efficiencies targeting different energy ranges determined by adjoint simulations. In this study, formulations are derived using adjoint transport simulations to estimate detector efficiencies. The formulations is applied to investigate several neutron detector designs for Block IV, which has its peak efficiency in the thermal range, and Block V, designed to maximize the total neutron counts over the entire energy spectrum. Other Blocks detect different neutron energies. All five neutron detector blocks and the gamma-ray block are assembled in both MCNP and deterministic simulation models, with detector responses calculated to validate the fully assembled design using a 30-group library. The simulation results show that the 30-group library, collapsed from an 80-group library using an adjoint-weighting approach with the YGROUP code, significantly reduced the computational cost while maintaining accuracy. (authors)

  18. LISe pixel detector for neutron imaging

    NASA Astrophysics Data System (ADS)

    Herrera, Elan; Hamm, Daniel; Wiggins, Brenden; Milburn, Rob; Burger, Arnold; Bilheux, Hassina; Santodonato, Louis; Chvala, Ondrej; Stowe, Ashley; Lukosi, Eric

    2016-10-01

    Semiconducting lithium indium diselenide, 6LiInSe2 or LISe, has promising characteristics for neutron detection applications. The 95% isotopic enrichment of 6Li results in a highly efficient thermal neutron-sensitive material. In this study, we report on a proof-of-principle investigation of a semiconducting LISe pixel detector to demonstrate its potential as an efficient neutron imager. The LISe pixel detector had a 4×4 of pixels with a 550 μm pitch on a 5×5×0.56 mm3 LISe substrate. An experimentally verified spatial resolution of 300 μm was observed utilizing a super-sampling technique.

  19. 1 mm ultrafast superconducting stripline molecule detector

    NASA Astrophysics Data System (ADS)

    Zen, N.; Casaburi, A.; Shiki, S.; Suzuki, K.; Ejrnaes, M.; Cristiano, R.; Ohkubo, M.

    2009-10-01

    Superconducting stripline detectors (SSLDs) are promising for detecting keV molecules at nanosecond response times and with mass-independent detection efficiency. However, a fast response time is incompatible with practical centimeter detector size. A parallel configuration of striplines provides a means to address this problem. Experimental results and simulation for promisingly large 1-mm-square parallel niobium SSLDs show that nanosecond pulses are produced by superconducting-normal transition within only one of the parallel striplines instead of cascade switching of all the parallel striplines. Successful detection of a series of multimers of immunoglobulin G up to 584 kDa supports the mass-independent efficiency for mass spectrometry.

  20. Superconducting nano-strip particle detectors

    NASA Astrophysics Data System (ADS)

    Cristiano, R.; Ejrnaes, M.; Casaburi, A.; Zen, N.; Ohkubo, M.

    2015-12-01

    We review progress in the development and applications of superconducting nano-strip particle detectors. Particle detectors based on superconducting nano-strips stem from the parent devices developed for single photon detection (SSPD) and share with them ultra-fast response times (sub-nanosecond) and the ability to operate at a relatively high temperature (2-5 K) compared with other cryogenic detectors. SSPDs have been used in the detection of electrons, neutral and charged ions, and biological macromolecules; nevertheless, the development of superconducting nano-strip particle detectors has mainly been driven by their use in time-of-flight mass spectrometers (TOF-MSs) where the goal of 100% efficiency at large mass values can be achieved. Special emphasis will be given to this case, reporting on the great progress which has been achieved and which permits us to overcome the limitations of existing mass spectrometers represented by low detection efficiency at large masses and charge/mass ambiguity. Furthermore, such progress could represent a breakthrough in the field. In this review article we will introduce the device concept and detection principle, stressing the peculiarities of the nano-strip particle detector as well as its similarities with photon detectors. The development of parallel strip configuration is introduced and extensively discussed, since it has contributed to the significant progress of TOF-MS applications.

  1. Development of silicon micropattern pixel detectors

    NASA Astrophysics Data System (ADS)

    Heijne, E. H. M.; Antinori, F.; Beker, H.; Batignani, G.; Beusch, W.; Bonvicini, V.; Bosisio, L.; Boutonnet, C.; Burger, P.; Campbell, M.; Cantoni, P.; Catanesi, M. G.; Chesi, E.; Claeys, C.; Clemens, J. C.; Cohen Solal, M.; Darbo, G.; Da Via, C.; Debusschere, I.; Delpierre, P.; Di Bari, D.; Di Liberto, S.; Dierickx, B.; Enz, C. C.; Focardi, E.; Forti, F.; Gally, Y.; Glaser, M.; Gys, T.; Habrard, M. C.; Hallewell, G.; Hermans, L.; Heuser, J.; Hurst, R.; Inzani, P.; Jæger, J. J.; Jarron, P.; Karttaavi, T.; Kersten, S.; Krummenacher, F.; Leitner, R.; Lemeilleur, F.; Lenti, V.; Letheren, M.; Lokajicek, M.; Loukas, D.; Macdermott, M.; Maggi, G.; Manzari, V.; Martinengo, P.; Meddeler, G.; Meddi, F.; Mekkaoui, A.; Menetrey, A.; Middelkamp, P.; Morando, M.; Munns, A.; Musico, P.; Nava, P.; Navach, F.; Neyer, C.; Pellegrini, F.; Pengg, F.; Perego, R.; Pindo, M.; Pospisil, S.; Potheau, R.; Quercigh, E.; Redaelli, N.; Ridky, J.; Rossi, L.; Sauvage, D.; Segato, G.; Simone, S.; Sopko, B.; Stefanini, G.; Strakos, V.; Tempesta, P.; Tonelli, G.; Vegni, G.; Verweij, H.; Viertel, G. M.; Vrba, V.; Waisbard, J.; CERN RD19 Collaboration

    1994-09-01

    Successive versions of high speed, active silicon pixel detectors with integrated readout electronics have been developed for particle physics experiments using monolithic and hybrid technologies. Various matrices with binary output as well as a linear detector with analog output have been made. The hybrid binary matrix with 1024 cells (dimension 75 μm×500 μm) can capture events at ˜5 MHz and a selected event can then be read out in < 10 μs. In different beam tests at CERN a precision of 25 μm has been achieved and the efficiency was better than 99.2%. Detector thicknesses of 300 μm and 150 μm of silicon have been used. In a test with a 109Cd source a noise level of 170 e - r.m.s. (1.4 keV fwhm) has been measured with a threshold non-uniformity of 750 e - r.m.s. Objectives of the development work are the increase of the size of detecting area without loss of efficiency, the design of an appropriate readout architecture for collider operation, the reduction of material thickness in the detector, understanding of the threshold non-uniformity, study of the sensitivity of the pixel matrices to light and low energy electrons for scintillating fiber detector readout and last but not least, the optimization of cost and yield of the pixel detectors in production.

  2. Germanium detector vacuum encapsulation

    NASA Technical Reports Server (NTRS)

    Madden, N. W.; Malone, D. F.; Pehl, R. H.; Cork, C. P.; Luke, P. N.; Landis, D. A.; Pollard, M. J.

    1991-01-01

    This paper describes an encapsulation technology that should significantly improve the viability of germanium gamma-ray detectors for a number of important applications. A specialized vacuum chamber has been constructed in which the detector and the encapsulating module are processed in high vacuum. Very high vacuum conductance is achieved within the valveless encapsulating module. The detector module is then sealed without breaking the chamber vacuum. The details of the vacuum chamber, valveless module, processing, and sealing method are presented.

  3. Detectors (4/5)

    ScienceCinema

    None

    2016-07-12

    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.

  4. Detectors (5/5)

    ScienceCinema

    None

    2016-07-12

    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.

  5. History of infrared detectors

    NASA Astrophysics Data System (ADS)

    Rogalski, A.

    2012-09-01

    This paper overviews the history of infrared detector materials starting with Herschel's experiment with thermometer on February 11th, 1800. Infrared detectors are in general used to detect, image, and measure patterns of the thermal heat radiation which all objects emit. At the beginning, their development was connected with thermal detectors, such as thermocouples and bolometers, which are still used today and which are generally sensitive to all infrared wavelengths and operate at room temperature. The second kind of detectors, called the photon detectors, was mainly developed during the 20th Century to improve sensitivity and response time. These detectors have been extensively developed since the 1940's. Lead sulphide (PbS) was the first practical IR detector with sensitivity to infrared wavelengths up to ˜3 μm. After World War II infrared detector technology development was and continues to be primarily driven by military applications. Discovery of variable band gap HgCdTe ternary alloy by Lawson and co-workers in 1959 opened a new area in IR detector technology and has provided an unprecedented degree of freedom in infrared detector design. Many of these advances were transferred to IR astronomy from Departments of Defence research. Later on civilian applications of infrared technology are frequently called "dual-use technology applications." One should point out the growing utilisation of IR technologies in the civilian sphere based on the use of new materials and technologies, as well as the noticeable price decrease in these high cost technologies. In the last four decades different types of detectors are combined with electronic readouts to make detector focal plane arrays (FPAs). Development in FPA technology has revolutionized infrared imaging. Progress in integrated circuit design and fabrication techniques has resulted in continued rapid growth in the size and performance of these solid state arrays.

  6. GaAs detectors irradiated by low doses of electrons

    NASA Astrophysics Data System (ADS)

    Šagátová, A.; Zat'ko, B.; Pavlovič, M.; Sedlačková, K.; Hybler, P.; Dubecký, F.; Nečas, V.

    2014-04-01

    Semi-insulating (SI) GaAs detectors were irradiated by 5 MeV electrons up to a dose of 69 kGy, in order to test their radiation hardness. The electric and spectrometric stability of detectors was examined as a function of the absorbed dose. Investigated detectors showed a very good detector radiation resistance within a dose up to 40 kGy followed by deterioration of some spectrometric and electric properties. However, the reverse current and the detector charge collection efficiency showed minimum changes with the overall applied doses. The obtained results will be used as a preliminary study for further radiation-hardness investigations of GaAs detectors against high energy electrons. This will complete our previous studies of GaAs detector radiation hardness against fast neutrons and γ-rays.

  7. Semiconductor detector performance for low-energy x-rays

    SciTech Connect

    Jaklevic, J.M.; Walton, J.T.; McMurray, R.E. Jr.; Madden, N.W.; Goulding, F.S.

    1987-06-01

    Factors that limit the capabilities of semiconductor detectors at photon energies below 5 keV include energy resolution, detector efficiency, and detector-related continuum background. These properties can be controlled to a certain extent by optimal detector design and fabrication techniques. We describe measurements on the low-energy response of Si(Li) detectors obtained using a tunable, low-energy monochromatic source. Window thicknesses have been measured for a number of devices using different materials for the entry contact. The interpretation of these results in terms of existing detector window models is discussed. Results obtained using a new contact structure demonstrate that a dramatic reduction in window-related absorption in Si(Li) detectors can be achieved.

  8. Monolithic short wave infrared (SWIR) detector array

    NASA Technical Reports Server (NTRS)

    1983-01-01

    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.

  9. Simulation and Comparison of Various Gamma-Ray Imaging Detector Configurations for IPRL Devices

    SciTech Connect

    Manini, H A

    2006-12-27

    Simulations are performed for seven different geometrical configurations of CdZnTe (CZT) detector arrays for Intelligent Personal Radiation Locator (IPRL) devices. IPRL devices are portable radiation detectors that have gamma-ray imaging capability. The detector performance is analyzed for each type of IPRL configuration, and the intrinsic photopeak efficiency, intrinsic photopeak count rate, detector image resolution, imaging efficiency, and imaging count rate are determined.

  10. Adaptors for radiation detectors

    DOEpatents

    Livesay, Ronald Jason

    2015-07-28

    Described herein are adaptors and other devices for radiation detectors that can be used to make accurate spectral measurements of both small and large bulk sources of radioactivity, such as building structures, soils, vessels, large equipment, and liquid bodies. Some exemplary devices comprise an adaptor for a radiation detector, wherein the adaptor can be configured to collimate radiation passing through the adapter from an external radiation source to the radiation detector and the adaptor can be configured to enclose a radiation source within the adapter to allow the radiation detector to measure radiation emitted from the enclosed radiation source.

  11. Adaptors for radiation detectors

    DOEpatents

    Livesay, Ronald Jason

    2014-04-22

    Described herein are adaptors and other devices for radiation detectors that can be used to make accurate spectral measurements of both small and large bulk sources of radioactivity, such as building structures, soils, vessels, large equipment, and liquid bodies. Some exemplary devices comprise an adaptor for a radiation detector, wherein the adaptor can be configured to collimate radiation passing through the adapter from an external radiation source to the radiation detector and the adaptor can be configured to enclose a radiation source within the adapter to allow the radiation detector to measure radiation emitted from the enclosed radiation source.

  12. The CDFII Silicon Detector

    SciTech Connect

    Julia Thom

    2004-07-23

    The CDFII silicon detector consists of 8 layers of double-sided silicon micro-strip sensors totaling 722,432 readout channels, making it one of the largest silicon detectors in present use by an HEP experiment. After two years of data taking, we report on our experience operating the complex device. The performance of the CDFII silicon detector is presented and its impact on physics analyses is discussed. We have already observed measurable effects from radiation damage. These results and their impact on the expected lifetime of the detector are briefly reviewed.

  13. Fabrication and Characterization of Superconducting NbN Nanowire Single Photon Detectors

    NASA Technical Reports Server (NTRS)

    Stern, Jeffrey A.; Farr, William H.

    2006-01-01

    We report on the fabrication and characterization of high-speed, single photon detectors using superconducting NbN nanowires at a wavelength of 1064 nm. A 15 by 15 micron detector with a detector efficiency of 40% has been measured. Due to kinetic inductance, the recovery time of such large area detectors is longer than that of smaller or single wire detectors. The recovery time of our detectors (50 ns) has been characterized by measuring the inter-arrival time statistics of our detector.

  14. Results on diamond timing detector for the TOTEM experiment

    NASA Astrophysics Data System (ADS)

    Bossini, E.

    2016-07-01

    We describe the results and status of our R&D on diamond timing detectors for the TOTEM experiment at CERN. Tests with commercial devices have been done and here reported; the unsatisfactory results push us to design a new detector. We present test beams results and the front-end electronics, critical point of the design. Efficiency studies and timing performance dependence from detector capacitance will be also reported.

  15. The vertex detector for the Lepton/Photon collaboration

    SciTech Connect

    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.

    1991-12-31

    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.

  16. The vertex detector for the Lepton/Photon Collaboration

    SciTech Connect

    Sullivan, J.P.; Boissevain, J.G.; Fox, D.; van Hecke, H.; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E.

    1991-12-31

    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 concentric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity {eta} 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.

  17. Type II superlattice technology for LWIR detectors

    NASA Astrophysics Data System (ADS)

    Klipstein, P. C.; Avnon, E.; Azulai, D.; Benny, Y.; Fraenkel, R.; Glozman, A.; Hojman, E.; Klin, O.; Krasovitsky, L.; Langof, L.; Lukomsky, I.; Nitzani, M.; Shtrichman, I.; Rappaport, N.; Snapi, N.; Weiss, E.; Tuito, A.

    2016-05-01

    SCD has developed a range of advanced infrared detectors based on III-V semiconductor heterostructures grown on GaSb. The XBn/XBp family of barrier detectors enables diffusion limited dark currents, comparable with MCT Rule-07, and high quantum efficiencies. This work describes some of the technical challenges that were overcome, and the ultimate performance that was finally achieved, for SCD's new 15 μm pitch "Pelican-D LW" type II superlattice (T2SL) XBp array detector. This detector is the first of SCD's line of high performance two dimensional arrays working in the LWIR spectral range, and was designed with a ~9.3 micron cut-off wavelength and a format of 640 x 512 pixels. It contains InAs/GaSb and InAs/AlSb T2SLs, engineered using k • p modeling of the energy bands and photo-response. The wafers are grown by molecular beam epitaxy and are fabricated into Focal Plane Array (FPA) detectors using standard FPA processes, including wet and dry etching, indium bump hybridization, under-fill, and back-side polishing. The FPA has a quantum efficiency of nearly 50%, and operates at 77 K and F/2.7 with background limited performance. The pixel operability of the FPA is above 99% and it exhibits a stable residual non uniformity (RNU) of better than 0.04% of the dynamic range. The FPA uses a new digital read-out integrated circuit (ROIC), and the complete detector closely follows the interfaces of SCD's MWIR Pelican-D detector. The Pelican- D LW detector is now in the final stages of qualification and transfer to production, with first prototypes already integrated into new electro-optical systems.

  18. Explosives (and other threats) detection using pulsed neutron interrogation and optimized detectors

    NASA Astrophysics Data System (ADS)

    Strellis, Dan A.; Elsalim, Mashal; Gozani, Tsahi

    2011-06-01

    We have previously reported results from a human-portable system using neutron interrogation to detect contraband and explosives. We summarized our methodology for distinguishing threat materials such as narcotics, C4, and mustard gas in the myriad of backgrounds present in the maritime environment. We are expanding our mission for the Domestic Nuclear Detection Office (DNDO) to detect Special Nuclear Material (SNM) through the detection of multiple fission signatures without compromising the conventional threat detection performance. This paper covers our initial investigations into using neutrons from compact pulsed neutron generators via the d(D,n)3He or d(T,n)α reactions with energies of ~2.5 and 14 MeV, respectively, for explosives (and other threats) detection along with a variety of gamma-ray detectors. Fast neutrons and thermal neutrons (after successive collisions) can stimulate the emission of various threat detection signatures. For explosives detection, element-specific gamma-ray signatures via the (n,n'γ) inelastic scattering reaction and the (n,'γ) thermal capture reaction are detected. For SNM, delayed gamma-rays following fission can be measured with the same detector. Our initial trade-off investigations of several gamma-ray detectors types (NaI, CsI, LaBr3, HPGe) for measuring gamma-ray signatures in a pulsed neutron environment for potential application in a human-portable active interrogation system are covered in this paper.

  19. Can scintillation detectors with low spectral resolution accurately determine radionuclides content of building materials?

    PubMed

    Kovler, K; Prilutskiy, Z; Antropov, S; Antropova, N; Bozhko, V; Alfassi, Z B; Lavi, N

    2013-07-01

    The current paper makes an attempt to check whether the scintillation NaI(Tl) detectors, in spite of their poor energy resolution, can determine accurately the content of NORM in building materials. The activity concentrations of natural radionuclides were measured using two types of detectors: (a) NaI(Tl) spectrometer equipped with the special software based on the matrix method of least squares, and (b) high-purity germanium spectrometer. Synthetic compositions with activity concentrations varying in a wide range, from 1/5 to 5 times median activity concentrations of the natural radionuclides available in the earth crust and the samples of popular building materials, such as concrete, pumice and gypsum, were tested, while the density of the tested samples changed in a wide range (from 860 up to 2,410 kg/m(3)). The results obtained in the NaI(Tl) system were similar to those obtained with the HPGe spectrometer, mostly within the uncertainty range. This comparison shows that scintillation spectrometers equipped with a special software aimed to compensate for the lower spectral resolution of NaI(Tl) detectors can be successfully used for the radiation control of mass construction products. PMID:23542118

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

    DOE PAGES

    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.; et al

    2012-11-09

    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. Furthermore, experiments that operate germanium detectors with a verymore » low energy threshold may benefit from the methods presented herein.« less

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

    SciTech Connect

    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.

    2012-11-09

    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. Furthermore, experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein.

  2. Cs based photocathodes for gaseous detectors

    SciTech Connect

    Borovick-Romanov, A.; Peskov, V.

    1993-08-01

    We demonstrated that some standard photocathodes SbCs, GaAs(Cs), Au(Cs) can easily be manufactured for use inside gaseous detectors. When filed with clean quenched gases such detectors have a quantum efficiency of a few percent in the visible region of the spectra and can operate at a gain >10{sup 3}. We tried to make these photocathodes more air stable by protecting their surfaces with a thin layer of CsI or liquid TMAE. The most air stable were photocathodes with a CsI protective layer. A wavelengths {le}185 nm such photocathodes have the highest quantum efficiency among all known air stable photocathodes, including CsI. Gaseous detectors with such photocathodes can operate at a gain of 10{sup 5}. Results of first tests of doped CsI photocathode are also presented. Possible fields of application of new photocathodes are discussed.

  3. Antimonide superlattice barrier infrared detectors

    NASA Astrophysics Data System (ADS)

    Ting, David Z.; Hill, Cory J.; Soibel, Alexander; Nguyen, Jean; Keo, Sam A.; Mumolo, Jason M.; Lee, Michael C.; Yang, Baohau; Gunapala, Sarath D.

    2009-08-01

    Unipolar barriers can block one carrier type but allow the un-impeded flow of the other. They can be used to implement the barrier infra-red detector (BIRD) design for increasing the collection efficiency of photo-generated carriers, and reducing dark current generation without impeding photocurrent flow. In particular, the InAs/GaSb/AlSb material system, which can be epitaxially grown on GaSb or InAs substrates, is well suited for implementing BIRD structures, as there is considerable flexibility in forming a variety of alloys and superlattices, and tailoring band offsets. We describe our efforts to achieve high-performance long wavelength InAs/GaSb superlattice infrared photodetectors based on the BIRD architecture. Specifically, we report a 10 μm cutoff device based on a complementary barrier infrared detector (CBIRD) design. The detector, without anti-reflection coating, exhibits a responsivity of 1.5 A/W and a dark current density of 1×10-5 A/cm2 at 77K under 0.2 V bias. It reaches 300 K background limited infrared photodetection (BLIP) operation at 101 K, with a black-body BLIP D* value of 2.6×1010 cm-Hz1/2/W for 2π field of view under 0.2 V bias.

  4. SCINTILLATION EXPOSURE RATE DETECTOR

    DOEpatents

    Spears, W.G.

    1960-11-01

    A radiation detector for gamma and x rays is described. The detector comprises a scintillation crystal disposed between a tantalum shield and the input of a photomultiplier tube, the crystal and the shield cooperating so that their combined response to a given quantity of radiation at various energy levels is substantially constant.

  5. Smoke Detectors and Legislation.

    ERIC Educational Resources Information Center

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

    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…

  6. Alkali ionization detector

    DOEpatents

    Hrizo, John; Bauerle, James E.; Witkowski, Robert E.

    1982-01-01

    A calibration filament containing a sodium-bearing compound is included in combination with the sensing filament and ion collector plate of a sodium ionization detector to permit periodic generation of sodium atoms for the in-situ calibration of the detector.

  7. The CLAS Cherenkov detector

    SciTech Connect

    G. Adams; V. Burkert; R. Carl; T. Carstens; V. Frolov; L. Houghtlin; G. Jacobs; M. Kossov; M. Klusman; B. Kross; M. Onuk; J. Napolitano; J. W. Price; C. Riggs; Y. Sharabian; A. Stavinsky; L. C. Smith; W. A. Stephens; P. Stoler; W. Tuzel; K. Ullrich; A. Vlassovc; A. Weisenberger; M. Witkowski; B. Wojtekhowski; P. F. Yergin; C. Zorn

    2001-06-01

    The design, construction, and performance of the CLAS Cerenkov threshold gas detector at Jefferson Lab is described. The detector consists of 216 optical modules. Each module consists of 3 adjustable mirrors, of lightweight composite construction, a Winston light collecting cone, a 5-inch photomultiplier tube, and specially designed magnetic shielding.

  8. Future particle detector systems

    NASA Astrophysics Data System (ADS)

    Clark, Allan G.

    2000-09-01

    Starting with a short summary of the major new experimental physics programs, we attempt to motivate the reasons why existing general-purpose detectors at Hadron Colliders are what they are, why they are being upgraded, and why new facilities are being constructed. The CDF and ATLAS detectors are used to illustrate these motivations. Selected physics results from the CDF experiment provide evidence for limitations on the detector performance, and new physics opportunities motivate both machine and detector upgrades. This is discussed with emphasis on the improved physics reach of the CDF experiment at the Fermilab Tevatron (√s =2 TeV). From 2005, the Large Hadron Collider (LHC) at CERN will become operational at a collision energy of √s =14 TeV, seven times larger than at the Tevatron Collider. To exploit the physics capability of the LHC, several large detectors are being constructed. The detectors are significantly more complex than those at the Tevatron Collider because of physics and operational constraints. The detector design and technology of the aspects of the large general-purpose detector ATLAS is described.

  9. Arsenic activation neutron detector

    DOEpatents

    Jacobs, E.L.

    1980-01-28

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5-MeV neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  10. Arsenic activation neutron detector

    DOEpatents

    Jacobs, Eddy L.

    1981-01-01

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5 Mev neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  11. Particle impact location detector

    NASA Technical Reports Server (NTRS)

    Auer, S. O.

    1974-01-01

    Detector includes delay lines connected to each detector surface strip. When several particles strike different strips simultaneously, pulses generated by each strip are time delayed by certain intervals. Delay time for each strip is known. By observing time delay in pulse, it is possible to locate strip that is struck by particle.

  12. Scanning Seismic Intrusion Detector

    NASA Technical Reports Server (NTRS)

    Lee, R. D.

    1982-01-01

    Scanning seismic intrusion detector employs array of automatically or manually scanned sensors to determine approximate location of intruder. Automatic-scanning feature enables one operator to tend system of many sensors. Typical sensors used with new system are moving-coil seismic pickups. Detector finds uses in industrial security systems.

  13. Special Nuclear Material Detection with a Water Cherenkov based Detector

    SciTech Connect

    Sweany, M; Bernstein, A; Bowden, N; Dazeley, S; Svoboda, R

    2008-11-10

    Fission events from Special Nuclear Material (SNM), such as highly enriched uranium or plutonium, produce a number of neutrons and high energy gamma-rays. Assuming the neutron multiplicity is approximately Poissonian with an average of 2 to 3, the observation of time correlations between these particles from a cargo container would constitute a robust signature of the presence of SNM inside. However, in order to be sensitive to the multiplicity, one would require a high total efficiency. There are two approaches to maximize the total efficiency; maximizing the detector efficiency or maximizing the detector solid angle coverage. The advanced detector group at LLNL is investigating one way to maximize the detector size. We are designing and building a water Cerenkov based gamma and neutron detector for the purpose of developing an efficient and cost effective way to deploy a large solid angle car wash style detector. We report on our progress in constructing a larger detector and also present preliminary results from our prototype detector that indicates detection of neutrons.

  14. Waveguide-Coupled Superconducting Nanowire Single-Photon Detectors

    NASA Technical Reports Server (NTRS)

    Beyer, Andrew D.; Briggs, Ryan M.; Marsili, Francesco; Cohen, Justin D.; Meenehan, Sean M.; Painter, Oskar J.; Shaw, Matthew D.

    2015-01-01

    We have demonstrated WSi-based superconducting nanowire single-photon detectors coupled to SiNx waveguides with integrated ring resonators. This photonics platform enables the implementation of robust and efficient photon-counting detectors with fine spectral resolution near 1550 nm.

  15. Nanomechanical resonance detector

    DOEpatents

    Grossman, Jeffrey C; Zettl, Alexander K

    2013-10-29

    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.

  16. Advanced far infrared detectors

    SciTech Connect

    Haller, E.E.

    1993-05-01

    Recent advances in photoconductive and bolometric semiconductor detectors for wavelength 1 mm > {lambda} > 50 {mu}m are reviewed. Progress in detector performance in this photon energy range has been stimulated by new and stringent requirements for ground based, high altitude and space-borne telescopes for astronomical and astrophysical observations. The paper consists of chapters dealing with the various types of detectors: Be and Ga doped Ge photoconductors, stressed Ge:Ga devices and neutron transmutation doped Ge thermistors. Advances in the understanding of basic detector physics and the introduction of modern semiconductor device technology have led to predictable and reliable fabrication techniques. Integration of detectors into functional arrays has become feasible and is vigorously pursued by groups worldwide.

  17. The Quantasyn, an improved quantum detector

    NASA Technical Reports Server (NTRS)

    Gorstein, M.; Mc Williams, I. G.; Seward, H. H.

    1969-01-01

    Quantasyn provides absolute measurement of radiation flux in the range 1000 A to 4500 A and into the vacuum ultraviolet. This radiation detector cimbines the high quantum efficiency and inherent linearity of the silicon solar cell with the constant quantum response of the fluorescent organic compound liumogen.

  18. SNM Detection with a Large Water Cerenkov Detector

    SciTech Connect

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

    2009-06-04

    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.

  19. Neutron beam imaging with GEM detectors

    NASA Astrophysics Data System (ADS)

    Albani, G.; Croci, G.; Cazzaniga, C.; Cavenago, M.; Claps, G.; Muraro, A.; Murtas, F.; Pasqualotto, R.; Perelli Cippo, E.; Rebai, M.; Tardocchi, M.; Gorini, G.

    2015-04-01

    Neutron GEM-based detectors represent a new frontier of devices in neutron physics applications where a very high neutron flux must be measured such as future fusion experiments (e.g. ITER Neutral beam Injector) and spallation sources (e.g. the European Spallation source). This kind of detectors can be properly adapted to be used both as beam monitors but also as neutron diffraction detectors that could represent a valid alternative for the 3He detectors replacement. Fast neutron GEM detectors (nGEM) feature a cathode composed by one layer of polyethylene and one of aluminium (neutron scattering on hydrogen generates protons that are detected in the gas) while thermal neutron GEM detectors (bGEM) are equipped with a borated aluminium cathode (charged particles are generated through the 10B(n,α)7Li reaction). GEM detectors can be realized in large area (1 m2) and their readout can be pixelated. Three different prototypes of nGEM and one prototype of bGEM detectors of different areas and equipped with different types of readout have been built and tested. All the detectors have been used to measure the fast and thermal neutron 2D beam image at the ISIS-VESUVIO beamline. The different kinds of readout patterns (different areas of the pixels) have been compared in similar conditions. All the detectors measured a width of the beam profile consitent with the expected one. The imaging property of each detector was then tested by inserting samples of different material and shape in the beam. All the samples were correctly reconstructed and the definition of the reconstruction depends on the type of readout anode. The fast neutron beam profile reconstruction was then compared to the one obtained by diamond detectors positioned on the same beamline while the thermal neutron one was compared to the imaged obtained by cadmium-coupled x-rays films. Also efficiency and the gamma background rejection have been determined. These prototypes represent the first step towards the

  20. APPLICATION OF AN IMAGING PLATE FOR EVALUATING THE UNCERTAINTY IN DIRECT ORGAN MEASUREMENTS DUE TO VARIATION IN DETECTOR LOCATION.

    PubMed

    Kurihara, Osamu; Kanai, Katsuta; Hirota, Masahiro; Kim, Eunjoo; Tani, Kotaro; Takada, Chie; Momose, Takumaro

    2016-09-01

    In direct organ measurements, there can be uncertainty to the quantified amount of activity due to variations in detector locations. Here, the authors demonstrate a new use of an imaging plate (IP) for evaluating this uncertainty. The method requires only that an array of regions of interest (ROIs) is set on a latent image obtained from the IP; each ROI conforms to an active area of the detector to be used. In this study, the proposed method was tested in an experiment using a realistic torso phantom containing an (241)Am liver source. The latent image of this source was obtained by irradiating the IP (20 × 40 cm(2)) from the anterior surface of the phantom. A comparison of responses between the IP and a high-purity germanium detector was made for 6 of the 144 circular ROIs arranged on the latent image, showing excellent correlation between the two sets of measures. The dispersion of the photostimulated luminescence values of the 144 ROIs was found to be 8.2% (1σ) and 1.09 as a log-normal scattering factor, which was expected to be the same as the uncertainty of concern in the present measurement with the HPGe detector.

  1. The next generation of crystal detectors

    NASA Astrophysics Data System (ADS)

    Zhu, Ren-Yuan

    2015-09-01

    Crystal detectors have been used widely in high energy and nuclear physics experiments, medical instruments and homeland security applications. Novel crystal detectors are continuously being discovered and developed in academia and in industry. In high energy and nuclear physics experiments, total absorption electromagnetic calorimeters (ECAL) made of inorganic crystals are known for their superb energy resolution and detection efficiency for photon and electron measurements. A crystal ECAL is thus the choice for those experiments where precision measurements of photons and electrons are crucial for their physics missions. For future HEP experiments at the energy and intensity frontiers, however, the crystal detectors used in the above mentioned ECALs are either not bright and fast enough, or not radiation hard enough. Crystal detectors have also been proposed to build a Homogeneous Hadron Calorimeter (HHCAL) to achieve unprecedented jet mass resolution by duel readout of both Cherenkov and scintillation light, where development of cost-effective crystal detectors is a crucial issue because of the huge crystal volume required. This paper discusses several R&D directions for the next generation of crystal detectors for future HEP experiments.

  2. Background studies for NaI(Tl) detectors in the ANAIS dark matter project

    SciTech Connect

    Amaré, J.; Borjabad, S.; Cebrián, S.; Cuesta, C.; Fortuño, D.; García, E.; Ginestra, C.; Gómez, H.; Martínez, M.; Oliván, M. A.; Ortigoza, Y.; Solórzano, A. Ortiz de; Pobes, C.; Puimedón, J.; Sarsa, M. L.; Villar, J. A.; Villar, P.

    2013-08-08

    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 {sup 238}U and {sup 232}Th, and {sup 40}K 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 {sup 40}K. 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 {sup 40}K 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 {sup 40}K activity at a level ten times lower than in ANAIS-0 has been determined.

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

    USGS Publications Warehouse

    Schimschal, Ulrich

    1980-01-01

    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)

  4. A prototype neutron veto for dark matter detectors

    NASA Astrophysics Data System (ADS)

    Westerdale, S.; Shields, E.; Calaprice, F.

    2016-06-01

    Neutrons are a particularly dangerous background for direct WIMP dark matter searches; their nuclear recoils with the target nuclei are often indistinguishable from nuclear recoils produced by WIMP-nuclear collisions. In this study, we explore the concept of a liquid scintillator neutron veto detector that would allow direct dark matter detectors to potentially reject neutrons with greater than 99% efficiency. Here we outline the construction and testing of a small prototype detector and the potential implications of this technology for future dark matter detectors.

  5. Plasmonic lens enhanced mid-infrared quantum cascade detector

    SciTech Connect

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

    2014-10-27

    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.

  6. Calibration of single-photon detectors using quantum statistics

    SciTech Connect

    Mogilevtsev, D.

    2010-08-15

    I show that calibration of the single-photon detector can be performed without knowledge of the signal parameters. Only partial information about the state statistics is sufficient for that. If one knows that the state is the squeezed one or the squeezed one mixed with the incoherent radiation, one can infer both the parameters of the state and the efficiency of the detector. For that one needs only to measure on/off statistics of detector clicks for the number of known absorbers placed before the detector. Thus, I suggest a scheme that performs a tomography of the signal and the measuring apparatus simultaneously.

  7. Multi-layer boron thin-film detectors for neutrons

    SciTech Connect

    Wang, Zhehui; Morris, Christopher L

    2010-01-01

    Intrinsic efficiencies of the multilayer boron detectors have been examined both theoretically and experimentally. It is shown that due to the charge loss in the boron layers, the practical efficiencies of most multi-layer {sup 10}B detectors are limited up to about 42%, much less than 77% of the 2 bar 2-inch diameter {sup 3}He detectors. It is suggested that the same charge loss mechanism will prevent essentially all substrate-based boron detectors from ever reaching the efficiencies of high-pressure {sup 3}He tubes, independent of the substrate geometry and material composition (including silicon). Meanwhile, the experimental data indicate that the multi-layer approach can increase the efficiencies up to the theoretical limit. Good n/{gamma} discrimination has also achieved using the ionization charnber technique.

  8. Detectors for Tomorrow's Instruments

    NASA Technical Reports Server (NTRS)

    Moseley, Harvey

    2009-01-01

    Cryogenically cooled superconducting detectors have become essential tools for a wide range of measurement applications, ranging from quantum limited heterodyne detection in the millimeter range to direct searches for dark matter with superconducting phonon detectors operating at 20 mK. Superconducting detectors have several fundamental and practical advantages which have resulted in their rapid adoption by experimenters. Their excellent performance arises in part from reductions in noise resulting from their low operating temperatures, but unique superconducting properties provide a wide range of mechanisms for detection. For example, the steep dependence of resistance with temperature on the superconductor/normal transition provides a sensitive thermometer for calorimetric and bolometric applications. Parametric changes in the properties of superconducting resonators provides a mechanism for high sensitivity detection of submillimeter photons. From a practical point of view, the use of superconducting detectors has grown rapidly because many of these devices couple well to SQUID amplifiers, which are easily integrated with the detectors. These SQUID-based amplifiers and multiplexers have matured with the detectors; they are convenient to use, and have excellent noise performance. The first generation of fully integrated large scale superconducting detection systems are now being deployed. I will discuss the prospects for a new generation of instruments designed to take full advantage of the revolution in detector technology.

  9. ACCESS: Detector Performance

    NASA Astrophysics Data System (ADS)

    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

    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.

  10. Barrier infrared detectors

    NASA Astrophysics Data System (ADS)

    Martyniuk, P.; Kopytko, M.; Rogalski, A.

    2014-06-01

    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.

  11. Advanced Gravitational Wave Detectors

    NASA Astrophysics Data System (ADS)

    Blair, D. G.; Howell, E. J.; Ju, L.; Zhao, C.

    2012-02-01

    Part I. An Introduction to Gravitational Wave Astronomy and Detectors: 1. Gravitational waves D. G. Blair, L. Ju, C. Zhao and E. J. Howell; 2. Sources of gravitational waves D. G. Blair and E. J. Howell; 3. Gravitational wave detectors D. G. Blair, L. Ju, C. Zhao, H. Miao, E. J. Howell, and P. Barriga; 4. Gravitational wave data analysis B. S. Sathyaprakash and B. F. Schutz; 5. Network analysis L. Wen and B. F. Schutz; Part II. Current Laser Interferometer Detectors: Three Case Studies: 6. The Laser Interferometer Gravitational-Wave Observatory P. Fritschel; 7. The VIRGO detector S. Braccini; 8. GEO 600 H. Lück and H. Grote; Part III. Technology for Advanced Gravitational Wave Detectors: 9. Lasers for high optical power interferometers B. Willke and M. Frede; 10. Thermal noise, suspensions and test masses L. Ju, G. Harry and B. Lee; 11. Vibration isolation: Part 1. Seismic isolation for advanced LIGO B. Lantz; Part 2. Passive isolation J-C. Dumas; 12. Interferometer sensing and control P. Barriga; 13. Stabilizing interferometers against high optical power effects C. Zhao, L. Ju, S. Gras and D. G. Blair; Part IV. Technology for Third Generation Gravitational Wave Detectors: 14. Cryogenic interferometers J. Degallaix; 15. Quantum theory of laser-interferometer GW detectors H. Miao and Y. Chen; 16. ET. A third generation observatory M. Punturo and H. Lück; Index.

  12. Geoneutrinos and the Sno+ Detector

    NASA Astrophysics Data System (ADS)

    Tolich, N.

    2014-12-01

    When the SNO+ detector begins operation within two years, it will be a sensitive geo-neutrino detector. The detectors location in Sudbury, Canada, will allow us to study the geo-neutrino signal originating from the surrounding continental crust. Combining future results from the SNO+ detector with those from the KamLAND and Borexino geo-neutrino detectors, respectively in Japan and Italy, will allow us to study the variation in the geo-neutrino signal for detectors located in very different crust types. I will talk about the status of the SNO+ detector along with the potential geo-neutrino results from such a detector.

  13. PIN Diode Detectors

    NASA Astrophysics Data System (ADS)

    Ramírez-Jiménez, F. J.

    2008-07-01

    A review of the application of PIN diodes as radiation detectors in particle counting, X- and γ-ray spectroscopy, medical applications and charged particle spectroscopy is presented. As a practical example of its usefulness, a PIN diode and a low noise preamplifier are included in a nuclear spectroscopy chain for X-ray measurements. This is a laboratory session designed to review the main concepts needed to set up the detector-preamplifier array and to make measurements of X-ray energy spectra with a room temperature PIN diode. The results obtained are compared with those obtained with a high resolution cooled Si-Li detector.

  14. Graphene vertical hot-electron terahertz detectors

    SciTech Connect

    Ryzhii, V.; Satou, A.; Otsuji, T.; Ryzhii, M.; Mitin, V.; Shur, M. S.

    2014-09-21

    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 A{sub 3}B{sub 5} 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.

  15. The detector system of the Daya Bay reactor neutrino experiment

    NASA Astrophysics Data System (ADS)

    An, F. P.; Bai, J. Z.; Balantekin, A. B.; Band, H. R.; Beavis, D.; Beriguete, W.; Bishai, M.; Blyth, S.; Brown, R. L.; Butorov, I.; Cao, D.; Cao, G. F.; Cao, J.; Carr, R.; Cen, W. R.; Chan, W. T.; Chan, Y. L.; Chang, J. F.; Chang, L. C.; Chang, Y.; Chasman, C.; Chen, H. Y.; Chen, H. S.; Chen, M. J.; Chen, Q. Y.; Chen, S. J.; Chen, S. M.; Chen, X. C.; Chen, X. H.; Chen, X. S.; Chen, Y. X.; Chen, Y.; Cheng, J. H.; Cheng, J.; Cheng, Y. P.; Cherwinka, J. J.; Chidzik, S.; Chow, K.; Chu, M. C.; Cummings, J. P.; de Arcos, J.; Deng, Z. Y.; Ding, X. F.; Ding, Y. Y.; Diwan, M. V.; Dong, L.; Dove, J.; Draeger, E.; Du, X. F.; Dwyer, D. A.; Edwards, W. R.; Ely, S. R.; Fang, S. D.; Fu, J. Y.; Fu, Z. W.; Ge, L. Q.; Ghazikhanian, V.; Gill, R.; Goett, J.; Gonchar, M.; Gong, G. H.; Gong, H.; Gornushkin, Y. A.; Grassi, M.; Greenler, L. S.; Gu, W. Q.; Guan, M. Y.; Guo, R. P.; Guo, X. H.; Hackenburg, R. W.; Hahn, R. L.; Han, R.; Hans, S.; He, M.; He, Q.; He, W. S.; Heeger, K. M.; Heng, Y. K.; Higuera, A.; Hinrichs, P.; Ho, T. H.; Hoff, M.; Hor, Y. K.; Hsiung, Y. B.; Hu, B. Z.; Hu, L. M.; Hu, L. J.; Hu, T.; Hu, W.; Huang, E. C.; Huang, H. Z.; Huang, H. X.; Huang, P. W.; Huang, X.; Huang, X. T.; Huber, P.; Hussain, G.; Isvan, Z.; Jaffe, D. E.; Jaffke, P.; Jen, K. L.; Jetter, S.; Ji, X. P.; Ji, X. L.; Jiang, H. J.; Jiang, W. Q.; Jiao, J. B.; Johnson, R. A.; Joseph, J.; Kang, L.; Kettell, S. H.; Kohn, S.; Kramer, M.; Kwan, K. K.; Kwok, M. W.; Kwok, T.; Lai, C. Y.; Lai, W. C.; Lai, W. H.; Langford, T. J.; Lau, K.; Lebanowski, L.; Lee, J.; Lee, M. K. P.; Lei, R. T.; Leitner, R.; Leung, J. K. C.; Lewis, C. A.; Li, B.; Li, C.; Li, D. J.; Li, F.; Li, G. S.; Li, J.; Li, N. Y.; Li, Q. J.; Li, S. F.; Li, S. C.; Li, W. D.; Li, X. B.; Li, X. N.; Li, X. Q.; Li, Y.; Li, Y. F.; Li, Z. B.; Liang, H.; Liang, J.; Lin, C. J.; Lin, G. L.; Lin, P. Y.; Lin, S. X.; Lin, S. K.; Lin, Y. C.; Ling, J. J.; Link, J. M.; Littenberg, L.; Littlejohn, B. R.; Liu, B. J.; Liu, C.; Liu, D. W.; Liu, H.; Liu, J. L.; Liu, J. C.; Liu, S.; Liu, S. S.; Liu, X.; Liu, Y. B.; Lu, C.; Lu, H. Q.; Lu, J. S.; Luk, A.; Luk, K. B.; Luo, T.; Luo, X. L.; Ma, L. H.; Ma, Q. M.; Ma, X. Y.; Ma, X. B.; Ma, Y. Q.; Mayes, B.; McDonald, K. T.; McFarlane, M. C.; McKeown, R. D.; Meng, Y.; Mitchell, I.; Mohapatra, D.; Monari Kebwaro, J.; Morgan, J. E.; Nakajima, Y.; Napolitano, J.; Naumov, D.; Naumova, E.; Newsom, C.; Ngai, H. Y.; Ngai, W. K.; Nie, Y. B.; Ning, Z.; Ochoa-Ricoux, J. P.; Olshevskiy, A.; Pagac, A.; Pan, H.-R.; Patton, S.; Pearson, C.; Pec, V.; Peng, J. C.; Piilonen, L. E.; Pinsky, L.; Pun, C. S. J.; Qi, F. Z.; Qi, M.; Qian, X.; Raper, N.; Ren, B.; Ren, J.; Rosero, R.; Roskovec, B.; Ruan, X. C.; Sands, W. R.; Seilhan, B.; Shao, B. B.; Shih, K.; Song, W. Y.; Steiner, H.; Stoler, P.; Stuart, M.; Sun, G. X.; Sun, J. L.; Tagg, N.; Tam, Y. H.; Tanaka, H. K.; Tang, W.; Tang, X.; Taychenachev, D.; Themann, H.; Torun, Y.; Trentalange, S.; Tsai, O.; Tsang, K. V.; Tsang, R. H. M.; Tull, C. E.; Tung, Y. C.; Viaux, N.; Viren, B.; Virostek, S.; Vorobel, V.; Wang, C. H.; Wang, L. S.; Wang, L. Y.; Wang, L. Z.; Wang, M.; Wang, N. Y.; Wang, R. G.; Wang, T.; Wang, W.; Wang, W. W.; Wang, X. T.; Wang, X.; Wang, Y. F.; Wang, Z.; Wang, Z.; Wang, Z. M.; Webber, D. M.; Wei, H. Y.; Wei, Y. D.; Wen, L. J.; Wenman, D. L.; Whisnant, K.; White, C. G.; Whitehead, L.; Whitten, C. A.; Wilhelmi, J.; Wise, T.; Wong, H. C.; Wong, H. L. H.; Wong, J.; Wong, S. C. F.; Worcester, E.; Wu, F. F.; Wu, Q.; Xia, D. M.; Xia, J. K.; Xiang, S. T.; Xiao, Q.; Xing, Z. Z.; Xu, G.; Xu, J. Y.; Xu, J. L.; Xu, J.; Xu, W.; Xu, Y.; Xue, T.; Yan, J.; Yang, C. G.; Yang, L.; Yang, M. S.; Yang, M. T.; Ye, M.; Yeh, M.; Yeh, Y. S.; Yip, K.; Young, B. L.; Yu, G. Y.; Yu, Z. Y.; Zeng, S.; Zhan, L.; Zhang, C.; Zhang, F. H.; Zhang, H. H.; Zhang, J. W.; Zhang, K.; Zhang, Q. X.; Zhang, Q. M.; Zhang, S. H.; Zhang, X. T.; Zhang, Y. C.; Zhang, Y. H.; Zhang, Y. M.; Zhang, Y. X.; Zhang, Y. M.; Zhang, Z. J.; Zhang, Z. Y.; Zhang, Z. P.; Zhao, J.; Zhao, Q. W.; Zhao, Y. F.; Zhao, Y. B.; Zheng, L.; Zhong, W. L.; Zhou, L.; Zhou, N.; Zhou, Z. Y.; Zhuang, H. L.; Zimmerman, S.; Zou, J. H.

    2016-03-01

    The Daya Bay experiment was the first to report simultaneous measurements of reactor antineutrinos at multiple baselines leading to the discovery of νbare oscillations over km-baselines. Subsequent data has provided the world's most precise measurement of sin2 2θ13 and the effective mass splitting Δ mee2. The experiment is located in Daya Bay, China where the cluster of six nuclear reactors is among the world's most prolific sources of electron antineutrinos. Multiple antineutrino detectors are deployed in three underground water pools at different distances from the reactor cores to search for deviations in the antineutrino rate and energy spectrum due to neutrino mixing. Instrumented with photomultiplier tubes, the water pools serve as shielding against natural radioactivity from the surrounding rock and provide efficient muon tagging. Arrays of resistive plate chambers over the top of each pool provide additional muon detection. The antineutrino detectors were specifically designed for measurements of the antineutrino flux with minimal systematic uncertainty. Relative detector efficiencies between the near and far detectors are known to better than 0.2%. With the unblinding of the final two detectors' baselines and target masses, a complete description and comparison of the eight antineutrino detectors can now be presented. This paper describes the Daya Bay detector systems, consisting of eight antineutrino detectors in three instrumented water pools in three underground halls, and their operation through the first year of eight detector data-taking.

  16. Why compton-suppressed germanium detector arrays?

    SciTech Connect

    Diamond, R.M.

    1993-10-01

    Nuclear spectroscopic studies have provided a strong incentive to obtain {gamma}-ray detectors with increasingly better energy resolution, higher full-energy peak efficiencies, and greater sensitivity or resolving power. A major step was the introduction of Ge detectors in the early 60`s. But because of the low atomic number of Ge they have a poor response function; a majority of interacting gamma rays of moderate energy Compton scatter out of the detector leaving a large low-energy background. The remedy was to add a Compton-suppression shield made of NaI around the Ge crystal, and if interactions occurred simultaneously in the NaI scintillator and in the Ge detector to veto that event. Efficiencies also increased greatly when an English-Danish collaboration assembled five Ge detectors, each with a NaI suppressor, into the first array at the end of 1980. Obviously, a system of five such detectors gave much better statistics than the usual two bare detectors used for obtaining coincidence data (by a factor of 10). A few years later, another major improvement came with replacement of the NaI suppressors with shields made of the much denser bismuth germanate (BGO) as scintillator, as these could be thinner leading to arrays with of order 20 detectors. Use of such a large number of detectors led to the realization that for cascades of coincident gamma rays, as in going down a band, the improvement in the peak/background ratio observed and already appreciated in going from singles spectra to gated (double-) coincidence spectra continued when doubly-gated triple-coincidence data were compared for the first time to singly-gated double-coincidence ones. The higher-gated spectra were much cleaner and more selective, though with poorer statistics, and the advantages of higher folds and efficiencies led to the proposals for the larger 4{pi} arrays of today, Eurogam and GASP in Europe and Gammasphere in the U.S.

  17. A Figure-of-Merit for Beta Cell Detector Characterization

    SciTech Connect

    Foxe, Michael P.; Miller, Brian W.; Suarez, Rey; Hayes, James C.

    2015-09-02

    In order to decrease the minimum detectable activities (MDAs) of beta-gamma radioxenon detectors, it is important to increase the ability to resolve the individual isotopes. One proposed method for doing this is to increase the energy resolution of the beta cell through the use of silicon detectors. While silicon detectors can improve the energy resolution, it is accompanied with a decrease in detection efficiency compared to plastic scintillator beta cells. Due to the uncertainty on the impact of the competing variables, we have developed a figure-of-merit (FOM) capable of determining the impact of detector parameters on the MDAs. By utilizing the FOM to analyze different detectors, we are able to directly compare current and future detectors and estimate their impact on the radioxenon MDAs.

  18. Recent astronomical detector development at the University of Arizona

    NASA Astrophysics Data System (ADS)

    Lesser, Michael

    2012-07-01

    The University of Arizona Imaging Technology Laboratory (ITL) has been developing back illuminated detectors and detector technologies for several astronomical projects in recent years. These projects include the WIYN telescope One Degree Imager (ODI) mosaic of Orthogonal Transfer Array CCDs, the VIRUS detectors for the University of Texas' Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), detector and packaging development for the Large Synoptic Survey Telescope (LSST), and 10kx10k and 4kx4k CCDs for several instruments. In this paper we discuss these projects with an emphasis on backside processing issues and detector characterization results which may be relevant to other groups. We will also focus packaging techniques and metrology for achieving very flat and stable focal planes. Results will include device flatness at cryogenic temperatures, process yield, photo-response non-uniformity and cosmetics, quantum efficiency, read noise, linearity, charge transfer efficiency, and photon transfer data.

  19. Detector-decoy high-dimensional quantum key distribution.

    PubMed

    Bao, Haize; Bao, Wansu; Wang, Yang; Chen, Ruike; Zhou, Chun; Jiang, Musheng; Li, Hongwei

    2016-09-19

    The decoy-state high-dimensional quantum key distribution provides a practical secure way to share more private information with high photon-information efficiency. In this paper, based on detector-decoy method, we propose a detector-decoy high-dimensional quantum key distribution protocol. Employing threshold detectors and a variable attenuator, we can promise the security under Gsussian collective attacks with much simpler operations in practical implementation. By numerical evaluation, we show that without varying the source intensity, our protocol performs much better than one-decoy-state protocol and as well as the two-decoy-state protocol in the infinite-size regime. In the finite-size regime, our protocol can achieve better results. Specially, when the detector efficiency is lower, the advantage of the detector-decoy method becomes more prominent. PMID:27661950

  20. SOLAR SYSTEM OBJECTS AS COSMIC RAYS DETECTORS

    SciTech Connect

    Privitera, P.; Motloch, P.

    2014-08-10

    In a recent Letter, Jupiter is presented as an efficient detector for Ultra-High Energy Cosmic Rays (UHECRs), through measurement by an Earth-orbiting satellite of gamma rays from UHECRs showers produced in Jupiter's atmosphere. We show that this result is incorrect, due to erroneous assumptions on the angular distribution of shower particles. We evaluated other solar system objects as potential targets for UHECRs detection, and found that the proposed technique is either not viable or not competitive with traditional ground-based UHECRs detectors.

  1. Advances in Detector Technology for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    McCreight, Craig; Cheng, P. L. (Technical Monitor)

    1995-01-01

    Progress in semiconductor materials and processing technology has allowed the development of infrared detector arrays with unprecedented sensitivity, for imaging and spectroscopic applications in astronomy. The earlier discrete-detector approach has been replaced by large-element (up to 1024 x 1024 pixel), multiplexed devices. Progress has been made against a number of key limiting factors, such as quantum efficiency, noise, spectral response, linearity, and dark current. Future developments will focus on the need for even larger arrays, which operate at higher temperatures.

  2. Burst diaphragm leak detector

    NASA Technical Reports Server (NTRS)

    Pascolla, J. A.

    1969-01-01

    New method replaces flowmeter approach with readily available burst diaphragm leak detector assembly mounted to all drain ports. This allows simultaneous leak detection of all flange seals under operating conditions.

  3. Microwave Radiation Detector

    NASA Technical Reports Server (NTRS)

    Lesh, J. R.

    1984-01-01

    Direct photon detector responds to microwave frequencies. Method based on trapped-ion frequency-generation standards proposed to detect radio-frequency (RF) radiation at 40.5 GHz. Technique used for directdetection (RF) communication, radar, and radio astronomy.

  4. Improved CO [lidar detector

    SciTech Connect

    Jacobson, P.L.; Busch, G.E.; Thompson, D.C.; Remelius, D.K.; Wells, F.D.

    1999-07-18

    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.

  5. The CBM RICH detector

    NASA Astrophysics Data System (ADS)

    Adamczewski-Musch, J.; Akishin, P.; Becker, K.-H.; Belogurov, S.; Bendarouach, J.; Boldyreva, N.; Chernogorov, A.; Deveaux, C.; Dobyrn, V.; Dürr, M.; Eschke, J.; Förtsch, J.; Heep, J.; Höohne, C.; Kampert, K.-H.; Kochenda, L.; Kopfer, J.; Kravtsov, P.; Kres, I.; Lebedev, S.; Lebedeva, E.; Leonova, E.; Linev, S.; Mahmoud, T.; Michel, J.; Miftakhov, N.; Niebur, W.; Ovcharenko, E.; Pauly, C.; Pfeifer, D.; Querchfeld, S.; Rautenberg, J.; Reinecke, S.; Riabov, Y.; Roshchin, E.; Samsonov, V.; Tarasenkova, O.; Traxler, M.; Ugur, C.; Vznuzdaev, E.; Vznuzdaev, M.

    2016-05-01

    The CBM RICH detector will use CO2 as radiator gas, focussing glass mirrors with Al+MgF2 reflective and protective coating and Hamamatsu H12700 MAPMTs as photon detectors. The detector will serve for electron to pion separation up to momenta of 8 GeV/c and thus enable in CBM the measurement of electromagnetic radiation from the early and dense fireball in A+A collisions at SIS 100. In this article, the current status of the CBM RICH development will be presented including new measurements of the radiation hardness of the H12700 MAPMT and WLS coatings with p-terphenyl, the new concept for the readout electronics, and optimizations ongoing with respect to the mirror mount structure and overall geometry. Prior to the usage in CBM, part of the already ordered MAPMTs will be used to upgrade the HADES RICH detector for a new measurement campaign at SIS 18 from 2018-2020.

  6. Ultrafast neutron detector

    DOEpatents

    Wang, C.L.

    1985-06-19

    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.

  7. Subspace Detectors: Theory

    SciTech Connect

    Harris, D B

    2006-07-11

    Broadband subspace detectors are introduced for seismological applications that require the detection of repetitive sources that produce similar, yet significantly variable seismic signals. Like correlation detectors, of which they are a generalization, subspace detectors often permit remarkably sensitive detection of small events. The subspace detector derives its name from the fact that it projects a sliding window of data drawn from a continuous stream onto a vector signal subspace spanning the collection of signals expected to be generated by a particular source. Empirical procedures are presented for designing subspaces from clusters of events characterizing a source. Furthermore, a solution is presented for the problem of selecting the dimension of the subspace to maximize the probability of detecting repetitive events at a fixed false alarm rate. An example illustrates subspace design and detection using events in the 2002 San Ramon, California earthquake swarm.

  8. Pendulum detector testing device

    DOEpatents

    Gonsalves, J.M.

    1997-09-30

    A detector testing device is described which provides consistent, cost-effective, repeatable results. The testing device is primarily constructed of PVC plastic and other non-metallic materials. Sensitivity of a walk-through detector system can be checked by: (1) providing a standard test object simulating the mass, size and material content of a weapon or other contraband, (2) suspending the test object in successive positions, such as head, waist and ankle levels, simulating where the contraband might be concealed on a person walking through the detector system; and (3) swinging the suspended object through each of the positions, while operating the detector system and observing its response. The test object is retained in a holder in which the orientation of the test device or target can be readily changed, to properly complete the testing requirements. 5 figs.

  9. Pendulum detector testing device

    DOEpatents

    Gonsalves, John M.

    1997-01-01

    A detector testing device which provides consistent, cost-effective, repeatable results. The testing device is primarily constructed of PVC plastic and other non-metallic materials. Sensitivity of a walk-through detector system can be checked by: 1) providing a standard test object simulating the mass, size and material content of a weapon or other contraband, 2) suspending the test object in successive positions, such as head, waist and ankle levels, simulating where the contraband might be concealed on a person walking through the detector system; and 3) swinging the suspended object through each of the positions, while operating the detector system and observing its response. The test object is retained in a holder in which the orientation of the test device or target can be readily changed, to properly complete the testing requirements.

  10. Modular optical detector system

    DOEpatents

    Horn, Brent A.; Renzi, Ronald F.

    2006-02-14

    A modular optical detector system. The detector system is designed to detect the presence of molecules or molecular species by inducing fluorescence with exciting radiation and detecting the emitted fluorescence. Because the system is capable of accurately detecting and measuring picomolar concentrations it is ideally suited for use with microchemical analysis systems generally and capillary chromatographic systems in particular. By employing a modular design, the detector system provides both the ability to replace various elements of the detector system without requiring extensive realignment or recalibration of the components as well as minimal user interaction with the system. In addition, the modular concept provides for the use and addition of a wide variety of components, including optical elements (lenses and filters), light sources, and detection means, to fit particular needs.

  11. Multi Electrode Semiconductor Detectors

    NASA Astrophysics Data System (ADS)

    Amendolia, S. R.; Batignani, G.; Bertolucci, E.; Bosisio, L.; Budinich, M.; Bradaschia, C.; Fidecaro, F.; Foà, L.; Focardi, E.; Giazotto, A.; Giorgi, M. A.; Marrocchesi, P. S.; Menzione, A.; Ristori, L.; Rolandi, L.; Scribano, A.; Stefanini, A.; Vincelli, M. L.

    1981-04-01

    Detectors with very high space resolution have been built in our laboratory and tested at CERN in order to investigate their possible use in high energy physics experiments. These detectors consist of thin layers of silicon crystals acting as ionization chambers. Thin electrodes, structured in strips or in more fancy shapes are applied to their surfaces by metal coating. The space resolution which could be reached is of the order of a few microns. An interesting feature of these solid state detectors is that they can work under very high or low external pressure or at very low temperature. The use of these detectors would strongly reduce the dimensions and the cost of high energy experiments.

  12. 6Li foil thermal neutron detector

    SciTech Connect

    Ianakiev, Kiril D; Swinhoe, Martyn T; Favalli, Andrea; Chung, Kiwhan; Macarthur, Duncan W

    2010-01-01

    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.

  13. Fiber optic detector

    NASA Astrophysics Data System (ADS)

    Partin, Judy K.; Ward, Thomas E.; Grey, Alan E.

    1990-04-01

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  14. Fiber optic detector

    SciTech Connect

    Partin, J.K.; Ward, T.E.; Grey, A.E.

    1990-12-31

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  15. MONDE: MOmentum Neutron DEtector

    NASA Astrophysics Data System (ADS)

    Santa Rita, P.; Acosta, L.; Favela, F.; Huerta, A.; Ortiz, M. E.; Policroniades, R.; Chávez, E.

    2016-07-01

    MONDE is a large area neutron momentum detector, consisting of a 70x160x5 cm3 plastic scintillator slab surrounded by 16 photomultiplier tubes, standard NIM signal processing electronics and a CAMAC data acquisition system. In this work we present data from a characterization run using an external trigger. For that purpose, coincident gamma rays from a 60Co radioactive source were used together with a NaI external detector. First results with an "external" trigger are presented.

  16. Gaseous leak detector

    DOEpatents

    Juravic, Jr., Frank E.

    1988-01-01

    In a short path length mass-spectrometer type of helium leak detector wherein the helium trace gas is ionized, accelerated and deflected onto a particle counter, an arrangement is provided for converting the detector to neon leak detection. The magnetic field of the deflection system is lowered so as to bring the non linear fringe area of the magnetic field across the ion path, thereby increasing the amount of deflection of the heavier neon ions.

  17. Improved gaseous leak detector

    DOEpatents

    Juravic, F.E. Jr.

    1983-10-06

    In a short path length mass-spectrometer type of helium leak detector wherein the helium trace gas is ionized, accelerated and deflected onto a particle counter, an arrangement is provided for converting the detector to neon leak detection. The magnetic field of the deflection system is lowered so as to bring the nonlinear fringe area of the magnetic field across the ion path, thereby increasing the amount of deflection of the heavier neon ions.

  18. Test beam results of Silicon Drift Detector prototypes for the ALICE experiment

    NASA Astrophysics Data System (ADS)

    Nouais, D.; Bonvicini, V.; Busso, L.; Cerello, P.; Giubellino, P.; Gregorio, A.; Hernández-Ontoya, R.; Idzik, M.; Kolojvari, A.; Mazza, G.; Montano, L. M.; Nilsen, B. S.; Petta, C.; Randazzo, N.; Rashevsky, A.; Reito, S.; Rivetti, A.; Tosello, F.; Trzaska, W. H.; Vacchi, A.; Alice Collaboration

    1999-08-01

    We report preliminary beam test results of linear Silicon Draft Detector prototypes for the ALICE experiment. Linearity, resolution, charge transport and collection, and efficiency have been studied using a minimum ionizing particle beam for a very large area detector prototype read out with the OLA preamplifier/shaper and for another detector read out using a new transimpedance amplifier with a non linear response.

  19. Using induced signals to sense position from a microchannel plate detector

    NASA Astrophysics Data System (ADS)

    deSouza, R. T.; Gosser, Z. Q.; Hudan, S.

    2012-05-01

    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.

  20. Alkali metal ionization detector

    DOEpatents

    Bauerle, James E.; Reed, William H.; Berkey, Edgar

    1978-01-01

    Variations in the conventional filament and collector electrodes of an alkali metal ionization detector, including the substitution of helical electrode configurations for either the conventional wire filament or flat plate collector; or, the substitution of a plurality of discrete filament electrodes providing an in situ capability for transferring from an operationally defective filament electrode to a previously unused filament electrode without removing the alkali metal ionization detector from the monitored environment. In particular, the helical collector arrangement which is coaxially disposed about the filament electrode, i.e. the thermal ionizer, provides an improved collection of positive ions developed by the filament electrode. The helical filament design, on the other hand, provides the advantage of an increased surface area for ionization of alkali metal-bearing species in a monitored gas environment as well as providing a relatively strong electric field for collecting the ions at the collector electrode about which the helical filament electrode is coaxially positioned. Alternatively, both the filament and collector electrodes can be helical. Furthermore, the operation of the conventional alkali metal ionization detector as a leak detector can be simplified as to cost and complexity, by operating the detector at a reduced collector potential while maintaining the sensitivity of the alkali metal ionization detector adequate for the relatively low concentration of alkali vapor and aerosol typically encountered in leak detection applications.