FACT -- Influence of SiPM Crosstalk on the Performance of an Operating Cherenkov Telescope
share
The First G-APD Cherenkov Telescope (FACT) is the first operational telescope of its kind, employing a camera equipped with silicon photon detectors (G-APD aka. SiPM). SiPMs have a high photon detection efficiency (PDE), while being more robust to bright light conditions than the commonly used photo-multiplier tubes. This technology has allowed us to increase the duty cycle beyond that of the current generation of imaging air Cherenkov telescopes. During the last four years, the operation of FACT has proven that SiPMs are a suitable photon detectors for an application in the field of ground-based gamma-ray astronomy. Nevertheless, it has been argued that crosstalk, after-pulses and dark counts are the main drawback of SiPMs, as these effects produce photon-like signals that would add up the signal background. Consequently, it is necessary to understand their impact on the analysis of data from FACT. In this contribution, we will show the current status of a study about the influence of different settings of crosstalk and dark counts on the performance of FACT. For that purpose, Monte Carlo simulations are used and compared to the actual data from the SiPM camera of FACT.
READ FULL TEXT