^(79)Se的AMS测量方法研究  

Study on AMS Measurement of ^(79)Se

作　　者：王晓波[1,2] 王伟[3] 何明[1] 管永精[2] 董克君[1] 武绍勇[1] 林德雨[1,2] 谢林波[1,4] 窦亮[1] 姜山[1] 

机构地区：[1]中国原子能科学研究院核物理研究所,北京102413 [2]广西大学物理科学与技术学院,广西南宁530004 [3]中国核工业集团公司,北京100822 [4]厦门大学海洋与地球学院,福建厦门361005

出　　处：《原子能科学技术》2013年第12期2317-2321,共5页Atomic Energy Science and Technology

基　　金：国家自然科学基金资助项目(10805010;41166002;11025313;11175266);广西自然科学基金资助项目(2011GXNSFC018016;2012GXNSFFA060005)

摘　　要：测定79Se时由于79Se尚无标准样品,需要建立79Se/Se(79Se、Se原子个数比,余同)的AMS测量方法。在79Se/Se的绝对测定中,为尽可能避免测量Se的同位素之间的差异,通常利用探测器测量79Se离子,本文用法拉第筒对78Se和80Se进行测量,但这造成两个测量系统之间的系统误差。为避免这种系统误差,利用同一探测器测定79Se、78Se和80Se。考虑到78Se和80 Se的计数率非常高,在CIAE-AMS系统中的静电分析器前和靶室内安装衰减片以降低78Se和80Se的计数率。实验结果表明:通过两个衰减片的衰减作用,能将78Se和80Se的束流降低到半导体探测器的检测范围内,实现了样品中79Se/Se的绝对测定,得到79Se/Se为(2.08±0.10)×10-7,为准确测定79Se半衰期奠定了基础。As there is no 79 Se standard sample for measurement of 79 Se, the characteriza- tions of r9Se are conducted by isotope ratio of 78Se/Se or 8＋Se/Se since the abundances of 78Se and 80Se are well known. However, beams of 78Se and 80Se both exceed the upper limit of semiconductor detector resulting in measurement failure. As a result, attenua tors were introduced into the CIAE-AMS system with the aim to measure the 79 Se. The results indicate that the beam of 78Se and 89Se is decreased into the detecting range of semiconductor detector by two attenuators, which would improve measurement sensitivity and efficiency significantly. In addition, the uncertainty of measurement is reduced greatly and it lays the foundation for the accuracy measurement of the half life of 79Se.

关 键 词：加速器质谱79Se测量 衰减片 半导体探测器 

分 类 号：TL817.4[核科学技术—核技术及应用]