摘要
微小角中子散射谱仪是中国散裂中子源(China spallation neutron source,CSNS)工程目前在建的谱仪之一,为了实现微小角散射模式下中子衍射的精确测量,要求中子探测器的位置分辨≤2 mm、探测效率≥60%@0.4 nm。在此物理精度需求下,研制了基于^(6)LiF/ZnS(Ag)闪烁屏、波移光纤阵列和硅光电倍增管(Silicon Photomultiplier,SiPM)结构的位置灵敏型闪烁体探测器,以实现热中子的高效率和高分辨实时探测。探测效率测试以标准3He管的入射中子数归一化计算得到,位置分辨通过含有“CSNS”字样的含硼铝板验证。本文详细研究了0.5 mm直径波移光纤的光传输性能,对比了不同硅光电倍增管的增益和热噪声特性,并以此设计了有效面积为300 mm×300 mm的探测器工程样机。经测试,该探测器的位置分辨为1.2 mm×1.2 mm,探测效率为(61.8±0.2)%@0.4 nm,达到了工程设计指标,满足了CSNS工程微小角谱仪的中子衍射测量需求。
[Background]The very small-angle neutron scattering(VSANS)spectrometer is currently being constructed at the China spallation neutron source(CSNS).The neutron detector plays a key role in meeting the detection requirements of the spectrometer.[Purpose]This study aims to achieve accurate measurement of neutron diffraction in the small angle scattering mode which requires the position resolution of the neutron detector to be≤2 mm,and the detection efficiency to be≥60%@0.4 nm.[Methods]A large-area position-sensitive neutron scintillator detector mainly composed of ^(6)LiF/ZnS(Ag)scintillation screen,wavelength shift fiber(WLSF),and a silicon photomultiplier(SiPM)was designed and developed to achieve high efficiency and high-resolution real-time detection of thermal neutrons.The optical transmission performance of the 0.5-mm-diameter wavelength shift fiber was investigated in detail.The gain and the thermal noise characteristics of various SiPMs were examined.Finally,a 300 mm×300 mm engineering prototype of the detector was developed and tested by experiments.The detection efficiency was calculated with comparison of the incident neutron counts of the stander 3He tube whilst the detector's position resolution was tested using a boron-doped aluminum plate with a narrow slit bearing the label'CSNS'.[Results]The neutron beam test results show that the position resolution of the detector is 1.2 mm×1.2 mm and that the neutron detection efficiency is(61.8±0.2)%@0.4 nm.[Conclusions]The high-resolution neutron scintillator detector developed in this study satisfies the engineering design target,and meets the neutron scintillator detector meets the neutron diffraction measurement needs for the VSANS spectrometer of the CSNS.
作者
刘慧银
杨洁
黄畅
唐彬
周诗慧
蔡小杰
王修库
曾莉欣
岳秀萍
陈少佳
许虹
郭大威
陈旭
孙志嘉
LIU Huiyin;YANG Jie;HUANG Chang;TANG Bin;ZHOU Shihui;CAI Xiaojie;WANG Xiuku;ZENG Lixin;YUE Xiuping;CHEN Shaojia;XU Hong;GUO Dawei;CHEN Xu;SUN Zhijia(Zhengzhou University,Zhengzhou 450001,China;Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;Spallation Neutron Source Science Center,Dongguan 523803,China)
出处
《核技术》
EI
CAS
CSCD
北大核心
2024年第2期66-75,共10页
Nuclear Techniques
基金
国家自然科学基金(Nos.11975255,11875273)
广东省基础与应用基础研究基金(Nos.2020B1515120025,2022B1515120071)资助。
关键词
闪烁体探测器
硅光电倍增管
波移光纤
位置分辨
探测效率
Neutron scintillator detector
Silicon photomultiplier
Wavelength shift fiber
Position resolution
Detection efficiency
