基于GEANT4探讨入射窗材料对HPGe探测器探测效率的影响  

Study on the Influence of Incident Window Material on the Detection Efficiency of HPGe Detector Based on GEANT4

作　　者：张庆 Zhang Qing(School of Nuclear Science and Engineering, East China University of Technology, Nanchang 330013, China)

机构地区：[1]东华理工大学核科学与工程学院

出　　处：《广东化工》2019年第12期9-12,25,共5页Guangdong Chemical Industry

摘　　要：针对不同入射窗材料影响HPGe探测器探测效率的问题,首先用GEANT4模拟HPGeγ谱仪标准点源的探测效率并与实测效率进行对此,其相对偏差在4%以内,验证了GEANT4所建立的模型可用于HPGeγ谱仪点源探测效率的模拟。然后基于所建立的HPGe探测模型针对不同入射窗材料、不同入射窗厚度、不同点源发射立体角和不同能量射线对于高纯锗探测器探测效率的影响进行模拟。研究结果表明,在低能射线方面,铍窗的探测效率最高,碳窗与铍窗接近,铝窗的探测效率最低,但随着点源发射立体角的增大,碳窗、铝窗和铍窗的探测效率趋于接近;在中高能射线方面,碳窗、铝窗和铍窗的探测效率几乎相同。在入射窗厚度的选择方面,在入射窗很薄(0.5mm)时,铝窗和铍窗的探测效率相同,在入射窗厚度为1cm之内时,达到相同的探测效率,铝窗的厚度只需要碳窗和铍窗厚度的一半。这为高纯锗探测器在用于不同能量伽马射线的探测时入射窗的选择提供指导。To solve the problem that different incident window materials affect the detection efficiency of HPGe detector, the detection efficiency of standard point source of HPGe gamma spectrometer was simulated with GEANT4 and compared with the measured efficiency. The relative deviation was within 4%, which verified that the model established by GEANT4 could be used to simulate the detection efficiency of point source of HPGe gamma spectrometer. Then based on the HPGe detection model established, the influence of different incident window materials, different incident window thickness, different point source emission solid Angle and different energy rays on the detection efficiency of high purity germanium detector was simulated. The results show that the detection efficiency of beryllium window is the highest, that of carbon window is close to beryllium window, and that of aluminum window is the lowest. In terms of medium and high energy rays, the detection efficiency of carbon window, aluminum window and beryllium window is almost the same. In terms of the choice of incident window thickness, when the incident window is very thin (0.5mm), the detection efficiency of aluminum window and beryllium window is the same;when the incident window thickness is within 1cm ,to achieve the same detection efficiency ,the thickness of aluminum window only needs half of the thickness of carbon window and beryllium window. This provides guidance for the choice of incident window of high purity germanium detector in the detection of gamma rays with different energies.

关 键 词：HPGEΓ谱仪 入射窗 蒙卡方法 点源 

分 类 号：TQ[化学工程]