FACT -- the First Cherenkov Telescope using a G-APD Camera for TeV Gamma-ray Astronomy (HEAD 2010)

TL;DR

The paper introduces the first Cherenkov telescope using G-APD technology, aiming to evaluate its performance for gamma-ray astronomy and its potential to replace traditional PMT-based cameras.

Contribution

It presents the design and implementation of a G-APD-based camera on an existing IACT, demonstrating its feasibility for high-energy gamma-ray observations.

Findings

Successful construction of a G-APD camera for IACT

Initial observations of the Crab Nebula with the new system

Assessment of G-APD performance in Cherenkov astronomy

Abstract

Geiger-mode Avalanche Photodiodes (G-APD) bear the potential to significantly improve the sensitivity of Imaging Air Cherenkov Telescopes (IACT). We are currently building the First G-APD Cherenkov Telescope (FACT) by refurbishing an old IACT with a mirror area of 9.5 square meters and construct a new, fine pixelized camera using novel G-APDs. The main goal is to evaluate the performance of a complete system by observing very high energy gamma-rays from the Crab Nebula. This is an important field test to check the feasibility of G-APD-based cameras to replace at some time the PMT-based cameras of planned future IACTs like AGIS and CTA. In this article, we present the basic design of such a camera as well as some important details to be taken into account.