Use of3d-impurity-ion absorption to study the distribution of radiation damage in crystals

The oscillator strengths of spin-forbidden optical transitions of ${\mathrm{Mn}}^{2+}$ are enhanced by the presence of radiation-produced $F$ centers. These enhanced transitions can be used to monitor the presence of other defects in the vicinity of ${\mathrm{Mn}}^{2+}-F-\mathrm{center}$ complexes. Thus, from absorption and emission changes following irradiation at different temperatures, it appears possible to obtain information on the distribution of radiation-induced interstitials. These data in turn lead to a better understanding of the mechanisms of radiation production and annihilation.