The Small-Sized Telescopes for the Southern Site of the Cherenkov Telescope Array

TL;DR

This paper discusses the design, technology, and development of the Small-Sized Telescopes for the Cherenkov Telescope Array's southern site, highlighting their innovative dual-reflector design and advanced camera system for high-energy gamma-ray detection.

Contribution

It introduces the final design and technological advancements of the SSTs, including the dual-reflector Schwarzschild-Couder configuration and SiPM-based cameras, for the CTA southern site.

Findings

Successful operation of prototype telescopes and cameras.

Development of a cost-efficient, compact design.

Enhanced sensitivity to gamma rays above 1 TeV.

Abstract

The Cherenkov Telescope Array (CTA) will use three telescope sizes to efficiently detect cosmic gamma rays in the energy range from several tens of GeV to hundreds of TeV. The Small-Sized Telescopes (SSTs) will form the largest section of the array, covering an area of many square kilometres on the CTA southern site in Paranal, Chile. Up to 70 SSTs will be implemented by an international consortium of institutes and teams as an in-kind contribution to the CTA Observatory. The SSTs will provide unprecedented sensitivity to gamma rays above 1 TeV and the highest angular resolution of any instrument above the hard X-ray band. CTA has recently finalised the technology that will be used for the SSTs: the telescopes will be a dual-reflector design with a primary reflector of ~4 m diameter, equipped with an SiPM-based camera with full waveform readout from $\sim$2000 channels covering a $\sim$9$^\circ$ field of view. The Schwarzschild-Couder optical configuration leads to a small plate-scale, and consequently a compact, cost-efficient camera. In this contribution, we describe the experience gained operating telescope and camera prototypes during the CTA preparatory phase, and the development of the final SST design.