塑料闪烁光纤阵列探测器的结构设计

Structure Design of Plastic Scintillation Fiber Array Detector

具有多层阵列结构的塑料闪烁光纤探测器可实现土壤中^(90)Sr含量的直接、快速测量,闪烁光纤阵列结构和信号处理方式是提高^(90)Sr含量测量精度和抗γ射线干扰能力的关键参数。本文利用蒙特卡罗方法对探测器建模和计算,优化了探测器的结构。推荐的闪烁光纤阵列探测器为5层结构,第4层为厚度不小于6mm的聚甲基丙烯酸甲酯(PMMA)吸收层,其他层为厚度1mm的双涂层方形塑料闪烁光纤阵列。第1～3层信号符合后输出,可提高探测器对γ射线的甄别能力。

A plastic scintillation fiber detector with a multi-layer array structure could be used for the direct and rapid determination of 90Sr in soil.The measuring accuracy and the resistance toγ-ray interference of the detector depend on the specific structure design and signal processing mode.The structure of the detector was optimized by modeling and simulation using the Monte Carlo method.The recommended scintillation fiber array is composed of five layers.The fourth layer is the polymethyl methacrylate（PMMA）absorbing layer whose thickness is no less than 6 mm,while the other layers are two-clad square plastic scintillation fiber array with a thickness of 1 mm.Theγdiscrimination is improved by the coincidence of the signals from the first three layers.