Range profiles for 300- and 475-eV He+4 ions implanted in situ in tungsten at 60, 61, 80, 90 K were measured, directly and absolutely, employing an atom-probe field-ion microscope. A mean range (x̄) of 40 ± 4 and a parent standard deviation (σ) of 20 to 36 was obtained for 300-eV He+4; values of x̄ and σ of 56 ± 6 and 37 to 42 , respectively, were determined for 475-eV He+4. The existence of an isolated and immobile interstitial He4 atom was established and an enthalpy change of migration of 0.24 and 0.32 eV was determined.
ASJC Scopus subject areas
- Physics and Astronomy(all)