Low-level gamma-ray spectrometry using Ge-detectors (original) (raw)
Related papers
The dependence of Ge detectors efficiency on the density of the samples in gamma-ray spectrometry
Nuclear Technology & Radiation Protection, 2007
The ef fect of the den sity of en vi ron men tal sam ples on the count ing ef fi ciency of Ge detec tors used in gamma-spec trom e try was stud ied. The de pend ence e ff (r) was de termined for two HPGe de tec tors (rel a tive ef fi cien cies 18% and 20%), us ing five ra dio active stan dard ref er ence ma te ri als (sil i cone res ins, ep oxy resin, milk pow der, soil) with dif fer ent ma trix den si ties (0.45-1.22 g/cm 3 ) in Marinelli beak ers (V = 500 cm 3 ). The de pend ence of ef fi ciency vs. den sity was found to be lin ear and the re gres sion pa ram eters for en er gies in the range of 60-2000 keV were de ter mined, too. The ef fect of vari ation in den sity on the count ing ef fi ciency of Ge de tec tors is dom i nant in the range of lower en er gies (60-600 keV) and de creases with en er gies in the higher en ergy range.
IOSR Journals , 2019
The utilization and prolonged working of two gamma spectrometry (GS1 and GS2) in nuclear laboratories, UTM, causing one to questioning its performance. To achievethe higher quality outcomes of gamma spectrometry system. Itsperformance specifications should verify against the warranted values offered by the manufacturer. High purity germanium (HPGe) detectors is the most distinguished radiation measurement instrument that produced excellent energy resolution. The aims of this studyis to determine the working condition and compare the performances of two gamma spectrometry systems. The GS1 consist of n-type closed end coaxial HPGe detector GC 2018 model and GS2 consist of p-type closed end coaxial HPGe detector of GEM25-76-LB-C model. The test performance specifications such as resolution, peak shapes, peak-to-Compton ratio, figure of merit, and dead time for both spectrometry systems are measured using American ANSI/IEEE 325-1996 standard procedure.Four (4) standard source 60 Co, 152 Eu, 133 Ba, and 137 Cs were used. It covered energies range from (4.3 keV-3194.9) keV. The source-to-detector distance is set 25 cm to avoid the summing coincident gamma ray. The relative efficiency measured improve by 0.2% and 4% for GS1 and GS2 respectively. Peak-to-Compton ratio of both detectors improved by factor of 4.Dead time found to be less than 1% at 25 cm compared to 12 cm. From the results, GS1 has higher resolution compared to GS2 detector. Based on the results obtained, it can be concluded that the performance of two coaxial HPGe detectors in nuclear laboratories, (UTM) are in good working condition.Thisrevealed propercontrol and maintenance of the two detectors.
Study of the background components for a Ge(HP) detector in environmental radioactivity measurements
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1994
A quantitative study of the environmental background components of a gamma-ray spectrum recorded with an unshielded p-type germanium detector has been performed. The contribution of each component to the background spectrum was analyzed separately using Monte Carlo simulation techniques.
Well Ge and semi-planar Ge (HP) detectors for low-level gamma-spectrometry
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995
Two gamma spectrometers, a well Ge and a semi-planar Ge (HP). are now installed and calibrated for measurements of environmental radioactivity with special attention being paid to the requirements needed for aquatic mass-balance studies, including isotope-particle dynamics and dating of recent deposits. These facilities will complement the previously developed isotope dilution alpha spectrometry (PIPS detectors) and radon emanation (ionization chambers) techniques for ~"'Pb dating. A careful evaluation of efficiencies and background of the Ge detectors, together with the influence of the sample's intrinsic activity on the lower limit of detection (LLD), allowed us to study the relative importance of detector and shield specifications on low level gamma spectrometry of environmental samples with various sizes and composition.
A comprehensive calibration method of Ge detectors for low-level gamma-spectrometry measurements
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2002
This paper aims to show a general and simple method for gamma-ray efficiency calibration in the 186-1500 keV energy range with special attention to applications on environmental studies. This method accounts for differences in densities, composition and counting geometries between real and calibration samples. Self-absorption corrections can be easily determined from a single spectral measurement knowing only the apparent densities of the samples. We have evaluated the influence of background parameters in the response of the spectrometric system and moreover, we have calculated the minimum detectable activity due to background contribution. This calibration has been validated through three different and independent tests. r
Performance of an intrinsic germanium three-crystal ultralow background gamma-ray spectrometer
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1988
A-y-ray spectrometer with three large HpGe crystals totalling 560 cm3 in one cryostat was fabricated with a view to achieving ultralow background count rates in the energy region below 4 MeV. At 2 MeV, the continuum background is 1.7 x 10-3 counts per keV per 1000 h per cm3, making this one of the lowest background, large systems at the present time. Only passive shielding is used. Residual activities intrinsic to the detector and shielding materials have been identified with respect to their origin from fission and cosmogenic sources.
Characterization of high-purity germanium (Ge) crystals for developing novel Ge detectors
Journal of Instrumentation, 2020
High-purity germanium (HPGe) crystals are required to be well-characterized before being fabricated into Ge detectors. The characterization of HPGe crystals is often performed with the Hall Effect system, which measures the net carrier concentration, the Hall mobility, and the electrical resistivity. The reported values have a strong dependence on the size of the ohmic contacts and the geometry of the samples used in conducting the Hall Effect measurements. We conduct a systematic study using four samples cut from the same location in a HPGe crystal made into different sized ohmic contacts or different geometries to study the variation of the measured parameters from the Hall Effect system. The results are compared to the C-V measurements provided by the Ge detector made from the same crystal. We report the systematic errors involved with the Hall Effect system and find a reliable technique that minimizes the systematic error to be only a few percent from the Hall Effect measurements.
Isotopically modified Ge detectors for GERDA: from production to operation
Journal of Instrumentation, 2013
The GERDA experiment searches for the neutrinoless double beta (0νβ β) decay of 76 Ge using high-purity germanium detectors made of material enriched in 76 Ge. For Phase II of the experiment a sensitivity for the half life T 0ν 1/2 ∼ 2 • 10 26 yr is envisioned. Modified Broad Energy Germanium detectors (BEGe) with thick n + electrodes provide the capability to efficiently identify and reject background events, while keeping a large acceptance for the 0νβ β-decay signal through novel pulse-shape discrimination (PSD) techniques. The viability of producing thickwindow BEGe-type detectors for the GERDA experiment is demonstrated by testing all the production steps from the procurement of isotopically modified germanium up to working BEGe detectors. Comprehensive testing of the spectroscopic as well as PSD performance of the GERDA Phase II prototype BEGe detectors proved that the properties of these detectors are identical to those produced previously from natural germanium material following the standard production line of the manufacturer. Furthermore, the production of BEGe detectors from a limited amount of isotopically modified germanium served to optimize the production, in order to maximize the overall detector mass yield. The results of this test campaign provided direct input for the subsequent production of the enriched germanium detectors.
New Developments in HPGe Detectors for High Resolution Detection
Acta Physica Polonica B
High-Purity Germanium (HPGe) detectors continue to be a fundamental tool in nuclear gamma spectroscopy. The tracking of the gamma interactions inside the HPGe crystals is opening a new era in the use of these detectors for both basic science and applications, but they have also shown that new R&D is necessary for the production of even better and more reliable highly segmented detectors. In this work, we present recent results obtained in the framework of a multidisciplinary research program in HPGe detector technologies and we discuss the influence of these studies on the use of HPGe detectors.
Spectroscopic performance evaluation and modeling of a low background HPGe detector using GEANT4
arXiv (Cornell University), 2023
Low background gamma spectrometry employing HPGe detectors is a sensitive technique for measuring low-level radioactivity in environmental applications, material screening, and for rare decay searches. This work presents spectroscopic performance evaluation and modelling of a low background measurement setup developed at IIT Ropar in Punjab, India, to measure trace natural radioactive elements, with a particular interest in studying low-level radioactivity in soil and/or rock samples to generate specific inputs for low background experiments. The performance test and characterization of a low background cryocooled HPGe detector with relative efficiency of ∼33% have been carried out. An effective detector model has been developed using GEANT4 Monte Carlo simulation to determine the response of the detector over an energy range of 80.9-1408 keV and compared with the experimental performance of the detector. The response of the detector obtained using Monte Carlo simulations agrees reasonably well within 93% level of confidence, indicating only 7% deviation in the comparison. The present setup offers improved detection limits of primordial radionuclides (U/Th and K) to measure radioactive contamination in environmental matrices, which has been used elsewhere [1].