通过测量^(137)Cs的β衰变和内转换电子能谱研究其衰变特性  

Study of decay characteristic by measurement of energy spectrum ofβ decay and internal conversion electrons of ^(137)Cs

作　　者：任赞[1] 王选[1] 牛亚洲[1] 李盘根 张泽涛[1] 张高龙[1] 

机构地区：[1]北京航空航天大学物理科学与核能工程学院,北京100191

出　　处：《大学物理》2017年第2期61-65,共5页College Physics

基　　金：北京航空航天大学"大学生创新创业训练计划"项目的资助

摘　　要：本研究用Si(Li)漂移探测器测量了^(137)Cs的β衰变能谱和内转电子能谱,对β衰变能谱进行了居里描绘和从内转电子能谱取得了内转换系数.得到β衰变的最大能量为(513.11±1.76)ke V,与参考值误差为0.17%;得到内转换系数K/L=5.712±0.217和M/L=0.264±0.018,与参考值的误差分别为0.92%和1.54%;并确定了^(137)Cs在β和γ衰变中的跃迁级次,给出了^(137)Cs及其衰变子核137Ba各能级的自旋和宇称,绘制出了^(137)Cs的衰变纲图.说明该实验方法是可靠的,可用于实验方面的教学和原子核结构的研究,并为其提供必要的实验数据.The energy spectra of β decay and internal conversion electrons of ^（137）Cs are measured by Si（ Li）drift detector. The energy spectrum of β decay is studied by Curie plot and the internal conversion coefficients are obtained from the energy spectrum of internal conversion electron. The obtained maximum energy of β decay for^（137）Cs is（ 513.11±1.76） ke V with an error 0.17% with respect to the reference data and the obtained internal conversion coefficients correspond to K / L = 5.712± 0.217 and M / L = 0.264 ± 0.018 with the errors 0.92% and 1. 54%with respect to the reference data,respectively. Then the transition levels of β and γ decays for^（137）Cs and its decayed daughter nucleus are determined. The spins and parities of^（137）Cs and its daughter nucleus ^（137） Ba are obtained,then the decay scheme of^（137）Cs is plotted. As a result,it is indicated that the experimental technology is credible,and can be used for experimental teaching and study of nuclear structure as well as it can provide the necessary experimental data for nuclear structure.

关 键 词：Β衰变 内转换电子 居里描绘 内转换系数 衰变纲图 

分 类 号：O571.322[理学—粒子物理与原子核物理]