TWO-DIMENSIONAL HIGH RESOLUTION X-RAY DETECTORS FOR IMAGING AND INTENSITY MEASUREMENTS F. Fandrich and R. Köhler Max-Planck-Arbeitsgruppe ,,Röntgenbeugung" an der Humboldt-Universität zu Berlin, Hausvogteiplatz 5-7, D-10117 Berlin, Germany

Two CCD slow-scan camera based detector systems with different concepts for x-ray sensitivity provide a high lateral resolution and the capability of single x-ray photon counting. The performance of both systems was studied and compared at a photon energy of 8 keV (copper-K-radiation). While the concept of direct exposure has the better resolution of about 7 um, the camera using a phosphor and an image intensifier provides a much better quantum efficiency of 80 % compared with about 10 % of the direct system. The response of both systems is high enough in order to detect single x-ray photon `events' reliably. The image accumulation process is a numerical one, i.e. camera frames with single x-ray events are analyzed immediately after exposure. Accumulation means then counting the number of x-ray photons at those positions where they hit the sensitive area. These positions are calculated from the centres of the x-ray `events'. The image is build by accumulation of many frames. Topographic imaging or the detection of scattering intensities under different exit angles are possible fields of application. The well-defined intensity measurement based on the counting process during accumulation allows quatitative data evaluation. The performance of the systems is demonstrated by means of x-ray double crystal topographs.