Helium-Cooled Cavity Radiometer for Absolute Irradiance Measurements

摘要

The purpose of the research program is to develop a practical cryogenic radiometer capable of defining the scale of absolute irradiance to an accuracy on order of magnitude better than is realized in conventional radiometers operating at ambient temperatures. The aim of the Phase I effort has been to standardize an operating procedure for a prototype helium-cooled absolute radiometer (HCAR) and characterize its performance. Applications of the HCAR that were investigated include improved definition of the international irradiance scale; calibration and research on absolute yields of photo-detectors; highly reproducible space measurements of total solar irradiance; accurate calibration of UV detectors and standard lamps in aeronomy and space research; and low flux level calibrations of total radiative output from cryogenic black bodies used as calibration sources.