Experimental demonstration of a hybrid photon detector concept based on the Timepix detector

Hybrid photon detectors with pixelated readout electronics allow for photo-detection with a high spatial resolution. We present the concept of a hybrid photon detector based on the 65k-pixel detector “Timepix”. First experiments of the Timepix detector with photo-electrons were carried out and demonstrate that the concept combines good spatial and time resolutions for photo-electron detection. By comparison of the experimental data with GEANT4 simulations we identify the limiting factors for the time resolution: Electron backscattering from the sensor surface and charge-sharing among neighboring pixels in combination with the finite rise time of the preamplifier output pulse. Levers for its improvement in a future dedicated detector design are identified.