1. Simulation Studies for the First Pathfinder of the CATCH Space Mission
- Author
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Huang, Yiming, Zhang, Juan, Tao, Lian, Li, Zhengwei, Zhao, Donghua, Yin, Qian-Qing, Wen, Xiangyang, Xiao, Jingyu, Zhang, Chen, Zhang, Shuang-Nan, Xiong, Shaolin, Bu, Qingcui, Cang, Jirong, Cao, Dezhi, Chen, Wen, Ding, Siran, Gao, Min, Gao, Yang, Hou, Shujin, Jia, Liping, Jin, Ge, Li, Dalin, Li, Jinsong, Li, Panping, Li, Yajun, Liu, Xiaojing, Ma, Ruican, Pan, Xingyu, Qi, Liqiang, Rao, Jinhui, Sun, Xianfei, Tang, Qingwen, Tang, Ruijing, Wang, Yusa, Xu, Yibo, Yang, Sheng, Yang, Yanji, Yang, Yong, Zhang, Xuan, Zhang, Yueting, Zhou, Heng, Zhao, Kang, Zhao, Qingchang, Zhao, Shujie, and Zhao, Zijian
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The Chasing All Transients Constellation Hunters (CATCH) space mission is an intelligent constellation consisting of 126 micro-satellites in three types (A, B, and C), designed for X-ray observation with the objective of studying the dynamic universe. Currently, we are actively developing the first Pathfinder (CATCH-1) for the CATCH mission, specifically for type-A satellites. CATCH-1 is equipped with Micro Pore Optics (MPO) and a 4-pixel Silicon Drift Detector (SDD) array. To assess its scientific performance, including the effective area of the optical system, on-orbit background, and telescope sensitivity, we employ the Monte Carlo software Geant4 for simulation in this study. The MPO optics exhibit an effective area of $41$ cm$^2$ at the focal spot for 1 keV X-rays, while the entire telescope system achieves an effective area of $29$ cm$^2$ at 1 keV when taking into account the SDD detector's detection efficiency. The primary contribution to the background is found to be from the Cosmic X-ray Background. Assuming a 625 km orbit with an inclination of $29^\circ$, the total background for CATCH-1 is estimated to be $8.13\times10^{-2}$ counts s$^{-1}$ in the energy range of 0.5--4 keV. Based on the background within the central detector and assuming a Crab-like source spectrum, the estimated ideal sensitivity could achieve $1.9\times10^{-12}$ erg cm$^{-2}$ s$^{-1}$ for an exposure of 10$^4$ s in the energy band of 0.5--4 keV. Furthermore, after simulating the background caused by low-energy charged particles near the geomagnetic equator, we have determined that there is no need to install a magnetic deflector.
- Published
- 2024
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