双端读出提高快中子探测器时间分辨率方法的研究  

Temporal Resolution Optimization of Fast Neutron Detector Using Dual-Ended Readout Method

作　　者：张翱 孙世峰 张翔铭 欧阳晓平[2] ZHANG Ao;SUN Shifeng;ZHANG Xiangming;OUYANG Xiaoping(School of Nuclear Science and Engineering,North China Electric Power University,Beijing 102206,China;Northwest Institute of Nuclear Technology,Xi’an 710024,China)

机构地区：[1]华北电力大学核科学与工程学院,北京102206 [2]西北核技术研究所,西安710024

出　　处：《现代应用物理》2024年第5期11-16,共6页Modern Applied Physics

基　　金：抗辐照应用技术创新中心资助项目(KFZC2021020302)

摘　　要：对特殊核材料等进行无损检测时,快中子探测器的时间分辨率对系统的成像时间和图像质量等方面具有重要影响。提高时间分辨率的主要困难在于无法精准测量入射中子与物质相互作用深度(depth of interaction,DOI)。为了减小DOI效应对快中子探测的影响,利用Geant4模拟软件构建了基于塑料闪烁体的双端读出快中子探测器模型,系统地研究了闪烁体厚度对探测器时间分辨率性能的影响。在此基础上,提出了平均两端定时和重建中子作用点2种提高时间分辨率的方法。研究结果表明,这2种校准方法均能降低DOI测量不准确对快中子探测产生的影响,提高快中子探测器的时间分辨率。对于厚度为100 mm的闪烁体探测器,利用重建中子作用点法对光电倍增管(photomultiplier tube,PMT)定时补偿后,探测器的时间分辨率由(1030±5)ps提高到(612±2)ps。When performing non-destructive testing of special nuclear materials,the temporal resolution of fast neutron detectors has a significant effect on the imaging time and image quality of the system.The main difficulty in improving the temporal resolution is the inability to accurately measure the depth of interaction(DOI)of the incident neutrons.To reduce the influence of DOI effect on fast neutron detection,a fast neutron detector model based on plastic scintillator is constructed by using Geant4 software.The influence of scintillator thickness on performance of temporal resolution is systematically investigated.On this basis,two methods to improve the temporal resolution are proposed,namely,averaging two-end timing and reconstructing the neutron action point.The results show that both calibration methods can reduce the effect of DOI measurement inaccuracy in fast neutron detection and improve the temporal resolution of fast neutron detectors.For a 100 mm scintillator detector,the temporal resolution is improved from(1030±5)ps to(612±2)ps after the reconstructed neutron action point is compensated for PMT timing compensation.

关 键 词：快中子探测 相互作用深度 时间分辨率 双端读出 位置重建 

分 类 号：TL812[核科学技术—核技术及应用] O571[理学—粒子物理与原子核物理]