海水就地γ谱测量最小探测活度影响因素研究  

Research on Influence Factors of Minimum Detectable Activity in Seawater in Situ γ-Ray Spectrometry

作　　者：汪栋[1] 方方[1] 李婷[1] 张国华[2] 石慧[1] 

机构地区：[1]成都理工大学核技术与自动化工程学院,成都610059 [2]山东省科学院海洋仪器仪表研究所,青岛266001

出　　处：《核电子学与探测技术》2014年第6期744-749,共6页Nuclear Electronics & Detection Technology

基　　金：国家自然科学基金(41204133);公益性行业专项(201210044);成都理工大学"金景福"研究基金(J2013060603)资助

摘　　要：海水就地γ谱测量可实现海洋放射性环境的实时在线监测和预警。为了确保准确测量海水中低含量的放射性核素,利用实验和MC模拟研究了Na I(Tl)就地γ谱仪本底计数、测量时间和探测效率对最小探测活度的影响。结果表明:将γ谱仪放置在合适的测量深度可减小本底计数,从而降低最小探测活度;γ射线能量、探测器晶体类型及体积、封装材料类型及厚度也会对最小探测活度产生影响。研究结果可为海水就地γ谱仪的研发和改进提供重要参考依据。The seawater in situ γ-ray energy spectrum analysis is widely used to carry out in real time on-line monitoring and early warning of marine radioactivity environment.In the process of in situ measurement,the lower minimum detectable activity（MDA）,the more accurate instrument analysis is.To study influence factors of MDA and find ways to reduce MDA,The seawater in situ γ-ray spectrometer was applied to study the seawater background and volume source experiments.At the same time,the MCNP5 MC code has been used to simulate.The results show that γ-ray spectrometer placed in suitable measuring depth can reduce the background count,thereby reduce the MDA.γ-ray energy,detector crystal type and size,type of packaging material and its thickness will also affect the MDA.The research contributes to provide important reference for the seawater in situ γ-ray spectrometer development and improvement.

关 键 词：就地γ能谱仪 最小探测活度 海水 M C模拟 

分 类 号：TL81[核科学技术—核技术及应用]