THE FRACTIONATION OF CA ISOTOPES BY SPUTTERING

This paper presents data which indicate that extensive isotopic fractionation occurs during ion sputtering. The observed effects are very much larger than the experimental uncertainties. Such mass fractionation may be a general property of the sputtering process, although this has not yet been tested by investigating other energy regimes (e. g. , 100-1000 eV) or other ion/target combinations. The Ca results demonstrate that the presence of species with the same chemical properties but distinct masses can be sufficient to produce significantly different sputtering rates.