New transition radiation detection technique based on DEPFET silicon pixel matrices

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.