基于判断限的高灵敏度γ峰筛选方法  

A high sensitivity screening method for γ peaks based on the critical level

作　　者：张新军 王世联[1] 贾怀茂 李奇[1] 石建芳[1] 樊元庆[1] 赵允刚 ZHANG Xinjun;WANG Shilian;JIA Huaimao;LI Qi;SHI Jianfang;FAN Yuanqing;ZHAO Yungang(CTBT Beijing National Data Centre and Radionuclide Laboratory, Beijing 100085, China)

机构地区：[1]禁核试北京国家数据中心和北京放射性核素实验室

出　　处：《核技术》2019年第7期15-18,共4页Nuclear Techniques

摘　　要：天然放射性核素是全面禁止核试验条约(Comprehensive Nuclear-Test-Ban Treaty,CTBT)放射性核素台站气溶胶样品的主要放射性成分,CTBT相关放射性核素的弱γ峰处于这些天然放射性核素形成的复杂高本底基线上。针对高环境本底基线上弱γ峰检测难题,提出了一种基于判断限的γ峰筛选方法,结合二阶导数寻峰法,显著提高了HPGeγ能谱中弱γ峰的准确检出率。使用IMS核素台站获取的HPGeγ能谱对该峰筛选方法进行测试,结果显示:峰识别率为97.4%,峰误识别率仅为10.4%。[Background] Radionuclide monitoring is critical to determine whether a suspicious nuclear event detected is a nuclear explosion test. Trace released radionuclides will be transported in the atmosphere, their decay and dilution induce that comprehensive nuclear-test-ban treaty (CTBT) relevant radionuclide monitoring belongs to the ultra-low level radioactive monitoring. The weak γ peaks of CTBT relevant radionuclides are interfered by the complex high environment radioactivity background.[Purpose] This study aims to search accurately the weak γ peaks of CTBT relevant radionuclides in γ spectra of aerosol samples from CTBT radionuclide stations.[Methods] A screening method for γ peaks based on the critical level was proposed to detect weak γ peaks immerged in high environmental radioactive background. Combining the second derivative peak finding method, accurate detection for γ peaks was achieved. Finally, verification was performed on HPGe γ spectra from CTBT radionuclide stations.[Results] The identification rate of γ peaks by using proposed method is 97.4% and the error identification rate of γ peaks can be reduced from 274% to 10.4%.[Conclusion] The high sensitivity screening method for γ peaks based on the critical level can improve the accurate detection rate of the weak γ peaks.

关 键 词：全面禁止核试验条约 γ峰 判断限 筛选方法 

分 类 号：TL816.4[核科学技术—核技术及应用]