The European Photon Imaging Camera on XMM-Newton: The MOS cameras

¹ Dept. of Physics & Astronomy, Leicester University, LE1 7RH, UK
² CEA/DSM/DAPNIA Service d'Astrophysique, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France
³ Laben S.p.A, S.S. Padana Superiore, 290, 20090 Vimodrone, Milano, Italy
⁴ Osservatorio Astronomico di Palermo, Palermo, 90134, Italy
⁵ Institut d'Astrophysique Spatiale, Bât. 121, Université Paris Sud, 91405 Orsay, France
⁶ IFC Milan, 20133 Milano, Italy
⁷ Centre d'Étude Spatiale des Rayonnements, 9 avenue du colonel Roche, BP 4346, 31028 Toulouse Cedex 4, France
⁸ MPE D-85740 Garching, 8046, Germany
⁹ School of Physics and Astronomy, University of Birmingham, B15 2TT, UK
¹⁰ Laboratoire pour l'Utilisation du Rayonnement Électromagnétique, Bât. 209 D, Université Paris Sud, 91405 Orsay, France
¹¹ ITESRE, 41010 Bologna, Italy
¹² IAAP Tuebingen, 72076, Germany
¹³ PX ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
¹⁴ Space Science Department, ESTEC, 2200 AG Noordwijk, The Netherlands

Corresponding author: M. J. L. Turner, mjlt@star.le.ac.uk

Received: 4 October 2000
Accepted: 31 October 2000

Abstract

The EPIC focal plane imaging spectrometers on XMM-Newton use CCDs to record the images and spectra of celestial X-ray sources focused by the three X-ray mirrors. There is one camera at the focus of each mirror; two of the cameras contain seven MOS CCDs, while the third uses twelve PN CCDs, defining a circular field of view of 30′ diameter in each case. The CCDs were specially developed for EPIC, and combine high quality imaging with spectral resolution close to the Fano limit. A filter wheel carrying three kinds of X-ray transparent light blocking filter, a fully closed, and a fully open position, is fitted to each EPIC instrument. The CCDs are cooled passively and are under full closed loop thermal control. A radio-active source is fitted for internal calibration. Data are processed on-board to save telemetry by removing cosmic ray tracks, and generating X-ray event files; a variety of different instrument modes are available to increase the dynamic range of the instrument and to enable fast timing. The instruments were calibrated using laboratory X-ray beams, and synchrotron generated monochromatic X-ray beams before launch; in-orbit calibration makes use of a variety of celestial X-ray targets. The current calibration is better than 10% over the entire energy range of 0.2 to 10 keV. All three instruments survived launch and are performing nominally in orbit. In particular full field-of-view coverage is available, all electronic modes work, and the energy resolution is close to pre-launch values. Radiation damage is well within pre-launch predictions and does not yet impact on the energy resolution. The scientific results from EPIC amply fulfil pre-launch expectations.