Ring-Imaging Cherenkov Detectors for LHCb

The particle identification system proposed for the LHCb experiment is presented. It consists of ring-imaging Cherenkov detectors with three radiator materials, including the novel use of aerogel in an imaging detector. The photodetectors under development are multipixel hybrid photodiodes, which will allow high performance to be achieved due to their excellent single-photon efficiency and high spatial resolution. Significant pion/kaon separation will be possible for isolated tracks with momenta between 1 and 150 GeV/c; the first studies of pattern recognition in regions of high track density are described.