X-RAY-INDUCED PROCESSES IN BI12TIO20 SINGLE-CRYSTALS

X-ray induced luminescence (radioluminescence or RL) in the visible ra nge, thermally stimulated luminescence (thermoluminescence or TL), and X-ray induced optical damage and its bleaching are studied in nominal ly pure Bi12TiO20 crystals within the temperature range 12 to 330 K. A single emission band of complex shape is observed at 495 nm in the RL spectra and its behaviour with dose and temperature is studied. This band is proposed to have an intrinsic origin. The optical absorption i nduced by X-ray irradiation shows a broad band in the visible region s imilar to those reported for Bi12GeO20 and Bi12SiO20, but presents a d ifferent behaviour with the temperature of irradiation. This absorptio n structure is proposed to be related to holes trapped at the oxygen s ublattice.