Statistical estimation of the performance of a fast-neutron multiplicity system for nuclear material accountancy
Statistical estimation of the performance of a fast-neutron multiplicity system for nuclear material accountancy
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用于核材料衡算的快中子多重系统性能的统计估计
DOI：
10.1016/j.nima.2014.09.027
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发表时间：
2015
影响因子：
1.4
通讯作者：
S. Pozzi
中科院分区：
文献类型：
--
作者：
D. Chichester;S. Thompson;M. Kinlaw;James T. Johnson;J. Dolan;M. Flaska;S. Pozzi
已进行统计分析，以开发的概念快中子多重性系统（FNMS）的预期性能的边界估计，用于分析钚。FNMS的概念设计包括32个立方体液体闪烁体探测器，每边测量7.62厘米，配置成4个堆叠环，每个环有8个探测器。根据先前的验证实验，使用蒙特卡罗模拟确定了单个FNMS检测器的预期响应特性以及整个FNMS的响应特性。这些模拟的结果，然后被用来估计钚测定能力的FNMS的计数时间，测定质量，和测定质量方差，使用测定质量方差作为一个因素的优点。分析结果与常用的热中子符合计数器进行了比较。与热中子计数系统相比，使用快中子计数系统的优点是显著的。最值得注意的是，由于快速系统随机求和的概率降低，与热中子系统相比，快速中子系统大大减少了进行等效分析质量方差的分析所需的时间，减少了一个数量级以上。改进的FNMS性能对于涉及10 g或更大的Pu质量的测定特别相关。
Statistical analyses have been performed to develop bounding estimates of the expected performance of a conceptual fast-neutron multiplicity system (FNMS) for assaying plutonium. The conceptual FNMS design includes 32 cubic liquid scintillator detectors, measuring 7.62 cm per side, configured into 4 stacked rings of 8 detectors each. Expected response characteristics for the individual FNMS detectors, as well as the response characteristics of the entire FNMS, were determined using Monte Carlo simulations based on prior validation experiments. The results from these simulations were then used to estimate the Pu assay capabilities of the FNMS in terms of counting time, assay mass, and assay mass variance, using assay mass variance as a figure of merit. The analysis results are compared against a commonly used thermal-neutron coincidence counter. The advantages of using a fast-neutron counting system versus a thermal-neutron counting system are significant. Most notably, the time required to perform an assay to an equivalent assay mass variance is greatly reduced with a fast-neutron system, by more than an order of magnitude compared with that of the thermal-neutron system, due to the reduced probability of random summing with the fast system. The improved FNMS performance is especially relevant for assays involving Pu masses of 10 g or more.