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",
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language = "English",
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pages = "266--270",
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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

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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

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M3 - Article

VL - 332

SP - 266

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

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