<title>Direct emissivity measurements of IR materials</title>

Emissivity measurements of ZnS, Sapphire, ALON, MgO, and Yttria were performed in 3.9-4.0 micrometers and 4.4-4.9 micrometers bands, for temperatures between 300 degrees C and 600 degrees C. The average radiance was measured over each waveband. Emissivity was calculated as the ratio of the radiance of the sample to that of a black body source at the same temperature. The results of the emissivity measurements for the above-mentioned materials will be reported. Measurement techniques that allowed increasing the dynamic range of the measurement and significantly reducing the noise will be discussed.