A G-APD based Camera for Imaging Atmospheric Cherenkov Telescopes

Imaging Atmospheric Cherenkov Telescopes ( IACT) for Gamma-ray astronomyare presently using photomultipliertubes as photo sensors. Geiger-mode avalanche photodiodes(G- APD) promise an improvement in sensitivity and, important for this application, ease of construction, operation and ruggedness. G- APDshave proven many of their features in the laboratory, but a qualified assessment of their performance in an IACTcamera is best undertaken with a prototype. This paper describes the design and construction of a full-scale camera based on G- APDsrealized within the FACT project (First G- APDCherenkov Telescope). (C) 2010 Elsevier B.V. All rights reserved.