基于塑料闪烁体的两级中子源散射相机技术研究

Neutron source imaging can be used in anti-terrorism, nuclear meterial monitoring and some other fields. Bad position resolution or energy resolution of existing neutron source imaging systems and cross-talk caused by multi-neutrons from neutron source result an low quality image of neutron source. In this application, position, time and deposited energy information are measured when a neutron from neutron source hits on plastic scintillator. Algorithms of neutron cross-talk identification,neutron spectrum and neutron source image rebuilding which are devoted to the neutron source imaging would be suggested based on the research of neutron scattering with palstic scintillator.. These algorithms are verified with the Geant4 simulation. Influences from position,time,energy resolution, neutron energy, configuration of detectors on neutron source image are investigated quantitatively, which is used for the optimization of these algorithms and detector system.. Detector system will be designed based on the reasonable detectors and optimized algorithms.experiments on plastic scintillators will be carried out to handle the accurate measurement of position, time and energy. Detector system, electronic and DAQ will be established to measure the neutron source and get an image of it.. The methods of neutron source imaging is expected to be handled through this project.

中子源成像技术在反恐、核材料监测等领域有着较好的应用前景。现有中子源成像系统的位置分辨或能量分辨不甚理想，也没有考虑对双中子的串扰排除，从而限制了成像质量。本课题力图使用两块塑料闪烁体，来较精确的测量中子在闪烁体上被探测到时的位置，时间和能量信息。深入研究中子散射成像原理，提出中子能谱重建、双中子认定及中子源图像重建算法，实现中子源的散射成像。在GEANT4的仿真模拟环境下对上述算法进行技术验证。研究位置、能量及时间分辨能力、入射中子能量和探测系统几何构型及其他物理参数对探测效率、能谱重建、双中子判定及中子图像重建等的定量影响，迭代优化上述算法。提出测量参数合理优化的探测系统设计方案。选定实验所需要的探测器，搭建测试平台，掌握位置、能量和时间精确测量的方法。构建成像系统，在中子源场中进行中子源图像实验。预期通过本课题的研究，掌握中子源图像重建技术。