γ灵敏切伦科夫光纤阵列探测器的γ/n分辨能力研究  

Experimental study of γ/n discrimination of Cherenkov fiber matrix detector sensitive to gamma ray

作　　者：郑小海[1] 鲍杰[1] 侯龙[1] 曹锦云[2] 张子川[2] 

机构地区：[1]中国原子能科学研究院核数据重点实验室,北京102413 [2]西北核技术研究所,西安710024

出　　处：《核技术》2014年第11期35-38,共4页Nuclear Techniques

摘　　要：在脉冲辐射混合场(n,γ)中进行γ射线参数测量,要求探测器系统必须有很快的时间响应,还应有很高的γ/n分辨能力。本文详述了切伦科夫(Cherenkov)辐射原理,用蒙特卡罗软件MCNP模拟计算了γ、中子在不同光纤阵列材料中的能量沉积,根据计算结果选择铅玻璃作为光纤阵列切伦科夫辐射体,配合常聚甲基丙烯甲酯(polymethylmethacrylate,PMMA)塑料光纤光导传输,由光电倍增管转换为电信号输出,研制了一种γ灵敏切伦科夫铅玻璃光纤阵列探测器。在中国原子能科学研究院的600 k V高压倍加器上进行了14.1 MeV中子灵敏度实验,又在西北核技术研究所60Co源上完成了1.25 MeVγ灵敏度实验。实验数据与模拟结果推算得出的数据基本相符,表明该探测器系统具有较高的γ/n分辨能力,可满足在脉冲中子、γ辐射混合场中对γ射线参数测量的分辨能力要求。Background：To measure gamma ray in pulsed radiant hybrid field of gamma ray and neutron,the detector system is required to have a very fast time response,and a good γ/n discrimination.Purpose：The aim is to do experimental study on the detector of Cherenkov plumbic-glass fiber matrix sensitive to gamma ray.Methods：Based on the Cherenkov radiant theory,simulation calculation of energy deposition of the gamma,neutron in fiber arrays materials was done by using MCNP.According to the calculation data,plumbic-glass was selected as Cherenkov scintillated optical fiber,combining with the material of gathering and transmitting scintillated light,the photomultiplier（PMT）,we designed detector of Cherenkov plumbic-glass fiber matrix sensitive to gamma ray.And then the 14.1-Me V neutron sensitivity experiments are performed on the Cockcroft-Walton generator in China Institute of Atomic Energy,the 1.25-Me V gamma sensitivity experiments on 60 Co source in Northwest Institute of Nuclear Technology.Results：The experimental γ /n discrimination is about 42.3 at incident angle of 45°,which is accord basically with the result of simulation calculation.Conclusion：The detector system has high γ/n discrimination,which can fulfill the requirements for gamma ray measurement in pulsed radiation hybrid field.

关 键 词：切伦科夫 光纤阵列探测器 探测灵敏度 脉冲辐射混合场 

分 类 号：TL822[核科学技术—核技术及应用]