Mirror production for the Cherenkov telescopes of the ASTRI mini-array and the MST project for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) is the next ground-based gamma-ray observatory in the TeV gamma-ray spectral region operating with the Imaging Atmospheric Cherenkov Technique. It is based on almost 70 telescopes of different class diameters- Large-Sized Telescope, Medium-Sized Telescope (MST), and Small-Sized Telescope (SST) of 23, 12, and 4 m, respectively-to be installed in two sites in the two hemispheres (at La Palma, Canary Islands, and near Paranal, Chile). Several thousands of reflecting mirror tiles larger than 1 m(2) will be produced for realizing the segmented primary mirrors of a so large number of telescopes. Almost in parallel, the ASTRI mini-array (MA) is being implemented in Tenerife (Canary Islands), composed of nine 4-m diameter dual-mirror Cherenkov telescopes (very similar to the SSTs). We completed the mirror production for all nine telescopes of the ASTRI MA and two MSTs (400 segments in total) using the cold glass slumping replication technology. The results related to the quality achieved with a large-scale production are presented, also discussing the adopted testing methods and approaches. They will be very useful for the adoption and optimization of the quality assurance process for the huge production (almost 3000 m(2) of reflecting surface) of the MST and SST CTA telescopes. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License.