Refractive Index of Sodium Iodide

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3689746· OSTI ID:1036576

Jellison, Jr, Gerald Earle ^[1]; Boatner, Lynn A ^[1]; Ramey, Joanne Oxendine ^[1]; Kolopus, James A ^[1]; Ramey, Lucas A ^[1]; Singh, David J ^[1]

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1. ORNL

The refractive index of sodium iodide, an important scintillator material that is widely used for radiation detection, is based on a single measurement made by Spangenberg at one wavelength using the index-matching liquid immersion method (Z. Kristallogr., 57, 494-534 (1923)). In the present paper, we present new results for the refractive index of sodium iodide as measured by the minimum deviation technique at six wavelengths between 436 nm (n=1.839 0.002) and 633 nm (n=1.786 0.002). These 6 measurements can be fit to a Sellmeier model, resulting in a 2 of 1.02, indicating a good fit to the data. In addition, we report on ellipsometry measurements, which suggest that the near-surface region of the air sensitive NaI crystal seriously degrades, even in a moisture-free environment, resulting in a significantly lower value of the refractive index near the surface. First-principles theoretical calculations of the NaI refractive index that agree with the measured values within 0.025-0.045 are also presented and discussed.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: NNSA USDOE - National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1036576
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 4 Vol. 111; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AIR
DATA
ELLIPSOMETRY
PHOSPHORS
RADIATION DETECTION
REFRACTIVE INDEX
SODIUM IODIDES
WAVELENGTHS