학술논문
Simulation Studies for the First Pathfinder of the CATCH Space Mission
Document Type
Working Paper
Author
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; Zhao, Zijian
Source
Subject
Language
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.