1994 Volume 78 Issue 10 Pages 568-573
Electrotechnical Laboratory has established a standard of spectral response at 633 nm based on the self-calibration of a silicon photodiode and an absolute radiometer (operating at room temperature). The standard was maintained a windowed silicon photodiode and transferred by a calibration system using a monochromator. The change in the response of the windowed silicon photodiode was 0.04% over five years. The accuracy of this standard was verified through three international comparisons: the first one organized by CCPR in 1986, the second by CIE in 1988, and the third by CCPR in 1992. The uncertainty of the standard is estimated to be 0.2%.