地下铁室铅室组合屏蔽低本底 HPGe γ 谱测量系统及其应用研究

LOW BACKGROUND HPGe γ SPECTROSCOPY SYSTEM WITH LEAD SHIELDING IN UNDERGROUND IRON ROOM AND ITS APPLICATION

本文介绍一地下室铁室铅室组合屏蔽低本底ＨＰＧｅγ谱测量系统。该系统由地下铁室和在其内的铅室组成组合物质屏蔽；在１００～２０００ｋｅＶ能区，相对效率为３８．４％的ＨＰＧｅ探测器积分本底计数率为０．７／ｓ，本底效率比为１．８２／ｓ；谱数据收集时间为１０００ｍｉｎ时对１３７Ｃｓ点源的探测下限为３．４ｍＢｑ。作为举例，还介绍了用该系统分析测量反应堆退役清洗去污后的不锈钢管道样品中１３７Ｃｓ和６０Ｃｏ含量及分布的结果。

This paper describes a low background HPGe γ spectroscopy system of which main shielding is made up of lead cell and underground iron room.In this system,the background counting rate is 0.7/s and background efficiency ratio is 1.82/s for HPGe detector of 38.4% relative efficiency in 100～2 000 keV energy range.The lower detectable limit is 3.4 mBq for 137 Cs point source when counting time is 1 000 min.As examples,Measuring results of 137 Cs and 60 Co contents and distributions in decontaminated stainless steel tap samples from decommissioned nuclear reactor using are presented. (