Damage at a tungsten surface induced by impacts of self-atoms

• Published in: Journal of nuclear materials 2015-12, Vol.467 (Part 1), p.480-487
• Main Authors: Wu, Yong, Krstic, Predrag, Zhou, Fu Yang, Meyer, Fred
• Format: Article
• Language: English
• Subjects: Counting; Interstitials; Mathematical analysis; Molecular dynamics; Saturation; Sputtering; Tungsten; Vacancies
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2015.09.049

We study evolution of the surface defects of a 300 K tungsten surface due to the cumulative impact of 0.25–10 keV self-atoms. The simulation is performed by molecular dynamics with bond-order Tersoff-form potentials. At all studied impact energies the computation shows strong defect-recombination effect of both created Frenkel pairs as well as recombination of the implanted atoms with the vacancies created by the sputtering. This leads to a saturation of the cumulative count of vacancies, evident at energies below 2 keV, as long as the implantation per impact atom exceeds sputtering and to a saturation of the interstitial count when production of the sputtered particles per impact atom becomes larger than 1 (in the energy range 2-4 keV). The number of cumulative defects is fitted as functions of impact fluence and energy, enabling their analytical extrapolation outside the studied range of parameters. [Display omitted] •We calculated cumulative creation of defects in tungsten by self-atom impact.•At some energies, the defect count saturate with increasing damage dose.•The defects are accumulated in the first few layers of the tungsten surface.•The interstitials are formed predominantly as adatoms.