Thermal desorption measurements were performed to investigate He trapping in α-Fe and a reduced activation martensitic steel bombarded at room temperature with mono-energetic He+ ions. Incident energies were both 8keV and 150eV. Prior to He implantation, the samples of α-Fe were plastically deformed by rolling at room temperature followed by annealing at 673, 873 and 1073K for 2, 12 and 2h, respectively. These samples were called PR1, PR2 and FA, respectively, and the as-rolled sample was called CW. The dislocation densities of the samples decreased in the order: CW, PR1, PR2 and FA. The thermal desorption spectra exhibited a clear peak at around 800K only for the CW, PR1, PR2 and reduced activation martensitic steel samples. This was suggested to correspond to the desorption of He atoms trapped by dislocations. The effects of dislocations on micro-structural evolution in Fe and the steel during He implantation were discussed.

Effects of Dislocation on Thermal Helium Desorption from Iron and Ferritic Steel. R.Sugano, K.Morishita, H.Iwakiri, N.Yoshida: Journal of Nuclear Materials, 2002, 307-311[2], 941-5