CARR冷中子瞬发γ活化分析系统主要性能测试

Performance Test of CARR based Cold Neutron Prompt Gamma Activation Analysis System

使用N型HPGe探测器第一次在中国先进研究堆上通过冷中子束流进行瞬发γ活化分析系统(PGNAA)测量技术研究。应用PGNAA测量系统对NH4CL、Eu、Au、In、Gd、Al、Fe等单质和化合物进行测量,得到实验测量灵敏度值,同时利用标准放射源152Eu、137Cs、60Co以及35Cl(n,γ)和157Gd(n,γ)瞬发γ源对探测器在宽能区0.1~8 MeV进行能量刻度和相对效率刻度,并利用金片活化法测量了中国先进研究堆运行功率为15 MW时有无冷源情况下的中子注量率,结果显示有冷源时中子注量率约提高一个数量级,最后论述了瞬发k0法,为定量实验做好准备。

Cold neutron prompt gamma activation analysis system(CNPGAA)coupled with N-type high purity Germanium(HPGe)detector was firstly studied on China Advanced Research Reactor(CARR)at China Institute of Atomic Energy(CIAE).The prompt gamma spectra and corresponding sensitivity values of elements are obtained such as Eu,Au,In,Gd,Al,N,H and Cl,etc,.and the energy and relative efficiency calibrations of HPGe detector were carried out combining decay radioactive sources(152Eu,137Cs,and 60Co)and prompt gamma rays from 35Cl(n,γ)and 157Gd(n,γ)reactions in the wide energy region of 0.1~8.0 MeV.Besides,the neutron flux rates of CARR operated power of 15 MW with and without cold source were measured by the Au foil activation method.The results show that the neutron flux rate increases by an order of magnitude than which without cold source.Finally,the k0 method of prompt gamma rays based is discussed to prepare for quantitative experiments.