Spectral irradiance primary scale realization and characterization of deuterium lamps from 200 to 400 nm.

Abstract

To meet the increasing metrology demand of spectral irradiance in the short UV spectral range, a new spectral irradiance scale from 200 to 400 nm was realized at National Institute of Metrology (NIM) based on a high-temperature blackbody BB3500M, and a group of stable deuterium lamps are used as the transfer standards. Accurate real-time temperature of a blackbody is derived to reduce the temperature drift during the measurement period. A combination of an absolute and relative measurement system is designed to reduce repeatability uncertainty, and a selective optical filter method is used to remove fluorescence with a peak at 330 nm. A seven-point bandwidth novel correction method based on differential quadrature formula is put forward to correct the bandwidth error of the monochromator. The expanded uncertainties of the new spectral irradiance scale are 5.3% at 200 nm, 1.8% at 250 nm, 1.9% at 330 nm, and 3.6% at 400 nm, respectively. In the overlap wavelength from 250 to 400 nm, the average deviation between two types transfer standards, deuterium lamps and tungsten halogen lamps, is verified to be 0.39%, which are consistent with the associated measurement uncertainties.