Optical absorption and thermoluminescence of barytes single crystals irradiated with γ-rays

The optical absorption in the wavelength region 200 to 800 nm of barytes single crystals before and after γ-ray irradiation for different times has been measured. The thermoluminescence (TL) of the irradiated crystals has also been studied. γ-ray irradiation produces absorption bands at 590 and 370 nm possibly due to Ba+ and (SO4)- centres, respectively. Partial thermal bleaching experiments carried out on these absorption bands show that the absorption in both bands gradually decreases up to 200 deg C beyond which it falls rapidly. The γ-ray irradiated barytes exhibits TL peaks at 90, 180 and 208 deg C. An attempt is made to understand the results. (author)