Microscopic deformation of tungsten surfaces by high energy and high flux helium/hydrogen particle bombardment with short pulses

Masayuki Tokitani, Naoaki Yoshida, Kazutoshi Tokunaga, Hajime Sakakita, Satoru Kiyama, Haruhisa Koguchi, Yoichi Hirano, Suguru Masuzaki

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The neutral beam injection facility in the National Institute of Advanced Industrial Science and Technology was used to irradiate a polycrystalline tungsten specimen with high energy and high flux helium and hydrogen particles. The incidence energy and flux of the beam shot were 25 keV and 8.8 × 1022 particles/m2s, respectively. The duration of each shot was approximately 30 ms, with 6 min intervals between each shot. Surface temperatures over 1800K were attained. In the two cases of helium irradiation, total fluence of either 1.5 × 1022 He/m2 or 4.0 × 1022 He/m2 was selected. In the former case, large sized blisters with diameter of 500 nm were densely observed. While, the latter case, the blisters were disappeared and fine nanobranch structures appeared instead. Cross-sectional observations using a transmission electron microscope (TEM) with the focused ion beam (FIB) technique were performed. According to the TEM image, after irradiation with a beam shot of total fluence 4.0 × 1022 He/m2, there were very dense fine helium bubbles in the tungsten of sizes 1-50 nm. As the helium bubbles grew the density of the tungsten matrix drastically decreased as a result of void swelling. These effects were not seen in hydrogen irradiation case.

Original languageEnglish
Article number012
JournalPlasma and Fusion Research
Volume5
DOIs
Publication statusPublished - 2010

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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