Microstructure and inhomogeneous fuel trapping at divertor surfaces in the JET tokamak

H Bergsåker (Corresponding Author), I Bykov, P Petersson, G Possnert, Jari Likonen, Seppo Koivuranta, J P Coad, A M Widdowson

    Research output: Contribution to journalArticleScientificpeer-review

    9 Citations (Scopus)

    Abstract

    The plasma deposited layers at divertor surfaces in the JET tokamak with carbon wall have been studied post mortem, using micro ion beam analysis (µ-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 µ-IBA a 3 MeV 3He beam was used, focused to about 5-15 µm 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 µm 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
    Original languageEnglish
    Pages (from-to)266-270
    Number of pages4
    JournalNuclear Instruments and Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms
    Volume332
    Issue numberAugust
    DOIs
    Publication statusPublished - 2014
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Deuterium
    deuterium
    trapping
    microstructure
    Microstructure
    tiles
    Tile
    Plasmas
    plasma layers
    Nuclear reactions
    fiber composites
    Substrates
    carbon fibers
    nuclear reactions
    Ion beams
    Particles (particulate matter)
    Carbon fibers
    Optical microscopy
    Dust
    dust

    Keywords

    • Deposited layers
    • deuterium retention
    • fusion
    • microbeam
    • microstructure

    Cite this

    @article{11629475683546d0b66e8e58e1c64d31,
    title = "Microstructure and inhomogeneous fuel trapping at divertor surfaces in the JET tokamak",
    abstract = "The plasma deposited layers at divertor surfaces in the JET tokamak with carbon wall have been studied post mortem, using micro ion beam analysis (µ-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 µ-IBA a 3 MeV 3He beam was used, focused to about 5-15 µm 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 µm 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",
    keywords = "Deposited layers, deuterium retention, fusion, microbeam, microstructure",
    author = "H Bergs{\aa}ker and I Bykov and P Petersson and G Possnert and Jari Likonen and Seppo Koivuranta and Coad, {J P} and Widdowson, {A M}",
    year = "2014",
    doi = "10.1016/j.nimb.2014.02.075",
    language = "English",
    volume = "332",
    pages = "266--270",
    journal = "Nuclear Instruments and Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms",
    issn = "0168-583X",
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    }

    Microstructure and inhomogeneous fuel trapping at divertor surfaces in the JET tokamak. / Bergsåker, H (Corresponding Author); Bykov, I; Petersson, P; Possnert, G; Likonen, Jari; Koivuranta, Seppo; Coad, J P; Widdowson, A M.

    In: Nuclear Instruments and Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms, Vol. 332, No. August, 2014, p. 266-270.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Microstructure and inhomogeneous fuel trapping at divertor surfaces in the JET tokamak

    AU - Bergsåker, H

    AU - Bykov, I

    AU - Petersson, P

    AU - Possnert, G

    AU - Likonen, Jari

    AU - Koivuranta, Seppo

    AU - Coad, J P

    AU - Widdowson, A M

    PY - 2014

    Y1 - 2014

    N2 - The plasma deposited layers at divertor surfaces in the JET tokamak with carbon wall have been studied post mortem, using micro ion beam analysis (µ-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 µ-IBA a 3 MeV 3He beam was used, focused to about 5-15 µm 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 µm 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

    AB - The plasma deposited layers at divertor surfaces in the JET tokamak with carbon wall have been studied post mortem, using micro ion beam analysis (µ-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 µ-IBA a 3 MeV 3He beam was used, focused to about 5-15 µm 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 µm 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

    KW - Deposited layers

    KW - deuterium retention

    KW - fusion

    KW - microbeam

    KW - microstructure

    U2 - 10.1016/j.nimb.2014.02.075

    DO - 10.1016/j.nimb.2014.02.075

    M3 - Article

    VL - 332

    SP - 266

    EP - 270

    JO - Nuclear Instruments and Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms

    JF - Nuclear Instruments and Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms

    SN - 0168-583X

    IS - August

    ER -