The Projectile Spectator Detector for measuring the geometry of heavy ion collisions at the CBM experiment on FAIR

摘要

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) is aimed to explore the QCD phase diagram in the region of high baryon densities. The Projectile Spectator Detector (PSD) is the forward hadron calorimeter that will be used in the CBM to measure the event centrality as well as the reaction plane orientation in heavy-ion collisions in the beam energy range of 2-11 AGeV with beam interaction rates up to 10 MHz. The supermodule consisting of 9 modules has been assembled to explore the performance of the PSD. Its response has been studied with proton beams in the momentum range 2-10 GeV/c at the CERN Proton Synchrotron (PS) T9 and T10 beam lines. For the first time, the energy resolution and the linearity of the response have been measured at such low energies. The PSD operation under radiation conditions at the CBM, as well as the results of one PSD module measurements with irradiated photodetectors are discussed.