Radiation defects in SrB4O7:Eu2+ crystals

Radiation-induced defects in SrB4O7:Eu2+ (0.033 at.%) single crystal irradiated with γ and X-ray quanta has been studied. The induced optical absorption in the 400–700 nm region has been ascribed to F+ centers. The Eu2+ ions have been shown to act simultaneously as traps and as radiative recombination centers of charge carriers. Basing on the thermally stimulated luminescence (TSL), optical absorption and photoluminescence studies of SrB4O7:Eu2+ crystals, a TSL mechanism has been proposed associated with the decay of F+ centers being in non-equivalent crystallographic positions followed by radiative recombination of charge carriers on europium ions. Various positions of localization of the radiation-induced defects in the SrB4O7 crystal structure have been discussed.