Thermal annealing and recoil reactions of 128I atoms in thermal neutron activated iodate-nitrate mixed crystals

Recoil reaction of 128I atoms in neutron irradiated mixed crystals (iodate-nitrate) have been studied by thermal annealing methods. The retention of 128I (i.e. radioactivity of 128I retained in the parent chemi cal form) decreases sharply in the beginning and then attains saturation value with the increase in concentration of nitrate. The annealing followed the usual characteristic pattern, viz., a steep rise in retention within the first few minutes and then a saturation value thereafter but these saturation values in case of mixed crystals are lower in comparison to those of pure iodate targets. The process obeys simple first order kinetics and the activation energy obtained are of lower order than those obtained in case of pure targets. The results are discussed in the light of present ideas and the role of nitrate ion and its radiolytic products have also been invoked. (author)