多能量γ射线源屏蔽下活度估算方法研究  

Study on the activity estimation method of shielded multi-energy gamma-ray sources

作　　者：熊茂淋 张庆贤[1] 张建 杨津 葛良全[1] 孙坤 XIONG Maolin;ZHANG Qingxian;ZHANG Jian;YANG Jin;GE Liangquan;SUN Kun(Key Laboratory of Applied Nuclear Techniques in Geosciences,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]成都理工大学地学核技术四川省重点实验室,成都610059

出　　处：《核技术》2020年第11期13-19,共7页Nuclear Techniques

基　　金：国家重点研发计划(No.2017YFC0602105);国家自然科学基金(No.41774190);四川省科技计划资助(No.2020JDRC0108)资助。

摘　　要：在同位素放射源检查或“孤儿源”处理中,为了能够及时、准确地处理放射源,需要现场快速估计放射源活度。但当屏蔽体厚度未知时,快速确定放射源活度存在困难。基于γ射线在物质中衰减系数与能量之间的关系,研究屏蔽下多特征能量点状γ射线源的活度估算方法,分别对测量目标特征γ射线能量选取原则,探测器位置偏差和统计涨落对活度定量结果的影响进行了讨论,总结了常见多特征能量γ射线源的可选射线能量与可分析的屏蔽厚度。实验验证结果表明:估算的屏蔽厚度与实际厚度的相对误差小于4%,估算活度与实际活度的相对误差小于5%。本文所提方法能够应用于放射源检查或者“孤儿源”处理。[Background]During the radioactive source inspection or the orphan source disposal,it is essential to estimate the activity of the radioactive source quickly and effectively.However,this may be difficult,especially when the source is under shield with unknown shield thickness.[Purpose]This study aims to establish an activity estimation method of shielded multi-energy gamma-ray sources.[Methods]First of all,based on the relationship between the material attenuation coefficient and energy of the gamma-ray source,a method for the activity estimation of shielded multi-energy gamma-ray source was established.Then,influences of the position bias between the radioactive source and the detector,the characteristic energy selection,and the effect of statistical fluctuations were investigated by experiments.Finally,the optimal characteristic energy of common multi-energy gamma-ray sources and the maximum measurable shield thickness of the radioactive sources with different activities were analyzed.[Results]The experimental results show that the relative errors between the estimated thickness and the real thickness is less than 4%,and the relative errors between the estimated activity and the real activity is less than 5%.[Conclusions]The method proposed in the paper can be applied to the radioactive source inspection or the orphan source disposal.

关 键 词：辐射探测 活度估算 误差分析 蒙特卡罗模拟 

分 类 号：TL99[核科学技术—核技术及应用]