Ranges of 27A1+ ions in nine metals measured by (p, γ) resonance broadening

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Abstract
Concentration distributions of 27AJ+ ions implanted in Ti, Ni. Cu, Mo, Ag, Ta, W, Au and Pb substrates have been measured in the energy range of 20–100 keV by means of the broadening of the Ep = 633 keV or 992 keV resonance yield curve from the 27 Al(p.γ)28 Si reaction. The implanted atom concentrations were about 3 at.%. The proton stopping powers needed in the derivation of the ranges were determined experimentally, except for Pb where the tabulated value was used. Proton energy straggling was included in the 27Al range analysis. In comparing the distribution predictions of the Lindhard-Scharff-Schiøtt (LSS) theory with the experimental results the fraction of 27Al reflections was taken into account through the Monte-Carlo calculations. The mean ranges were found to be from 7 to 60% larger than those predicted by the LSS theory with the Thomas-Fermi potential. The consistency could be improved with about 10% by inclusion of the Hartree ∼ Fock potential. The merits of the method used, the effects of diffusion and the theoretical interpretation of the range values are discussed.