Microstructure and inhomogeneous fuel trapping at divertor surfaces in the JET tokamak
2014 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, Vol. 332, 266-270 p.Article in journal (Refereed) Published
The plasma deposited layers at divertor surfaces in the JET tokamak with carbon wall have been studied post mortem, using micro ion beam analysis (mu-IBA) methods, optical microscopy and scanning electron microscopy (SEM). The layers were formed during plasma operations over different periods through 1998-2009. They frequently have a columnar structure. For mu-IBA a 3 MeV He-3 beam was used, focused to about 5-15 mu m size. Nuclear reaction analysis was used to measure D, Be and C. Elemental mapping was carried out both at the original surface and on polished layer cross sections. Trapped deuterium is predominantly found in remote areas on the horizontal bottom divertor tiles and in regions with locally enhanced deuterium concentration on the vertical tiles. Pockets with enhanced deuterium concentration are found in the carbon fibre composite (CFC) substrate. Areas with dimensions of about 100 mu m with enhanced deuterium concentration are also found inside the deposited layers. The inhomogeneous fuel trapping is tentatively explained with co-deposition in partly protected pits in the substrate and by incorporation of dust particles in the growing layers.
Place, publisher, year, edition, pages
2014. Vol. 332, 266-270 p.
Deposited layers, Deuterium retention, Fusion, Microbeam, Microstructure
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-145072DOI: 10.1016/j.nimb.2014.02.075ISI: 000339131200059ScopusID: 2-s2.0-84902548923OAI: oai:DiVA.org:kth-145072DiVA: diva2:716110
21st International Conference on Ion Beam Analysis (IBA), Amer Vacuum Soc, Pacific NW Chapter, Seattle, WA
QC 201408192014-05-082014-05-082014-08-19Bibliographically approved