Synchrotron measurements of the energy response functions of CdTe Medipix2 MXR detectors with pixel pitches of 110 and 165 μm

The energy resolution of photon counting pixel detectors depends strongly on the pixelpitch. Small pixels increase the effects of characteristic X-rays and the sharing of charges betweenadjacent pixels. To investigate the effects of different pixel pitches, measurements with Medipix2 MXR detectors attached to CdTe sensors with pixel pitches of 110 and 165 mu m were carried outat the Topo-Tomo beamline of the ANKA synchrotron at the Karlsruhe Institute of Technology (KIT). Photo peaks are measured at a number of energies and are used to calculate the fraction ofevents in the photo peak compared to the total. Finally, we investigate the linearity of the energycalibration curves as a function of the pixel pitch.