Development of a strategy for calibrating the novel SiPM camera of the SST-1M telescope proposed for the Cherenkov Telescope Array

TL;DR

This paper presents a fully automated calibration strategy for the SiPM camera of the SST-1M telescope, designed for the Cherenkov Telescope Array, ensuring reliable performance in gamma-ray observations.

Contribution

It introduces a novel calibration method using a Camera Test Setup with LED boards, integrated into CTA pipeline software for large-scale validation and online calibration.

Findings

Successful calibration of the SST-1M SiPM camera using LED-based tests

Compatibility of calibration software with CTA pipeline demonstrated

Enhanced performance during high night sky background conditions

Abstract

CTA will comprise a sub-array of up to 70 small size telescopes (SSTs) at the southern array. The SST-1M project, a 4 m-diameter Davies Cotton telescope with 9 degrees FoV and a 1296 pixels SiPM camera, is designed to meet the requirements of the next generation ground based gamma-ray observatory CTA in the energy range above 3 TeV. Silicon photomultipliers (SiPM) cameras of gamma-ray telescopes can achieve good performance even during high night sky background conditions. Defining a fully automated calibration strategy of SiPM cameras is of great importance for large scale production validation and online calibration. The SST-1M sub-consortium developed a software compatible with CTA pipeline software (CTApipe). The calibration of the SST-1M camera is based on the Camera Test Setup (CTS), a set of LED boards mounted in front of the camera. The CTS LEDs are operated in pulsed or continuous mode to emulate signal and night sky background respectively. Continuous and pulsed light data analysis allows us to extract single pixel calibration parameters to be used during CTA operation.