Developments in the New Spectral Irradiance Scale at the National Institute of Standards and Technology

摘要

Recent developments for a new spectral irradiance scale realization at the National Institute of Standards and Technology (NIST) have been targeted to reduce the present relative expanded uncertainties of 0.67% to 4.34% (for a coverage factor of k=2, or equivalently two standard deviations) in the spectral irradiance scale to 0.17% for the range from 350 nm to 1100 nm. To accomplish this goal, a suite of filter radiometers calibrated using NIST's high accuracy cryogenic radiometer have been used to measure the temperature of a high-temperature blackbody. A comparison of the filter radiometer calibrations with the spectral irradiance scale along with an evaluation of the blackbody calibration technique have been performed. With the aid of a monochromator, the calibrated filter radiometers will then be utilized to calibrate primary and secondary spectral irradiance standard lamps at NIST.