학술논문
Substrate temperature and strain during sputter deposition of aluminum on cast borosilicate glass in a Gemini Observatory coating chamber
Document Type
Report
Author abstract
Author abstract
Source
Applied Optics. August 20, 2010, Vol. 49 Issue 24, p4610, 11 p.
Subject
Language
English
ISSN
1559-128X
Abstract
Temperature and strain measurements obtained during coating of spin-cast borosilicate samples are presented here with an analysis of these results. These tests were performed for the Large Synoptic Survey Telescope (LSST) project to verify the possible use of sputtering deposition of optical coating on its large 8.4 m diameter primary--tertiary mirror. Made of spin-cast borosilicate glass, the working stress of the mirror's nonpolished surfaces is 100 psi (0.69 MPa), resulting in a local temperature difference limit of 5[degrees]C. To ensure representative environmental conditions, the tests were performed in the Gemini Observatory coating chamber located in Hawaii, whose design was utilized to develop the LSST coating chamber design. In particular, this coating chamber is equipped with linear magnetrons built with cooled heat shields directly facing the mirror surface. These measurements have demonstrated that it will be safe for the LSST to use a magnetron sputtering process for coating its borosilicate primary--tertiary mirror. [c] 2010 Optical Society of America OCIS codes: 310.0310, 310.1860, 310.3840, 310.4925.