The Greenwood-Foreman-Rimmer loop punching mechanism as applied to helium bubble growth in nickel implanted with 5 keV He⁺ ions at 273 K

Abstract

It is shown that as a result of the Greenwood-Foreman-Rimmer loop punching mechanism applied for helium bubble growth in nickel implanted with 5 keV He⁺ ions at 273 K, a considerable amount of helium remains outside the bubbles which are visible in a transmission electron microscope (TEM). It is also shown that even when it is assumed that there is an energy barrier with an upper limit equal to the formation energy of a self-interstitial atom, not all implanted helium can be accumulated in the bubbles below the critical dose for blistering.

The experimental observation of bubble growth in a helium pre-implanted nickel specimen during 1 MeV e⁻ irradiation may demonstrate that indeed a significant amount of helium remains between the bubbles visible in TEM.