Prototype studies for the CLEO III RICH

We describe a prototype RICH detector that has been built as part of design work for the CLEO III RICH. Cherenkov photons are produced in a LiF radiator, and are detected in a multiwire chamber with a CaF/sub 2/ entrance window containing a gas mixture of methane and TEA. Signals are read out from 2016 cathode pads using low noise Viking chips. First results from this prototype show a yield of 13 photoelectrons per image in agreement with our design studies.