The eROSITA Camera Array on the SRG Satellite

摘要

The SRG satellite with the eROSITA X-ray telescope as scientific payload was successfully launched on July 13. 2019 and deployed in a 6-month halo orbit around the second Lagrange point of the Sun Earth system. The telescope comprises an array of seven mirror systems with seven focal plane cameras. The spectroscopic CCD cameras are a further development of the very successful EPIC PN camera on the XMM-Newton satellite, which is still successfully operating after 20 years in space. Key component of the camera is the detector, which matches the large field of view of 1 ° to permit an all-sky survey in the energy range from 0.2 keV to 8 keV with state-of-the-art energy resolution. The image area of the PNCCD comprises 384 x 384 pixels. Their size of 75 × 75 μm~2 each, matches the angular resolution of the mirror system. Readout of the full frame is achieved in 9.18 ms but for thermal and onboard event pre-processing reasons, the time resolution is slowed down to 50 ms. The photon entrance window of five of the seven CCDs is equipped with an optical blocking filter, which turned out to be advantageous. In this work, the improved concept and design of the eROSITA cameras will be explained as well as their operation and performance in space.