Design and Performance of the Upgraded Prototype Schwarzschild-Couder Telescope Camera Module

TL;DR

This paper details the design, upgrade, and performance testing of the prototype Schwarzschild-Couder Telescope camera module, enhancing gamma-ray detection capabilities for the Cherenkov Telescope Array.

Contribution

It introduces an upgraded camera module with 11,328 SiPM pixels, improved electronics, and a calibration procedure, advancing the pSCT's observational performance.

Findings

Low noise and minimal crosstalk achieved in modules

Excellent charge resolution demonstrated in calibration tests

Successful upgrade prepares for full camera deployment

Abstract

The Cherenkov Telescope Array Observatory (CTAO) is a ground-based observatory that will improve upon the sensitivities of the current generation of very-high-energy gamma-ray instruments. The Schwarzschild-Couder Telescope (SCT) is a dual-mirror candidate design for a CTAO Medium-Sized Telescope (MST). The prototype Schwarzschild-Couder Telescope (pSCT) was inaugurated in 2019 at Fred Lawrence Whipple Observatory (FLWO) in Arizona and observed significant gamma-ray emission from the Crab Nebula with a partially populated camera. The pSCT camera is currently being upgraded to fully instrument the focal plane with 11,328 silicon photomultiplier (SiPM) pixels split between 177 camera modules. Additionally, the modules will feature upgraded electronics designed to reduce electronics crosstalk and noise. A module calibration procedure has been developed using a preproduction test module. Following this calibration procedure, performance testing shows that the upgrade module has low noise, minimal electronics crosstalk, and excellent charge resolution. After calibration and optimization, the 177 production modules will be installed in the pSCT camera for commissioning. This will be followed by observations of known VHE gamma-ray sources for camera performance validation.