The ring imaging Cherenkov detector for the BRAHMS experiment at RHIC

Abstract A ring imaging Cherenkov counter, to be read out by four 100-channel PMTs, is a key element of the BRAHMS experiment. We report here the most recent results obtained with a prototype tested at the BNL AGS using several radiator gases, including the heavy fluorocarbon C 4 F 10 . Ring radii were measured for different particles ( π − , μ − , e − ) for momenta ranging from 2 to 12 GeV/ c employing pure C 4 F 10 as radiator.