一种塑料闪烁体建模与仿真研究方法

A Research Method of Modeling and Simulation of Plastic Scintillator Detector

辐射粒子探测器是对空间辐射环境进行探测的工具。为了更好地评估塑料闪烁体探测器,针对辐射粒子输运问题,采用蒙特卡罗方法对辐射粒子输运方程进行数值模拟求解,在Geant4软件平台的基础上进行二次开发,从而实现了对塑料闪烁体中粒子输运过程的模拟。该程序根据需求对探测器参数进行定义,从而实现不同条件下粒子相互作用和闪烁光输运过程的仿真研究,并能扩展入射粒子的种类、能量等。利用开发的Pl_Sc软件程序对电子和γ入射塑料闪烁体的过程进行模拟分析,并与前人的研究成果和理论分析进行对比,验证了通过此程序进行模拟的可行性,特别是降低了对电子射程的模拟的误差;通过对入射粒子、闪烁体尺寸等变量进行变更,演示了此程序的易用性。对中能电子在EJ200塑料闪烁体中沉积能量的模拟研究表明,电子沉积能量分布可以较好地反映入射的单能电子能量,并符合理论预测;对能量为4 MeV的γ的能量沉积谱的仿真研究表明,在本文研究的能量范围内γ能量沉积谱的康普顿边缘较明显,多次康普顿散射和累计效应的影响不明显,为实际探测中通过观测到的康普顿边缘计算入射γ光子能量提供了技术积累。

The radiation particle detector is a tool for detecting the radiation environment in space.In order to evaluate the plastic scintillator detector better,aiming at the radiation particle transport problem,Monte Carlo method is used to solve the radiative particle transport equation,and the secondary development is carried out on the basis of Geant4 software platform.Thus,the simulation of particle transport process in plastic scintillator is realized.The program defines the detector parameters according to the requirements so as to realize the simulation research of particle interaction and scintillation light transport process under different conditions,and it can also expand the type and energy of incident particles.The process of electron and γ incident on the plastic scintillator is simulated and analyzed by using the developed Pl_Sc software program.And by comparing it with previous research results and theoretical analysis,the feasibility of simulation by this program is verified,especially the simulation error of electron range is reduced.And the usability of this program is demonstrated by changing the size of incident particles and scintillator.The simulation study on the deposition energy of medium energy electrons in EJ-200 plastic scintillator shows that the energy distribution of electron deposition can fairly reflect the energy of single energy incident electron,and conform to the theoretical prediction.And the simulation study on the energy deposition spectrum of 4 MeV γ shows that the Compton edge of the γ energy deposition spectrum in the energy range studied in this paper is obvious,multiple Compton scattering and accumulation effect is not obvious,which provides a technical accumulation for calculating the energy of incident gamma photons through the Compton edge observed in the actual detection.