Journal articles: 'HPGe detectors'

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Abdulla, Karima, Abtisam A. Alakrout, Manal Omer, and Samah Aghtisa. "EVALUATION STUDY OF LANTHANUM HALIDE DETECTORS (LABR3:CE , LACL3:CE, NAI(TL), (HPGE)." Scientific Journal of Applied Sciences of Sabratha University 3, no. 2 (September 27, 2020): 42–52. http://dx.doi.org/10.47891/sabujas.v3i2.42-52.

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Through the use of thesources spectrums 22Na (S311.PH), 60Co (S297.PH), 133Ba (S295.PH), 137Cs (S296.PH) and 152Eu (S285.PH) the properties of Lanthanum Tri-Bromide (LaBr3:Ce) and Lanthanum Tri-Chloride (LaCl3:Ce) scintillation detectors were compared against Sodium Iodide (NaI(Tl)) scintillation and Hyper Pure Germanium (HPGe) semiconductor detectors. In all instances the HPGe detector was found to be superior, So, Hyper Pure Germanium detectors (HPGe) are outstanding devices for radioactivity spectroscopy. In addition the LaBr3:Ce and LaCl3:Ce detectors were always found to be superior to the NaI(Tl) detector.

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McCarthy, J. J., M. W. Ales, and D. J. McMillan. "High Purity Germanium Detectors for EDS." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 90–91. http://dx.doi.org/10.1017/s0424820100134041.

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High purity germanium (HPGe) detectors offer multiple advantages for x-ray microanalysis in electron microscopes. These advantages include improved detection efficiency at energies above 20 keV, lower noise and higher energy resolution than can be obtained with a lithium drifted silicon detector. In the past, the use of HPGe detectors for EDS at energies below about 2 keV was impossible due to severe distortions of peak shapes and shifts in peak positions. These effects are the result of incomplete charge collection and are most pronounced at energies just above the energy of the germanium L absorption edges (1.2 to 1.4 keV). Using new processing techniques, we have manufactured 30 mm2 HPGe detectors that do not exhibit significant spectral distortion due to incomplete charge collection. Figure 1 presents a comparison of the peak shapes obtained from an HPGe detector produced by a previous method and a new detector produced with our current process. These detectors have been used for EDS applications in (S)TEM and SEM.

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Peoviti, Maria, Michail Axiotis, Efstathia Georgali, Sotirios Harissopulos, Anastasios Lagoyannis, and Nikolaos Patronis. "Characterisation of the new HPGe detectors at INPP/NCSR “Demokritos”... and future (n,2n) reactions to be studied." HNPS Advances in Nuclear Physics 28 (October 17, 2022): 207–10. http://dx.doi.org/10.12681/hnps.3580.

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Within the present work the HPGe detectors of the Institute of Nuclear and Particle Physics at NCSR “Demokritos” were fully characterized in terms of their efficiency. The three n-type 80% relative efficiency HPGe were recently acquired in the framework of the CALIBRA project. All detectors are equipped with carbon epoxy windows that allow detection of low energy γ-rays. Beside the efficiency characterization, the three detectors were fully modeled by means of GEANT4. In all cases the simulated detector geometries were fine-tuned so as to fully reproduce the experimental efficiency data at different source-to-detector distances. Finally, as a demonstration of the new offered abilities, the efficiency characterization and the GEANT4 modeling of the three HPGe detectors was used for a feasibility study of possible/future (n,2n) activation measurements on medium-weight nuclei.

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Georgali, Efstathia, and Et al. "Characterization of the Canberra BE5030 Broad Energy High Purity Germanium Detector by means of the GEANT4 Monte Carlo simulation package." HNPS Proceedings 27 (April 17, 2020): 152. http://dx.doi.org/10.12681/hnps.3002.

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The accurate determination of the efficiency of HPGe detectors is a challenging procedure due to possible self-attenuation phenomenaand/or coincidence summing effects. Both of these phenomena become important when close detection geometries and extended samples are considered. To deal with these features the simulation of HPGe detectors is used so as to calculate the corresponding correction factors, especially for those cases where low energy γ-ray are considered. Through the present work the Canberra BE5030 Broad Energy HPGe detector of the Enviromental Radioactivity Monitoring Department of Greek Atomic Energy Comission was simulated through the GEANT4 toolkit. Experimental efficiency and counting rate data were compared with the simulation results for different geometries of the detector so as to idetify the one for which the experimental data are better reproduced.

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Gurov, Yu B., V. S. Karpukhin, S. V. Rozov, V. G. Sandukovsky, D. Borowicz, J. Kwiatkowska, B. Rajchel, and J. Yurkowski. "Passivation of HPGe detectors." Instruments and Experimental Techniques 52, no. 1 (January 2009): 137–40. http://dx.doi.org/10.1134/s0020441209010230.

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Zákoucký, Dalibor, Dušan Srnka, Jaromír Šlesinger, Drahoslav Vénos, and Josef Stehno. "Low-temperature HPGe detectors." Czechoslovak Journal of Physics 46, S5 (May 1996): 2911–12. http://dx.doi.org/10.1007/bf02570442.

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Steel, E. B. "High-purity Ge x-ray detectors: Sensitivity factors and usefulness." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 548. http://dx.doi.org/10.1017/s0424820100136350.

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High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

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8

Sina, Sedigheh, Zahra Molaeimanesh, Mehrnoosh Karimipoorfard, Zeinab Shafahi, Maryam Papie, and Mohammad Amin Nazari Jahromi. "Evaluation of virtual point detector, for HPGe spectrometers of different sizes, using Monte Carlo simulations, and artificial neural networks." Scientific Research Journal 17, no. 1 (February 29, 2020): 15. http://dx.doi.org/10.24191/srj.v17i1.6325.

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The virtual point detector concept is a useful concept in gamma ray spectroscopy. In this study, the virtual point detector, h0, was obtained for HPGe detectors of different sizes using MCNP5 Monte Carlo simulations. The HPGe detectors with different radii (rd), and height (hd), having Aluminum, or Carbon windows, were simulated. A point photon source emitting several gammas with certain energies was defined at distance x of the detectors. The pulse height distribution was scored using F8 tally. Finally, artificial neural network was used for predicting the h0 values for every value of hd, rd, and x. Because of the high simulation duration of MCNP code, a trained ANN is used to predict the value of h0 for each detector size. The results indicate that the Artificial Neural Network (ANN) can predict the virtual point detector good accuracy.

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Sina, Sedigheh, Zahra Molaeimanesh, Mehrnoosh Karimipoorfard, Zeinab Shafahi, Maryam Papie, and Mohammad Amin Nazari Jahromi. "Evaluation of Virtual Point Detector for High Purity Germanium (Hpge) Detector, using Monte Carlo Simulations, and Artificial -Neural Networks." Scientific Research Journal 17, no. 1 (February 29, 2020): 15. http://dx.doi.org/10.24191/srj.v17i1.9345.

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The virtual point detector concept is useful in gamma-ray spectroscopy. In this study, the virtual point detector, h0, was obtained for High Purity Germanium (HPGe) detectors of different sizes using MCNP5 Monte Carlo simulations. The HPGe detectors with different radii (rd), and height (hd), having aluminum, or Carbon windows, were simulated. A point photon source emitting several gammas with specific energies was defined at a distance x of the detectors. The pulse height distribution was scored using F8 tally. Finally, the artificial neural network was used for predicting the h0 values for every value of hd, rd, and x. Because of the high simulation duration of MCNP code, a trained ANN is used to predict the value of h0 for each detector size. The results indicate that the Artificial Neural Network (ANN) can predict the virtual point detector good accuracy.

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10

Yakovlevs, O., V. Malgin, and V. Gostilo. "Development of Unified Spectrometric Module Based on HPGE Detectors with Electric Machine Cooling." Nuclear and Radiation Safety, no. 3(79) (August 28, 2018): 48–55. http://dx.doi.org/10.32918/nrs.2018.3(79).08.

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The development results of unified spectrometric module based on HPGe detectors with electric machine cooling for application in nuclear physical equipment of various application are presented. Unified module has cryostat with HPGe detector of the required size, electric machine cooler and electronic unit. The analysis of the cooling processes dynamics and HPGe detectors heating in cryostats, cooled by liquid nitrogen and EMC is made on the sample of the typical cooling circuits. Much attention is paid to design technological aspects of the cryostat development, cooled with electric coolers. With Solidworks software package the modal analysis of the cryostat cover and HPGe detector with various registration efficiency and weight was carried out. Based on the modal analysis of HPGe detector assembly the design of the holders where axial vibration mode was removed to the area of higher harmonics with smaller amplitudes was selected. The design of the developed unified module is reviewed. To increase EMC efficiency the additional radiators with heat tubes are installed and active method of blow off was applied. It secured the temperature decrease of EMC extender and accordingly provided the heat mode comfort for EMC operation what increases the safety of the developed module. The spectra of radioisotopes Co-57 and Co-60 are presented, registered by unified spectrometric module with HPGe detector with gamma radiation registration efficiency of 40%. The energy resolution by energies 122 and 1332 keV is 0,98 and 1,85 accordingly. The overall sizes of the unified module is 280×315×265 mm, its weight with the detector is about 20 kg. The module provides the radiation registration in any spatial position. It allows easy installation of the developed module on various equipment. The samples of the manufactured devices with unified spectrometric module are presented.

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Ohera, Marcel, Daniel Sas, and Petr Sladek. "Calibration of spectrometric detectors for air kerma rates in environmental monitoring." Nuclear Technology and Radiation Protection 35, no. 4 (2020): 323–30. http://dx.doi.org/10.2298/ntrp2004323o.

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The spectrometric systems, especially based on NaI(Tl) and HPGe detectors, are used for nuclide identification and calculation of their activities from the ground measurements and air-borne monitoring. The determination of the air kerma (dose) rates is also very important for environmental measurements. In such cases, the detectors should be calibrated for air kerma (dose) rates in nGyh?1 or ?Gyh?1. A simple calibration of NaI(Tl), HPGe as well as plastic detectors for the low-level air kerma rates is presented in this contribution. This calibration is based on comparing the relative absorbed energy rate in detectors (MeVs?1) calculated from spectra with the air kerma rates calculated by the Monte Carlo simulation and supplementary to the data from the RSS Reuter&Stokes high pressure ion chamber. This method also eliminates the conversion from the non-air kerma rates in crystals to the air kerma rates. Three different types of small cylindrical detectors were calibrated for the air kerma rates from the background of 26 nGyh?1 to some tens of ?Gyh?1 in the energy range to the maximum of 3 MeV. The results of calibrations of the 3" x 3" NaI(Tl), HPGe detector and a small plastic detector (made of polystyrene) including soxme examples of environmental measurements are presented.

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Nayak, S. S., and G. Mukherjee. "SIMSPEC-G: a simple code for the simulation of HPGe detectors for gamma rays up to 1 MeV." Journal of Instrumentation 17, no. 07 (July 1, 2022): P07030. http://dx.doi.org/10.1088/1748-0221/17/07/p07030.

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Abstract A new program called SIMSPEC-G has been developed to simulate the interaction of gamma-rays of energies upto 1 MeV with different materials. In this work, 3 different geometries of high purity Ge (HPGe) detectors have been studied: single crystal HPGe, segmented single crystal HPGe and clover geometry composed of four HPGe crystals in clover-leaf arrangement. Contributions of different processes to peak formation have also been examined. The simulated spectrum, for a single crystal of clover, and for 662 keV gamma-ray (from 137Cs source) has been compared with experimentally obtained spectrum. The addback factor (gain in full energy peak efficiency due to the addition of the energies of the Compton scattered gamma rays in more than one crystal of a clover HPGe detector) and the hit pattern for a range of gamma-ray energies from the experiment have been excellently reproduced by the simulation leading to its validation. The fraction of total events in which highest or full energy is deposited in the first hit crystal is estimated and the use of this idea to improve angular resolution of a Clover detector has been explored.

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Sarasti-Zambonino, Sebastián, Tania Barahona, and Santos Roque. "Simulation of a HPGe Detector with GEANT4." Revista Politécnica 50, no. 2 (August 4, 2022): 7–14. http://dx.doi.org/10.33333/rp.vol50n2.01.

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Gamma spectroscopy is an analytic technique that identifies isotopes through gamma rays. Currently, gamma spectroscopy is widely used in several science fields, for instance, the study of the hydrodynamics of soils and other applications. Considering the development of computers, it has been developed Monte-Carlo simulation packages, in order to estimate the response of gamma spectroscopy detectors. This work aims to develop a GEANT4 application to estimate the full energy peak efficiency for a HPGe detector and determine the deviation with experimental data. It was carried out measurements of the next radioactive sources, Am-241, Eu-152, Cs-137, and Co-60. These measurements were made at different distances, they were at 0, 5, 10, 20, and 25 cm from the detector’s cover layer. Meanwhile, the simulation was carried out through user action classes to extract energy deposited in the sensitive detector. It was determined full energy peak efficiency of experimental data, through these results, it was estimated a detection factor that measures the deviation between experimental and simulated data. A reason for the deviation was that the simulation did not include the electronic chain of acquisition. Finally, it was suggested that future works should develop a more accurate simulation for multi-emitters isotopes.

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Bukartas, Antanas, Jonas Wallin, Robert Finck, and Christopher Rääf. "Bayesian algorithm to estimate position and activity of an orphan gamma source utilizing multiple detectors in a mobile gamma spectrometry system." PLOS ONE 16, no. 1 (January 22, 2021): e0245440. http://dx.doi.org/10.1371/journal.pone.0245440.

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To avoid harm to the public and the environment, lost ionizing radiation sources must be found and brought back under the regulatory control as soon as possible. Usually, mobile gamma spectrometry systems are used in such search missions. It is possible to estimate the position and activity of point gamma sources by performing Bayesian inference on the measurement data. The aim of this study was to theoretically investigate the improvements in the Bayesian estimations of the position and activity of a point gamma source due to introduction of data from multiple detectors with angular variations of efficiency. Three detector combinations were tested—a single 123% HPGe detector, single 4l NaI (Tl) detector and a 123% HPGe with 2x4l NaI (Tl) detector combination—with and without angular efficiency variations for each combination resulting in six different variants of the Bayesian algorithm. It was found that introduction of angular efficiency variations of the detectors did improve the accuracy of activity estimation slightly, while introduction of data from additional detectors lowered the signal-to-noise ratio threshold of the system significantly, increasing the stability and accuracy of the estimated source position and activity, for a given signal-to-noise ratio.

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Tsang, R. H. M., O. Nusair, and A. Piepke. "Sensitivity analysis towards trace-uranium detection with γ-γ coincidence NAA." Journal of Instrumentation 16, no. 10 (October 1, 2021): P10007. http://dx.doi.org/10.1088/1748-0221/16/10/p10007.

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Abstract We present an improved approach for detection of trace amounts of 238U by means of neutron activation analysis (NAA). The analysis enhancement is obtained by utilizing γ-γ coincidence counting. An empirical method for evaluating the sensitivity gain in the presence of a large source-related background is presented. A comparison of detection limits is made between two counting schemes; namely, counting single gammas using one HPGe detector versus counting coincident gammas using two HPGe detectors placed face-to-face. A data-validated radiation transport model, created in GEANT4 for a single HPGe detector, is extended to handle the two-detector setup. In this counting scheme, a 238U-detection sensitivity enhancement of about a factor of 8 is predicted for a sample of Saint-Gobain G3 Sapphire when compared to the simpler singles counting approach.

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Beach, L. A., and G. W. Phillips. "Electronics Package for Rugged HPGE Detectors." IEEE Transactions on Nuclear Science 33, no. 1 (1986): 664–67. http://dx.doi.org/10.1109/tns.1986.4337189.

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Presler, O., O. Peled, U. German, Y. Leichter, and Z. B. Alfassi. "Off-center efficiency of HPGe detectors." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 484, no. 1-3 (May 2002): 444–50. http://dx.doi.org/10.1016/s0168-9002(01)02056-3.

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Kail, Artjoms, Matthias Kaiser, Sergey Kim, Edward Loshevich, and Alexander Sokolov. "Development of portable HPGe spectrometer for in situ measurements." Nuclear Technology and Radiation Protection 30, no. 2 (2015): 154–57. http://dx.doi.org/10.2298/ntrp1502154k.

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In situ applications require a very high level of portability of high-resolution spectrometric equipment. Usage of HPGe detectors for radioactivity measurements in the environment or for nuclear safeguard applications, to combat illicit trafficking of nuclear materials or uranium and plutonium monitoring in nuclear wastes, has become a norm in the recent years. Portable HPGe-based radionuclide spectrometer with electrical cooling has lately appeared on the market for in situ applications. At the same time deterioration of energy resolution associated with vibrations produced by cryocooler or high weight of the instrument, short time of autonomous operation and high price of these spectrometers are limiting their usage in many cases. In this paper we present development results of ultra compact hand held all-in-one spectrometer for in situ measurements based on HPGe detector cooled by liquid nitrogen without listing the above disadvantages.

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Wei, Hongyan, Yuqiang Xun, Jinghui Cai, and Lijuan Wang. "Vibration Reduction in a Pulse Tube-Cooled High Purity Germanium Detector." Applied Sciences 12, no. 4 (February 10, 2022): 1827. http://dx.doi.org/10.3390/app12041827.

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High-purity germanium (HPGe) is a vibration-sensitive, high-resolution detector. It has been found that microphonic noise induced by vibration and electromagnetic interference from EMC causes energy resolution degradation in HPGe detectors. In this paper, to enhance the energy resolution of a pulse tube-cooled high purity germanium detector, a passive vibration isolation system for the portable pulse tube cooler (PTC) was employed and investigated. In order to evaluate the performance of the vibration isolation system, micro-vibration tests of the compressor with a vibration isolation kit and detector mounting interface were performed. Meanwhile, detector energy resolution and detector signal noise were tested, respectively, under the PTC, with the isolation system switched to either an on or off condition. The test results indicate that the effectiveness of passive vibration isolation techniques is confirmed, and no degradation was induced by PTC vibration on detector energy resolution.

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Griffin, Brendon J., and Andrew W. S. Johnson. "Experiences with HPGe EDS detectors on a philips EM430 and a JEOL 6300F FESEM." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1232–33. http://dx.doi.org/10.1017/s0424820100130791.

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A turreted 10mm2 HPGe Link EDS detector has been mounted on a JEOL 6300F field emission SEM and the performance compared to that of a Si(Li) Link detector on a JEOL 6400 conventional SEM with identical geometry and construction.A second HPGe Link EDS detector has been mounted on a Philips EM430.The detector is 30 mms. sq.in area,with a type LZ5 ultra thin window and is mechanically configured to retract behind a gate valve and in addition, has a pneumatically operated shutter to provide a rapid protection from excessive electron and x-ray doses.Both detectors were shipped 'wet' from the factory and appeared to be contaminated by ice when initially tested on the columns. The FESEM detector was de-iced after two conditioning events and achieved an on-column resolution at Mn Kα of 115ev which matched the factory performance. Principal changes to spectra through the de-icing were improvement of resolution, decrease of dead time, reduction of oxygen Kα peak and improvement in copper Lα : Kα peak ratio. The EM430 detector has been more problematical.

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Uyar, E., G. Aksoy, H. Ünlü, and M. H. Bölükdemir. "Investigation of the effect of copper contact pin on efficiency in HPGe detectors using Monte Carlo method." Journal of Instrumentation 16, no. 11 (November 1, 2021): T11003. http://dx.doi.org/10.1088/1748-0221/16/11/t11003.

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Abstract The full energy peak efficiency (FEPE) determined by experimental or Monte Carlo (MC) simulation methods is a very important parameter in HPGe detectors. Since FEPE depends on the detector's geometric parameters, the parameters provided by the manufacturer are of great importance in modeling the detector with the MC method. The most important reason for the discrepancy between MC and experimental calculations is the lack of accurate information about the detector's geometric properties. The thickness of the copper contact pin in the middle of the detector hole is not given by the manufacturer. In this study, the effect of copper contact pin thickness on detector efficiency was investigated by using the PHITS 3.24 MC simulation program both at different copper contact pin radii and at different detector-source distances. The efficiency values were calculated for photons in the energy range of 59.5 keV-1408 keV, at 4 different distances, namely 5 cm, 13.25 cm, 15 cm, and 20 cm and for the radii of copper contact pins increased from 1 mm to 3.5 mm at 0.5 mm intervals. According to the results, it has been determined that the presence of copper contact pins causes a change in detector efficiency up to 1.9%, especially in the high energy region, and has no effect on the detector efficiency in the low energy region. In addition, it has been observed that the effect of copper contact pin thickness on detector efficiency is almost independent of the source-detector distance.

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Saizu, Mirela Angela. "Monte Carlo simulation of gamma-ray interactions in an over-square high-purity germanium detector for in-vivo measurements." International Journal of Modern Physics: Conference Series 44 (January 2016): 1660225. http://dx.doi.org/10.1142/s2010194516602258.

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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 [Formula: see text]Am, [Formula: see text]Co, [Formula: see text]Ba, [Formula: see text]Cs, [Formula: see text]Co, and [Formula: see text]Eu 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.

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Botta, E., and A. Feliciello. "HPGe detectors for hypernuclear γ-ray spectroscopy." European Physical Journal Special Topics 162, no. 1 (August 2008): 191–203. http://dx.doi.org/10.1140/epjst/e2008-00794-7.

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Tsang, R. H. M., A. Piepke, D. J. Auty, B. Cleveland, S. Delaquis, T. Didberidze, R. MacLellan, Y. Meng, O. Nusair, and T. Tolba. "GEANT4 models of HPGe detectors for radioassay." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 935 (August 2019): 75–82. http://dx.doi.org/10.1016/j.nima.2019.04.085.

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Hedman, A., J. Bahar Gogani, M. Granström, L. Johansson, J. S. Andersson, and H. Ramebäck. "Characterization of HPGe detectors using Computed Tomography." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 785 (June 2015): 21–25. http://dx.doi.org/10.1016/j.nima.2015.02.041.

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Trigano, Thomas, Antoine Souloumiac, Thierry Montagu, FranÇois Roueff, and Eric Moulines. "Statistical Pileup Correction Method for HPGe Detectors." IEEE Transactions on Signal Processing 55, no. 10 (October 2007): 4871–81. http://dx.doi.org/10.1109/tsp.2007.896300.

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Zákoucký, D., D. Srnka, D. Vénos, V. Golovko, I. Kraev, T. Phalet, P. Schuurmans, N. Severijns, B. Vereecke, and S. Versyck. "HPGe detectors for low-temperature nuclear orientation." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 520, no. 1-3 (March 2004): 80–83. http://dx.doi.org/10.1016/j.nima.2003.11.226.

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Urlass, Sebastian, Roland Beyer, Arnd Rudolf Junghans, Toni Kögler, Ronald Schwengner, and Andreas Wagner. "Measurement of the prompt fissionγ-ray spectrum of 242Pu." EPJ Web of Conferences 169 (2018): 00026. http://dx.doi.org/10.1051/epjconf/201816900026.

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The prompt γ-ray spectrum of fission fragments is important in understanding the dynamics of the fission process, as well as for nuclear engineering in terms of predicting the γ-ray heating in nuclear reactors. The γ-ray spectrum measured from the fission fragments of the spontaneous fission of 242Pu will be presented here. A fission chamber containing in total 37mg of 242Pu was used as active sample. The γ-quanta were detected with high time- and energy-resolution using LaBr3 and HPGe detectors, respectively, in coincidence with spontaneous fission events detected by the fission chamber. The acquired γ-ray spectra were corrected for the detector response using the spectrum stripping method. About 70 million fission events were detected which results in a very low statistical uncertainty and a wider energy range covered compared to previous measurements. The prompt fission γ-ray spectrum measured with the HPGe detectors shows structures that allow conclusions about the nature of γ-ray transitions in the fission fragments. The average photon multiplicity of 8.2 and the average total energy release by prompt photons per fission event of about 6.8 MeV were determined for both detector types.

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Foitzik, A. H., J. S. Sears, A. H. Heuer, and N. J. Zaluzec. "Massive icing of a high-purity Ge EDS detector with an ultrathin window." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 752–53. http://dx.doi.org/10.1017/s0424820100088075.

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High Purity Germanium (HPGe) EDS detectors are now commercially available. Their main advantage over the commonly used Si(Li) EDS detectors is the increased absorption at higher energies due to the higher mass density of germanium. As a result, in modern medium voltage TEMs the K-shells of even heavy elements can be utilized for analytical electron microscopy. In addition, in order to increase the detector performance in the low energy range, an ultrathin window is used instead of a beryllium window. While detectors with a beryllium window are baked, evacuated and then sealed during the manufacturing process (the detecting crystal, therefore, being in a closed environment), our detector with an ultrathin window is not sealed and when in use, is constantly pumped by the microscope vacuum system. While not in use, the detector is retracted behind a valve, at which time it is not pumped.

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Dalaka, Ekaterini, Georgios Kuburas, Konstantinos Eleftheriadis, and Marios Anagnostakis. "Efficiency calibration of a well-type HPGe detector using experimental and Monte Carlo simulation techniques." Nuclear Technology and Radiation Protection 35, no. 2 (2020): 121–29. http://dx.doi.org/10.2298/ntrp2002121d.

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Well-type high-purity germanium detectors are well suited for the analysis of small samples, as they combine high detection efficiency with low background radiation. The well geometry however makes efficiency calibration more difficult than that of ordinary HPGe detectors, due to intense true coincidence and possibly random summing effects. Such a detector has been installed at the Environmental Radioactivity Laboratory of the National Centre for Scientific Research "Demokritos". For the calibration of this detector, experimental and Monte Carlo simulation techniques were applied. To this end, calibration sources were produced from the radionuclides available at the Environmental Radioactivity Laboratory. Starting from the geometrical characteristics of the detector as provided by the manufacturer, using the calibration sources and applying Monte Carlo simulation techniques, the detector was characterized and peak efficiency, as well as total-to-peak calibration curves were produced. The results of the calibration finally obtained by simulation are found to be in good agreement with the respective experimental calibration results.

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M. M. Hosamani, A. S. Bennal, and N. M. Badiger. "Determination of the Thermal Neutron Flux by Measuring Gamma Radiations with High and Low Resolution Detectors." Journal of Nuclear Physics, Material Sciences, Radiation and Applications 6, no. 2 (February 26, 2019): 187–93. http://dx.doi.org/10.15415/jnp.2019.62027.

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Thermal neutron flux (Фth) of Americium-Beryllium (Am-Be) neutron source has been measured by adopting the foil activation method. The neutrons emitted from Am-Be source are used to activate the indium-115 (115In) foil. The gamma radiations emitted from the activated isomer 116m1In are measured with NaI(Tl) and HPGe detectors. The thermal neutron flux is measured by adopting the cadmium (Cd) foil difference technique in which the Cd foil placed in front of the source to prevent the thermal neutrons from entering into the indium foil. The neutron flux is determined by measuring the gamma radiation emitted from indium foil using a low and high energy resolution NaI(Tl) and HPGe detectors respectively. The measured thermal neutron flux obtained from both detectors has been compared and found that the Фth does not depend on the resolution and type of the detectors used in the present investigations.

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Alfassi, Z. B., O. Pelled, and U. German. "The virtual point detector concept for HPGe planar and semi-planar detectors." Applied Radiation and Isotopes 64, no. 5 (May 2006): 574–78. http://dx.doi.org/10.1016/j.apradiso.2005.11.007.

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Hao, J., L. He, and Z. Deng. "A cryogenic low-background low-noise CMOS preamplifier for HPGe detectors." Journal of Instrumentation 17, no. 06 (June 1, 2022): P06018. http://dx.doi.org/10.1088/1748-0221/17/06/p06018.

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Abstract A cryogenic low-noise CMOS preamplifier has been successfully developed for HPGe detectors in low-background experiments. Commonly used auxiliary off-chip devices, such as decoupling capacitors and resistors, were removed to control the radioactive emission. The prototype chip was implemented in XFAB 350 nm CMOS process and was fully evaluated. A minimum ENC of 8.9 electrons was obtained at a 12 μs shaping time at 77 K, and the rise time was measured to be 60 ns through a 1-meter-long cable. The performances with and without decoupling capacitors for the power supply and bias voltages were compared, and there was no evident difference between these cases. The performance upon connection to a 0.5 kg point-contact HPGe detector was also measured. A minimum ENC of 15.5 electrons was achieved. The energy spectrum of the 57Co radiation source was obtained, and the FWHM of the 122 keV energy peak was measured to be 0.6 keV.

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Bronson, F. L. "Initial Performance Testing of Sri Gamma Spectroscopy Scintillators and Comparison to Other Improved-Resolution Detectors for Typical Health Physics Applications." EPJ Web of Conferences 225 (2020): 09004. http://dx.doi.org/10.1051/epjconf/202022509004.

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Europium-doped Strontium Iodide (SrI) scintillation gamma detectors have only recently become commercially available. SrI has very high light output ranging from 80,000-100,000 ph/MeV and energy resolution as good as 2.9% at 662 keV and 14.8% at 32 keV. The high density of 4.6 g/cc in combination with a high effective Atomic number and the absence of internal activity make SrI a very attractive sensor material for spectroscopic radiation monitoring devices. This new entrant into the field of commercially available gamma spectroscopy detectors offers improved energy resolution over NaI, without the elevated background of LaBr. While CZT and HPGe detectors have better resolution, the small available size of CZT and the cooling requirement of HPGe limit their usefulness in portable applications. Of these scintillators, SrI2 has the lowest detection limits when compared to other equal- size scintillation detectors, especially at low energies where U and Pu are of interest.

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Chand, Bakhshish, Jatinder Goswamy, Devinder Mehta, Nirmal Singh, and P. N. Trehan. "Study of the radioactive decays of 140Ba and 140La." Canadian Journal of Physics 69, no. 2 (February 1, 1991): 90–101. http://dx.doi.org/10.1139/p91-014.

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The intensities of X rays and γ rays from the decays of 140Ba and 140La were measured precisely using Si(Li) and HPGe detectors. The L X-ray intensities in 140Ba decay are reported for the first time. The conversion electrons from these decays are investigated using a mini-orange electron spectrometer. The electron intensities for the (M + N.) conversion of 329, 487, 1596, and 1903 keV transitions in 140Ce were measured for the first time. From the present conversion-electron and γ-ray intensities, the conversion coefficients for various transitions in 140La and 140Ce were determined. Also, the γ–γ directional correlations for 15 cascades in,140Ce were studied using a HPGe–HPGe detector coincidence setup (time resolution = 7 ns). The 109–(329)– 487, 131–242, and 131–266 keV cascades in 140Ce were studied for the first time. The multipole mixing ratios for the 109, 131, 242, 266, 329, 432, 487, 751, 816, 868, 919, 925, and 951 keV transitions in 140Ce are deduced from the present directional correlation and conversion-coefficient measurements.

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Lee, I. Y., and A. O. Macchiavelli. "Effects of magnetic fields on HPGe tracking detectors." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 992 (March 2021): 165017. http://dx.doi.org/10.1016/j.nima.2021.165017.

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Sanchez Lorente, A., P. Achenbach, M. Agnello, T. Bressani, S. Bufalino, B. Cederwall, A. Feliciello, et al. "Performance of HPGe detectors in high magnetic fields." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 573, no. 3 (April 2007): 410–17. http://dx.doi.org/10.1016/j.nima.2006.12.030.

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Crespi, F. C. L., F. Camera, O. Wieland, G. Benzoni, S. Brambilla, B. Million, and D. Montanari. "A pulse shape analysis algorithm for HPGe detectors." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 570, no. 3 (January 2007): 459–66. http://dx.doi.org/10.1016/j.nima.2006.10.003.

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Crespi, F. C. L., V. Vandone, S. Brambilla, F. Camera, B. Million, S. Riboldi, and O. Wieland. "HPGe detectors timing using pulse shape analysis techniques." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 620, no. 2-3 (August 2010): 299–304. http://dx.doi.org/10.1016/j.nima.2010.02.273.

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40

Owens, Alan, Sebastian M. Pascarelle, Neil Gehrels, and Bonnard J. Teegarden. "Empirical efficiency and volume relationships for HPGe detectors." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 310, no. 3 (December 1991): 681–84. http://dx.doi.org/10.1016/0168-9002(91)91117-e.

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41

Andreotti, E., M. Hult, G. Marissens, G. Lutter, A. Garfagnini, S. Hemmer, and K. von Sturm. "Determination of dead-layer variation in HPGe detectors." Applied Radiation and Isotopes 87 (May 2014): 331–35. http://dx.doi.org/10.1016/j.apradiso.2013.11.046.

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42

Bellia, G., A. Del Zoppo, C. Agodi, R. Alba, R. Coniglione, E. Migneco, G. Russo, and P. Sapienza. "Performances of large volume p-type HPGe detectors." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 284, no. 2-3 (December 1989): 399–404. http://dx.doi.org/10.1016/0168-9002(89)90308-2.

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43

Vetter, K., M. Burks, and L. Mihailescu. "Gamma-ray imaging with position-sensitive HPGe detectors." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 525, no. 1-2 (June 2004): 322–27. http://dx.doi.org/10.1016/j.nima.2004.03.087.

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Pullia, A., R. Isocrate, R. Venturelli, D. Bazzacco, R. Bassini, and C. Boiano. "Characterization of HPGe-segmented detectors from noise measurements." IEEE Transactions on Nuclear Science 51, no. 6 (December 2004): 3086–89. http://dx.doi.org/10.1109/tns.2004.839099.

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Twomey, T. R., and R. M. Keyser. "Advances in large-diameter, low-energy HPGe detectors." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 339, no. 1-2 (January 1994): 78–86. http://dx.doi.org/10.1016/0168-9002(94)91783-3.

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Li, Zhuo Xin, Run Sheng Yu, Xing Zhong Cao, Peng Zhang, Xiu Bo Qin, and Bao Yi Wang. "An AMOC System with Two Detectors." Materials Science Forum 733 (November 2012): 326–29. http://dx.doi.org/10.4028/www.scientific.net/msf.733.326.

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In this work, a single scintillator detector setup for AMOC measurement is considered to improve coincidence efficiency. A planar HPGe detector provide both the timing signal of stop channel and the energy spectrum signal for an annihilation events of positronium. Experiment results show that the system can get a count rate ~20cps/μCi with a time resolution of 2.2ns.

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Eftekhari Zadeh, E., S. A. H. Feghhi, E. Bayat, and G. H. Roshani. "Gaussian Energy Broadening Function of an HPGe Detector in the Range of 40 keV to 1.46 MeV." Journal of Experimental Physics 2014 (October 7, 2014): 1–4. http://dx.doi.org/10.1155/2014/623683.

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High-purity germanium (HPGe) detectors are widely used in nuclear spectroscopy (e.g., neutron activation analysis) due to their high resolution. Resolution function of a GMX series coaxial detector system (model number GMX40P4-83) in the range of 40 keV to 1.46 MeV has been measured using standard γ-ray sources. The energy response function also was calculated using Monte Carlo simulation through the precise modeling of the detector structure. The simulated energy response function was verified with the measured energy response function obtained using calibration sources. A new approach was used and the agreement between both results has been improved.

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Dhal, A., F. Ramirez, G. Suliman, T. Roman, G. Ciocan, D. Testov, C. Petcu, B. Tatulea, C. A. Ur, and D. L. Balabanski. "Liquid nitrogen cooling, control and monitoring system for the ELIADE HPGe clover detectors at ELI-NP." Journal of Instrumentation 17, no. 07 (July 1, 2022): T07008. http://dx.doi.org/10.1088/1748-0221/17/07/t07008.

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Abstract We present a liquid nitrogen (LN2) cooling station for the high-purity germanium (HPGe) segmented clover detectors of the ELI-NP Array of DEtectors (ELIADE) spectrometer, including its associated filling control and monitoring systems, all designed and built in-house at Extreme Light Infrastructure - Nuclear Physics (ELI-NP), Măgurele, Romania. The automated LN2 filling process is controlled by a CompactRIO (cRIO) system from National Instruments through a custom LabVIEW software used for monitoring both the internal germanium crystal temperatures as well as the temperatures of external Pt100 sensors (used for detection of overflow of LN2 from detectors during a filling process). The detectors are filled with LN2 by opening their individual filling valves (which are mounted on the cooling station) and the process is automatically stopped once an overflow condition is fulfilled by the corresponding external Pt100 sensor located downstream. A twelve-hour cycle is used to periodically fill all of the detector dewars and keep their germanium crystals cool at all times. The associated Graphic User Interface (GUI), Command Line Interface (CLI) and Text User Interface (TUI) are used for both controlling and monitoring the above mentioned process. Alert and warning email messages were also enabled via the cRIO system so that users can be alerted in real-time in the event of any cooling malfunction. In this way, any issues related to the cyclic filling procedure, as well as any abnormal observations regarding the germanium crystal temperatures can be quickly and efficiently addressed before the detectors have a chance to warm back up to room temperature. Temperature data of all the Pt100 sensors corresponding to detectors as well as to the solenoid valves are made available in an influx database by the cRIO control system. The web application Grafana access the database and plots them in real-time for online monitoring.

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Krneta Nikolić, Jelena, Milica Rajačić, Dragana Todorović, Marija Janković, Nataša Sarap, Gordana Pantelić, and Ivana Vukanac. "Semiempirical Efficiency Calibration in Semiconductor HPGe Gamma-Ray Spectroscopy." Journal of Spectroscopy 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/5392658.

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One of the main problems in quantitative gamma-ray spectroscopy is the determination of detection efficiency, for different energies, source-detector geometries, and composition of samples or sources. There are, in principle, three approaches to this issue: experimental, numerical, and semiempirical. Semiempirical approach is based on the calculation of the efficiency for the measured sample on the basis of an experimental efficiency measured on the same detector, but with a calibration source that can be of different size, geometry, density, or composition—the so-called efficiency transfer. The aim of this paper is to analyze the semiempirical approach, using EFFTRAN and MEFFTRAN software as a typical example. These software were used in the Department of Radiation and Environmental Protection, Vinča Institute of Nuclear Sciences, on three HPGe detectors. The results were compared to the experimentally obtained efficiency, and further validation is performed by measuring reference materials issued within the framework of several interlaboratory intercomparisons. The analysis of the results showed that the efficiency transfer produces good results with the discrepancies within the limits of the measurement uncertainty. Also, for intercomparison measurement, utest criterion for the trueness of the result was applied showing that the majority of the obtained results were acceptable. Some difficulties were identified, and the ways to overcome them were discussed.

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Napoli, D. R., G. Maggioni, S. Carturan, J. Eberth, V. Boldrini, D. De Salvador, E. Napolitani, et al. "New Developments in HPGe Detectors for High Resolution Detection." Acta Physica Polonica B 48, no. 3 (2017): 387. http://dx.doi.org/10.5506/aphyspolb.48.387.

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Journal articles on the topic 'HPGe detectors'

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