A thermal neutron detection system based on boron-coated straw detector with prompt gamma coincidence
A thermal neutron detection system based on boron-coated straw detector with prompt gamma coincidence
复制标题
基于硼涂层秸秆探测器的瞬发伽马符合热中子探测系统
DOI：
10.1088/1748-0221/17/09/p09021
复制
发表时间：
2022
影响因子：
1.3
通讯作者：
Tuchen Huang
中科院分区：
文献类型：
--
作者：
Yongyu Pan;Fengzhao Shen;Qibin Fu;Tuchen Huang
抽象的。中子注量率的准确测量对于地下实验室中的稀有事件搜寻实验至关重要。探测器的本征放射性本底成为探测极低中子注量率的限制因素。本研究以硼涂吸管（BCS）中子探测器为基础，研制了一套用于低通量测量的热中子探测系统。通过中子和瞬发γ射线的符合测量，可以区分中子事件和探测器本底。采用最先进的BCS中子探测器和NaI（Tl）γ探测器，系统灵敏度达到120 cps/cm ~ 2，与常用的~ 3 He计数器相当。根据选定的符合标准，本底事件被拒绝到0.1%，保留45.3%的中子。系统的本底偶然符合计数率为2.3×10- 5cps，对应的可测热中子注量下限为1.9×10-7 n/cm ~ 2/s。系统的性能可以通过使用具有较低中子吸收的其他伽马闪烁体（例如BGO）和增加对环境伽马射线的额外屏蔽来进一步改善。
Abstract. Accurate measurement of the neutron flux is of crucial importance for rare event search experiments in underground laboratories. The intrinsic radioactive background of the detector becomes the limiting factor for the detection of extremely low neutron flux. In this study, a thermal neutron detection system aimed at low flux measurement was developed based on boron-coated straw (BCS) neutron detectors. The neutron events can be distinguished from the detector background by coincidence measurement of neutron and the prompt gamma ray. With state-of-the-art BCS neutron detectors and NaI(Tl) gamma detector, a system sensitivity of ∼120 cps/nv was achieved, comparable to that of the commonly used 3He counters. Based on the selected coincidence criteria, the background events were rejected to 0.1% with 45.3% of the neutrons preserved. The background accidental coincidence count rate of the system was measured as 2.3×10-5 cps, corresponding to a lower limit of measurable thermal neutron flux of 1.9×10-7 n/cm2/s. The performance of the system can be further improved by using other gamma scintillator with lower neutron absorption (such as BGO) and adding extra shielding for ambient gamma rays.