中国锦屏地下实验室缪子辐射环境蒙特卡罗方法模拟

Monte Carlo simulation of muon radiation environment in China Jinping Underground Laboratory

用蒙特卡罗方法对中国锦屏地下实验室(CJPL)的缪子辐射本底进行了模拟。在对宇宙线缪子进行模拟时,依据海平面缪子流强Gaisser公式建立模型,并利用MUSIC程序,模拟了CJPL实验室的剩余缪子归一化能谱,进一步利用FLUKA程序模拟得到了缪致光子、中子的产额和平均能量。结果表明:剩余缪子的平均能量369GeV,通量3.17×10-6 m-2·s-1,次级光子总的注量率约1.57×10-4 m-2·s-1,次级中子总的注量率约8.37×10-7 m-2·s-1。通过与世界上其他地下实验室本底水平的对比,表明CJPL的缪子辐射环境低于世界上大多数地下实验室。

Muon radiation background of China Jinping Underground Laboratory（CJPL） was simulated by Monte Carlo method.According to the Gaisser formula and the MUSIC soft,the model of cosmic ray muons was established.Then the yield and the average energy of muon-induced photons and muon-induced neutrons were simulated by FLUKA.With the single-energy approximation,the contribution to the radiation background of shielding structure by secondary photons and neutrons was evaluated.The estimation results show that the average energy of residual muons is 369 GeV and the flux is 3.17×10^-6 m^-2·s^-1.The fluence rate of secondary photons is about 1.57×10^-4 m-2·s-1,and the fluence rate of secondary neutrons is about 8.37×10^-7 m^-2·s^-1.The muon radiation background of CJPL is lower than those of most other underground laboratories in the world.