Separation of electrons and protons in the GAMMA-400 gamma-ray telescope

The bulk of cosmic rays are protons and helium nuclei, whereas the lepton component in the total flux is ∼10−3 at high energy. In the present paper, the simulated capability of the GAMMA-400 telescope to distinguish electrons and positrons from protons in cosmic rays is addressed. The individual contribution to the proton rejection from each detector system of GAMMA-400 is studied separately. The use of the combined information from all detectors allows us to reach a proton rejection of the order of ∼4 × 105 for vertical incident particles and ∼3 × 105 for particles with initial inclination of 30° in the electron energy range from 50 GeV to 1 TeV.