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

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.

Automated summary

The Cherenkov Telescope Array (CTA) is a new generation gamma-ray observatory on the ground. It consists of different types of telescopes, with the large-sized telescopes (LSTs) covering the energy range from 20 GeV to 200 GeV. The first LST is currently being tested at the Roque de los Muchachos Observatory in La Palma, Canary Islands. To improve the camera performance, researchers are studying a novel Advanced Camera equipped with Silicon Photomultipliers (SiPMs) and a fully digital electronics system. Laboratory measurements have been conducted to validate the design choices regarding timing and charge resolution.