Active pixel matrix for X-ray satellite missions

We present an active pixel matrix for high rate, spectroscopic and imaging X-ray detection. It is foreseen as a wide field imager on the XEUS (X-ray E volving Universe Spectroscopy) satellite. A 1024 x 1024 pixel device with p ixel sizes of 50 - 75 mu m shall cover an area of 76 mm x 76 mm. A single pixel consists of a p-channel DEPFET (DEPleted Field Effect Transi stor). It is realized on high-ohmic detector grade silicon allowing the bul k to be fully depleted to achieve high quantum efficiency. In a matrix arrangement pixels are interconnected in such a way that single rows can be randomly accessed and read-out. Various read-out modes can be realized making this detector an ideal instrument for the high dynamics in the photon flux on XEUS. A 64 x 64 pixel matrix prototype has been produced at the HLL. We will desc ribe the test system setup, and present measurements, which characterize th e expected performance for a focal plane instrument.