宇宙线缪子散射成像模拟与算法研究

本文验证了基于Micromegas探测器的宇宙线缪子散射成像系统进行快速核材料检测的可行性，并对实验室宇宙线缪子成像系统原型进行参数估算。基于Geant4程序开发了用于模拟宇宙线缪子物理过程、传输径迹及Micromegas探测器响应的模拟程序。在模拟数据的基础上，实现并改进了两种主要的宇宙线缪子散射成像算法。根据模拟和成像结果，1 m×1 m成像系统可在10 min内检测到被重元素屏蔽的核材料。10 cm×10 cm成像系统的缪子事例触发率为0.16 s^-1，要获得较为清晰的成像结果，要求探测器位置分辨率达到300 μm，探测器增益为1 000时实际测量事例至少需要20 h。

Research on Cosmic Ray Muon Scattering Tomography Simulation and Imaging Algorithm

The feasibility of rapid nuclear material inspection with cosmic ray muon scattering tomography system based on Micromegas detector was verified, and essential parameters of the laboratory cosmic ray muon tomography system prototype were estimated. A simulation program based on Geant4 simulation toolkit was developed to simulate the physical processes and propagation tracks of cosmic ray muons, and responses of Micromegas detector to cosmic ray muons. Based on the simulation data, two main cosmic ray muon scattering tomography algorithms were implemented and improved. According to the simulation and imaging results, the tomography system of 1 m×1 m size is able to inspect nuclear materials shielded by heavy elements within 10 min. The tomography system of 10 cm×10 cm size is estimated to have a trigger rate of 0.16 s^-1. To obtain a clearer imaging result from the 10 cm×10 cm tomography system, the detector position resolution needs to reach 300 μm, and the actual measurement time needs to be at least 20 h with the detector gain of 1 000.