A ring-imaging \v{C}erenkov counter read out by a 100-channel PMT of active
area 10×10 cm2 was operated successfully in a test beam at the BNL
AGS with several radiator gases, including the heavy fluorocarbon
C4F10. Ring radii were measured for electrons, muons, pions and kaons
over the particle momentum range from 2 to 12 GeV/c, and a best resolution of
σr/r=2.3% was obtained.Comment: 11 pages (LaTeX) plus 7 figures in Postscript (gz-compressed and
uuencoded