Effect of SiPM correlated noise and Photon Detection Efficiency into Imaging Atmospheric Cherenkov Telescopes

Discussion timeslot (ZOOM-Meeting): 16. July 2021 - 18:00
ZOOM-Meeting URL: https://icrc2021.desy.de/pf_access_abstracts
Corresponding Session: https://icrc2021-venue.desy.de/channel/Presenter-Forum-1-Evening-All-Categories/48
Abstract:
'Silicon Photomultiplier (SiPM) detectors have become the preferred photosensors for many applications in high-energy particle and astroparticle physics, LIDAR and medical imagining. Due to their robustness, low working voltage, ability to work during moon light and high photon detection efficiency, SiPM devices are good choice for cameras of Imaging Atmospheric Cherenkov Telescopes (IACTs), as pioneering works of FACT, SST-1M and other small size telescope projects in CTA, such a ASTRI and CHEC, demonstrated. However, the overvoltage (the difference between the applied and breakdown voltages) affects almost all device parameters like gain, photodetection efficiency or PDE, uncorrelated and correlated noise. In particular, by increasing the overvoltage a high PDE of 60% can be reached. On the other hand, high overvoltage leads to higher correlated noise, affecting image reconstruction. 

    In this work we study the effect of SiPM correlated noise and PDE on the charge resolution of IACTs, with the goal to find the optimal overvoltage value providing the best balance between these to parameters. The study was done with Monte Carlo simulation (i.e. sim_telarray – simulation of the imaging atmospheric Cherenkov technique) and validated with measurements in the laboratory with calibrated light sources (one to mimic Cherenkov light and another for night sky background NSB). The studies were performed for SiPM devices produced by Hamamatsu and FBK. The studies were performed at different NSB levels from 3MHz up to 1 GHz of photon rate per sensor at room temperature (T = 25 C).'

Authors: Andrii Nagai | Teresa Montaruli | Domenico della Volpe | Matthieu Heller | Mykhailo Dalchenko | David Medina Miranda
Indico-ID: 1305
Proceeding URL: https://pos.sissa.it/395/762