NIST develops an improved modular radiometer/photometer system - News Briefs - National Institute of Standards and Technology

Journal of Research of the National Institute of Standards and Technology, Jan, 2002

A new generation photo/radiometer system has been established to realize and propagate the high accuracy detector-based radiometric scales maintained by NIST. The radiometers can measure a variety of radiometric quantities such as radiant power, irradiance, and radiance over spectral regions from the ultraviolet to the near infrared. The photometers measure illuminance and luminance.

The new radiometers and photometers are modular systems. The detectors can be cooled to improve the noise performance and the stability of the meters, while the filter packages, positioned in front of the detectors, can be heated slightly above room temperature to ensure stable spectral transmission without condensation. A variety of photodiode detectors (e.g., nitrided-Si, Si, Ge, InGaAs, and extended InGaAs) are positioned behind the different filter and diffuser combinations to cover the spectral regions over which the instrument is sensitive. Typical relative standard uncertainties of radiometric and photometric measurements made using the new standards are 0.1 %.

CONTACT: George Eppeldauer, (301) 975-2338; george.eppeldauer@nist.gov