塑料闪烁体的闪烁时间特性

摘要

Background: The plastic scintillator is mostly used for the inertia confinement fusion determination systems. It is necessary to know the scintillator decay time.Purpose:The aim is tomeasure the decay time of the plastic scintillator and analyze the applicability of single photon method.Method:The plastic scintillator is excited by137Cs, and the decay time of the plastic scintillator is measured by single photon method. The ST401 and EJ232 plastic scintillators are measured by this device. The theory of single photon method is analyzedvia statistics and the measurement process is simulated by Monte Carlo method.Results:The results are 2.9 ns with 50 ns for ST401 and 1.6 ns with 30 ns for EJ232via double exponential fitting. The device has a dynamic range of over 104 and an intrinsic time resolution under 0.8 ns. The experiment result agrees to the simulated one.Conclusion:The comparison between the experiment result and the simulation result indicates that with the mean counts of stop detector no more than 0.1, the result measured by single photon method can be approximated to the decay time of plastic scintillator.%采用137Cs激发塑料闪烁体发光，应用单光子计数法测量塑料闪烁体发光衰减曲线。根据测量原理搭建了实验平台，测量了ST401和EJ232两种闪烁体的闪烁时间特性。实验结果用双指数拟合法进行分析可得， ST401发光衰减常数为2.9 ns和50 ns，EJ232发光衰减常数为1.6 ns和30 ns。实验平台所测幅度动态范围大于104，时间分辨小于0.8 ns。从统计学分析单光子计数法的物理过程，并采用蒙特卡罗方法模拟整个探测过程，探讨单光子计数法的适用条件。实验结果与数值模拟结果相洽。若终止探测器平均探测到的光子数不大于0.1，则多道测量结果可以近似为塑料闪烁体发光衰减曲线。