Studies of impurity deposition/implantation in JET divertor tiles using SIMS and ion beam techniques

Jari Likonen, Sari Lehto, J. Coad, T. Renvall, T. Ahlgren, D. Hole, G. Matthews, K.-D. Zastrow, K. Lawson, Contributors to the EFDA-JET Work Programme

    Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsScientific

    Abstract

    Deposition in JET divertor tiles has been observed to be asymmetric; i.e. heavy deposition occurs in the SOL at the inner divertor whereas there is little deposition at the outer divertor. Heavy deposition at the inner divertor has lead to flaking on the water-cooled louvres and after the DTE1 tritium experiment at JET it was observed that majority of the retained tritium is in the flakes that have spallen from the louvres. Erosion/deposition issues have thus a great impact on the tritium retention and lifetime of first wall components in present and future fusion devices. The asymmetry in the deposition implies a drift in the SOL. To investigate material transport and SOL flows observed at JET, 13CH4 and SiH4 were injected into the plasma boundary in the last day of discharges prior to the JET 2001 shutdown. Methane was puffed at the top of the vessel, and the silane at the outer divertor wall. Silicon was observed spectroscopically as an impurity in the plasma. A set of special tiles was installed in the Mk IIGB divertor during the 1999 shutdown. The tiles were coated with poloidal stripes of a boron doped carbon layer on a rhenium interlayer. These tiles were removed in the 2001 shutdown, and have been analysed in 2002 to determine the erosion/deposition profile, and 13C and 28Si distribution over the entire divertor cross-section. The analysis techniques used have been Secondary Ion Mass Spectrometry (SIMS) and the Ion Beam Analysis (IBA) methods Time of Flight Elastic Recoil Detection Analysis (TOF-ERDA) and Rutherford backscattering (RBS). 13C could be found in large amounts on the surfaces of the inner divertor tiles whereas in the outer divertor it was hardly detected. Under the 13C layer a deuterium rich carbon layer was found on the inner divertor tiles. Thick deposits of beryllium were buried under the carbon layer. Also the silicon distribution was recorded. The observed 13C and Si distributions are discussed in relation to the position of strike point and the ion fluxes measured with divertor Langmuir probes. This work has been conducted under the European Fusion Development Agreement and is partly funded by EURATOM.
    Original languageEnglish
    Title of host publication22nd Symposium on Fusion Technology
    Subtitle of host publicationBook of Abstracts
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Pages172-172
    ISBN (Electronic)951-38-5731-X
    ISBN (Print)951-38-5730-1
    Publication statusPublished - 2002
    Event22nd Symposium on Fusion Technology - Helsinki, Finland
    Duration: 9 Sep 200213 Sep 2002
    Conference number: 22

    Publication series

    SeriesVTT Symposium
    Number220
    ISSN0357-9387

    Conference

    Conference22nd Symposium on Fusion Technology
    Abbreviated titleSOFTA
    CountryFinland
    CityHelsinki
    Period9/09/0213/09/02

    Fingerprint

    tiles
    secondary ion mass spectrometry
    implantation
    ion beams
    impurities
    shutdowns
    tritium
    louvers
    erosion
    carbon
    fusion
    flaking
    flakes
    rhenium
    silicon
    electrostatic probes
    beryllium
    silanes
    vessels
    deuterium

    Cite this

    Likonen, J., Lehto, S., Coad, J., Renvall, T., Ahlgren, T., Hole, D., ... Programme, C. T. T. EFDA-JET. W. (2002). Studies of impurity deposition/implantation in JET divertor tiles using SIMS and ion beam techniques. In 22nd Symposium on Fusion Technology: Book of Abstracts (pp. 172-172). [BO-4] Espoo: VTT Technical Research Centre of Finland. VTT Symposium, No. 220
    Likonen, Jari ; Lehto, Sari ; Coad, J. ; Renvall, T. ; Ahlgren, T. ; Hole, D. ; Matthews, G. ; Zastrow, K.-D. ; Lawson, K. ; Programme, Contributors to the EFDA-JET Work. / Studies of impurity deposition/implantation in JET divertor tiles using SIMS and ion beam techniques. 22nd Symposium on Fusion Technology: Book of Abstracts. Espoo : VTT Technical Research Centre of Finland, 2002. pp. 172-172 (VTT Symposium; No. 220).
    @inbook{860e8ae2b37f46bab322b1d44f0f5d4e,
    title = "Studies of impurity deposition/implantation in JET divertor tiles using SIMS and ion beam techniques",
    abstract = "Deposition in JET divertor tiles has been observed to be asymmetric; i.e. heavy deposition occurs in the SOL at the inner divertor whereas there is little deposition at the outer divertor. Heavy deposition at the inner divertor has lead to flaking on the water-cooled louvres and after the DTE1 tritium experiment at JET it was observed that majority of the retained tritium is in the flakes that have spallen from the louvres. Erosion/deposition issues have thus a great impact on the tritium retention and lifetime of first wall components in present and future fusion devices. The asymmetry in the deposition implies a drift in the SOL. To investigate material transport and SOL flows observed at JET, 13CH4 and SiH4 were injected into the plasma boundary in the last day of discharges prior to the JET 2001 shutdown. Methane was puffed at the top of the vessel, and the silane at the outer divertor wall. Silicon was observed spectroscopically as an impurity in the plasma. A set of special tiles was installed in the Mk IIGB divertor during the 1999 shutdown. The tiles were coated with poloidal stripes of a boron doped carbon layer on a rhenium interlayer. These tiles were removed in the 2001 shutdown, and have been analysed in 2002 to determine the erosion/deposition profile, and 13C and 28Si distribution over the entire divertor cross-section. The analysis techniques used have been Secondary Ion Mass Spectrometry (SIMS) and the Ion Beam Analysis (IBA) methods Time of Flight Elastic Recoil Detection Analysis (TOF-ERDA) and Rutherford backscattering (RBS). 13C could be found in large amounts on the surfaces of the inner divertor tiles whereas in the outer divertor it was hardly detected. Under the 13C layer a deuterium rich carbon layer was found on the inner divertor tiles. Thick deposits of beryllium were buried under the carbon layer. Also the silicon distribution was recorded. The observed 13C and Si distributions are discussed in relation to the position of strike point and the ion fluxes measured with divertor Langmuir probes. This work has been conducted under the European Fusion Development Agreement and is partly funded by EURATOM.",
    author = "Jari Likonen and Sari Lehto and J. Coad and T. Renvall and T. Ahlgren and D. Hole and G. Matthews and K.-D. Zastrow and K. Lawson and Programme, {Contributors to the EFDA-JET Work}",
    year = "2002",
    language = "English",
    isbn = "951-38-5730-1",
    series = "VTT Symposium",
    publisher = "VTT Technical Research Centre of Finland",
    number = "220",
    pages = "172--172",
    booktitle = "22nd Symposium on Fusion Technology",
    address = "Finland",

    }

    Likonen, J, Lehto, S, Coad, J, Renvall, T, Ahlgren, T, Hole, D, Matthews, G, Zastrow, K-D, Lawson, K & Programme, CTTEFDA-JETW 2002, Studies of impurity deposition/implantation in JET divertor tiles using SIMS and ion beam techniques. in 22nd Symposium on Fusion Technology: Book of Abstracts., BO-4, VTT Technical Research Centre of Finland, Espoo, VTT Symposium, no. 220, pp. 172-172, 22nd Symposium on Fusion Technology, Helsinki, Finland, 9/09/02.

    Studies of impurity deposition/implantation in JET divertor tiles using SIMS and ion beam techniques. / Likonen, Jari; Lehto, Sari; Coad, J.; Renvall, T.; Ahlgren, T.; Hole, D.; Matthews, G.; Zastrow, K.-D.; Lawson, K.; Programme, Contributors to the EFDA-JET Work.

    22nd Symposium on Fusion Technology: Book of Abstracts. Espoo : VTT Technical Research Centre of Finland, 2002. p. 172-172 BO-4 (VTT Symposium; No. 220).

    Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsScientific

    TY - CHAP

    T1 - Studies of impurity deposition/implantation in JET divertor tiles using SIMS and ion beam techniques

    AU - Likonen, Jari

    AU - Lehto, Sari

    AU - Coad, J.

    AU - Renvall, T.

    AU - Ahlgren, T.

    AU - Hole, D.

    AU - Matthews, G.

    AU - Zastrow, K.-D.

    AU - Lawson, K.

    AU - Programme, Contributors to the EFDA-JET Work

    PY - 2002

    Y1 - 2002

    N2 - Deposition in JET divertor tiles has been observed to be asymmetric; i.e. heavy deposition occurs in the SOL at the inner divertor whereas there is little deposition at the outer divertor. Heavy deposition at the inner divertor has lead to flaking on the water-cooled louvres and after the DTE1 tritium experiment at JET it was observed that majority of the retained tritium is in the flakes that have spallen from the louvres. Erosion/deposition issues have thus a great impact on the tritium retention and lifetime of first wall components in present and future fusion devices. The asymmetry in the deposition implies a drift in the SOL. To investigate material transport and SOL flows observed at JET, 13CH4 and SiH4 were injected into the plasma boundary in the last day of discharges prior to the JET 2001 shutdown. Methane was puffed at the top of the vessel, and the silane at the outer divertor wall. Silicon was observed spectroscopically as an impurity in the plasma. A set of special tiles was installed in the Mk IIGB divertor during the 1999 shutdown. The tiles were coated with poloidal stripes of a boron doped carbon layer on a rhenium interlayer. These tiles were removed in the 2001 shutdown, and have been analysed in 2002 to determine the erosion/deposition profile, and 13C and 28Si distribution over the entire divertor cross-section. The analysis techniques used have been Secondary Ion Mass Spectrometry (SIMS) and the Ion Beam Analysis (IBA) methods Time of Flight Elastic Recoil Detection Analysis (TOF-ERDA) and Rutherford backscattering (RBS). 13C could be found in large amounts on the surfaces of the inner divertor tiles whereas in the outer divertor it was hardly detected. Under the 13C layer a deuterium rich carbon layer was found on the inner divertor tiles. Thick deposits of beryllium were buried under the carbon layer. Also the silicon distribution was recorded. The observed 13C and Si distributions are discussed in relation to the position of strike point and the ion fluxes measured with divertor Langmuir probes. This work has been conducted under the European Fusion Development Agreement and is partly funded by EURATOM.

    AB - Deposition in JET divertor tiles has been observed to be asymmetric; i.e. heavy deposition occurs in the SOL at the inner divertor whereas there is little deposition at the outer divertor. Heavy deposition at the inner divertor has lead to flaking on the water-cooled louvres and after the DTE1 tritium experiment at JET it was observed that majority of the retained tritium is in the flakes that have spallen from the louvres. Erosion/deposition issues have thus a great impact on the tritium retention and lifetime of first wall components in present and future fusion devices. The asymmetry in the deposition implies a drift in the SOL. To investigate material transport and SOL flows observed at JET, 13CH4 and SiH4 were injected into the plasma boundary in the last day of discharges prior to the JET 2001 shutdown. Methane was puffed at the top of the vessel, and the silane at the outer divertor wall. Silicon was observed spectroscopically as an impurity in the plasma. A set of special tiles was installed in the Mk IIGB divertor during the 1999 shutdown. The tiles were coated with poloidal stripes of a boron doped carbon layer on a rhenium interlayer. These tiles were removed in the 2001 shutdown, and have been analysed in 2002 to determine the erosion/deposition profile, and 13C and 28Si distribution over the entire divertor cross-section. The analysis techniques used have been Secondary Ion Mass Spectrometry (SIMS) and the Ion Beam Analysis (IBA) methods Time of Flight Elastic Recoil Detection Analysis (TOF-ERDA) and Rutherford backscattering (RBS). 13C could be found in large amounts on the surfaces of the inner divertor tiles whereas in the outer divertor it was hardly detected. Under the 13C layer a deuterium rich carbon layer was found on the inner divertor tiles. Thick deposits of beryllium were buried under the carbon layer. Also the silicon distribution was recorded. The observed 13C and Si distributions are discussed in relation to the position of strike point and the ion fluxes measured with divertor Langmuir probes. This work has been conducted under the European Fusion Development Agreement and is partly funded by EURATOM.

    M3 - Conference abstract in proceedings

    SN - 951-38-5730-1

    T3 - VTT Symposium

    SP - 172

    EP - 172

    BT - 22nd Symposium on Fusion Technology

    PB - VTT Technical Research Centre of Finland

    CY - Espoo

    ER -

    Likonen J, Lehto S, Coad J, Renvall T, Ahlgren T, Hole D et al. Studies of impurity deposition/implantation in JET divertor tiles using SIMS and ion beam techniques. In 22nd Symposium on Fusion Technology: Book of Abstracts. Espoo: VTT Technical Research Centre of Finland. 2002. p. 172-172. BO-4. (VTT Symposium; No. 220).