AGC supplies magnetron sputtering coater for mirror of the world’s largest telescope

Through its newly created unit AGC Plasma Technology Solutions(1), AGC Glass Europe has been awarded a contract by the European Southern Observatory (ESO) to supply the magnetron sputtering coating(2) plant aimed at producing the mirror for the world’s largest optical telescope, the Extremely Large Telescope (ELT). This telescope manufactured by ESO will be installed at Cerro Armazones (3,046m) in the Atacama desert (Chilean Andes). It will be equipped with a gigantic 39-meter segmented primary mirror(3) to collect the light from the cosmos and allow astronomers discover unexplored galaxies, study exoplanets and investigate other objects and phenomena across the universe.

The plant will perform the initial coating and subsequent re-coating with a protected silver layer stack on the mirror segments. These coating operations are required by the harsh climate conditions such as sandstorms that are liable to affect the silver layers of the primary mirror. AGC will do the design, manufacture, on-site assembly and commissioning of the mirror segment coating plant at the ELT Technical Facility located at Paranal Observatory in Chile. Patrick Van Bortel, Vice-President, New Business & Industrial Glass of AGC Glass Europe, concludes: “The selection of the proposed coater solution comes in recognition of our expertise and knowhow in building custom-designed plasma coating equipment by our teams in Gosselies, Belgium and Lauenförde, Germany.”

1: Specialised in developing and industrialising innovative vacuum plasma coating technologies.

2: Magnetron sputtering is a plasma-based coating technique for depositing very thin layers of materials, including metals, onto substrate materials such as glass. As a result, coated materials gain specific properties in terms of thermal insulation, solar control, reflection, etc.

3: The primary mirror consists of 798 segments, each 1.4 metres wide but only 50 mm thick.