Tritium centers in neutron-irradiated LiF studied by ESR spectroscopy and dissolution in deuterated nitric acid

The resting state of tritium in a neutron-irradiated LiF single crystal was studied. The sample was annealed thermally and subjected to ESR measurement and to dissolution in deuterated nitric acid. From the results, it was deduced that there are five tritium centers, T0, T-, T+, HT and T2, in the non-annealed sample and that their relative abundance changes with the annealing temperature, suggesting a different stability of each center in reaction to thermal treatment. The most stable center is Tsub(S)- (T- in substitutional position), whose concentration increases with the annealing temperature to give the maximum amount of 95% at 3500C. However, Tsub(S)- thus formed decays out at 4500C, which corresponds to the release-commencing temperature in constant rate heating at 50C/min. (orig.)