P-type point contact (PPC) HPGe detectors are a leading technology for rare event searches due to their excellent energy resolution, low thresholds, and multi-site event rejection capabilities. We have characterized a PPC detector's response to particles incident on the sensitive passivated and p surfaces, a previously poorly-understood source of background. The detector studied is identical to those in the Majorana Demonstrator experiment, a search for neutrinoless double-beta decay ( ) in Ge. decays on most of the passivated surface exhibit significant energy loss due to charge trapping, with waveforms exhibiting a delayed charge recovery (DCR) signature caused by the slow collection of a fraction of the trapped charge. The DCR is found to be complementary to existing methods of identification, reliably identifying background events on the passivated surface of the detector. We demonstrate effective rejection of all surface events (to within statistical uncertainty) with a loss of only 0.2% of bulk events by combining the DCR discriminator with previously-used methods. The DCR discriminator has been used to reduce the background rate in the region of interest window by an order of magnitude in the Majorana Demonstrator and will be used in the upcoming LEGEND-200 experiment.
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http://dx.doi.org/10.1140/epjc/s10052-022-10161-y | DOI Listing |
Isotopes Environ Health Stud
January 2025
Research Institute of Biology, Yerevan State University, Yerevan, Republic of Armenia.
Plant test systems are a sensitive way to detect the genetic effects of various contaminants in environmental compartments: water, soil and sediments. Biotesting of the genotoxicity of soil samples with various activity concentrations of naturally occurring (Ra, Th, K) and artificial (Cs) radionuclides in soil, from the territory of the Aragats Massif (Armenia) was carried out with the application of the micronucleus (Trad-MСN) and stamen hair mutation (Trad-SHM) bioassays of (clone 02) model test-object in the soil - plant system. Undisturbed soil sampling was performed in the southern slopes of the Aragats Massif, from different altitudes (from 1000 to 3200 m above sea level).
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Institute of Safety Engineering, Fire University, 52/54 Słowackiego St., 01-629 Warsaw, Poland.
The concentration of natural radionuclides Ra, Th and K in ceramic tiles manufactured in Poland is presented in this paper. The concentration of natural radioactive isotopes in the tested samples was determined using a low-level digital gamma ray spectrometer equipped with an HPGe semiconductor detector. The mean concentrations of Ra, Th and K in the analyzed samples were found to be 48 ± 3 Bq∙kg, 49 ± 3 Bq∙kg and 476 ± 23 Bq∙kg, respectively.
View Article and Find Full Text PDFSci Rep
January 2025
Physics Department, Faculty of Science, Fayoum University, Fayoum, Egypt.
For the purpose of this study, four natural rock samples-namely, diorite, granodiorite, tonalite, and granite-are being investigated about their radiation attenuation. The elemental composition of the rocks was obtained through Energy dispersive X-ray spectroscopy (EDX) which examines the microstructural and localized area elemental analyses of the four rock samples. A Monte Carlo simulation (MCNP) was used to determine and evaluate the investigated samples.
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December 2024
Nuclear Safeguards and Physical Protection Department, Egyptian Atomic Energy Authority (EAEA), Cairo, Egypt.
The effective implementation of domestic and international safeguards necessitates verification techniques for Nuclear Materials (NM). Even in the case of very small quantities of NMs, accounting for and analyzing such traces can provide insights into the mass balance of NMs and/or state activities, ensuring consistency in state declarations. This paper proposes and benchmarks an absolute calibration methodology for estimating the uranium-mass content in large-volume barrels (200 L).
View Article and Find Full Text PDFAppl Radiat Isot
December 2024
Bingöl University, Faculty of Arts and Science, Department of Physics, 12000, Bingöl, Türkiye.
In this study, the gamma radiation shielding properties of concrete samples reinforced with 10%, 20%, 30%, 40% and 50% of the cement weight of brass alloy were investigated. To test gamma shielding performance of the samples, mass and linear attenuation coefficients, half and tenth value layers, effective atomic number and radiation protection efficiency parameters were determined experimentally, theoretically and Monte Carlo simulations (GEANT4 and FLUKA). The studies were performed at 11 different gamma energies that range from 59.
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