Two Blackbody Radiometers of High Accuracy

• DOI: 10.1364/ao.9.001082
• Publication Date: 2008-11-21T13:52:46Z
• Authors: J. M. Kendall; C. M. Berdahl
• Keywords: Black-body radiation; Radiometry; Halogen lamp; Aperture (computer memory); Absorptance

Two cavity-type radiometers have been developed, based on first principles, having the capability of measuring an irradiance with indicated error 0.3%. The prerequisites for this accuracy are a measured aperture area, measurement electric voltages, and effective absorptance its blackbody cavity from 0.998 to 0.999 throughout uv, visible, ir spectral ranges. radiometer is designed operate only in vacuum <10−5 Torr measure intensities 10 mW cm−1 300 cm−2. By using evacuated cold chamber, experimental determination Stefan-Boltzmann constant obtained at value that differs theoretical by 0.3%, which indicates degree confidence can be expected measurements made radiometers. second type either air or vacuum. Although opening windowless, it unaffected wind. range accurately measurable about cm−2 800 cm−2; also