主动中子多重性质询方法是核保障的重要手段,其过程复杂,质询结果准确性受多种因素影响.文章通过蒙特卡罗方法,研究基于超热中子多重计数器(ENMC)的主动中子多重性质询影响因素,为准确测量提供理论及数据支撑.通过对比统计耦合系数与标定C-M方程获取耦合系数两种方法获得的核材料质量差异,证明标定的探测效率及衰减时间偏差都会通过C-M方程的引入进一步传递而增大,尤其是当探测效率相差1%时,质询结果相对偏差约为9%.质询源强度与门宽都对质询结果有影响,源越强,门宽的影响越大,随着源强的增加最佳门宽逐渐减小,且减小的速率逐渐变缓,当R+A 门内时间相关中子占比大于3%时,质询结果相对偏差较为稳定.
Active neutron multiplicity is an important means of nuclear safeguard.Its process is complex and the accuracy of inquiry result is affected by many factors.In this paper,the Monte Carlo method is used to study the influence factors of active neutron multiplicity based on the epithermal neutron multiplicity counter(ENMC),which provides theoretical and data support for accurate measurement.By comparing the statistical coupling coefficient and the calibration C-M equation to obtain the coupling coefficient,the calibration detection efficiency and decay time deviation will be further transmitted by the introduction of the C-M equation,especially when the detection efficiency difference is 1%,the relative deviation of inquiry results is about 9%.Both the source strength and gate width have an impact on the inquiry results.The stronger the source is,the greater the impact of gate width is.With the increase of source strength,the optimal gate width gradually decreases,and the reduction rate gradually slows down.When the proportion of time-dependent neutrons in the R+A gate is greater than 3%,the relative deviation of the mass inquiry results is relatively stable.