Crystal structure and kinetic studies of gamma exposed Ca₃B₂O₆:Tb³⁺ nanophosphor

This paper reports the crystal structure, thermoluminescence glow curves and kinetic studies of the terbium (Tb³⁺) doped calcium borate (Ca₃B₂O₆) nanophosphors. The crystal structure has rhombohedral symmetry with space group R-3c. The lattice parameters after refinement have been found to be a = b = 8.623 Å and c = 11.853 Å and V = 763.45 Å3. The analyses of structure and morphology of the nanophosphor are carried out by X-ray diffraction and transmission electron microscopy. In gamma exposed samples, the thermoluminescence glow curve consists of a single thermoluminescence glow peak at 414 K and a shoulder at 496 K. The dependence of the dose and heating rate on the thermoluminescence peak intensity is investigated. The thermoluminescence response curve shows subliner response. Kinetic parameters such as activation energy (E), order of kinetics (b) and frequency factor (s) of gamma irradiated materials are determined by using a thermoluminescence Anal computer program and compared with the values calculated by Chen's formulae. (author)