PERFORMANCE OF AN AEROGEL THRESHOLD PARTICLE IDENTIFICATION DETECTOR READOUT BY HYBRID PHOTON DETECTORS

This paper describes an aerogel threshold particle identification dete ctor developed for use in BABAR, the experiment to be run at the asymm etric e(+)e(-) B-factory PEP-II under construction at the Stanford Lin ear Accelerator Center (SLAG). Results of extensive tests performed at the CERN PS indicate that this detector is capable of separating pion s from below-threshold particles in a wide momentum range, The detecto r is read by a new version of a hybrid photon detector (HPD). The HPD has been chosen because of its excellent behavior in high magnetic fie lds, where it can be successfully exploited to preserve the required p article identification (PID) performance.