Performance Evaluation of Three Silicon Photomultiplier Detector Modules within the MAGIC Telescopes PMT-based camera

TL;DR

This paper evaluates the performance of three silicon photomultiplier detector modules integrated into the MAGIC telescopes' camera, comparing simulated expectations with actual measurements to assess their suitability for Cherenkov light detection.

Contribution

It introduces and tests three SiPM-based detector modules compatible with MAGIC telescopes, including thermal performance analysis and signal-to-noise ratio evaluation.

Findings

Simulations of Cherenkov and LoNS responses conducted

Measured SNR aligns with simulation predictions

Thermal PCB designs impact detector performance

Abstract

MAGIC is a system of two imaging atmospheric Cherenkov telescopes (IACTs) located on the Canary island of La Palma. Each telescope's imaging camera consists of 1039 photomultiplier tubes (PMTs). We developed three detector modules based on silicon photomultipliers (SiPMs) of seven pixels each that are mechanically and electronically compatible with those used in the MAGIC camera. These prototype modules are installed next to the PMTs in the imaging camera and are operated in parallel. To achieve a similar active area per pixel we used seven to nine SiPMs for producing a composite pixel. The SiPM signals within one such pixel are actively summed up for retaining the fast signal pulse shapes. Two different PCB designs are tested for thermal performance. We present our simulations of Cherenkov and light of the night sky (LoNS) responses. Based on those we calculate the signal-to-noise ratio (SNR) for this imaging application. We compare our expectations with the measurements of one of the SiPM-based detector modules.