Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Comparison of a detector-based near-IR radiance-scale to an ITS-90 calibrated radiation thermometer



George P. Eppeldauer, Howard W. Yoon, Jinan Zeng, Thomas C. Larason


Integrating-sphere-input InGaAs radiometers have been developed at the National Institute of Standards and Technology (NIST) to extend the detector-based calibrations from the Si range to the near-IR. These near-IR radiometers are used to determine the reference spectral irradiance responsivity scale based on the primary standard cryogenic radiometer. The irradiance responsivity scale is then propagated to spectral radiance at the exit port of an integrating sphere. The near-infrared radiation thermometer (NIRT) is calibrated against this detector-based radiance scale. The first phase of this research work is reported here where the relative spectral radiance responsivity of the NIRT has been determined using a monochromator-based system. Thereafter, the relative spectral reponsivity of the NIRT is converted into an absolute responsivity using the signal at the Zn fixed-point blackbody, and then used to extend these calibrations for temperature measurements between 157 degree C and 1000 degree C. The NIRT has also been calibrated in this temperature range against the five fixed points of the ITS-90. The two different calibration approaches for temperature measurements are compared.
International Journal of Thermophysics


InGaAs detector, irradiance responsivity, ITS-90, near-infrared, optical radiation, radiance, radiation thermometer, radiance temperature, spectral responsivity, temperature scales


Eppeldauer, G. , Yoon, H. , Zeng, J. and Larason, T. (2011), Comparison of a detector-based near-IR radiance-scale to an ITS-90 calibrated radiation thermometer, International Journal of Thermophysics, [online], (Accessed July 16, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created August 7, 2011, Updated February 19, 2017