LOW-ENERGY HELIUM IMPLANTATION IN EVAPORATED NICKEL SURFACES

This paper reports data on helium (He) implantation at low energy (100-200 eV) in nickel (Ni) that support a concept for He self-pumping in tokamaks, and specifically for an experiment in TEXTOR. These data indicate trapping saturates at about 4 X 10(19) He/m2 areal density for He implanted at 100 eV He in Ni at 500-degrees-C. Neither prior implantation of deuterium (D) nor D bombardment of Ni surfaces already containing implanted He significantly changed the He saturation value. A model for trapping capacity and these data were used to predict He self-pumping in TEXTOR.