Lithium fluoride material properties as applied on the NIRCam instrument

E. Todd Kvamme; James C. Earthman; Douglas B. Leviton; Bradley J. Frey

doi:10.1117/12.614180

25 August 2005 Lithium fluoride material properties as applied on the NIRCam instrument

E. Todd Kvamme, James C. Earthman, Douglas B. Leviton, Bradley J. Frey

Proceedings Volume 5904, Cryogenic Optical Systems and Instruments XI; 59040N (2005) https://doi.org/10.1117/12.614180
Event: Optics and Photonics 2005, 2005, San Diego, California, United States

Abstract

Single crystal Lithium Fluoride (LiF) has been base-lined as one of the optical materials for the Near Infra-Red Camera (NIRCam) on the James Webb Space Telescope (JWST). Optically, this material is outstanding for use in the near IR. Unfortunately, it has poor mechanical properties that make it very difficult for use in any appreciable size on cryogenic space based instruments. In addition to a dL/L from 300K to 30K of ~-0.48% and room temperature CTE of ~37ppm/K, LiF deforms plastically under relatively small stresses. This paper will discuss the heritage of LiF in space-based systems and summarize the mechanical and thermal material data for LiF that is available in the literature. New data will be presented relative to a design limit load for the material so that designers can use this material for space flight applications. Additional new data relative to the cryogenic index of refraction of the material over the near infrared is also provided.

Citation Download Citation

E. Todd Kvamme, James C. Earthman, Douglas B. Leviton, and Bradley J. Frey "Lithium fluoride material properties as applied on the NIRCam instrument", Proc. SPIE 5904, Cryogenic Optical Systems and Instruments XI, 59040N (25 August 2005); https://doi.org/10.1117/12.614180

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