A fast RICH detector for particle identification in ALICE at LHC

The ALICE collaboration proposes to investigate central ion-ion collisions (PbPb) at the Large Hadron Collider operated in the ion mode. The core of the detector covers 1.8 units of rapidity centered at midrapidity. The maximum expected rapidity density is 8000 charged particles. The proposed detector is planned to measure the momentum, charge and mass of the majority of the particles in the range of transverse momentum of 0.05–2.0 GeVc. In the range of momenta where charged particle identification, by means of ionization losses, is not possible (by the TPC, and/or silicon detectors), i.e. above 0.8 GeV/c for pions and kaons, the ALICE detector envisages two alternatives currently actively investigated — a time of flight wall or a RICH detector. The RICH detector under study is of the proximity focusing type with a liquid C6F14 radiator, using a MWPC with pad readout equipped with a solid photocathode for UV light detection.