X-ray imaging with high-Z sensors for the ESRF-EBS Upgrade

The Extremely Brilliant Source (EBS) upgrade of the European Synchrotron Radiation Facility (ESRF) sets new requirements for the detection schemes used in various beamlines. In order to facilitate direct x-ray detection at moderate and high energies in the range of 30-100 keV we investigate the performance of pixelated photon counting detectors using high-Z semiconductor sensors as the sensitive medium. In the context of this work, several prototype modules based on CdTe, CZT and GaAs: Cr pixelated sensors have been developed and tested at ESRF using laboratory X-ray sources and monochromatic synchrotron beams. Each module, consisting of a pixelated sensor bonded to a single Timepix chip, is coupled to the MAXIPIX readout system. A common characterisation procedure is applied to each detector module, focusing on the sensor quality, the spatial characteristics and the imaging performance. The results presented in this work along with further tests will provide the means to determine the best compromise between sensor material and performance for future detector systems.