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 material...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.展开更多
为了给强脉冲辐射场中应用超快闪烁探测器进行精密物理测试以及相关晶体抗核加固提供实验测量数据参考,针对近年新研制的Yb∶YAG超快无机闪烁体与GD40光电管构成的快闪烁探测器,在源强近万居的强稳态辐照场中,细致测量了辐射累计伽马剂...为了给强脉冲辐射场中应用超快闪烁探测器进行精密物理测试以及相关晶体抗核加固提供实验测量数据参考,针对近年新研制的Yb∶YAG超快无机闪烁体与GD40光电管构成的快闪烁探测器,在源强近万居的强稳态辐照场中,细致测量了辐射累计伽马剂量从约1 Gy开始到最高约1 k Gy全过程中Yb∶YAG超快闪烁探测器输出电流的变化数据;在测点注量率大于1017cm-2·s-1的"强光一号"短γ脉冲辐射场中,测量了Yb∶YAG超快闪烁探测器输出脉冲波形响应情况。实验测量结果表明:在强稳态辐射场情况下,对应累计剂量5~10Gy时,YAG(Yb)闪烁探测器灵敏度下降约5~10%(相对辐照1 Gy时的情况);测点累计伽马剂量约1 k Gy时,Yb∶YAG超快闪烁探测器的电流输出与约1 Gy时的比值约50%;短γ脉冲辐射情况下,测点累计注量约4×109cm-2,Yb∶YAG超快闪烁探测器输出电流约1 A时,灵敏度下降约10%(相对累计注量约3×109cm-2的情况),当测点注量大于1010cm-2(累积剂量超过100 m Gy),Yb∶YAG超快闪烁探测器会出现较明显的损伤现象。展开更多
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)。
文摘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.
文摘为了给强脉冲辐射场中应用超快闪烁探测器进行精密物理测试以及相关晶体抗核加固提供实验测量数据参考,针对近年新研制的Yb∶YAG超快无机闪烁体与GD40光电管构成的快闪烁探测器,在源强近万居的强稳态辐照场中,细致测量了辐射累计伽马剂量从约1 Gy开始到最高约1 k Gy全过程中Yb∶YAG超快闪烁探测器输出电流的变化数据;在测点注量率大于1017cm-2·s-1的"强光一号"短γ脉冲辐射场中,测量了Yb∶YAG超快闪烁探测器输出脉冲波形响应情况。实验测量结果表明:在强稳态辐射场情况下,对应累计剂量5~10Gy时,YAG(Yb)闪烁探测器灵敏度下降约5~10%(相对辐照1 Gy时的情况);测点累计伽马剂量约1 k Gy时,Yb∶YAG超快闪烁探测器的电流输出与约1 Gy时的比值约50%;短γ脉冲辐射情况下,测点累计注量约4×109cm-2,Yb∶YAG超快闪烁探测器输出电流约1 A时,灵敏度下降约10%(相对累计注量约3×109cm-2的情况),当测点注量大于1010cm-2(累积剂量超过100 m Gy),Yb∶YAG超快闪烁探测器会出现较明显的损伤现象。
