Effects of γ-radiation on fluorite crystals with a trivalent rare-earth ions

Abstract

The paper considers phenomena of formation of color centers due to intrinsic and impurity defects in fluorite crystals activated by rare-earth ions Pr3+, Nd3+, Yb3+ under γ- and UV-radiation. Using CaF2 activated with Yb3+ and Pr3+ ions as an example, the work shows the effect of the photodynamic process on the photochemical resistance to formation of color centers of a Yb-containing crystal. It also demonstrates the effect of heating on the restoration of the original color of a Pr-containing crystal after γ-radiation as a result of change in the electronic state of praseodymium ions. The features of the formation of ions in the R2+ state in CaF2:R3+ (R3+ = Pr, Nd, Yb) crystals after γ-irradiation are investigated and explained, and quantitative estimates of the R3+→R2+ conversion processes are given.