Effects of D and He implantation depth on D retention in tungsten under simultaneous D–He ion irradiation

The effects of addition of ~3% He+ in simultaneous D–He irradiation at various D and He ion energies were studied for polycrystalline W at 300 and 500 K. Combinations of 250–750 eV/D+ and 500–1000 eV/He+ were used to vary the D and He ion range relative to each other. Total D and He retention were measured by thermal desorption spectroscopy up to 1473 K, and select specimens implanted at 500 K were analyzed by nuclear reaction analysis and electron recoil detection analysis. At both 300 and 500 K, D retention was reduced and trapping changed due to the addition of He+; however, consistent with the literature, D and He diffused well beyond the ion ranges. Furthermore, varying the ion ranges had little effect on D retention, depth profile, and trapping. D diffusion into the bulk was reduced from far beyond 7 μm to less than 2 μm with the addition of He+.