Characterization of defect clusters in ion-irradiated tungsten by X-Ray diffuse scattering

Defect clusters in ion-irradiated tungsten are characterized by X-ray diffuse scattering. Single crystal tungsten samples are irradiated at 300 K by 0.5-5 MeV copper ions with total doses of 0.2, 0.6, 2, and 5 displacements per atom (DPA). Analysis of the diffuse scattering intensities allows the determination of the concentration of vacancy- and interstitial-type dislocation loops as a function of loop radius for each sample. More vacancies than interstitials are observed in each sample, and the radius of the vacancy loops increases with irradiation dose. For the 0.2DPA sample the average vacancy loop radius is 10.1±3.0Å with a defect density (counting all atoms in the loops) of (10.2±1.5)×10−4 per tungsten atom, increasing to an average loop radius of 16.1±3.1Å at a density of (8.5±1.0)×10−4 per tungsten atom for the 5DPA sample.