Influence of phosphate as a dopant on the retention and thermal annealing of reactor-irradiated K2SeO4

The influence of the dopant PO43- anion on the retention after reactor irradiation and after thermal annealing is investigated in solid K2SeO4. Assuming that on doping both hole acceptor and donor species are introduced into the lattice, the effect of the impurity on the initial retention is explained in terms of the relative efficiencies of these species at a specified irradiation temperature, resulting in little change at low (194 K) and in an increase in the retention at high (313 K) temperature. Three steps are observed in annealing isochronals, the amplitude of the first, below 373 K, decreasing with increased dopant concentration. This decrease is ascribed to additional hole acceptors introduced in the lattice when doping, thermally unstable above 373 K. These results are consistent with a previous model involving reactions triggered by hole captures. (orig.)