Probing helium nano-bubble formation in tungsten with grazing incidence small angle x-ray scattering. (11th March 2015)

• Record Type: Journal Article
• Authors: Thompson, M.; Kluth, P.; Doerner, R.P.; Kirby, N.; Corr, C.
• Is Part Of: Nuclear fusion. Volume 55:Number 4(2015:Apr.)
• Publication Date: 2015-03-11
• Subjects: tungsten -- helium nano-bubbles -- GISAXS -- helium damage; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/55/4/042001
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: Helium nano-bubble formation in plasma facing materials has emerged as a major concern for the next-step fusion experiment ITER, where helium plasmas will be used during the tokamak's start-up phase. Here, we demonstrate that grazing incidence small-angle x-ray scattering is a powerful technique for the analysis of helium nano-bubble formation in tungsten. We measured helium bubbles with sizes between 1.5–2.5 nm in tungsten exposed to helium plasma at 700 °C, where a smaller number of larger bubbles were also observed. Depth distributions can be estimated by taking successive measurements across a range of x-ray incidence angles. Compared with traditional approaches in the field, such as transmission electron microscopy, this technique provides information across a much larger volume with high statistical precision, whilst also being non-destructive.