Comparison of LIBS results on ITER-relevant samples obtained by nanosecond and picosecond lasers

Peeter Paris, Jelena Butikova, Matti R. Laan, A. Hakola, I. Jõgi, J. Likonen, Eduard Grigore, Cristian Ruset

Research output: Contribution to journalArticleScientificpeer-review

Abstract

ITER foresees applying laser induced breakdown spectroscopy (LIBS) as a tool for quantitative assessment of fuel retention in the first walls. One open problem related to LIBS application is the choice of the laser type. Here we compare two Nd/YAG lasers with different pulse durations, 0.15 and 8 ns, working at λ = 1064 nm for LIBS studies of samples with D-doped W/Al coatings of ≈ 3 μm thickness (Al is used as a proxy of Be) on Mo. Low pressure argon was used as a background gas. Experiments were done in conditions where other factors (broadening of spectral lines, signal-to-noise ratio, limited thickness of coatings etc.) did not shadow the effect of laser pulse duration. For these reasons, low pressure argon was used as the background gas and fluences were kept at comparatively low values. Spectra of laser-produced plasma were recorded as a function of the number of laser pulses. Partially overlapping lines of hydrogen isotopes were fitted with Voigt contours, intensities were fitted and depth profiles of deuterium were reconstructed. The relative standard error of curve-fitting of spectra recorded with the laser of shorter pulse duration was two times smaller than that recorded by the longer pulse laser. The electron density was found from the Stark broadening of Hα line of the laser-produced plasma and the electron temperature of plasma was found on the basis W and Mo lines. It was found that in the case of ps laser an acceptable accuracy of the detection of deuterium was possible at considerably lower values of fluence. Steps needed for comparison of ps and ns lasers in ITER-relevant conditions were discussed.

Original languageEnglish
Pages (from-to)1-5
Number of pages5
JournalNuclear Materials and Energy
Volume18
Early online date30 Nov 2018
DOIs
Publication statusPublished - Jan 2019
MoE publication typeNot Eligible

Fingerprint

Laser induced breakdown spectroscopy
laser-induced breakdown spectroscopy
Laser pulses
Lasers
Laser produced plasmas
Argon
Deuterium
lasers
pulse duration
Gases
laser plasmas
Coatings
deuterium
fluence
Electron temperature
low pressure
Curve fitting
argon
H lines
Isotopes

Keywords

  • Detection of hydrogen isotopes
  • Elemental depth profiles
  • ITER-relevant coatings
  • LIBS diagnostics
  • Temperature of laser-produced plasma

Cite this

Paris, Peeter ; Butikova, Jelena ; Laan, Matti R. ; Hakola, A. ; Jõgi, I. ; Likonen, J. ; Grigore, Eduard ; Ruset, Cristian. / Comparison of LIBS results on ITER-relevant samples obtained by nanosecond and picosecond lasers. In: Nuclear Materials and Energy. 2019 ; Vol. 18. pp. 1-5.
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abstract = "ITER foresees applying laser induced breakdown spectroscopy (LIBS) as a tool for quantitative assessment of fuel retention in the first walls. One open problem related to LIBS application is the choice of the laser type. Here we compare two Nd/YAG lasers with different pulse durations, 0.15 and 8 ns, working at λ = 1064 nm for LIBS studies of samples with D-doped W/Al coatings of ≈ 3 μm thickness (Al is used as a proxy of Be) on Mo. Low pressure argon was used as a background gas. Experiments were done in conditions where other factors (broadening of spectral lines, signal-to-noise ratio, limited thickness of coatings etc.) did not shadow the effect of laser pulse duration. For these reasons, low pressure argon was used as the background gas and fluences were kept at comparatively low values. Spectra of laser-produced plasma were recorded as a function of the number of laser pulses. Partially overlapping lines of hydrogen isotopes were fitted with Voigt contours, intensities were fitted and depth profiles of deuterium were reconstructed. The relative standard error of curve-fitting of spectra recorded with the laser of shorter pulse duration was two times smaller than that recorded by the longer pulse laser. The electron density was found from the Stark broadening of Hα line of the laser-produced plasma and the electron temperature of plasma was found on the basis W and Mo lines. It was found that in the case of ps laser an acceptable accuracy of the detection of deuterium was possible at considerably lower values of fluence. Steps needed for comparison of ps and ns lasers in ITER-relevant conditions were discussed.",
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Comparison of LIBS results on ITER-relevant samples obtained by nanosecond and picosecond lasers. / Paris, Peeter; Butikova, Jelena; Laan, Matti R.; Hakola, A.; Jõgi, I.; Likonen, J.; Grigore, Eduard; Ruset, Cristian.

In: Nuclear Materials and Energy, Vol. 18, 01.2019, p. 1-5.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Comparison of LIBS results on ITER-relevant samples obtained by nanosecond and picosecond lasers

AU - Paris, Peeter

AU - Butikova, Jelena

AU - Laan, Matti R.

AU - Hakola, A.

AU - Jõgi, I.

AU - Likonen, J.

AU - Grigore, Eduard

AU - Ruset, Cristian

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N2 - ITER foresees applying laser induced breakdown spectroscopy (LIBS) as a tool for quantitative assessment of fuel retention in the first walls. One open problem related to LIBS application is the choice of the laser type. Here we compare two Nd/YAG lasers with different pulse durations, 0.15 and 8 ns, working at λ = 1064 nm for LIBS studies of samples with D-doped W/Al coatings of ≈ 3 μm thickness (Al is used as a proxy of Be) on Mo. Low pressure argon was used as a background gas. Experiments were done in conditions where other factors (broadening of spectral lines, signal-to-noise ratio, limited thickness of coatings etc.) did not shadow the effect of laser pulse duration. For these reasons, low pressure argon was used as the background gas and fluences were kept at comparatively low values. Spectra of laser-produced plasma were recorded as a function of the number of laser pulses. Partially overlapping lines of hydrogen isotopes were fitted with Voigt contours, intensities were fitted and depth profiles of deuterium were reconstructed. The relative standard error of curve-fitting of spectra recorded with the laser of shorter pulse duration was two times smaller than that recorded by the longer pulse laser. The electron density was found from the Stark broadening of Hα line of the laser-produced plasma and the electron temperature of plasma was found on the basis W and Mo lines. It was found that in the case of ps laser an acceptable accuracy of the detection of deuterium was possible at considerably lower values of fluence. Steps needed for comparison of ps and ns lasers in ITER-relevant conditions were discussed.

AB - ITER foresees applying laser induced breakdown spectroscopy (LIBS) as a tool for quantitative assessment of fuel retention in the first walls. One open problem related to LIBS application is the choice of the laser type. Here we compare two Nd/YAG lasers with different pulse durations, 0.15 and 8 ns, working at λ = 1064 nm for LIBS studies of samples with D-doped W/Al coatings of ≈ 3 μm thickness (Al is used as a proxy of Be) on Mo. Low pressure argon was used as a background gas. Experiments were done in conditions where other factors (broadening of spectral lines, signal-to-noise ratio, limited thickness of coatings etc.) did not shadow the effect of laser pulse duration. For these reasons, low pressure argon was used as the background gas and fluences were kept at comparatively low values. Spectra of laser-produced plasma were recorded as a function of the number of laser pulses. Partially overlapping lines of hydrogen isotopes were fitted with Voigt contours, intensities were fitted and depth profiles of deuterium were reconstructed. The relative standard error of curve-fitting of spectra recorded with the laser of shorter pulse duration was two times smaller than that recorded by the longer pulse laser. The electron density was found from the Stark broadening of Hα line of the laser-produced plasma and the electron temperature of plasma was found on the basis W and Mo lines. It was found that in the case of ps laser an acceptable accuracy of the detection of deuterium was possible at considerably lower values of fluence. Steps needed for comparison of ps and ns lasers in ITER-relevant conditions were discussed.

KW - Detection of hydrogen isotopes

KW - Elemental depth profiles

KW - ITER-relevant coatings

KW - LIBS diagnostics

KW - Temperature of laser-produced plasma

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JF - Nuclear Materials and Energy

SN - 2352-1791

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