Performance optimization of scintillator neutron detectors for EMD in CSNS  

作　　者：蔡小杰 于潜 黄畅 唐彬 周诗慧 王小胡 岳秀萍 孙志嘉 Xiaojie Cai;Qian Yu;Chang Huang;Bin Tang;Shihui Zhou;Xiaohu Wang;Xiuping Yue;Zhijia Sun(Spallation Neutron Source Science Center,Dongguan 523803,China;Southwest University of Science and Technology,Mianyang 621002,China;Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China;Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology,Center for Advanced Material Diagnostic Technology,and College of Engineering Physics,Shenzhen Technology University,Shenzhen 518118,China)

机构地区：[1]Spallation Neutron Source Science Center,Dongguan 523803,China [2]Southwest University of Science and Technology,Mianyang 621002,China [3]Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China [4]Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China [5]Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology,Center for Advanced Material Diagnostic Technology,and College of Engineering Physics,Shenzhen Technology University,Shenzhen 518118,China

出　　处：《Chinese Physics B》2023年第11期207-213,共7页中国物理B(英文版)

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos. 11975255 and 11875273);Guangdong Basic and Applied Basic Research Foundation (Grant No. 2020B1515120025)。

摘　　要：Chinese Spallation Neutron Source(CSNS) has successfully produced its first neutron beam in 28th August 2017. It has been running steadily from March, 2018. According to the construction plan, the engineering materials diffractometer(EMD) will be installed between 2019–2023. This instrument requires the neutron detectors with the cover area near3 m2in two 90° neutron diffraction angle positions, the neutron detecting efficiency is better than 40%@1A, and the spatial resolution is better than 4 mm×200 mm in horizontal and vertical directions respectively. We have developed a onedimensional position-sensitive neutron detector based on the oblique6Li F/Zn S(Ag) scintillators, wavelength shifting fibers,and Si PMs(silicon photomultipliers) readout. The inhomogeneity of the neutron detection efficiency between each pixel and each detector module, which caused by the inconsistency of the wave-length shifting fibers in collecting scintillation photons, needs to be mitigated before the installation. A performance optimization experiment of the detector modules was carried out on the BL20(beam line 20) of CSNS. Using water sample, the neutron beam with Φ5 mm exit hole was dispersed related evenly into the forward space. According to the neutron counts of each pixel of the detector module, the readout electronics threshold of each pixel is adjusted. Compared with the unadjusted detector module, the inhomogeneity of the detection efficiency for the adjusted one has been improved from 69% to 90%. The test result of the diffraction peak of the standard sample Si showed that the adjusted detector module works well.

关 键 词：scintillator neutron detector silicon photomultipliers wavelength shifting fiber LiF/ZnS scintil-lator detection efficiency inhomogeneity 

分 类 号：O571.53[理学—粒子物理与原子核物理]