Sergey Furletov’s research while affiliated with University of Bonn and other places

This paper presents new developments in Monte Carlo simulation for test beam measurements of a silicon transition radiation detector based on DEPFET—a silicon active pixel detector. The test of DEPFET with fiber radiator has been carried out at the DESY 5 GeV electron beam. Monte Carlo simulation of the test beam setup is based on Geant4. A comparison of Geant4 simulation with test beam data is presented.

Transition Radiation Detectors (TRD) have the attractive feature of being able to separate particles by their gamma factor. Replacing the xenon based gaseous detectors by modern silicon detectors is complicated by the large energy losses of charged particles in 300–700μm of silicon. A silicon active pixel detector—DEPFET—has features which allows another detection technique to be used, in order to overcome the existing limitation on separating transition radiation photons with an energy loss from a charged particle in the same pixel. The tests of DEPFET with fiber radiator have been carried out at CERN SPS and DESY beams. The first results of test-beam measurements and Monte Carlo simulation are presented.

The DEPFET pixel detector offers first stage in-pixel amplification by incorporating a field effect transistor in the high resistivity silicon substrate. In this concept, a very small input capacitance can be realized thus allowing for low noise measurements. This makes DEPFET sensors a favorable technology for tracking in particle physics. Therefore a system with a DEPFET pixel matrix was developed to test DEPFET performance for an application as a vertex detector for the Belle II experiment. The system features a current based, row-wise readout of a DEPFET pixel matrix with a designated readout chip, steering chips for matrix control, a FPGA based data acquisition board, and a dedicated software package. The system was successfully operated in both test beam and lab environment. In 2009 new DEPFET matrices have been characterized in a 120GeV pion beam at the CERN SPS. The current status of the DEPFET system and test beam results are presented.