Growing energies of particles at modern or planned particle accelerator experiments as well as various cosmic ray experiments require particle identification at gamma factors of up to $\approx 10^5$. At present there are no detectors capable of identifying single charged particles with reliable efficiency in this range of gamma-factors.
New developments in pixel detectors allow to perform simultaneous measurements of the energies and the emission angles of generated Transition Radiation X-rays and to identify particles on the basis of maximum available information about generated TR photons.
Preliminary results of studies of TR energy-angular distributions using Si and GaAs sensors bonded to TimePix3 chips are presented.
Studies were carried out at the CERN SPS facility with 20 $GeV/c$ electrons and muons from 120 to 290 $GeV/c$ using different types of radiators.
This talk will discuss the measurement and analysis techniques used for this experiments as well as comparison of efficiencies of TR registration for both types of sensors.