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Pulsed-laser ablation of hydrogen-dposited graphite target

Research Project

Project/Area Number 17540468
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Plasma science
Research InstitutionOsaka University

Principal Investigator

SAKAWA Youichi  Osaka University, Institute of Laser Engineering, Associate Professor, レーザーエネルギー学研究センター, 助教授 (70242881)

Co-Investigator(Kenkyū-buntansha) SHOJI Tatsuo  Nagoya University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (50115581)
TANABE Tetsuo  Kyusyu University, Interdisciplinary School of Engineering, Professor, 総合理工学研究院, 教授 (00029331)
YAMAZAKI Kouzou  Nagoya University, Graduate School of Engineering, Professor, 工学研究科, 教授 (50115648)
Project Period (FY) 2005 – 2006
Project Status Completed (Fiscal Year 2006)
Budget Amount *help
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2005: ¥2,100,000 (Direct Cost: ¥2,100,000)
KeywordsLaser ablation / Tritium removal / Graphite / Pulsed laser / Tokamak / Divertor
Research Abstract

Carbon materials are one of the candidates for plasma facing materials in ITER and nuclear-fusion reactors because of its superior nature at high-heat flux and low atomic number. However, when carbon is eroded by hydrogenic plasmas containing tritium, it co-deposits with tritium, and periodical removal is required from the safety reason. For the purpose of tritium removal from carbon co-deposits on plasma-facing material of fusion device, pulsed-laser induced desorption of hydrogen from co-deposits on JT-60 open-divertor tile has been investigated.
The fundamental (L=1064 nm) and fourth harmonic (L=266 nm) emission of Nd:YAG laser (laser energy <35 mJ/pulse for 1064 nm and <3 mJ/pulse for 266 nm, pulse duration 〜20 ps, I_L<6 x 10^<12> W/cm^2 for 1064 nm and 5 x 10^<11> W/cm^2 for 266 nm, repetition rate=10 Hz) were used.
Ablation depth per laser shot vs I_L showed that whereas the threshold laser intensity for ablation I_<ablation> 〜10^<10> W/cm^2 was nearly independent on L, the linear absorption-coefficient was larger for L=266 nm. A large difference in the threshold laser intensities of the strong ionization of carbon I_<ionization> between L=1064 and 266 nm was observed ; I_<ionization>= 9 x 10^<10> and (3.4〜7.4) x 10^<11>W/cm^2 for L=266 and 1064 nm, respectively. The lower I_<ionization> for L=266 nm was explained by three-photon ionization of carbon. Hydrogen-desorption efficiency, defined as the ratio between the number of desorbed hydrogen by laser irradiation and that of hydrogen retained in the ablated volume, was largest in the region, where strong ionization of C^+ occurred, and was larger for L=266 nm, in which a laser photon can cut C-H bond, compared with that for L=1064 nm. For the ablative removal of hydrogen, a short-wavelength and high-power laser is desirable.

Report

(3 results)
  • 2006 Annual Research Report   Final Research Report Summary
  • 2005 Annual Research Report
  • Research Products

    (14 results)

All 2007 2006 2005

All Journal Article (14 results)

  • [Journal Article] Pulsed-laser ablation of co-deposits on JT-60 graphite tile2007

    • Author(s)
      Y.Sakawa
    • Journal Title

      Journal of Nuclear Materials (印刷中)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Annual Research Report 2006 Final Research Report Summary
  • [Journal Article] Properties of hydrogen desorption from co-deposits on JT-60 graphite tile by pulsed laser ablation2007

    • Author(s)
      D.Watanabe
    • Journal Title

      Journal of Nuclear Materials (印刷中)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Annual Research Report 2006 Final Research Report Summary
  • [Journal Article] Properties of hydrogen desorption from co-deposits on JT-60 graphite tile by pulsed laser ablation2007

    • Author(s)
      D.Watanabe
    • Journal Title

      Journal of Nuclear Materials (in press)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Pulsed-laser ablation of co-deposits on JT-60 graphite tile2007

    • Author(s)
      Y.Sakawa
    • Journal Title

      Journal of Nuclear Materials (in press)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Ablation of hydrogen-implanted graphite target using pulsed laser beam2006

    • Author(s)
      Y.Sakawa
    • Journal Title

      Fusion Engineering and Design 81

      Pages: 381-386

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Laser ablation properties of JT-60 re-deposited carbon layers2006

    • Author(s)
      T.Shibahara
    • Journal Title

      Journal of Nuclear Science and Technology 43

      Pages: 316-319

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Pulsed laser ablation of hydrogen-implanted graphite target2006

    • Author(s)
      Y.Sakawa
    • Journal Title

      Journal of Plasma and Fusion Research SERIES 7

      Pages: 138-141

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Annual Research Report 2006 Final Research Report Summary
  • [Journal Article] レーザーアブレーションによる水素同位体の除去2006

    • Author(s)
      坂和洋一
    • Journal Title

      真空 49(2)

      Pages: 80-84

    • NAID

      10017277416

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Laser ablation properties of JT-60 re-deposited carbon layers2006

    • Author(s)
      T.Shibahara
    • Journal Title

      Journal of Nuclear Science and Technology 43 (4)

      Pages: 316-319

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Annual Research Report 2006 Final Research Report Summary
  • [Journal Article] Removal of hydrogen isotopes using laser ablation2006

    • Author(s)
      Y.Sakawa
    • Journal Title

      Journal of Vacuum Society of Japan 49(2)

      Pages: 80-84

    • NAID

      10017277416

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] レーザーアブレーションによる水素同位体の除去2006

    • Author(s)
      坂和洋一
    • Journal Title

      真空 49 (2)

      Pages: 80-84

    • NAID

      10017277416

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Ablation of hydrogen- implanted graphite target using pulsed laser beam2006

    • Author(s)
      Youichi Sakawa
    • Journal Title

      Fusion Engineering and Design 81

      Pages: 381-386

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Hydrogen release behavior from graphite under pulsed laser irradiation2005

    • Author(s)
      T.Shibahara
    • Journal Title

      Journal of Nuclear Materials 337-339

      Pages: 654-658

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Hydrogen release behavior from graphite under pulsed laser ablation2005

    • Author(s)
      T.Shibahara
    • Journal Title

      Journal of Nuclear Materials 337-339

      Pages: 654-658

    • Related Report
      2005 Annual Research Report

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Published: 2005-04-01   Modified: 2016-04-21  

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