The crystal barrel Si-vertex detector

We have built and operated a silicon microstrip detector for the Crystal Barrel spectrometer used at LEAR at CERN, to trigger on final states of p̄p annihilations at rest and in flight containing one or more long-lived neutral particles which decay into charged secondaries. Both strip side and backplane of the single-sided strip detectors are read out, and the information is used in the first and second level trigger stages. The characteristics and performance of this detector are discussed.