Thermoluminescence and other optical studies on RbBr:Tb3+ crystals

Optical absorption, photoluminescence, photostimulated luminescence (PSL) and thermoluminescence (TL) studies on RbBr:Tb3+ crystals irradiated with X-rays is reported. The optical absorption in the UV region confirms the presence of terbium in the host matrix in the trivalent state. Photoluminescence of these crystals exhibits characteristic Tb3+ emissions due to transitions from the D-5(3) and D-5(4) levels to various levels of the F-7 septet. On F-bleaching X-irradiated crystals Z(3) centers are observed. The TL glow curve indicates a two-step thermal annihilation process for the radiatively created defects. The presence of the characteristic emissions due to terbium ions in the photostimulation at the F band confirms the participation of Tb ions in the defect-production process. Trap parameters for the TL process are calculated and presented. Emissions under the TL glow peaks contain the characteristic emissions of Tb3+ in addition to the emission due to the recombination of the F electron with V-type centers. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.