R&D studies of a RICH detector using pressurized C4F8O radiator gas and a CsI-based gaseous photon detector

We report on studies of layout and performance of a new Ring Imaging Cherenkov detector using for the first time pressurized C4F8O radiator gas and a photon detector consisting of a MWPC equipped with a CsI photocathode. In particular, we present here the results of beam tests of a MWPC having an adjustable anode–cathode gap, aiming at the optimization of single photoelectron detection and Cherenkov angle resolution. This system was proposed as a Very High Momentum Particle Identification (VHMPID) upgrade for the ALICE experiment at LHC to provide charged hadron track-by-track identification in the momentum range 5–25GeV/c. •The concept and design of a novel RICH counter operated with pressurized gaseous Cherenkov radiator have been validated.•We used for the first time C4F8O gaseous Cherenkov radiator pressurized up to 3.5atm in a RICH counter.•The refractive index of C4F8O in the UV range is similar to the per-mil level to that of C4F10.•A variable gap MWPC has been used to optimize the layout of the gaseous photon counter, based on CsI photocathodes and MWPC, for the detection of single photoelectrons.