Emissivity measurement under vacuum in the wavelength range from 4 μm to 100 μm and temperature range from -40 ℃ to 500 ℃ at PTB

摘要

A new facility of the Physikalisch-Technische Bundesanstalt (PTB) for emissivity measurement underrnvacuum was brought into operation capable to measure directional spectral emissivity in thernwavelength range from 4 μm to 100 μm and temperature range from -40 ℃ to 500 ℃. Here wernpresent the measurement scheme with respect to the spectral radiance of two blackbodies at differentrntemperatures and discuss the evaluation of the emissivity results.rnWe present first results of emissivity measurements under vacuum in the wavelength range from 4 μmrnto 100 μm and temperature range from -20 ℃ to 200 ℃, compare them with results obtained in airrnand show that samples with very low emissivity can be measured with sufficiently low uncertainty.