Performance of the transition radiation detector of the PAMELA space mission

The performance of the transition radiation detector (TRD) of the PAMELA telescope has been studied using beam test data and simulation tools. PAMELA is a satellite-borne magnetic spectrometer designed to measure particles and antiparticles spectra in cosmic rays. The particle identification at high energy will be achieved by combining the measurements by the TRD and a Si-W imaging calorimeter. The TRD is composed of 9 planes of straw tubes, interleaved with carbon fiber radiators. A prototype of the detector has been exposed to particle beams of electrons, pions and muons of various momenta at the CERN-PS and SPS accelerator facilities. In addition a dedicated Monte Carlo code has been developed to simulate the detector. Here we illustrate both simulation results and experimental data analysis procedures and we will discuss the estimated TRD performance. (15 refs).