Muon trapping at vacancies in pure and doped iron

This paper gives a summary of the results obtained by the Konstanz group on electron-irradiated iron. The main achievement was the observation of a number of different frequencies in Fe, which could be assigned to isolated vacancies and to vacancy-impurity pairs. The annealing behaviour of these frequencies was studied. In the present paper, the framework for the analysis of the data and the main conclusions are reviewed.