基于Geant4低本底液闪谱仪屏蔽与反符合设计  

Shield and Anti-coincidence Design of the Low Background Liquid Scintillation Spectrometer Based on Geant4

作　　者：梁烨 吴英[1] 杨斌[2] 吴永乐[2] LIANG Ye;WU Ying;YANG Bin;WU Yongle(School of nuclear science and engineering,North China Electric Power University,Beijing,102206,China;Nuclear and Radiation Safety Center,Beijing,100082,China)

机构地区：[1]华北电力大学核科学与工程学院,北京102206 [2]环保部核与辐射安全中心,北京100082

出　　处：《核科学与工程》2019年第4期666-671,共6页Nuclear Science and Engineering

基　　金：国家自然科学基金项目（11275071）;国家环境保护标准制修订项目（2018-59）;中央高校基本科研业务费专项资金（2018ZD10）

摘　　要：本文设计了一种较已有低本底液闪谱仪结构更为简单的低本底液闪谱仪,即在谱仪外围布置铅铜屏蔽体,以屏蔽墙体中放射性核素衰变释放出的γ射线,同时采用反符合技术以减少宇宙射线μ子引起的液闪谱仪本底计数.采用Geant4模拟计算了不同厚度的铅铜屏蔽体对墙体发出的γ射线的屏蔽效果,得到了几乎可以屏蔽所有γ射线的屏蔽体最优尺寸.此外,还采用Geant4模拟计算了反符合技术中,闪烁瓶的几种不同摆放方式和反符合闪烁瓶的几种不同尺寸的设计下,反符合技术减少宇宙射线μ子引起的液闪谱仪本底计数的份额,给出了较无反符合设计时μ子引起的液闪谱仪本底计数能减少99%的一种简单高效的反符合设计方案.In this paper,a low background liquid scintillation spectrometer with a simpler structure than the existing low background liquid scintillation spectrometers is designed.In this spectrometer,a lead-copper shield is arranged on the periphery of the spectrometer to shield the gamma rays emitted by the decay of the radionuclide in the wall,at the same time,anti-coincidence technology is used to reduce the background count of liquid scintillation spectrometer caused by cosmic muon.The shielding effects of the shields with different thicknesses of lead and copper against the gamma rays emitted from the walls are calculated by Geant4,and the optimal size of the shield that can shield against almost all of the gamma rays is obtained.In addition,the Geant4 software is also used in anti-coincidence technique,to calculate the reducing degrees of the anti-coincidence technology to background counts in spectrometer caused by cosmic muon,under the design of placing the scintillation bottles in several different ways and using different sizes of anti-coincidence scintillation bottles.By analyzed and compared,a simple and efficient anti-coincidence design which can reduce 99% of the background counts in the spectrometer without anti-coincidence technology caused by cosmic muon is given.

关 键 词：低本底液闪谱仪 Geant4模拟 铅铜屏蔽 反符合技术 

分 类 号：TL812.2[核科学技术—核技术及应用]