Integrating sphere photometer for infrared region on the basis of chemically treated aluminum

In the practice of spectrophotometric studies, a need often arises for measurements of the transmission and reflection factors of various diffusing objects. In the visible band of wavelengths, this problem has been practically solved by using a sphere photometer with an inner coating of BaSO 4 paint, or a polyvinyl alcohol, MgO, and others. For these aims, in the infrared region of the spectrum use is made, as a rule, of systems allowing us to concentrate on a photodetector with the radiation scattered by a specimen to the half-space. The sphere photometers, available at present for the infrared region, either are slightly efficient or may be applied in a comparatively narrow spectral range. We are suggesting specially treated aluminum as an inner coating for the sphere photometer surface. The factor of diffusion reflection of such a coating reaches 0.92 and is slightly selective up to 25 micrometers , the diffusion indicatrix is close to the Lambert one and remains unchanged in the entire stated interval, the deviation from the Lambert law at an oblique illumination of up to 70 degree(s) does not exceed 10%.