Surface-morphology changes and damage in hot tungsten by impact of 80 eV _ 12 keV He-ions and keV-energy self-atoms

28th International Conference on Photonic, Electronic and Atomic Collisions

Meyer, F.W.^1 ; Krstic, P.S.^2,3 ; Hijazi, H.^1 ; Bannister, M.E.^1 ; Dadras, J.^2 ; Parish, C.M.^4 ; Meyer, H.M.^4

Physics Division, Oak Ridge National Laboratory, Oak Ridge

TN

37831-6372, United States^1

University of Tennessee, Knoxville

TN

37831-6173, United States^2

TheoretiK, Knoxville

TN

37921, United States^3

Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge

TN

37831-6064, United States^4

关键词: Defect numbers;    Defect recombinations;    Individual grains;    Multi-charged ion;    Near-surface bubbles;    Research facilities;    University of Tennessee;    Whisker growth;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/488/1/012036/pdf
DOI  :  10.1088/1742-6596/488/1/012036

来源: IOP

【 摘 要 】

We report results of measurements on the evolution of the surface morphology of a hot tungsten surface due to impacting low-energy (80-12,000 eV) He ions, performed at the ORNL Multicharged Ion Research Facility (MIRF). Surface-morphology changes were investigated over a broad range of fluences, energies and temperatures for both virgin and pre-damaged W-targets. At low fluences, ordered coral-like and ridge-like surface structures are observed, with great grain-to-grain variability. At the largest fluences, individual grain characteristics disappear in FIB/SEM scans, and the entire surface is covered by a multitude of near-surface bubbles with a broad range of sizes, and disordered whisker growth, while in top-down SEM imaging the surface is virtually indistinguishable from the nanofuzz produced on linear plasma devices. These features are evident at progressively lower fluences as the He-ion energy is increased. In addition, simulations were carried out of damage caused by cumulative bombardment of 1 keV W self-atoms, using LAMMPS at the Kraken supercomputing facility of the University of Tennessee. The simulations show strong defect-recombination effects that lead to a saturation of the total defect number after a few hundred impacts, while sputtering and implantation lead to an imbalance of the vacancy and interstitial numbers.