Einstein Probe is a Chinese Academy of Science (CAS) mission due for launch at the end of 2022 with its primary goals to discover high-energy transients and monitor variable objects. The mission consists of two instruments, the Wide field X-ray Telescope (WXT), a lobster eye X-ray telescope consisting of twelve identical modules; and the Follow-up X-ray Telescope (FXT), which is a traditional Wolter X-ray telescope, which is jointly developed by CAS, the European Space Agency (ESA) and the Max Planck Institute for Extraterrestrial Physics (MPE). Each of the WXT modules comprise of 36 micro pore optics (MPOs), with a 375 mm focal length, a field of view of more than 3600 square degrees, a goal of 5 arcmin resolution and working in the energy range of 0.5-4 keV. As part of the collaboration between CAS and ESA, the University of Leicester (UoL) is acting as a testing facility and repeatability check for several elements of the WXT optic development. This includes calibration of individual MPOs, temperature measurements on a prototype module, calibration of a qualification module and full calibration of one of the flight module optics. The majority of these tests will be performed in the two X-ray facilities at the University of Leicester, the Tunnel Test Facility (TTF) and the Vertical Test Facility (VTF). Presented here are details of the tests carried out and the results obtained from the first batch of individual MPOs and the plan for the thermal tests of the prototype in the TTF.
China’s Einstein Probe (EP) mission is designed for time-domain astrophysics with energy band of 0.5-4 keV. The payloads of EP include a wide-field X-ray telescope (WXT) and a follow-up X-ray telescope (FXT). The field of view (FOV) of WXT is about 3600 square degrees with sensitivity at least 10 times better than traditional X-ray all-sky monitors applying collimators or coded-masks. Back-side illuminated scientific CMOS (BSI sCMOS) is the best choice for WXT after several types of X-ray detectors are investigated. In this work, we study a BSI sCMOS sensor, GSENSE400BSI developed by Gpixel Inc., which is treated as a pathfinder for the focal plane detector of WXT. GSENSE400BSI has a pixel array of 2048×2048 with pixel size of 11 μm. We have characterized this BSI sCMOS as an X-ray detector. Based on the excellent performance of GSENSE400BSI, a new BSI sCMOS device with large sensitive area of 6×6 cm2 has been proposed as the focal plane detector for WXT.