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Aero-thermal simulations of the TMT Laser Guide Star Facility

Vogiatzis, Konstantinos and Boyer, Corrine and Wei, Kai and Tang, Jinlong and Ellerbroek, Brent (2014) Aero-thermal simulations of the TMT Laser Guide Star Facility. In: Adaptive Optics Systems IV. Proceedings of SPIE. No.9148. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 914868. ISBN 9780819496164. http://resolver.caltech.edu/CaltechAUTHORS:20180619-161057988

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Abstract

The Laser Guide Star Facility (LGSF) system of the Thirty Meter Telescope (TMT) will generate the artificial laser guide stars required by the TMT Adaptive Optics (AO) systems. The LGSF uses multiple sodium lasers to generate and project several asterisms from a laser launch telescope located behind the TMT secondary mirror. The laser beams are transported from a location below the primary mirror to the launch telescope using conventional optics to relay the beams along the telescope structure. The beams and relay optics are enclosed into hermetic ducts for safety reasons and to protect the optics against the environment. A Computational Solid Fluid Dynamics (CSFD) model of the LGSF ducts has been developed. It resolves the duct thickness, laser beam transfer lenses, mirrors and their framework for most of the laser beam path that is subject to significant temperature gradients and/or large vertical change. It also resolves the air inside the duct and its thermal interaction with the aforementioned components through conjugate heat transfer. The thermal interaction of the laser beam with the optics is also captured. The model provides guidance to the LGSF design team and a first estimate of the laser beam stability performance and requirement compliance. As the telescope structure design has evolved in the recent years, a new optical path has been proposed for the LGSF. Both the original and the new optical paths are compared against optical, mechanical and other telescope performance related criteria. The optical performance criteria include a first order analysis of the optical turbulence generated within the ducts. In this study simulations of the thermal environment within the ducts of the two candidate paths are performed and conclusions are drawn.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.1117/12.2057208DOIArticle
Additional Information:© 2014 Society of Photo-Optical Instrumentation Engineers (SPIE). The TMT Project gratefully acknowledges the support of the TMT collaborating institutions. They are the Association of Canadian Universities for Research in Astronomy (ACURA), the California Institute of Technology, the University of California, the National Astronomical Observatory of Japan, the National Astronomical Observatories of China and their consortium partners, and the Department of Science and Technology of India and their supported institutes. This work was supported as well by the Gordon and Betty Moore Foundation, the Canada Foundation for Innovation, the Ontario Ministry of Research and Innovation, the National Research Council of Canada, the Natural Sciences and Engineering Research Council of Canada, the British Columbia Knowledge Development Fund, the Association of Universities for Research in Astronomy (AURA), the U.S. National Science Foundation and the National Institutes of Natural Sciences of Japan.
Group:Thirty Meter Telescope
Funders:
Funding AgencyGrant Number
Association of Canadian Universities for Research in Astronomy (ACURA)UNSPECIFIED
CaltechUNSPECIFIED
University of CaliforniaUNSPECIFIED
National Astronomical Observatory of JapanUNSPECIFIED
National Astronomical Observatories, Chinese Academy of Sciences (NAOC)UNSPECIFIED
Department of Science and Technology (India)UNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Canada Foundation for InnovationUNSPECIFIED
Ontario Ministry of Research and InnovationUNSPECIFIED
National Research Council of CanadaUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
British Columbia Knowledge Development FundUNSPECIFIED
Association of Universities for Research in Astronomy (AURA)UNSPECIFIED
NSFUNSPECIFIED
National Institutes of Natural Sciences of JapanUNSPECIFIED
Subject Keywords:Computational Solid-Fluid Dynamics, Laser Guide Star Systems, Ground Based Telescopes
Record Number:CaltechAUTHORS:20180619-161057988
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180619-161057988
Official Citation:Konstantinos Vogiatzis, Corinne Boyer, Kai Wei, Jinlong Tang, Brent Ellerbroek, "Aero-thermal simulations of the TMT Laser Guide Star Facility", Proc. SPIE 9148, Adaptive Optics Systems IV, 914868 (7 August 2014); doi: 10.1117/12.2057208; https://doi.org/10.1117/12.2057208
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87245
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:20 Jun 2018 14:35
Last Modified:20 Jun 2018 14:35

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