A hybrid photodetector using the Timepix semiconductor assembly for photoelectron detection

We present a hybrid photomultiplier concept which employs the pixelated semiconductor detector Timepix for the detection of the photoelectrons. Timepix has been developed by the MEDIPIX collaboration. It comprises 256×256256×256 pixels with 55μm pixel pitch. By setting an energy threshold it allows to identify single electrons and, therefore, single photons with high resolution. An appropriate electric field between the photocathode and the Timepix configures an image of the photocathode on the Timepix. A high frequency clock enables the determination of the arrival time of each photon. Test measurements and further design considerations are presented.