Speaker
Description
In the last decade the Osservatorio Astronomico di Brera of the Italian Institute for Astrophysics, INAF, got deeply involved in Cherenkov optics manufacturing and testing contributing to the realization of mirrors for MAGIC and CTA projects. In this paper we would like to review the characterization facilities that INAF-OAB developed to qualify Cherenkov mirrors performance. The design of these facilities was driven by the general Cherenkov optics configuration, which is realised with a large number of mirrors with arc-minutes resolution. The capability to obtain arc-minutes resolution characterization in a short measuring time is hence a driving concept for an efficient Cherenkov mirror qualification facility. The first facility implemented by INAF-OAB for Cherenkov optics is an outdoor 2f optical bench equipped with a large area CCD detector. This facility is very advantageous for the Cherenkov spherical mirrors qualification allowing both radius of curvature and focal spot measurements. Nevertheless, as any 2f facility, this facility has the capability to manage exclusively focusing optics. On the other hand, the introduction of novel optical design for Cherenkov telescopes, like the Schwarzschild-Couder design, creates the necessity to qualify free-form non-focusing optics. For these reason the INAF-OAB developed a flexible deflectometry setup capable to qualify any kind of Cherenkov optics. This system, based on an inverse Ronchi test working in synergy with specific software, allows precise simulation of the focal spot at telescope focal plane. In this contribution we will describe these facilities, present some measurement results and discuss the wide range of possible application they offer.
