Abstract

Jadu Samuel^* and Sunil Culas

DOI : http://dx.doi.org/10.13005/ojc/290433

Thallous nitrate, TlNO₃ was irradiated with ⁶⁰Co γ-rays to 7x10² KGy at a dose rate of 2 kGy h^-1. The FT-IR spectrum was used to confirm the existence of damage nitrite while crystal transformations in TlNO₃ were established by TG/DTA analysis.The annealing data in the temperature range, 393-433 K was analysed using Fletcher-Brown, Waite and Conventional chemical kinetic methods in order to determine the order of the recovery process, the energy of activation and the fraction recovered as a function of temperature. Thermal annealing is found to be a combination of a fast first order process affecting a greater proportion of the fragments, followed by a predominantly slow second order process, with a higher energy of activation, governing the behaviour of the remainder. It is considered that the first order process is the combination of close-correlated pairs of O and NO₂^- fragments and the second order process involves the single reaction of random recombination of the fragments throughout the crystal.

Thallous nitrate; Gamma rays; Isothermal annealing; Irradiation damage; Activation energy

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