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Proceedings Paper

Design and performance of the VLT 8-m coating unit
Author(s): Michael W. Schneermann; Martin Groessl; U. Nienaber; E. Ettlinger; J. A. Spiteri; H. Clow
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Paper Abstract

The 8 m coating unit for the VLT mirrors is designed for the deposition of high reflective, homogeneous aluminum coatings. For the process of the film deposition the sputter technology is utilized. The design of the following major subsystems is completed: the vacuum vessel and the vacuum generation system, the thin film deposition equipment and the glow discharge cleaning device, the substrate support and rotation system as well as the supporting framework and the auxiliary equipment. Manufacturing of the coating unit has started. The pre- assembly and testing activities, which will take place prior to the shipment to the site, are defined. This paper describes the design features and the major performance requirements of the 8 m coating unit. The performance of the sputter source design has been verified in a qualification test. The deposition rate, the film thickness and reflectance, as well as the film purity have been measured. The test set-up and the results of the qualification tests of the selected magnetron type are presented and discussed.

Paper Details

Date Published: 21 March 1997
PDF: 9 pages
Proc. SPIE 2871, Optical Telescopes of Today and Tomorrow, (21 March 1997); doi: 10.1117/12.269032
Show Author Affiliations
Michael W. Schneermann, European Southern Observatory (Germany)
Martin Groessl, European Southern Observatory (Germany)
U. Nienaber, Linde A.G. (Germany)
E. Ettlinger, Linde A.G. (Germany)
J. A. Spiteri, Airco Coating Technology (United Kingdom)
H. Clow, Airco Coating Technology (United Kingdom)

Published in SPIE Proceedings Vol. 2871:
Optical Telescopes of Today and Tomorrow
Arne L. Ardeberg, Editor(s)

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