First results of the two square meters multilayer glass composite mirror design proposed for the Cherenkov Telescope Array developed at INFN

TL;DR

This paper presents the initial development and testing of a novel lightweight, cost-effective multilayer glass composite mirror design for the Cherenkov Telescope Array, aiming to meet large-scale production needs.

Contribution

It introduces a new mirror fabrication method using replication from a spherical mold with an open, multilayer glass and steel structure for CTA.

Findings

Produced initial mirrors with acceptable optical properties

Demonstrated the feasibility of the replication manufacturing process

Achieved a lightweight and potentially scalable mirror design

Abstract

The Cherenkov Telescope Array (CTA) is a future ground-based gamma-ray astronomy detector that will consist of more than 100 Imaging Atmospheric Cherenkov Telescopes of different sizes. The total reflective surface of roughly 10 000 m$^2$ requires unprecedented technological efforts towards a cost-efficient production of light-weight and reliable mirror substrates at high production rate. We report on a new mirror concept proposed for CTA developed by INFN, which is based on the replication from a spherical convex mold under low pressure. The mirror substrate is an open structure design made by thin glass layers at the mirror's front and rear interspaced by steel cylinders. A first series of nominal size mirrors has been produced, for which we discuss the optical properties in terms of radius of curvature and focusing power.