作为一项致力于时域天体物理研究的空间X射线成像任务，“爱因斯坦探测器”（EP）携带两种科学有效载荷，即宽视场X射线望远镜（WXT）和后续X射线望远镜（FXT）。FXT采用Wolter-I型反射镜和pn-CCD探测器。在这项工作中，我们调查的FXT的在轨背景的基础上Geant 4模拟。考虑了EP轨道环境中存在的各种空间成分的影响，例如宇宙光子背景、宇宙射线初级和次级粒子（例如质子、电子和正电子）、γ射线和地磁赤道附近的低能质子。所获得的主要由宇宙射线质子和宇宙光子背景诱导的0.5-10 keV的仪器背景对应于焦平面探测器（FPD）的成像区域中的$\sim$ 3.1 $\times$ 10 $^{-2}$计数s $^{-1}$ keV $^{-1}$的水平，即归一化后的3.7 $\times$ 10 $^{-3}$计数s $^{-1}$ keV $^{-1}$ cm $^{-2}$。与仪器背景相比，视场（FOV）背景，这是由宇宙光子反射的光学镜，占主导地位低于2 keV。基于焦点内的模拟背景水平（30 $^{\prime\prime}$半径的圆），计算FXT的灵敏度，理论上可以实现几个$μ$螃蟹（数量级为10 $^{-14}$ erg cm $^{-2}$ s $^{-1}$）（大约10 $^{-13}$ erg cm $^{-2}$ s $^{-1}$），用于25分钟曝光的定点观察。如果包括背景扣除的额外10%系统不确定性，则该灵敏度将变差$\sim2$。
英文摘要：
As a space X-ray imaging mission dedicated to time-domain astrophysics, the Einstein Probe (EP) carries two kinds of scientific payloads, the wide-field X-ray telescope (WXT) and the follow-up X-ray telescope (FXT). FXT utilizes Wolter-I type mirrors and the pn-CCD detectors. In this work, we investigate the in-orbit background of FXT based on Geant4 simulation. The impact of various space components present in the EP orbital environment are considered, such as the cosmic photon background, cosmic ray primary and secondary particles (e.g. protons, electrons and positrons), albedo gamma rays, and the low-energy protons near the geomagnetic equator. The obtained instrumental background at 0.5-10 keV, which is mainly induced by cosmic ray protons and cosmic photon background, corresponds to a level of $\sim$3.1$\times$10$^{-2}$ counts s$^{-1}$ keV$^{-1}$ in the imaging area of the focal plane detector (FPD), i.e. 3.7$\times$10$^{-3}$ counts s$^{-1}$ keV$^{-1}$ cm$^{-2}$ after normalization. Compared with the instrumental background, the field of view (FOV) background, which is induced by cosmic photons reflected by the optical mirror, dominates below 2 keV. Based on the simulated background level within the focal spot (a 30$^{\prime\prime}$-radius circle), the sensitivity of FXT is calculated, which could theoretically achieve several $μ$crab (in the order of 10$^{-14}$ erg cm$^{-2}$ s$^{-1}$) in 0.5-2 keV and several tens of $μ$crab (in the order of 10$^{-13}$ erg cm$^{-2}$ s$^{-1}$) in 2-10 keV for a pointed observation with an exposure of 25 minutes. This sensitivity becomes worse by a factor of $\sim2$ if additional 10% systematic uncertainty of the background subtraction is included.
The coded mask of the ECLAIRs telescope onboard the SVOM space mission
Université Paris Cité, CNRS, Astroparticule et Cosmologie（巴黎西岱大学，法国国家科学研究中心，粒子与宇宙学）；CEA Paris-Saclay, Institut de Recherche sur les lois Fondamentales de l’Univers（巴黎萨克雷原子能委员会，基础定律研究所）；CNES（法国国家空间研究中心）
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National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Innovation Academy for Microsatellites, Chinese Academy of Science（中国科学院微小卫星创新研究院）；Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences（中国科学院西安光学精密机械研究所）
Calibration database design for the wide-field X-ray telescope on board the Einstein Probe
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文学院）
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；National Space Science Center, Chinese Academy of Sciences（中国科学院国家空间科学中心）；The Shanghai Institute of Technical Physics of the Chinese Academy of Sciences（中国科学院上海技术物理研究所）
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Initial radiometric calibration of the High-Resolution EUV Imager ($\textrm{HRI}_\textrm{EUV}$) of the Extreme Ultraviolet Imager (EUI) instrument onboard Solar Orbiter
Royal Observatory of Belgium（比利时皇家天文台）；Institut d’Astrophysique Spatiale, CNRS, Univ. Paris-Sud, Université Paris-Saclay（空间天体物理研究所，法国国家科学研究中心，巴黎南大学，巴黎萨克雷大学）；European Commission, DG Energy, Directorate D: Nuclear Energy, Safety and ITER（欧盟委员会，能源总司，D局：核能、安全与ITER）；Laboratoire Charles Fabry, Institut d’Optique Graduate School, Université Paris-Saclay（夏尔·法布里实验室，高等光学研究院，巴黎萨克雷大学）；Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center（达沃斯物理气象观测站，世界辐射中心）；UCL-Mullard Space Science Laboratory（伦敦大学学院-穆拉德空间科学实验室）；Centre Spatial de Liège, Université de Liège（列日航天中心，列日大学）；Max Planck Institute for Solar System Research（马克斯·普朗克太阳系研究所）
Multi-scale optimal control for Einstein Telescope active seismic isolation
Dutch National Institute for Subatomic Physics, Nikhef（荷兰国家亚原子物理研究所，Nikhef）；Vrije Universiteit Amsterdam（阿姆斯特丹自由大学）；LIGO Laboratory, California Institute of Technology（LIGO实验室，加州理工学院）；Stanford University（斯坦福大学）；University of Twente（特文特大学）
Overlap reduction functions for a polarized stochastic gravitational-wave background in the Einstein Telescope-Cosmic Explorer and the LISA-Taiji networks
本文将基于球谐展开的重叠减少函数计算方法推广到第三代地基 Einstein Telescope-Cosmic Explorer 网络及 LISA-Taiji 空间联合任务，以分析极化随机引力波背景。
