Evidence for micrometeoroid damage in the pn-CCD camera system aboard XMM-Newton

The mirror systems of the X-ray observatory XMM-Newton were designed to ima ge X-rays up to 15 keV by grazing incidence reflection onto a focal plane, equipped with Charge Coupled Devices (CCDs). In orbit # 156 we have observe d a sudden increase of about 35 "bright" pixels spread over 15 cm(2) in the pn-CCD camera system. The amount of locally generated leakage current cann ot be explained by ionizing particles. We suggest that a micrometeoroid sca ttered under a small angle off the X-ray telescope mirror surface finally r eached the focal plane detector and produced the damage.