Features of Optical Degradation under Separate and Simultaneous Events of Irradiation of a BaSO4 Powder Modified by Nanoparticles.

Changes in the in-situ measured diffuse reflection spectra and the integrated absorption coefficient of a barium-sulfate powder modified by silicon-dioxide nanoparticles are analyzed comparatively after separate and simultaneous events of irradiation with 30-keV electrons and solar-spectrum quanta. Two kinetic regions on the curves of degradation of the optical properties are found. Simultaneous irradiation is additive with respect to separate irradiation in the first region. In the second region, the changes caused by simultaneous irradiation are smaller than the sum of changes caused by separate irradiation. [ABSTRACT FROM AUTHOR]