<title>Ground-calibration GSE for the XMM-EPIC instrument at the Orsay Synchrotron facility</title>

The European Photon Imaging Camera (EPIC) is one of the major instruments on board the European Space Agency's X-ray Multi-Mirror cornerstone mission planned for launch at the end of the century. Ground calibrations have been performed in 1997 and 1998 on the electrical and flight models of the MOS-CCD and on the flight model of the p-n-CCD focal plane cameras at he Synchrotron facility at IAS Orsay in France. The complexity of the imaging systems required a correspondingly sophisticated calibration equipment, capable of automatically setting and calibrating the synchrotron beam at a particular energy, controlling the camera head movement in synchronism with the CCD frame readout, initializing the instrument and acquiring both the instrument data and the facility monitor data in realtime. Furthermore, always in real-time, the data stream was unpacked and stored as photon lists in FITS format and made available via NFS to the off-line analysis software. Contemporaneously, a quick look program allowed the operator to continuously monitor the calibration procedure from a scientific point of view, ensuring the correct operation of the system. The calibration system from the point of view of the instrument and the current status of the project is described.