The European Photon Imaging Camera on XMM-Newton: The pn-CCD camera

TLDR

The EPIC consortium supplied the focal‑plane instruments for XMM‑Newton’s three X‑ray mirror systems, with two MOS‑CCD cameras for the grating spectrometers and a novel pn‑CCD imaging spectrometer for the full‑flux telescope. The pn‑CCD camera, led by MPE, was designed with a specific concept, multiple operational modes, and a compact electrical, mechanical, and thermal focal‑plane architecture. In orbit, the pn‑CCD delivers high energy resolution, quantum efficiency, and time resolution, remains stable over time, and shows low charged‑particle background, with radiation hardening mitigating ionizing‑particle damage observed over the first nine months.

Abstract

The European Photon Imaging Camera (EPIC) consortium has provided the focal plane instruments for the three X-ray mirror systems on XMM-Newton. Two cameras with a reflecting grating spectrometer in the optical path are equipped with MOS type CCDs as focal plane detectors (Turner [CITE]), the telescope with the full photon flux operates the novel pn-CCD as an imaging X-ray spectrometer. The pn-CCD camera system was developed under the leadership of the Max-Planck-Institut für extraterrestrische Physik (MPE), Garching. The concept of the pn-CCD is described as well as the different operational modes of the camera system. The electrical, mechanical and thermal design of the focal plane and camera is briefly treated. The in-orbit performance is described in terms of energy resolution, quantum efficiency, time resolution, long term stability and charged particle background. Special emphasis is given to the radiation hardening of the devices and the measured and expected degradation due to radiation damage of ionizing particles in the first 9 months of in orbit operation.