A CEMS investigation of57Fe implanted in Al and Cu at low temperature

A new type of CEM-spectrometer allows in situ measurements on metal foils implanted at low temperatures. It has been used to study defect association and clustering of⁵⁷Fe in Al and Cu. For⁵⁷FeAl, the substitutional fraction (f _s) in samples implanted at 120 K is somewhat smaller than expected for a random impurity distribution but much larger than after room temperature implantation. For⁵⁷FeCu,f _s for samples implanted at 120 K is less than 0.5 of the value expected for a random distribution and it falls to zero after annealing at 600 K, where more extensive Fe clustering occurs. Vacancy trapping in stage III does not contribute significantly to the observed defect sites.