Isotope effect in the diffusion of the stable germanium isotopes in copper

The isotope effect of Ge diffusion in Cu has been measured employing the stable non-radioactive Ge isotopes. The evaluation of the diffusion profile and the isotope ratios was performed by a SIMS technique, sputtering with O2+ ions and collecting and mass-separating GeO2− ions. The results obtained in this way for several mass combinations for the first time, agree within a narrow margin or error with data derived earlier from the radioactive tracers Ge 68 and Ge 77.