THE CLEOIII RING IMAGING CHERENKOV DETECTOR

The CLEO detector at the Cornell electron storage ring is in the midst of a major upgrade designed to extend dramatically its physics reach in the study of heavy quarks and leptons. The major component of this detector upgrade is the installation of a ''fast'' Ring Imaging Cheren kov detector (RICH). This device will provide efficient charged hadron identification up to momentum p = 2.8 GeV/c, the kinematic limit for decay daughters of B mesons produced at the Y(4S) resonance. This dete ctor covers 80% of the full solid angle and comprises a solid lithium fluoride radiator of novel geometry and multi-wire proportional chambe rs with 230400 total cathode pad readout channels and a TEA-methane ph oton conversion gas. The physics motivation for the detector is review ed, the design of its major components explained and prototype results discussed.