k_0-NAA相关核参数(^(97)Zr半衰期)的精确测定

Determination of k_0-related nuclear parameters-precise determination of ^(97)Zr half-life

以三种不同脉冲处理原理的测量系统测定了用于k0-NAA中热/超热中子注量率比计算的97Zr半衰期。结果为(16.755±0.013)h。澄清了目前国际上常用的两个值16.744h和16.90h之间的分歧。对使用不同测量系统时各种死时间校正方法的有效性进行了评价。对放射性强度跨越1000倍动态范围(10个半衰期)的跟踪测量中影响相对峰计数率精确测定的因素进行了讨论。

The half-life of ^97Zr, used for the calculation of thermal/epithermal neutron flux ratio in k0-NAA, is re-determined using three measurement systems with different pulse processing principles. The result of （16.755±0.013） h clarifies the discrepancy between two widely used literature values, （16.744±0.011） h and （16.90±0.05） h. Different dead-time correction methods used on various measurement systems are evaluated. Factors influencing precise measurement of relative peak counting rates are discussed in time-series measurements over a dynamic range of 1000-fold radioactive intensities （10 half-lives）.