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Record Details

Record 59 of 21631
High Accuracy, Absolute, Cryogenic Refractive Index Measurements of Infrared Lens Materials for JWST NIRCam using CHARMS
Author and Affiliation:
Leviton, Douglas(NASA Goddard Space Flight Center, Greenbelt, MD, United States)
Frey, Bradley(NASA Goddard Space Flight Center, Greenbelt, MD, United States)
Abstract: The current refractive optical design of the James Webb Space Telescope (JWST) Near Infrared Camera (NIRCam) uses three infrared materials in its lenses: LiF, BaF2, and ZnSe. In order to provide the instrument s optical designers with accurate, heretofore unavailable data for absolute refractive index based on actual cryogenic measurements, two prismatic samples of each material were measured using the cryogenic, high accuracy, refraction measuring system (CHARMS) at NASA GSFC, densely covering the temperature range from 15 to 320 K and wavelength range from 0.4 to 5.6 microns. Measurement methods are discussed and graphical and tabulated data for absolute refractive index, dispersion, and thermo-optic coefficient for these three materials are presented along with estimates of uncertainty. Coefficients for second order polynomial fits of measured index to temperature are provided for many wavelengths to allow accurate interpolation of index to other wavelengths and temperatures.
Publication Date: Jan 01, 2005
Document ID:
20050139745
(Acquired Apr 04, 2005)
Subject Category: INSTRUMENTATION AND PHOTOGRAPHY
Document Type: Preprint
Meeting Information: SPIE Conference; 31 Jul. - 4 Aug. 2005; San Diego, CA; United States
Meeting Sponsor: International Society for Optical Engineering; United States
Financial Sponsor: NASA Goddard Space Flight Center; Greenbelt, MD, United States
Organization Source: NASA Goddard Space Flight Center; Greenbelt, MD, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: CRYOGENICS; JAMES WEBB SPACE TELESCOPE; NEAR INFRARED RADIATION; ACCURACY; CAMERAS; OPTICAL MATERIALS; REFRACTION; BARIUM FLUORIDES; ZINC SELENIDES; POLYNOMIALS; REFRACTIVITY
Availability Source: Other Sources
Availability Notes: Abstract Only
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