Infrared Diffuse Reflectance Instrumentation and Standards at NIST

Published

June 29, 1998

Author(s)

Leonard M. Hanssen, Simon G. Kaplan

Abstract

A spectrophotometer system for spectral characterization of materials in the infrared has been built around a bench-top Fourier transform (FTIR) instrument. Its capabilities include the measurement of directional-hemispherical reflectance from 1 *m to 18 *m. The spectral reflectance measurement is performed with an integrating sphere with incidence angle of 8*. Both relative and absolute measurements can be made. Several methods can be used to determine the absolute value of the directional hemispherical reflectance of samples. The primary method used is independent of integrating sphere theory and the requisite assumptions associated with its use. The calibration of a standard reference material (SRM) is described. This SRM has a reflectance value near 0.9 over the complete calibration range of 2 *m to 18 *m. As part of the calibration procedure the spatial uniformity of the sphere throughput and the BRDF of the SRM material are evaluated.

Proceedings Title

Proceedings of Conference on Optical Spectrometry

Conference Dates

June 28-29, 1998

Conference Location

Egham, UK

Conference Title

Analytica Chimica Acta

Pub Type

Conferences

Keywords

diffuse, infrared, integrating sphere standard, reflectance, spectrometry

Citation

Hanssen, L. and Kaplan, S. (1998), Infrared Diffuse Reflectance Instrumentation and Standards at NIST, Proceedings of Conference on Optical Spectrometry, Egham, UK (Accessed September 18, 2025)