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  • 1.
    Bergsåker, H.
    et al.
    Kungliga Tekniska Högskolan.
    Emmoth, B.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Coad, J.P.
    Likonen, J.
    Nuclear reaction analysis with ion microbeam of cross sections of surface layers deposited in tokamak divertor2007In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 362, no 2-3, p. 215-221Article in journal (Refereed)
    Abstract [en]

    Ion micro beam analysis has been applied to the investigation of plasma deposited layers covering the divertor tiles in the JET tokamak. Since the layers are about 100 μm thick they are too thick to be completely investigated by ordinary ion beam analysis. Cross sections of the layers were prepared by cutting and polishing. Elemental depth profiles were determined from the two dimensional images that could be derived by nuclear reaction analysis and resonant backscattering spectrometry, using ion beams focused to a few μm spot size. A combination of analysis methods are shown, which allow measurements of the concentration profiles of carbon, beryllium, deuterium, oxygen and stainless steel components at levels of a few percent, with an accuracy better than 10%.

  • 2. Ivanova, D.
    et al.
    Rubel, M.
    Philipps, V.
    Schweer, B.
    Freisinger, M.
    Huber, A.
    Gierse, N.
    Penkalla, H.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Dittmar, T.
    Laser-based and thermal methods for fuel removal and cleaning of plasma-facing components2011In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 415, no 1, p. S801-S804Article in journal (Refereed)
    Abstract [en]

    The efficiency of two methods for in situ fuel removal has been tested on carbon and tungsten limiters retrieved from the TEXTOR and Tore Supra tokamaks: laser-induced ablation of co-deposits and annealing in vacuum at elevated temperature. The analyses of gas phase and surfaces performed with thermal desorption spectrometry, optical spectroscopy, ion beam analysis, surface profilometry and microscopy methods have shown: (i) the ablation leads to the generation of dust particles of 50 nm - 2 mu m; (ii) volatile products of ablation undergo condensation on surrounding surfaces; (iii) D/C ratio in such condensate is in the range 0.02-0.03; (iv) long-term annealing of 623 K for 70 h results in release of not more than 10% of deuterium accumulated in plasma-facing components; (v) effective removal is reached by heating to 900-1300 K.

  • 3. Ivanova, D.
    et al.
    Rubel, M.
    Philipps, V.
    Schweer, B.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Freisinger, M.
    Schmidt, A.
    Fuel re-absorption by thermally treated co-deposited carbon layers2011In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, no T145, p. 014006-Article in journal (Refereed)
    Abstract [en]

    Systematic studies have been conducted to address the fuel re-absorption by carbon deposits under repeated exposure to plasma after cleaning procedures. The investigation was done with graphite tiles from ALT-II (Advanced Limiter Test II), i.e. the main limiter at the TEXTOR tokamak. Pure graphite plates were used as the reference material. The experimental programme comprised the following: pre-characterization of specimens; D desorption by baking the tile at 1273 K; surface analyses of the fuel-depleted layers; exposure to deuterium in a laboratory plasma device and in TEXTOR; and quantitative assessment of deuterium re-absorption. The main result is that fuel retention in the re-exposed deposits is 30-40 times lower than that in the original co-deposit, showing that fuel re-absorption does not lead to an immediate re-saturation of deposits. Annealing at high temperatures enhances layer brittleness, leading eventually to detachment of co-deposits.

  • 4. Pegourie, B.
    et al.
    Panayotis, S.
    Languille, P.
    Martin, C.
    Dittmar, T.
    Gauthier, E.
    Hatchressian, J. -C
    Pascal, J. -Y
    Roubin, P.
    Ruffe, R.
    Tsitrone, E.
    Vartanian, S.
    Wang, H.
    Beaute, A.
    Bouvet, J.
    Brosset, C.
    Bucalossi, J.
    Cabie, M.
    Caprin, E.
    Courtois, X.
    Dachicourt, R.
    Delchambre, E.
    Dominici, C.
    Douai, D.
    Ekedahl, A.
    Gunn, J. P.
    Hakola, A.
    Jacob, W.
    Khodja, H.
    Likonen, J.
    Linez, F.
    Litnovsky, A.
    Marandet, Y.
    Markelj, S.
    Martinez, A.
    Mayer, M.
    Meyer, O.
    Monier-Garbet, P.
    Moreau, P.
    Negrier, V.
    Oddon, P.
    Pardanaud, C.
    Pasquet, B.
    Pelicon, P.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Philipps, V.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Reiter, D.
    Roth, J.
    Roure, I.
    Rubel, M.
    St-Laurent, F.
    Samaille, F.
    Vavpetic, P.
    Deuterium inventory in Tore Supra: Coupled carbon-deuterium balance2013In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 438, p. S120-S125Article in journal (Refereed)
    Abstract [en]

    This paper presents an analysis of the carbon-deuterium circulation and the resulting balance in Tore Supra over the period 2002-2007. Carbon balance combines the estimation of carbon gross erosion from spectroscopy, net erosion and deposition using confocal microscopy, lock-in thermography and SEM, and a measure of the amount of deposits collected in the vacuum chamber. Fuel retention is determined from post-mortem (PM) analyses and gas balance (GB) measurements. Special attention was paid to the deuterium outgassed during the nights and weekends of the experimental campaign (vessel under vacuum, Plasma Facing Components at 120 degrees C) and during vents (vessel at atmospheric pressure, PFCs at room temperature). It is shown that this outgassing is the main process reconciling the PM and GB estimations of fuel retention, closing the coupled carbon-deuterium balance. In particular, it explains why the deuterium concentration in deposits decreases with increasing depth. (C) 2013 Elsevier B.V. All rights reserved.

  • 5.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Ion Beam Analysis of First Wall Materials Exposed to Plasma in Fusion Devices2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One major step needed for fusion to become a reliable energy source is the development of materials for the extreme conditions (high temperature, radioactivity and erosion) caused by hot plasmas. The main goal of the present study is to use and optimise ion beam methods (lateral resolution and sensitivity) to characterise the distribution of hydrogen isotopes that act as fuel. Materials from the test reactors JET (Joint European Torus), TEXTOR (Tokamak Experiment for Technology Oriented Research) and Tore Supra have been investigated.

    Deuterium, beryllium and carbon were measured by elastic recoil detection analysis (ERDA) and nuclear reaction analysis (NRA). To ensure high 3D spatial resolution a nuclear microbeam (spot size <10 µm) was used with 3He and 28Si beams. The release of hydrogen caused by the primary ion beam was monitored and accounted for.

    Large variations in surface (top 10 µm) deuterium concentrations in carbon fibre composites (CFC) from Tore Supra and TEXTOR was found, pointing out the importance of small pits and local fibre structure in understanding fuel retention. At deeper depths into the CFC limiter tiles from Tore Supra, deuterium rich bands were observed confirming the correlation between the internal material structure and fuel storage in the bulk.

    Sample cross sections from thick deposits on the JET divertor showed elemental distributions that were dominantly laminar although more complex structures also were observed. Depth profiles of this kind elucidate the plasma-wall interaction and material erosion/deposition processes in the reactor vessel.

    The information gained in this thesis will improve the knowledge of first wall material for the next generation fusion reactors, concerning the fuel retention and the lifetime of the plasma facing materials which is important for safety as well as economical reasons.

    List of papers
    1. Measurement of hydrogen isotopes by nuclear microprobe
    Open this publication in new window or tab >>Measurement of hydrogen isotopes by nuclear microprobe
    2008 (English)In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100, no 6, p. 062029-Article in journal (Refereed) Published
    National Category
    Subatomic Physics Engineering and Technology
    Research subject
    Ion Physics
    Identifiers
    urn:nbn:se:uu:diva-111090 (URN)10.1088/1742-6596/100/6/062029 (DOI)000275655200225 ()
    Available from: 2009-12-03 Created: 2009-12-03 Last updated: 2022-01-28Bibliographically approved
    2. Mapping of hydrogen isotopes with a scanning nuclear microprobe
    Open this publication in new window or tab >>Mapping of hydrogen isotopes with a scanning nuclear microprobe
    Show others...
    2008 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 266, no 10, p. 2429-2432Article in journal (Refereed) Published
    Abstract [en]

    Elastic recoil detection analysis using heavy ions with a scanning nuclear microprobe was applied to determine the content of hydrogen isotopes in carbon material facing fusion plasma in the JET fusion reactor. The hydrogen and deuterium concentrations in re-deposited material were obtained by mapping a cross sectional cut of a wall sample. De-trapping and hydrogen release caused by the primary ion beam were investigated. For both the deuterium and hydrogen concentration a drop of similar to 75% was observed from an extrapolated initial value to a final steady state region. A procedure was used to determine the initial concentration. In this way a mapping of the initial deuterium concentration could be obtained.

    National Category
    Physical Sciences Subatomic Physics Engineering and Technology
    Research subject
    Ion Physics
    Identifiers
    urn:nbn:se:uu:diva-111087 (URN)10.1016/j.nimb.2008.03.059 (DOI)000257185600075 ()
    Available from: 2009-12-03 Created: 2009-12-03 Last updated: 2022-01-28Bibliographically approved
    3. Ion beam micro analysis of deposits at tokamak divertor surfaces
    Open this publication in new window or tab >>Ion beam micro analysis of deposits at tokamak divertor surfaces
    Show others...
    2010 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 11-12, p. 1838-1841Article in journal (Refereed) Published
    Place, publisher, year, edition, pages
    Amsterdam: Elsevier, 2010
    Keywords
    Nuclear reaction analysis; Micro-beam; Deuterium; Beryllium
    National Category
    Other Engineering and Technologies not elsewhere specified
    Identifiers
    urn:nbn:se:uu:diva-128871 (URN)10.1016/j.nimb.2010.02.025 (DOI)000278702300032 ()
    Available from: 2010-07-29 Created: 2010-07-29 Last updated: 2022-01-28Bibliographically approved
    4. Nuclear reaction analysis with ion microbeam of cross sections of surface layers deposited in tokamak divertor
    Open this publication in new window or tab >>Nuclear reaction analysis with ion microbeam of cross sections of surface layers deposited in tokamak divertor
    Show others...
    2007 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 362, no 2-3, p. 215-221Article in journal (Refereed) Published
    Abstract [en]

    Ion micro beam analysis has been applied to the investigation of plasma deposited layers covering the divertor tiles in the JET tokamak. Since the layers are about 100 μm thick they are too thick to be completely investigated by ordinary ion beam analysis. Cross sections of the layers were prepared by cutting and polishing. Elemental depth profiles were determined from the two dimensional images that could be derived by nuclear reaction analysis and resonant backscattering spectrometry, using ion beams focused to a few μm spot size. A combination of analysis methods are shown, which allow measurements of the concentration profiles of carbon, beryllium, deuterium, oxygen and stainless steel components at levels of a few percent, with an accuracy better than 10%.

    Keywords
    Divertor, Nuclear fusion reactor, Tokamak, Plasma deposition, Cross section (collision), Nuclear reaction
    National Category
    Physical Sciences Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-26270 (URN)10.1016/j.jnucmat.2007.01.046 (DOI)000246895400013 ()
    Available from: 2007-02-15 Created: 2007-02-15 Last updated: 2017-12-07Bibliographically approved
    5. Cross sections of deposited layers investigated by micro nuclear reaction analysis
    Open this publication in new window or tab >>Cross sections of deposited layers investigated by micro nuclear reaction analysis
    (English)Article in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-128874 (URN)
    Available from: 2010-07-29 Created: 2010-07-29 Last updated: 2010-08-19Bibliographically approved
    6. Nuclear micro-beam analysis of deuterium distribution in carbon fibre composites for controlled fusion devices
    Open this publication in new window or tab >>Nuclear micro-beam analysis of deuterium distribution in carbon fibre composites for controlled fusion devices
    2010 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 11-12, p. 1833-1837Article in journal (Refereed) Published
    Abstract [en]

    Probes made of carbon fibre composite NB41 were exposed to deuterium plasmas in the TEXTOR tokamak and in a simulator of plasma-wall interactions, PISCES. The aim was to assess the deuterium retention and its lateral and depth distribution. The analysis was performed by means of D(He-3, p)4He and C-12(He-3, p)14N nuclear reactions analysis using a standard (1 mm spot) and micro-beam (20 mu m resolution). The measurements have revealed non uniform distribution of deuterium atoms in micro-regions: differences by a factor of 3 between the maximum and minimum deuterium concentrations. The differences were associated with the orientation and type of fibres for samples exposed in PICSES. For surface structure in the erosion zone of samples exposed to a tokamak plasma the micro-regions were more complex. Depth profiling has indicated migration of fuel into the bulk of materials.

    Place, publisher, year, edition, pages
    Amsterdam: Elsevier, 2010
    Keywords
    Nuclear reaction analysis, Micro-beam, Deuterium, Tokamak, Carbon composites
    National Category
    Fusion, Plasma and Space Physics
    Identifiers
    urn:nbn:se:uu:diva-128872 (URN)10.1016/j.nimb.2010.02.024 (DOI)000278702300031 ()
    Available from: 2010-07-29 Created: 2010-07-29 Last updated: 2022-01-28Bibliographically approved
    7. An Overview of Nuclear Micro beam Analysis of Surface and Bulk Fuel Retention in Carbon-Fibre Composites from Tore Supra
    Open this publication in new window or tab >>An Overview of Nuclear Micro beam Analysis of Surface and Bulk Fuel Retention in Carbon-Fibre Composites from Tore Supra
    Show others...
    2011 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 451, no 1, p. s764-s764Article in journal (Refereed) Published
    Abstract [en]

    Surface and bulk retention of deuterium in tiles of the pump limiter from Tore Supra was examined with nuclear reaction analysis using both standard and micro-beam techniques. The aim was to determine the variations in the content and distribution of fuel species in carbon-fibre composites. On plasma-facing surfaces from the deposition zone, the D content reaches 2.5 × 1019 cm−2 in about 8 μm thick top layer, but lateral differences reach even more than one order of magnitude. This is also measured in the erosion zone: 6.6 × 1017 cm−2 to 7.7 × 1018 cm−2 D atoms. Bulk content was examined on cross-sections opened by fracturing the tiles. Fuel is detected up to the depth of 1–1.5 mm beneath the plasma-facing surface in tiles from both the erosion and deposition zones. It occurs in bands, about 100 μm wide and several mm long, roughly parallel to the original plasma-facing surface.

    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-128873 (URN)10.1016/j.jnucmat.2010.10.044 (DOI)000298128100173 ()
    Available from: 2010-07-29 Created: 2010-07-29 Last updated: 2017-12-12Bibliographically approved
    Download full text (pdf)
    FULLTEXT01
  • 6.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Bergsåker, H.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Coad, J. P.
    Koivuranta, S.
    Likonen, J.
    Ion beam micro analysis of deposits at tokamak divertor surfaces2010In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 11-12, p. 1838-1841Article in journal (Refereed)
  • 7.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Bergsåker, H.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Coad, J. P.
    Likonen, J.
    Koivuranta, S.
    Hakola, A.
    Cross sections of deposited layers investigated by micronuclear reaction analysis2011In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 415, no 1, p. S262-S265Article in journal (Refereed)
    Abstract [en]

    Cross sections of deposited layers from the divertor of the Joint European Torus (JET) have been investigated, microscopically and by ion microbeam analysis. The thickness of these layers on the studied samples varies between about 50 mu m and 800 mu m depending on the exposure time and poloidal location of the sample. For most of the thicker layers a laminar structure is observed. In some locations changes, such as gaps, are also observed along the laminar structure as well as more complex structures. The possibility to use the layers as historical reference was also investigated.

  • 8.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Kreter, A.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Rubel, M.
    Nuclear micro-beam analysis of deuterium distribution in carbon fibre composites for controlled fusion devices2010In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 11-12, p. 1833-1837Article in journal (Refereed)
    Abstract [en]

    Probes made of carbon fibre composite NB41 were exposed to deuterium plasmas in the TEXTOR tokamak and in a simulator of plasma-wall interactions, PISCES. The aim was to assess the deuterium retention and its lateral and depth distribution. The analysis was performed by means of D(He-3, p)4He and C-12(He-3, p)14N nuclear reactions analysis using a standard (1 mm spot) and micro-beam (20 mu m resolution). The measurements have revealed non uniform distribution of deuterium atoms in micro-regions: differences by a factor of 3 between the maximum and minimum deuterium concentrations. The differences were associated with the orientation and type of fibres for samples exposed in PICSES. For surface structure in the erosion zone of samples exposed to a tokamak plasma the micro-regions were more complex. Depth profiling has indicated migration of fuel into the bulk of materials.

  • 9.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Cross sections of deposited layers investigated by micro nuclear reaction analysisArticle in journal (Refereed)
  • 10.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Rubel, M
    Dittmar, T
    Pégouiré, B
    Tsitrone, E
    Wessel, E
    An Overview of Nuclear Micro beam Analysis of Surface and Bulk Fuel Retention in Carbon-Fibre Composites from Tore Supra2011In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 451, no 1, p. s764-s764Article in journal (Refereed)
    Abstract [en]

    Surface and bulk retention of deuterium in tiles of the pump limiter from Tore Supra was examined with nuclear reaction analysis using both standard and micro-beam techniques. The aim was to determine the variations in the content and distribution of fuel species in carbon-fibre composites. On plasma-facing surfaces from the deposition zone, the D content reaches 2.5 × 1019 cm−2 in about 8 μm thick top layer, but lateral differences reach even more than one order of magnitude. This is also measured in the erosion zone: 6.6 × 1017 cm−2 to 7.7 × 1018 cm−2 D atoms. Bulk content was examined on cross-sections opened by fracturing the tiles. Fuel is detected up to the depth of 1–1.5 mm beneath the plasma-facing surface in tiles from both the erosion and deposition zones. It occurs in bands, about 100 μm wide and several mm long, roughly parallel to the original plasma-facing surface.

  • 11. Porro, S.
    et al.
    De Temmerman, G.
    Lisgo, S.
    Rudakov, D. L.
    Litnovsky, A.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    John, P.
    Wilson, J. I. B.
    Diamond coatings exposure to fusion-relevant plasma conditions2011In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 415, no 1, p. S161-S164Article in journal (Refereed)
    Abstract [en]

    Several types of diamond layers have been deposited on molybdenum tiles by chemical vapour deposition techniques, and exposed under erosion-dominated conditions in the SOL of TEXTOR in order to assess them as a suitable candidate for plasma-facing material. Post-exposure characterisation of physical properties and surface modification induced by the plasma was performed by SEM imaging, investigation of diamond surface by micro-Raman spectroscopy and deuterium retention measurements by NRA. The analyses evidenced that lightly boron-doped micro-crystalline diamond is performing better than undoped and heavily doped samples, and nano-crystalline diamond and diamond-like carbon, as it showed lower surface modification, lower presence of arcing traces at the surface and lower deuterium retention. High concentration of boron in the layers led to higher retention of deuterium, whereas undoped (insulating) diamond showed increased arcing activity. Nano-crystalline diamond and diamond-like carbon layers generally showed poorer mechanical properties.

  • 12. Rubel, M.
    et al.
    Philipps, V.
    Marot, L.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Pospieszczyk, A.
    Schweer, B.
    Nitrogen and neon retention in plasma-facing materials2011In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 415, no 1, p. S223-S226Article in journal (Refereed)
    Abstract [en]

    Tungsten plate was exposed in the TEXTOR tokamak during nitrogen-assisted discharges. In order to determine material mixing on tungsten, the plate was examined ex situ with ion beam analysis techniques including time-of-flight heavy ion elastic recoil detection analysis and also with X-ray photoelectron spectroscopy. Nitrogen content in the range from 1.3 x 10(15) to 3.4 x 10(15) cm(-2) is measured in the outermost surface layer (20 nm) of the W plate. Photoelectron spectroscopy detects nitrogen both in the elemental and compound form, i.e. tungsten nitride (WN/W2N). Nitrogen is measured even in hot areas free from deuterium. Also neon co-implantation into the plasma-facing components has been identified following Ne-cooled pulses.

1 - 12 of 12
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