Current research / employment

The Timepix detector is a pixelated hybrid semiconductor detector which can measure either the time of detection or the energy of a photon. Timepix is a member of the Medipix detector family which was designed at CERN. These detectors consist of a sensor which is connected to the ASIC via bump bonds. The sensor material is a semiconductor like silicon or CdTe.

A new application of those detectors is for example the detection of photoelectrons in a Hybrid Photon Detector. The HPD consists of a vacuum tube with a photocathode on top and electric field shaping electrodes inside. The Timepix is placed at the bottom of the tube and detects the arrival time of the accelerated electrons released from the photocathode by optical photons.

An application of this HPD could be to measure Cherenkow light in astroparticle experiments, for example neutrino experiments like Antares. To increase the detection efficiency for the next generation detector KM3NeT it is essential to improve the existing photomultiplier tubes. For example one should be able to distinguish between noise, one and two or more photo electrons. This cannot easily be done with the current ANTARES PMTs but is provided by the described HPD. Other advantages of the Timepix are the possibility to suppress electronic noise by setting a threshold, its ability to deal with high dark rates because of the huge number of pixels and the fact that the electronics is directly located in the detector.

In my PhD-thesis I characterize a pumped test set-up of an HPD. I am looking e. g. at the time resolution, the point spread function of the system and I evaluate the background due to ion feedback events. For further investigations a sealed prototype of the HPD will be manufactured by a company.

Publications U. Gebert, T. K. Rügheimer, T. Michel, G. Anton, J. Séguinot, C. Joram, Detection of optical photons with the Timepix in an HPD set-up, NIM A, 623, 288-290, (2010)

G. Anton, U. Gebert, T. Michel, T. K. Rügheimer, A hybrid photodetector using the Timepix semiconductor assembly for photoelectron detection, NIM A, 602(1), 205-208, (2009)

T. K. Rügheimer, U. Gebert, T. Michel, G. Anton, J. Séguinot, C. Joram, Towards an asynchronously operating hybrid photon detector based on the Timepix readout chip, NIM A, 610(1), 72-74, (2009)

T. K. Rügheimer, U. Gebert, T. Michel, G. Anton, J. Séguinot, C. Joram, Experimental demonstration of a hybrid photon detector concept based on the Timepix detector, NIM A, 595(2), 353-358, (2008)