High photon detection efficiency avalanche photodiodes designed for use with scintillating fibers

Summary form only given. The authors discussed the properties of two new avalanche photodiodes (APDs) suited for application with scintillating fiber tracking systems, considered optimal packaging approaches for efficient optical coupling from scintillating fibers to APDs which allow the diode area to be minimized, and predicted their performance when used in either the Geiger mode, together with a fast quench circuit, or in the sub-Geiger mode, in conjunction with a low-noise preamplifier. In either case, detection efficiencies of over 85% for a five-photon pulse were predicted and measured. The use of these devices in the linear mode, with possible application to scintillating fiber calorimeters, was also considered. It was shown both theoretically and experimentally that, for short pulses (a few nanoseconds) of greater than about 10 photons, better signal-to-noise ratios are possible using APDs than using photomultiplier tubes.<>