Analog signal processing for large area SiPM in Cherenkov telescope camera

Abstract

We have developed a preamplifier which processes signals from large area pixel sensors each comprising a 4 × 4 array of SiPMs. These amplifiers constitute a front-end portion of 256 pixel camera for an Imaging Atmospheric Cherenkov Telescope (IACT). The camera would be mounted at the focal plane of the 4-m class telescope. The primary design objective of the camera is to detect the wide energy range of the celestial Gamma-rays by detecting the atmospheric Cherenkov photons produced by them in the atmosphere. The other important objective of the camera is to be able to resolve single photon response for accurate pixel gain calibration. There are several factors like large size sensor, long time response, single p.e. resolution, etc., which have led to a customized design of the preamplifier. We propose an original circuit topology to achieve the design goals. The paper describes the design features of the preamplifier and performance evaluation.