Design of a SiPM-based cluster for the Large Size Telescope camera of CTA

TL;DR

This paper presents the design and testing of a SiPM-based cluster for the CTA's Large Size Telescope camera, aiming to replace traditional PMT units with a silicon-based alternative.

Contribution

It introduces a novel SiPM cluster design compatible with existing telescope mechanics and electronics, demonstrating its performance and outlining future development steps.

Findings

Measured SiPM gain, efficiency, and cross-talk to optimize performance.

Built a 14-SiPM pixel prototype and evaluated its preliminary results.

Outlined future steps for full-scale implementation.

Abstract

A Silicon Photomultiplier (SiPM)-based photodetector is being built to demonstrate its feasibility for an alternative silicon-based camera design for the Large Size Telescope (LST) of the Cherenkov Telescope Array. It has been designed to match the size of the standard Photomultiplier Tube (PMT) cluster unit and to be compatible with mechanics, electronics and focal plane optics of the first LST camera. Here, we describe the overall SiPM cluster design along with the main differences with respect to the currently used PMT cluster unit. The fast electronics of the SiPM pixel and its layout are also presented. In order to derive the best working condition for the final unit, we measured the SiPM performances in terms of gain, photo-detection efficiency and cross-talk. One pixel, a unit of 14 SiPMs, has been built. We will discuss also some preliminary results regarding this device and we will highlight the future steps of this project.