Manufacturing of aluminum mirrors for cryogenic applications
Kinast J, Schlegel R, Kleinbauer K, Steinkopf R, Follert R, Dorn RJ, Lizon JL, Hatzes A, Tuennermann A (2018)
Publication Type: Conference contribution
Publication year: 2018
Journal
Publisher: SPIE
Book Volume: 10706
Conference Proceedings Title: Proceedings of SPIE - The International Society for Optical Engineering
Event location: Austin, TX, USA
ISBN: 9781510619654
DOI: 10.1117/12.2313126
Abstract
Several mirrors for the upgrade of the CRyogenic high-resulution InfraRed Echelle Sprectrograph (CRIRES) at the Very Large Telescope, were manufactured by diamond turning and polishing. These mirrors will be used in the crossdispersion unit (CDU) and the fore optics of the instrument. For background level reasons, the operational temperature of the CDU is set to 65 K. Therefore, the flat and spherical mirrors used in the CDU, which are made of melt-spun aluminum alloy Al6061, had to be artificially aged, to improve the dimensional stability at cryogenic temperatures. After diamond turning, magnetorheological finishing (MRF) was used for a deterministic shape correction and to remove the turning marks of the RSA6061 mirrors. To reduce the micro-roughness, a further smoothing step was necessary. A micro-roughness between 1 nm RMS and 5 nm RMS as well as shape deviations below 35 nm RMS were achieved. The mirrors were coated by inline magnetron sputtering with a high-reflective gold layer or protected silver, respectively.
Involved external institutions
Fraunhofer-Institut für Angewandte Optik und Feinmechanik (IOF) / Fraunhofer Institute for Applied Optics and Precision Engineering
Germany (DE)
Thüringer Landessternwarte Tautenburg (TLS) - Karl-Schwarzschild-Observatorium
Germany (DE)
European Southern Observatory (ESO)
Germany (DE)
Germany (DE)
Thüringer Landessternwarte Tautenburg (TLS) - Karl-Schwarzschild-Observatorium
Germany (DE)
European Southern Observatory (ESO)
Germany (DE)
How to cite
APA:
Kinast, J., Schlegel, R., Kleinbauer, K., Steinkopf, R., Follert, R., Dorn, R.J.,... Tuennermann, A. (2018). Manufacturing of aluminum mirrors for cryogenic applications. In Roland Geyl, Ramon Navarro (Eds.), Proceedings of SPIE - The International Society for Optical Engineering. Austin, TX, USA: SPIE.
MLA:
Kinast, Jan, et al. "Manufacturing of aluminum mirrors for cryogenic applications." Proceedings of the Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III 2018, Austin, TX, USA Ed. Roland Geyl, Ramon Navarro, SPIE, 2018.
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