Method for identifying low-energy antiprotons using the electromagnetic position-sensitive calorimeter of the PAMELA spectrometer

The PAMELA experiment on the study of cosmic rays in a wide energy range was performed onboard the Resurs-DK1 spacecraft from June 2006 to February 2016. The data on antiproton fluxes in the near-Earth space play an important role for this field of physics. Their detection by the PAMELA spectrometer is possible using two independent detectors: the track system in a magnetic field and the position-sensitive calorimeter (in the low-energy region, <1 GeV). The presented technique for identifying antiprotons is based on the analysis of tracks of the antiproton and secondary charged mesons produced during its annihilation in the calorimeter. This technique allows identification of antiprotons with energies of 200–800 MeV, independently confirming the data of a magnetic analysis and increasing the statistics due to the larger geometrical factor of the calorimeter in comparison with a track system.