大气中子实时计算模式

为实时评估0~100km高度范围内的大气中子全球分布，对宇宙线在地磁场和大气中的传输过程进行了分析.利用蒙特卡罗方法工具包Geant4，预先计算不同能量的粒子在大气层中产生的次级粒子能谱分布，形成大气次级粒子数据库，并与相关模型进行对比，验证了该数据库的有效性和可靠性.以实测或预报的空间环境参数作为输入，计算同步轨道银河宇宙线和太阳质子事件能谱以及100km高度上的地磁垂直截止刚度，最终得到大气层顶上的粒子能谱.通过对大气次级粒子数据库的线性插值，实现1h分辨率的大气中子能谱和辐射剂量全球分布的实时计算. 

A Model for Real-time Calculation of the Atmospheric Neutronormalsize

In order to evaluate the global distribution of atmospheric neutron at 0~100km altitude for real time, the propagation of cosmic rays in the geomagnetic field and the atmosphere is analyzed. By using the TSY05 and MAGNETOCOSMICS model, the real-time calculation of global geomagnetic cut-off rigidities with 1h resolution is realized. The spherical shell geometry model is established at intervals of 1km using NLRMSISE-00 model, and the spectrum distribution of secondary particles generated by different particles is calculated by the Monte Carlo simulation techniques, namely, the Geant4 toolkit, then an atmospheric neutron database is created. Compared with EXPACS model, the validity and reliability of the database are verified. Based on the observed or predicted space environment parameters, the energy spectra of the cosmic ray and the solar proton event in the synchronous orbit are calculated, and the effective vertical cut-off rigidities in function of latitude and longitude at the altitude of 100km. The atmospheric neutron and effective dose are calculated by using linear interpolation per hour.