【摘要】 设计了一套新型低本底α/β测量系统。该系统采用ZnS（Ag）薄板复合塑料闪烁体作为主探测器,平板形塑料闪烁体作为反符合探测器,实现样品中总α和总β的同时测量。利用ARM架构的MCU作为系统运行核心,FPGA硬件电路作为数据采集单元,基于脉冲宽度甄别方法实现测量系统的α/β脉冲甄别。对该系统进行了主要性能测试,测试结果表明:测量α粒子时,本底为0.003 min^-1·cm^-2,对²³⁹Puα标准平面源的探测效率为92.5%,α对β道的串道比为0.87%;测量β粒子时,本底为0.072 min^-1·cm^-2,对⁹⁰Sr-⁹⁰Yβ标准平面源的探测效率为62.0%,β对α道的串道比为0.03%。更多还原

【Abstract】 A new low background α/β measurement system was designed. The system uses ZnS（Ag） thin plate composite plastic scintillator as the main detector, and the flat plastic scintillator as the anti-coincidence detector to achieve simultaneous measurement of total α and total β in the same sample. The MCU of the ARM architecture is used as the core of the system, and the FPGA hardware circuit is used as the data acquisition unit to realize the α/β pulse discrimination based on the pulse width discrimination method. The main performance test of the system was carried out. The experiment result shows that for α particles, the background is 0.003 min^-1·cm^-2, and the detection efficiency of the ²³⁹Pu α standard plane source is 92.5%. The cross-channel ratio of α-to-β channel is 0.87%; for β particles, the background is 0.072 min^-1·cm^-2, the detection efficiency for the ⁹⁰Sr-⁹⁰Y β standard plane source is 62.0%, and the cross-channel ratio of β-to-α is 0.03%.更多还原