Thermal annealing of heavy ion latent tracks in soda and BP-1 phosphate glasses

Annealing behaviour of latent tracks in soda glass has been studied in the temperature range 100–300°C for different time intervals. These latent tracks are created by irradiating these samples with heavy ions viz., 238U (11.4 MeV/u) and 132Xe (11.4 and 5.9 MeV/u) from GSI Darmstadt and 56Fe (4.0 MeV/u) and 48Ti (4.0 MeV/u) from JINR, Dubna. A similar study has been made on Barium Phosphate glass (BP-1) irradiated with 238U (11.4 MeV/u) and fission fragments of 252Cf. The ‘Single Activation Energy’ model proposed by Modgil and Virk (1985) is used as an empirical approach for explaining the thermal fading of these latent tracks. This model always yields a unique value of activation energy of annealing and which is independent of the nature of the ion beam and the degree of annealing. In comparison to this model, Mark et al. (1973) and Green et al. (1985) approach on annealing phenomena has also been used to determine the activation energy. The value of activation energy for annealing of these heavy ion latent tracks is found to be 0.16 and 0.41 eV in soda and BP-1 phosphate glass, respectively. The results of ‘Single Activation Energy’ model are compared with those obtained by using models proposed by Mark et al. (1973) and Green et al. (1985).