Laser ablation tests performed on TORE-SUPRA graphite samples

Guern, F. Le; Hubert, Christophe; Mousset, S.; Gauthier, E.; Blanc, Cécile; Wodling, Pascal; Weulersse, Jean-Marc

doi:10.1016/j.jnucmat.2004.07.053

Cited by 23 publications

(9 citation statements)

References 11 publications

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“…One of the JT-60 open-divertor tiles, which were exposed to 1800 hydrogen discharges from June 1988 to October 1988, with the limiter configuration including 300 lower X-point divertor configura- [17] ps laser [7,19,20] JT-60 [10,12] Xe lamp (172 nm) [5,6,15] TORE-SUPRA [14] tions, was used as a sample. Hirohata et al have revealed that hydrogen was retained homogeneously in the co-deposits of the JT-60 open-divertor tiles with the nearly constant concentration of H/C $0.03 or 1.4 · 10 21 atoms m À2 lm À1 using thermal desorption spectroscopy [23].…”

Section: Methodsmentioning

confidence: 99%

“…Some advantages of tritium removal using lasers are that it is possible to remove tritium from plasma-shadow regions, the production of hazardous tritiated water is small, and it is not necessary to introduce gases. Many experiments on the removal of hydrogen isotopes from carbon materials have been conducted using several types of light sources with different wavelength, pulse duration, and intensity [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. See Table 1 for a summary.…”

Section: Introductionmentioning

confidence: 99%

“…In the region where I L is less than the threshold intensity I ablation for ablation or vapourization (non-ablation region; NAR), thermal desorption of hydrogen isotopes occurs [3,5,6,9,11,13,17]. When I L is larger than I ablation (ablation region; AR), sublimation of both carbon materials and hydrogen isotopes occurs, and ablative removal starts [3,7,8,10,12,[14][15][16][18][19][20]. When pulsed lasers are used, since thermal desorption in NAR is not effective, AR is usually used.…”

Section: Introductionmentioning

confidence: 99%

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Pulsed-laser ablation of co-deposits on JT-60 graphite tile

Sakawa

Watanabe

Shibahara

et al. 2007

Journal of Nuclear Materials

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Pulsed-laser ablation of co-deposits on JT-60 graphite tile

Sakawa

Watanabe

Shibahara

et al. 2007

Journal of Nuclear Materials

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“…Although this method is effective for tritium retained in the near surface, complete removal from thick codeposited layer is difficult. Another approach is the ablation-assisted removal by using high-power pulsed-laser irradiation [5][6][7][8][9][10][11][12], which is the topic of this paper. It is possible to remove not only tritium but also deposited layer itself by ablation, hence almost complete removal is expected.…”

Section: Introductionmentioning

confidence: 99%

Removal of the deposition on JT-60 tile by nano-sec pulsed-laser irradiation

Sugiyama

Sakawa

Tanabe

et al. 2010

Journal of Nuclear Materials

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To clarify the property of tritium removal from carbon codeposition by using pulsed-laser induced desorption, hydrogen removal from co-deposits on JT-60 divertor tile using a fourth-harmonic emission (266 nm) of a nano-sec Nd:YAG laser was demonstrated. The threshold laser fluence for ablation was ~ 0.3 J/cm 2 , which was slightly higher compared to that of the pico-sec laser irradiation. The energy absorption coefficient for the nano-sec laser, which was obtained by fitting the removal rate by so-called Beer's law, was larger than the pico-sec laser. Since the time constant of thermal wave propagation into the target is of the order of nanosecond, such differences between nano-and pico-sec lasers could be attributed to thermal effects. The ablation threshold of the deposited layer was lower than that of a pure graphite, which could be attributed to the difference of thermal conductivity between deposited layer and pure graphite. The removal rate of the nano-sec laser was higher than that of pico-sec laser in the fluence range of < 0.5 J/cm 2 . On the other hand, the production ratio [hydrocarbon species] / [H 2 ] continuously increased with the laser fluence, and no significant ionization of carbon was observed in this fluence range. This indicated that the fluence range in this study was "weak"-ablation range, which was still not sufficient to minimize the hydrocarbon production.

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“…However, it is also important to develop diagnostic method for real-time observation of the removal process. Based on experimental evidence presented in [16] it has been decided to introduce the spectroscopy diagnostics into the experimental set-up. The main focus of this paper is on description of the new spectroscopic diagnostics of the system for co-depostit removal and on discussion of obtained results.…”

Section: Introductionmentioning

confidence: 99%

Effective laser-induced removal of co-deposited layers from plasma-facing components in a tokamak

et al. 2006

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An experimental set-up and spectroscopy diagnostic method for laser-induced fuel removal and decomposition of co-deposited layers on plasma-facing components from tokamaks are described. For irradiation of a graphite limiter tile from the TEXTOR tokamak Nd:YAG 3.5-ns pulse laser with a repetition rate of 10 Hz and single pulse energy of up to 0,8 J at 1,06 µm has been used. The spectroscopy system allowed recording of spectra in the visible wavelength range including CII and Dα spectral lines . The evolution of CII and Dα spectral lines was observed pulse-by-pulse during the co-deposit removal. The efficient ablation of the 45 µm thick co-deposit occured after approximately 50 laser pulses.

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Laser ablation tests performed on TORE-SUPRA graphite samples

Cited by 23 publications

References 11 publications

Pulsed-laser ablation of co-deposits on JT-60 graphite tile

Pulsed-laser ablation of co-deposits on JT-60 graphite tile

Removal of the deposition on JT-60 tile by nano-sec pulsed-laser irradiation

Effective laser-induced removal of co-deposited layers from plasma-facing components in a tokamak

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