Depth profiles of trapped deuterium in nickel bombarded with helium-3

Abstract

Depth profiles of deuterium in nickel, continuously exposed to a deuterium plasma at 523 K, were in-situ observed using nuclear reaction analysis (NRA). The plasma-driven permeation rate was monitored at the same time. There were no traps in the sample at first, and the observed deuterium concentration agreed with the estimated value by the diffusion model from the permeation rate. After the bombardment of the 0.8-MeV 3He ions, the deuterium concentration was found to increase proportionately with the dose. The concentration approached to a nearly saturated value, when the 3He dose was large. The depth profiles of the trapped deuterium were quite similar to the estimated distributions of displaced host atoms. The traps were associated with the atomic displacement. At doses where the areal density of the traps was proportional to the dose, the production rate of the traps per displaced atom was 7×10 −3. This value was the same also for the 1.3-MeV 3He bombardment.