Pitch Angle Measurement Method based on Detector Counts Distribution. -I. Basic conception

Chenwei Wang; Shaolin Xiong; Hongbo Xue; Yiteng Zhang; Shanzhi Ye; Wei Xu; Jinpeng Zhang; Zhenghua An; Ce Cai; Peiyi Feng; Ke Gong; Haoxuan Guo; Yue Huang; Xinqiao Li; Jiacong Liu; Xiaojing Liu; Xiang Ma; Liming Song; Wenjun Tan; Jin Wang; Ping Wang; Yue Wang; Xiangyang Wen; Shuo Xiao; Shenlun Xie; Yanbing Xu; Wangchen Xue; Sheng Yang; Zhenghang Yu; Dali Zhang; Wenlong Zhang; Peng Zhang; Shuangnan Zhang; Yanqiu Zhang; Yanting Zhang; Zhen Zhang; Xiaoyun Zhao; Chao Zheng; Shijie Zheng

arXiv · 2505.06167

Pitch Angle Measurement Method based on Detector Counts Distribution. -I. Basic conception

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Abstract

As an X-ray and gamma-ray all-sky monitor aiming for high energy astrophysical transients, Gravitational-wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) has also made a series of observational discoveries on burst events of gamma-rays and particles in the low Earth orbit. Pitch angle is one of the key parameters of charged particles traveling around geomagnetic field. However, the usage of the GECAM-style instruments to measure the pitch angle of charged particles is still lacking. Here we propose a novel method for GECAM and similar instruments to measure the pitch angle of charged particles based on detector counts distribution. The basic conception of this method and simulation studies are described. With this method, the pitch angle of a peculiar electron precipitation event detected by GECAM-C is derived to be about 90$^\circ$, demonstrating the feasibility of our method. We note that the application of this method on GECAM-style instruments may open a new window for studying space particle events, such as Terrestrial Electron Beams (TEBs) and Lightning-induced Electron Precipitations (LEPs).

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Chenwei Wang, Shaolin Xiong, Hongbo Xue, Yiteng Zhang, Shanzhi Ye, Wei Xu, Jinpeng Zhang, Zhenghua An, Ce Cai, Peiyi Feng, Ke Gong, Haoxuan Guo, Yue Huang, Xinqiao Li, Jiacong Liu, Xiaojing Liu, Xiang Ma, Liming Song, Wenjun Tan, Jin Wang, Ping Wang, Yue Wang, Xiangyang Wen, Shuo Xiao, Shenlun Xie, Yanbing Xu, Wangchen Xue, Sheng Yang, Zhenghang Yu, Dali Zhang, Wenlong Zhang, Peng Zhang, Shuangnan Zhang, Yanqiu Zhang, Yanting Zhang, Zhen Zhang, Xiaoyun Zhao, Chao Zheng, Shijie Zheng. 2025-05-09. Pitch Angle Measurement Method based on Detector Counts Distribution. -I. Basic conception. https://arxiv.org/abs/2505.06167

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