137Cs γ射线空气比释动能基准石墨空腔电离室的研制  

Construction on Graphite Cavity Ionization Chamber as Air Kerma Primary Standard for 137Cs γ Rays

作　　者：李德红[1] 王培玮[1] 邬蒙蒙[1,2] 成建波[1,3] 郭彬[1] 

机构地区：[1]中国计量科学研究院,北京100029 [2]中国原子能科学研究院,北京102413 [3]兰州大学,甘肃兰州730000

出　　处：《计量学报》2016年第3期323-327,共5页Acta Metrologica Sinica

摘　　要：根据Bragg-Gray理论研制了圆柱形石墨空腔电离室，用于137Csγ空气比释动能基准的建立。通过理论计算灵敏体积内部电场分布，优化了电离室壁和收集极之间接地保护的结构设计，在此基础上，对研制的电离室的饱和曲线、本底电流以及稳定性等电学性能进行了测试，其结果表明完全达到设计要求。对电离室的各项修正因子进行了理论计算和实验测量，实现了137Csγ空气比释动能的量值复现，其合成标准不确定度为0．25％。A cylindrical graphite cavity ionization chamber is designed and constructed according to Bragg-Gray theory, which is used for the establishment for primary standard for cesium-137 γRays. Ground protection structural of the ionization chamber wall and the collector is optimized through theoretical calculations of the electric field distribution of sensitive volume of the ionization chamber. And the results of a series of tests including the saturation curve, the background current and the stability show that the design fully meet the requirements. The air kerma of the cesium-137 sources is directly realized using the graphite cavity ionization chamber whose correction factors are got though theoretical calculations and experimental measurements. At last, the combined standard uncertainty of air kerma measurement is 0. 25%.

关 键 词：计量学 空气比释动能 石墨空腔电离室 基准装置 137Csγ 

分 类 号：TB98[一般工业技术—计量学]