Colour centres of ceramic dielectrica rich in alumina

By influence of Co60 γ-radiation on ceramic dielectrica rich in alumina a formation of colour centres occurs up to radiation doses of about 258 C/kg. The centres exhibit the characteristic of impurities and were formed by changing the valence state of Cr3+, which is contained isomorphous in the corundum lattice. Influenced by radiation, Cr3+ changes in Cr2+ and Cr4+ and causes absorption in the ranges from 360 to 380 and 460 to 480 nm respectively. A thermal decomposition of colour centres is accompanied by thermoluminescence with a radiation spectrum in the field of the R-lines of chromium. (author)