LaBr_(3)(Ce)探测器点源效率函数研究  

Study on point source efficiency function of LaBr_(3)(Ce) detector

作　　者：叶二雷 南宏杰 沈春霞 许丰 史丽生 YE Erlei;NAN Hongjie;SHEN Chunxia;XU Feng;SHI Lisheng(Institution of NBC Defense,Beijing 102205,China;School of Physics and Optoelectronics and Engineering,Anhui University,Hefei 230601,China)

机构地区：[1]陆军防化学院,北京102205 [2]安徽大学物理与光电工程学院,合肥230601

出　　处：《核技术》2022年第9期15-22,共8页Nuclear Techniques

摘　　要：点源与探测器相对位置发生变化时,探测效率会发生很大变化,确定探测效率随探测距、角度变化的函数关系有利于快速得到点源在任意位置处的探测效率。利用蒙特卡罗软件MCNP5模拟计算了^(152)Eu、^(137)Cs、^(60)Co点源在特定位置处的探测效率,与实验结果相比,最大误差不超过6%。基于MCNP5对3.81 cm LaBr_(3)(Ce)探测器做效率刻度,并计算了点源在探测器正面2π空间范围内不同位置处的探测效率,拟合了探测效率与角度和距离的函数关系。结果表明:点源探测效率最大值出现在与探测器轴线夹角90°处,随着探测距离和能量的增大,角度对点源探测效率的影响逐渐减小;空间位置对探测效率的影响实际上是对点源相对于探测器的空间立体角效率。基于效率函数可计算出特定能量γ射线在空间任意位置处的探测效率,对LaBr_(3)(Ce)探测器效率矩阵的求解及效率刻度具有一定的参考价值和指导意义。[Background]When the relative position of the point source and the detector changes,the detection efficiency will also change.Determining the functional relationship of the detection efficiency with the alteration of the detection distance and angle is beneficial to quickly obtain the detection efficiency of the point source at any position.[Purpose]This study aims to determine the spatial point source efficiency function for a LaBr_(3)(Ce)of a specific size.[Methods]The detection efficiency of ^(152)Eu,^(137)Cs,and ^(60)Co point sources at specific positions were simulated and calculated by MCNP5,and the efficiency of the 3.81-cm(diameter and length)LaBr_(3)(Ce)detector was calibrated by simulation.The detection efficiency of the point source at different positions in the 2πspace range of the front of the LaBr_(3)(Ce)detector was calculated.The functional relationship between detection efficiency and angle and distance was obtained by data fitting.[Results]Compared with the experimental results,the maximum relative difference of detection efficiency of point sources calculated by MCNP5 is less than 6%.The maximum detection efficiency of LaBr_(3)(Ce)detector appears at an angle of 90°with the detector axis.With the increase of detection distance and energy,the influence of angle on the detection efficiency of point source gradually decreases.The effect of the spatial position on the detection efficiency is actually the spatial solid angle efficiency of the point source relative to the detector.[Conclusion]The detection efficiency of a point source at any position in space can be calculated based on the efficiency function,which has a good reference value and guiding significance for the solution of the LaBr_(3)(Ce)detector efficiency matrix and the efficiency calibration.

关 键 词：LaBr_(3)(Ce)探测器 效率刻度 点源效率函数 

分 类 号：TL99[核科学技术—核技术及应用]