J. Phys.: Conf. Ser. J. Phys.: Conf. Ser. 1742-6596 Registration of the transition radiation with GaAs detector: Data/MC comparison Alozy J CERN Belyaev N Bergmann B L IEAP CTU, Prague Billoud T R V IEAP CTU, Prague Broulim P Pilsen, Coll. Mech. Elect. Eng. Burian P IEAP CTU, Prague Pilsen, Coll. Mech. Elect. Eng. Campbell M CERN Chelkov G Dubna, JINR Cherry M Louisiana State U. Dachs F CERN Doronin S Moscow Phys. Eng. Inst. Filippov K Moscow Phys. Eng. Inst. Fusco P INFN, Bari Gargano F Bari U. Heijne E H M CERN IEAP CTU, Prague Konovalov S LPI, Moscow (main) Cudie X Llopart CERN Loparco F INFN, Bari Bari U. Mazziotta M N Bari U. Meduna L IEAP CTU, Prague Pernegger H CERN Ponomarenko D Moscow Phys. Eng. Inst. Pospisil S IEAP CTU, Prague Rastorguev D Dubna, JINR Rembser C CERN Romaniouk A Moscow Phys. Eng. Inst. Savchenko A A Moscow Phys. Eng. Inst. Schioppa E J Salento U. Smirnov S Moscow Phys. Eng. Inst. Smirnov Y Moscow Phys. Eng. Inst. Smolyanskiy P IEAP CTU, Prague Spinelli P INFN, Bari Strikhanov M Moscow Phys. Eng. Inst. Teterin P Moscow Phys. Eng. Inst. Tikhomirov V Lebedev Inst. Vorobev K Moscow Phys. Eng. Inst. Zhukov K Lebedev Inst. 2020 1690 New developments of pixel detectors based on GaAs sensors offer effective registration of the transition radiation (TR) X-rays and perform simultaneous measurements of their energies and emission angles. This unique feature opens new possibilities for particle identification on the basis of maximum available information about generated TR photons. Results of studies of TR energy-angular distributions using a 500 |j.m thick GaAs sensor attached to a Timepix3 chip are presented. Measurements, analysis techniques and a comparison with Monte Carlo (MC) simulations are described and discussed. research-article