Calibration of 253.7nm irradiance based on the silicon photodiode self-calibration technique (2)

Analysis of the uncertainties

Abstract

An attempt was made to intercompare the accuracy for the 3 methods of 253.7nm irradiance calibration. The first method, which we have already reported, is based on the silicon photodiode self-calibration technique. In this method, the absolute responsivity at 253.7nm of the photodiode was determined by the absolute responsivity at 632.8nm calibrated by the self-calibration technique and the relative spectral responsivity measurement. The second method uses a thermal detector calibrated by standard lamps and optical filters. The third method is a comparison measurement with the blackbody using a monochromator. The scales of 253.7nm irradiance realized by the three methods agreed within 1.5% and it is confirmed that each method has sufficient accuracy for primary standards of the 253.7nm irradiance.