HEMISPHERICAL REFLECTANCE MEASUREMENTS IN THE THERMAL SPECTRUM OF DIFFUSE SURFACES
In the thermal spectrum measurement of the hemispherical reflectance is not easy due to the low intensity of the radiation so background radiation and the thermal emittance of the surface must be accounted for. This contribution describes two measuring devices which have been constructed for determining the hemispherical reflectance of diffuse surfaces; an integrating sphere and ellipsoidal mirror. Both installations use a conventional infrared spectrophotometer. With this equipment we can obtain the directional emittance in the infrared region (2.5-2.5 /um) of the spectrally selective rough surfaces. These surfaces, which are produced in our laboratory, are not only diffuse reflective in the solar spectrum but also partly diffuse in the infrared spectrum.
Bibliographic Reference: JOURNEES INTERNATIONALES SUR LES TRANSFERTS HELIOTHERMIQUES, MONASTIR (TUNIS), APRIL 4-10, 1983. WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 30886 ORA
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Record Number: 1989122019900 / Last updated on: 1987-01-01
Available languages: en