Dipole → Z centre conversion in Mg-doped lithium fluoride

Abstract

For the description of the trapping process in LiF two models are developed. One model interprets dipoles formed by Mg2+–cation vacancies as trapping centres, the other model Z centres formed by pairs of Mg2+–electron occupied anion vacancies. To find a link between both models the radiation induced Z centre concentration in LiF:Mg is measured as function of different preirradiation annealing temperatures and as function of dose. The comparison of the results with dipole concentration measurements of other authors shows a strong correlation between dipole and Z centre concentration. A possible explanation is that cation vacancies are converted during irradiation into anion vacancies. The result confirms the Z centre model.