Measurement and detailed simulation of the Modulation Transfer Function of the Medipix2

The Modulation Transfer Function (MTF) is an important quality characteristic for the description of the spatial resolution of imaging systems. For X-ray detectors, like the Medipix2, it depends for instance on the pixel size and the incident spectrum. The detection of single photons in the Medipix2 is additionally influenced by the lower energy threshold. The dependency of the MTF on this threshold and on the incident spectrum has been evaluated by simulations and measurements. By choosing an adequate threshold, the so-called low frequency drop can be suppressed or the spatial resolution in general is influenced.