金属铀部件235U富集度中子时间关联符合测量实验优化分析

摘要

金属铀部件235U富集度中子时间关联符合测量实验采用252Cf源驱动噪声分析法来获得金属铀部件的标签参数——源与探测器间的中子时间关联符合计数,用于相同几何、不同富集度的金属铀部件间的识别.本文对该实验进行了蒙特卡罗数值模拟,模拟计算结果表明,直穿布局下泄漏中子不能得到利用,且探测中子能量区间的选择会影响测量效果.根据实验布局和探测中子能量区间,对实验进行添加含氢反射层布置优化,方案优化后的实验模拟计算和测量结果均表明,优化实验方案提高了该测量方法对相同几何、不同富集度金属铀部件的识别能力.%To identify metal uranium components with same geometry but different enrichments, 252Cf source-driven noise analysis method was used to measure neutron time correlation coincidence counts between 252Cf source and detector (the label data). Monte-Carlo simulation of the measurement shows that, under experimental configuration without any shield, the neutrons that leak out from uranium component completely can not be used, and the choice of measured energy span for neutrons will affect experiment result. Based on above two points, optimizations for the measurement were made. Results of simulation and experiment under optimized configuration finally show that optimizations on the measurement improve the result of measurement.