A water-based neutron detector as a well multiplicity counter
A water-based neutron detector as a well multiplicity counter
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作为井多重计数器的水基中子探测器
DOI：
10.1016/j.nima.2014.10.028
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发表时间：
2014
影响因子：
1.4
通讯作者：
V. Mozin
中科院分区：
文献类型：
--
作者：
S. Dazeley;A. Asghari;A. Bernstein;N. Bowden;V. Mozin
报道了一种用于裂变源无损分析的水基中子探测多重数计数器的性能特点。这项技术可以替代或补充现有的基于3He的多重数计数器。计数器是一个1.02立方米的水箱，里面装着掺有0.5%GdCl3的纯去离子水。它有高反光墙和八个10英寸。安装在顶部的PMTS。安装在顶部和中心的直径为19厘米的非屏蔽源井向下延伸73厘米进入探测器。该计数器使用低强度的252Cf和60Co源进行评估，并使用快速脉冲LED来模拟较高强度的背景。在低伽马射线强度(~200kBq或更低)下，我们报道的绝对中子探测效率为28%，a60Co拒绝/抑制因子为~108：1。对于高伽马射线强度的源，中子效率为22%±1%，而60Co当量活度为4kBq。探测器的背景事件率，主要是由于µ子和其他宇宙起源粒子，被发现在近三个月的时间里是稳定的。假设一小时的数据采集，本底以上的最小可探测中子源强度为3.1N/S。
We report the performance characteristics of a water-based neutron detecting multiplicity counter for the non-destructive assay of fissile sources. This technique could replace or supplement existing3He-based multiplicity counters. The counter is a 1.02 m3tank containing pure deionized water doped with 0.5% GdCl3. It has highly reflective walls and eight 10-in. PMTs mounted at the top. An unshielded source well of 19 cm diameter, mounted at the top and center, extends 73 cm down into the detector. The counter was evaluated using low intensity252Cf and60Co sources, and a fast pulsing LED to simulate higher intensity backgrounds. At low gamma ray intensities (~200 kBq or less) we report an absolute neutron detection efficiency of 28% and a60Co rejection/suppression factor of ~108to 1. For sources with high gamma ray intensities, the neutron efficiency was 22%±1% up to a60Co equivalent activity of 4 MBq. The detector background event rate, primarily due to muons and other cosmogenic particles, was found to be stable over a period of almost three months. The minimum detectable neutron source intensity above background was 3.1 n/s, assuming a one-hour data acquisition.