A compact gas Cherenkov detector with novel optics

We discuss the design and performance of a threshold Cherenkov counter for identification of charged hadrons. The radiator is pressurized gas, which is contained in thin-walled cylindrical modules. A mirror system of novel design transports Cherenkov photons to photomultiplier tubes. This system is compact, contains relatively little material, and has a large fraction of active volume. A prototype of a module designed for the proposed CLEO III detector has been studied using cosmic rays. Results from these studies show good agreement with a detailed Monte Carlo simulation of the module and indicate that it should achieve separation of pions and kaons at the 2.5σ-3.0σ level in the momentum range 0.8-2.8 {GeV}/{c}. We predict performance for specific physics analyses using a GEANT-based simulation package.