Ion Microbeam Analyses of Dust Particles and Codeposits from JET with the ITER-Like Wall

• Published in: Analytical chemistry (Washington) 2018-05, Vol.90 (9), p.5744-5752
• Main Authors: Fazinić, Stjepko, Tadić, Tonči, Vukšić, Marin, Rubel, Marek, Petersson, Per, Fortuna-Zaleśna, Elżbieta, Widdowson, Anna
• Format: Article
• Language: English
• Subjects: Aluminum; Beryllium; Chemistry; Chromium; Codeposition; Copper; Deuterium; Dust; Emission analysis; Heating; Ions; Joint European Torus; Microbeams; Molybdenum; Nickel base alloys; Nuclear engineering; Nuclear fuels; Nuclear safety; Plasma; Plasma heating; Silicon; Superalloys; Titanium; Tokamak devices; Tungsten
• ISSN: 0003-2700; 1520-6882; 1520-6882
• DOI: 10.1021/acs.analchem.8b00073

Generation of metal dust in the JET tokamak with the ITER-like wall (ILW) is a topic of vital interest to next-step fusion devices because of safety issues with plasma operation. Simultaneous Nuclear Reaction Analysis (NRA) and Particle-Induced X-ray Emission (PIXE) with a focused four MeV 3He microbeam was used to determine the composition of dust particles related to the JET operation with the ILW. The focus was on “Be-rich particles” collected from the deposition zone on the inner divertor tile. The particles found are composed of a mix of codeposited species up to 120 μm in size with a thickness of 30–40 μm. The main constituents are D from the fusion fuel, Be and W from the main plasma-facing components, and Ni and Cr from the Inconel grills of the antennas for auxiliary plasma heating. Elemental concentrations were estimated by iterative NRA-PIXE analysis. Two types of dust particles were found: (i) larger Be-rich particles with Be concentrations above 90 at% with a deuterium presence of up to 3.4 at% and containing Ni (1–3 at%), Cr (0.4–0.8 at%), W (0.2–0.9 at%), Fe (0.3–0.6 at%), and Cu and Ti in lower concentrations and (ii) small particles rich in Al and/or Si that were in some cases accompanied by other elements, such as Fe, Cu, or Ti or W and Mo.