Development of a Hybrid Photo-Diode and its Front-End Electronics for the BTEV Experiment

The most problematic decision in the design of any RICH Detector is the choice of the photon detector technology. The context of the present photon detector R&D effort is the design of the RICH Detector for the BTEV Experiment [1], in which there is need to efficiently image visible Cherenkov photons from a C4F10 gas radiator over a large area. For BTEV, we require that the RICH photon detector have high single-photon detection efficiency, high responsivity in the visible spectrum (280–600 nm), large area coverage (for a 6.2 m detector plane), small dead area (for large overall efficiency), modestly high resolution (σpix ≈ 0.5mrad ⇒ 5mm), fast time response (for the Tevatron bunch crossing of 132 nsec or 7.6 MHz), withstand our radiation environment and fringe magnetic field, and have long life and high reliability (over an experiment life of ∼10 years). After consideration of extant technologies for high-efficiency, large-area photon detection (MAPMTs, FP-PMTs, etc.), we decided that Hybrid Photon Detectors (HPDs, also Hybrid PhotoDiodes) had the potential to meet our requirements, and we have pursued a solution based on this technology. Hence, a HPD development project was begun, jointly between Syracuse University and DEP (Netherlands) to produce the detector; and in parallel, a readout electronics development project was begun, jointly with IDEAS (Norway), to produce the front-end electronics. There are several important antecedents to our HPD work, most notably the LHCb RICH HPD development [2,3], the CMS HCAL HPD effort [4], the LAA Project [5], and for readout, the CLEO-III RICH va rich ASIC development [6].