Correlated counting and energy resolving properties of photon counting X-ray detectors like the medipix detectors

There is a strong effort in the development of semiconductor photon counting pixel detectors to determine the energy deposition of every single interacting photon. With this additional energy information, it is possible to use for example energy weighting and material reconstruction methods in medical imaging. Due to small pixel sizes needed for high spatial resolution, charge sharing has a strong impact on the counting principle and energy resolution, as it leads to multiple counts and an energy dissipation of a detected single photon. Therefore, we examined with experiments and Monte Carlo simulations the aspect of multiple counts in the average multiplicity framework in respect to photon energy and detector settings. These investigations were done with the Timepix detector and its two different counting modes. Furthermore simulations of the upcoming Medipix3 detector were performed to evaluate the energy resolving and counting properties of the new detector design.