LHAASO实验中宇宙线次级粒子特性的模拟研究  

Simulation study on the characteristics of secondary cosmic ray with LHAASO

作　　者：闫瑞瑞 赵兵 高兰兰[1] 周勋秀[1] YAN Rui-Rui;ZHAO Bing;GAO Lan-Lan;ZHOU Xun-Xiu(School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China)

机构地区：[1]西南交通大学物理科学与技术学院

出　　处：《四川大学学报（自然科学版）》2019年第3期481-486,共6页Journal of Sichuan University(Natural Science Edition)

基　　金：国家自然科学基金(11475141,11747311)

摘　　要：高海拔宇宙线观测站(LHAASO)位于四川稻城海子山,海拔约4400 m,该实验采用多种手段,对进入大气层的宇宙线粒子进行精确的复合测量.高海拔区域,雷暴天气频繁,广延大气簇射中宇宙线次级粒子的数目、方向和能量都会受到雷暴电场的影响.本文利用Monte Carlo方法,模拟了宇宙线原初粒子进入大气层后的广延大气簇射过程,研究了次级粒子中光子、电子、μ子的纵向分布、横向分布和能量分布.结果表明,在LHAASO探测面,电子的数目比μ子多2~3倍、μ子横向分布范围比电子宽广、μ子的能量比电子大.若在雷暴期间,大气电场对电子(质量小、数目多)的影响将会更加明显.本工作对研究雷暴电场加速宇宙线次级带电粒子的物理机制具有重要意义,同时为理解地面实验的观测现象提供有用信息.The Large High Altitude Air Shower Observatory(LHAASO) is located at Haizi Mountain in Daocheng County(4400 m a.s.l., Sichuan, China). This experiment is realized by using various methods for an accurate duplex measurement on the secondary cosmic rays entering the atmosphere. The thunderstorms occur frequently in high altitude areas, so the number, direction and energy of secondary particles of cosmic rays in the Extensive Air Shower(EAS) will be affected by thunderstorms electric field. In this paper, employing Monte Carlo method, we simulate the process of EAS for the primary particles cosmic rays entering the atmosphere and study the longitudinal distribution, the lateral distribution and the energy distribution of photons, electrons and muons in the secondary particles. The results show that the number of electrons on the LHAASO detector surface is 2 ~ 3 times more than that of the muons;the muons have a wide range of horizontal distribution, while the electrons are of concentrated distribution;the muon’s energy is much larger than that of the electron. Considering the influence of the electric field, the effect of the electric field will be more evident on the electrons, which has tiny mass. Our simulation results are significant in studying the acceleration mechanism of secondary charged particles caused by electric field and provide important information to understand the observation of ground experiments during thunderstorms.

关 键 词：雷暴电场 宇宙线 MONTE CARLO模拟 LHAASO 

分 类 号：O572.1[理学—粒子物理与原子核物理]