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arXiv · 1410.4291

Simulation of background reduction and Compton depression in low-background HPGe spectrometer at a surface laboratory

ShunLi Niu·Xiao Cai·ZhenZhong Wu·YuGuang Xie·BoXiang Yu·ZhiGang Wang·Jian Fang·XiLei Sun·LiJun Sun·YingBiao Liu·Long Gao·Xuan Zhang·Hang Zhao·Li Zhou·JunGuang Lv·Tao Hu
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Abstract

High-purity germanium detectors are well suited to analysis the radioactivity of samples. In order to reduce the environmental background, low-activity lead and oxygen free copper are installed outside of the probe to shield gammas, outmost is a plastic scintillator to veto the cosmic rays, and an anti-Compton detector can improve the Peak-to-Compton ratio. Using the GEANT4 tools and taking into account a detailed description of the detector, we optimize the sizes of the detectors to reach the design indexes. A group of experimental data from a HPGe spectrometer in using were used to compare with the simulation. As to new HPGe Detector simulation, considering the different thickness of BGO crystals and anti-coincidence efficiency, the simulation results show that the optimal thickness is 5.5cm, and the Peak-to-Compton ratio of 40K is raised to 1000 when the anti-coincidence efficiency is 0.85. As 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 (50keV~2.8MeV), which is about 10-5 of environmental background.

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ShunLi Niu, Xiao Cai, ZhenZhong Wu, YuGuang Xie, BoXiang Yu, ZhiGang Wang, Jian Fang, XiLei Sun, LiJun Sun, YingBiao Liu, Long Gao, Xuan Zhang, Hang Zhao, Li Zhou, JunGuang Lv, Tao Hu. 2014-10-16. Simulation of background reduction and Compton depression in low-background HPGe spectrometer at a surface laboratory. https://doi.org/10.1088/1674-1137%2F39%2F8%2F086002

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