Development of a SiPM Pixel Prototype for the Large-Sized Telescope of the Cherenkov Telescope Array

TL;DR

This paper presents the development and laboratory validation of a SiPM-based pixel prototype for the CTA's Large-Sized Telescope, aiming to improve timing and charge resolution in gamma-ray detection.

Contribution

It introduces a novel SiPM pixel prototype with redesigned electronics for the CTA LST, demonstrating enhanced performance over traditional PMT-based modules.

Findings

Prototype achieves high timing resolution

Charge resolution meets design goals

Laboratory tests validate design choices

Abstract

The Cherenkov Telescope Array (CTA) will be the next generation ground-based gamma-ray observatory. CTA consists of different telescope types of which the largest ones (Large-Sized Telescopes, LSTs) cover the lower energy range, between 20 GeV and 200 GeV. The first LST is currently being commissioned at the Roque de los Muchachos Observatory, La Palma, Canary Islands. Its camera has 1855 photomultipliers (PMTs) with 1.5 inch cathodes. Silicon Photomultipliers (SiPMs) are increasingly becoming valid alternatives to PMTs also in gamma-ray astronomy. In the context of the LST project, there is an effort to study a novel Advanced Camera, equipped with SiPMs and a completely redesigned electronics based on a fully digital approach. To study and develop solutions on the sensors of these camera, we built a prototype camera module with a fully re-designed pre-amplifying stage and sensor bias control while re-using the digitizing and triggering stages of the existing LST camera module. We report on the design choices made to achieve the highest performance in terms of timing and charge resolution and the laboratory measurements validating those choices.