Performance of the CAPRICE94 RICH Detector during the 1994 Balloon Flight

Abstract

A RICH detector capable of detecting unit charged particles, e.g. antiprotons and positrons, was in 1994 used successfully for the first time in a balloon borne magnet spectrometer. The thin and compact CAPRICE94 RICH detector uses a NaF solid radiator, TMAE vapor as photo-converter and cathode pad readout in the photosensitive MWPC operated at low gain. 15 photoelectrons are detected per ring for ß = 1, perpendicular incidence particles giving a resolution on the Cherenkov angle of 8 mrad, increasing to 14 mrad at 20oC incidence angle. Besides particle identification on an event-by-event basis it efficiently rejects multiparticle events and albedo particles (Barbiellini, 1996).