FTIR and TL studies of gamma rays irradiated natural quartz

摘要

In the present paper, we have performed the Fourier transform infrared (FTIR) and thermoluminescence (TL) characterizations of gamma-irradiated (dose 0.5-50 kGy) colorless natural quartz of Indian origin. Investigations of structural changes in irradiated quartz crystal in terms of crystallinity index have been carried out based on assignment of infrared bands of SiO_4 tetrahedron in the fingerprint mid-infrared region. Colorless quartz containing aluminum as impurity modifies its color to dark smoky after exposure to ionizing radiations. The TL glow curves analysis shows that there are four trapping sites corresponding to four TL peaks at 169, 212, 279 and 370 °C. Chen's peak shape method and initial rise method have been used to determine the kinetic parameters (order of kinetics, activation energy and frequency factor). The role of [Al_(Si)O_4/h~+]~0 (substitutional center formed on replacement of Si~(4+) with Al~(3+) and charge compensated by a hole) centers in color development and as luminescence centers is discussed by making a correlation between FTIR and TL studies.