The CLEO III RICH Detector

In the past 20 years of its existence, the CLEO detector has been associated with many discoveries and precision measurements of heavy flavour physics. The latest generation of the detector, the CLEO III, has been upgraded. One of the new features of the CLEO III detector is it’s particle identification system, the Ring Imaging CHerenkov (RICH) detector. The basic principle of the differential Cherenkov detector is, given by the relation ∆ cosθ = ∆m/(n p), where n is the refractive index of LiF, p is momentum and ∆m is the mass square difference between two particles. In order to achieve efficient particle identification with low fake rates, a design goal of 4σ K/π separation at 2.65GeV was set. This momentum is given by two-body B decays. At this momentum, difference between K/π Cherenkov angle, ∆θγ = 14.4 mrad. Along with the 1.8σ dE/dx identification from the drift chamber, one requires a per track angular resolution of σθtrk = 4mrad. Using a naive approximation σθtrk = σθγ/ √