A second generation low stress cryogenic mount for space-borne lithium fluoride optics

E. Todd Kvamme; Michael Jacoby

doi:10.1117/12.742095

12 September 2007 A second generation low stress cryogenic mount for space-borne lithium fluoride optics

E. Todd Kvamme, Michael Jacoby

Proceedings Volume 6692, Cryogenic Optical Systems and Instruments XII; 66920I (2007) https://doi.org/10.1117/12.742095
Event: Optical Engineering + Applications, 2007, San Diego, California, United States

Abstract

Single crystal Lithium Fluoride 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, this material has poor mechanical properties, which 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 a room temperature CTE of ~37ppm/K, the material deforms plastically under relatively small tensile loading. This paper will update a paper presented in 2005 on the same optical mount [1]. The mount has been proven via vibration and thermal-vacuum testing to successfully mount large (70 mm-94 mm) Lithium Fluoride optics for application in space. An overview of Lithium Fluoride material properties and characteristics is given and updated yield strength test data is provided and discussed. A design limit load is determined for the material based on strength values from the literature as well as independent testing. The second generation mount design is then presented along with test data and results. Finally, the test results are discussed showing survival and performance of the optic and mount during cool-down to the operational thermal environment.

Citation Download Citation

E. Todd Kvamme and Michael Jacoby "A second generation low stress cryogenic mount for space-borne lithium fluoride optics", Proc. SPIE 6692, Cryogenic Optical Systems and Instruments XII, 66920I (12 September 2007); https://doi.org/10.1117/12.742095

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available