基于CLYC闪烁体的空间中子能谱测量方法研究

Space neutron which produced by cosmic showers, is one of the main radiation hazards which threaten the safety of astronauts and spacecraft. The real-time monitoring of space neutron spectra is an urgent problem in space exploration. The existing methods have the features of offline measurement, narrow energy-range response, poor particle identification capacity and complex structure. Hence, this project studies a new method for space neutron spectra measurement with the newly developed CLYC scintillator. Based on the simulation works and established CLYC detector in the pre-research, a multi-particle identification method is obtained by combing a veto detector with pulse shape discrimination; CLYC’s responses to monoenergetic neutrons are analyzed by Monte Carlo simulation and experimental measurement; the genetic algorithm and the least square algorithm are used to reconstruct the energy spectrum with the established response matrix; and ultimately, the suitability of the CLYC detector for space neutron detection is testing in the simulated space environment with the key factors of temperature, thermal vacuum, vibration, etc.. This project applies a new material and a new method to fix the problem of onboard monitoring of space neutron spectra, and thus facilitate the development of China's space exploration.

空间中子由初级宇宙射线簇射产生，是危害宇航员与航天器安全的主要辐射之一。有效、实时地监测空间中子能谱是目前空间探索亟需解决的技术难题。针对目前已有测量手段存在非实时监测、能区响应窄、粒子甄别差、结构复杂等问题，本项目提出基于Cs2LiYCl6:Ce3+(CLYC)闪烁体的空间中子能谱测量方法，在物理方案和探测器预研基础上，结合符合探测器与脉冲波形甄别建立多粒子甄别方法；通过模拟和实验分析中子在CLYC中的响应物理模型；建立宽能区单能中子响应矩阵，联立遗传算法和最小二乘算法开展能谱重建方法研究；最后开展空间环境(温度、热真空、震动等因素)影响测试研究，评价探测器空间环境适用性。本项目拟将新型探测材料和智能优化算法应用到宽能区中子探测和能谱重建中，解决卫星、空间站等空间环境下的中子辐射监测难题，进而助力我国空间探索事业的发展。

空间中子是危害宇航员与航天器安全的主要辐射之一。有效、实时地监测空间中子能谱是目前空间探索亟需解决的技术难题。针对目前已有测量手段存在非实时监测、能区响应窄、粒子甄别差、结构复杂等问题，本项目提出了基于CLYC闪烁体的空间中子能谱测量方法，结合符合探测器与脉冲波形甄别建立了多粒子甄别方法，通过符合探测器中子误判率≤20%，优化PSD算法将热中子区FoM提升至2.45；通过模拟和实验分析掌握了热中子~100 MeV能区中子在CLYC中的响应机理，建立了相应的物理模型；以实验和模拟结合，建立了宽能区单能中子响应矩阵，通过最小二乘算法有效重建了Am-Be中子源能谱，与标准中子能谱分布的平均偏差值为0.034；开展了空间环境(温度和辐照)影响测试研究，证实了探测器的空间环境适用性。基于该方法设计的中子测量单元搭载于我国空间站问天实验舱中，为我国空间站安全、宇航员出舱、空间材料以及生物实验提供关键参考参数。基于本项目研究发表期刊论文6篇，申请发明专利3项，参加国内外学术会议4次，培养研究生3名。