Spectrométrie IR pour la mesure de faibles variations d'émissivité

We describe here a double beam infrared spectrometer (0.5-10 μm) well adapted for the measurement of small variation in spectral and directional emissivity of surface. With an original switch system, we measure under high vacuum (10 −7 torr), the difference between the radiative power of each side of the sample. In this way, we have measured, the difference between the radiative power of each side of a carbon ribbon, when under vacuum we deposit platinum on one side. We show, that it is possible to measure 0.3% of variation of emissivity, with an accuracy of 10%. Such a variation, is the result a deposit of 3.6×10 15 atoms/cm 2 of platinum on the carbon surface Spectrometre IR double faisceau. Mesure de la difference d'emissivite des 2 faces d'un ruban de carbone lorsqu'un depot de platine est effectuee sur l'une de celles-ci