自研塑料闪烁体探测器中子/γ甄别能力测试  

Neutron/gamma discrimination performance test for self-developed plastic scintillation detectors

作　　者：宋云 左晶鑫 梁勇飞[1] 韩冰[1] 白立新[1] 杨朝文[1] SONG Yun;ZUO Jingxin;LIANG Yongfei;HAN Bing;BAI Lixin;YANG Chaowen(School of Physics,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学、物理学院,成都610065

出　　处：《核技术》2023年第3期59-66,共8页Nuclear Techniques

基　　金：国家自然科学基金(No.U1967205)资助。

摘　　要：塑料闪烁体在中子探测领域具有重要应用前景。对于自研两种尺寸(?2.54 cm×2.54 cm、?5.08 cm×5.08 cm)的塑料闪烁体进行了测试。采用光电倍增管(Photomultiplier Tube,PMT)搭建了探测系统,利用高速示波器采集功能对自研塑料闪烁体进行能量刻度,通过测量^(137)Csγ放射源的脉冲幅度谱并与MCNP5模拟谱对比,以获取康普顿边缘位置信息,实现准确的γ射线能量标定。利用电荷积分法对从241Am-Be中子源上获取的数据进行分析,采用品质因子(Figure Of Merit,FOM)、中子峰谷比、中子漏计数率等参数量化不同能区的n-γ甄别效果,对比自研塑料闪烁体相对于EJ-299-33A的探测效率。结果表明:?2.54 cm×2.54 cm自研塑料闪烁体相比于?5.08 cm×5.08 cm自研塑料闪烁体具有较高的FOM值;两种自研塑料闪烁体相对于EJ-299-33A的探测效率分别约为0.49和1.0,可见自研的?5.08 cm×5.08 cm塑料闪烁体与同尺寸的商用塑料闪烁体EJ-299-33A性能相当。[Background]Plastic scintillators have potential for application in neutron detection.Two sizes(ø2.54 cm×2.54 cm,ø5.08 cm×5.08 cm)of plastic scintillators are self-developed by scientific research team in the school of physics,Sichuan University.[Purpose]This study aims to experimental test the neutron/gamma(n-)discrimination performance for two self-developed plastic scintillators.[Methods]A photomultiplier tube(PMT)was used to build detection systems,and high speed oscilloscope(LECROY HDO6104A)was employed to sample signal of detector for the energy calibration of the self-developed plastic scintillator.The pulse amplitude spectrum of ^(137)Csγradiation source was measured and compared with the MCNP5 simulation spectrum to obtain the position information of the Compton edge and accurately calibrate the energies ofγrays.The data obtained from a 241Am-Be neutron source were analyzed using the charge integration method,and parameters such as the figure of merit(FOM),peak-to-valley ratio for neutrons,and the proportion of leaked neutrons over all neutron events were used to quantify the n-γdiscrimination in different energy zones.The detection efficiencies of two self-developed plastic scintillators relative to the Commercial off-the-Shelf(COTS)EJ-299-33A were determined.[Results]The results show that the FOM ofø2.54 cm×2.54 cm self-developed plastic scintillator is higher that ofø5.08 cm×5.08 cm self-developed plastic scintillator,and the detection efficiency of two self developed plastic scintillators relative to EJ-299-33A is about 0.49 and 1.0,respectively.[Conclusions]The performance of theø5.08 cm×5.08 cm self-developed plastic scintillator is comparable to that of the COTS plastic scintillator EJ-299-33A with near the same discrimination ability.

关 键 词：塑料闪烁体 能量标定 中子/γ甄别 甄别能力量化 

分 类 号：TL812.1[核科学技术—核技术及应用]