Development of Surface Morphologies on Single Crystal Tungsten Irradiated with 30 keV Helium Ions at 900ºC

Single crystal tungsten samples with (110) and (100) surface orientations were irradiated with 30 keV He⁺ at 900ºC to fluences of 3×10¹⁷ to 1×10¹⁹ He⁺/cm² at normal incidence. The samples exhibited various microstructures and increasing sample mass loss as a function of increasing fluence for both cases. Pores observed on the sample surface at each fluence were ~45 nm in diameter merging into larger surface pores up to ~800 nm in length at the highest irradiation fluence of 1×10¹⁹ He⁺/cm².