Characterization of a X-ray pixellated CdTe detector with TIMEPIX photon-counting readout chip

A prototype 1mm CdTe detector bonded to a TIMEPIX chip with 256*256 pixels at 55μm pitch is evaluated for use at synchrotron beamlines. A complete characterization was performed. At the tested energies above 50 keV, a 10 times efficiency increase and a higher spatial resolution have been exhibited with reference to Silicon-based pixel detectors and to current CCD systems of similar pixel size. Background-free powder diffraction spectra were obtained, owing to the energy thresholding feature. The energy-resolved detection capabilities are limited by a high charge sharing. The major limitations preventing a wider use of these devices at synchrotron X-ray sources are the lack of homogeneity of the crystal exhibiting numerous defects, and the unavailability of large detection areas.