Author/Authors :
Anderhub، نويسنده , , H. and Backes، نويسنده , , M. and Biland، نويسنده , , A. and Boller، نويسنده , , A. and Braun، نويسنده , , I. and Bretz، نويسنده , , T. and Commichau، نويسنده , , S. and Commichau، نويسنده , , V. and Dorner، نويسنده , , D. and Gendotti، نويسنده , , A. and Grimm، نويسنده , , O. and von Gunten، نويسنده , , H. F. Hildebrand، نويسنده , , D. and Horisberger، نويسنده , , U. and Kِhne، نويسنده , , J.-H. and Krنhenbü، نويسنده ,
Abstract :
The maximization of the photon detection efficiency (PDE) is a key issue in the development of cameras for Imaging Atmospheric Cherenkov Telescopes. Geiger-mode Avalanche Photodiodes (G-APD) are a promising candidate to replace the commonly used photomultiplier tubes by offering a larger PDE and in addition a facilitated handling. The FACT (First G-APD Cherenkov Telescope) project evaluates the feasibility of this change by building a camera based on 1440 G-APDs for an existing small telescope. As a first step towards a full camera, a prototype module using 144 G-APDs was successfully built and tested. The strong temperature dependence of G-APDs is compensated using a feedback system, which allows to keep the gain of the G-APDs constant to 0.5%.
