LIBS for tungsten diagnostics in vacuum: Selection of analytes

Lissovski, A.; Piip, K.; Hämarik, Lauri; Aints, M.; Laan, M.; Paris, P.; Hakola, A.; Karhunen, J.

doi:10.1016/j.jnucmat.2014.11.096

Cited by 15 publications

(4 citation statements)

References 8 publications

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“…Because the Gibbs free energy of formation at 450 °C for WS 2 is lower than that for Ag 2 S, 41,42 it is WS 2 that will form first.…”

Section: Discussionmentioning

confidence: 95%

“…In the initial step of the growth process, ablated S and W atoms arrive on the surface of the substrate. Because the Gibbs free energy of formation at 450 °C for WS 2 is lower than that for Ag 2 S, , it is WS 2 that will form first. While the WS 2 platelets are growing, S diffuses around or through the WS 2 grains to react with the Ag layer.…”

Section: Discussionmentioning

confidence: 95%

See 1 more Smart Citation

Origin of Hybrid 1T- and 2H-WS₂ Ultrathin Layers by Pulsed Laser Deposition

Loh

Chua

2015

J. Phys. Chem. C

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Partial 2H-to-1T phase transition in two-dimensional (2D) WS2 grown by pulsed laser deposition is discovered through X-ray photoelectron spectroscopy. The resulting hybrid structure is observed only on substrates of the noble metals Ag and Au, whereas other metals such as Ni and Al produced only 2H-WS2. The origin of the 1T-phase is attributed to electron doping of the WS2 lattice by Ag or Au atoms, in a mechanism reminiscent of Li in the intercalation of WS2 and the related MoS2 structure. The doping process is viable as both Ag and Au atoms are able to donate one electron each, leading to the formation of a stable d10 shell and a phase transformation in the WS2 structure from 2H-to-1T. In the case of Ni, however, the formation of nickel oxides at the metal surface inhibits its ability to donate electrons to the WS2 lattice, whereas Al is unable to act as electron donor for WS2. Thus, the 1T-phase is absent in either of these substrates.

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“…Because the Gibbs free energy of formation at 450 °C for WS 2 is lower than that for Ag 2 S, 41,42 it is WS 2 that will form first.…”

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 95%

Origin of Hybrid 1T- and 2H-WS₂ Ultrathin Layers by Pulsed Laser Deposition

Loh

Chua

2015

J. Phys. Chem. C

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“…where ε z ji is the emissivity of the lines, λ ji is the wavelength, T is the electron temperature [K], E z j is the energy of the upper level [eV], n e is the electron density [m −3 ], A z ji g z ji is the Einstein coefficient multiplied by statistical weight, and z−1 k=0 E k ∞ − E k ∞ is the sum of ionization energies corresponding to the ionization level. The whole list of W lines used in the Boltzmann plot is shown in Table 1 and is based on other works regarding tungsten [15,17,18].…”

Section: Methodsmentioning

confidence: 99%

Tungsten plasma density and temperature time analysis using 1.064 $$\upmu $$m nanosecond dual-pulse laser

Gromelski

Gąsior

2021

Eur. Phys. J. Plus

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The information about time evolution of plasma electron temperature and density plays a fundamental role in numerous physics-related sciences. For CF DP-LIBS (calibration-free double-pulse laser-induced breakdown spectroscopy), not only may it serve to minimize the impact on the investigated sample, but also to optimize the laser and spectral parameters, or even to pave the way for real-time chemical analysis of the sample. To evaluate this impact and describe the plasma time behavior, electron temperature and density are calculated for plasma induced by double-pulse Nd:YAG laser with various (0–500 ns) inter-pulse delays. The parameters are calculated using various methods, such as Stark broadening, Boltzmann plot and Saha equation to provide complementary calculations for comparison. To ensure validity of the results, calibration of the measurement setup was performed. In the work, tungsten samples are investigated, because the W is chosen as the preferred material for plasma-facing components in future fusion devices such as ITER. Since LIBS method will be used to monitor tritium retention in ITER, the results may be utilized to improve the diagnostics.

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“…The LIBS spectra were recorded simultaneously by two spectrometers. Details of the setups are presented in [7]. The first, the Mechelle5000 recorded the spectrum in the entire 245-850 nm range for every laser shot.…”

Section: Methodsmentioning

confidence: 99%

Development of laser induced breakdown spectroscopy for studying erosion, deposition, and fuel retention in ASDEX Upgrade

Paris

Piip

Hakola

et al. 2015

Fusion Engineering and Design

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The paper deals with the development of laser induced breakdown spectroscopy (LIBS) into an in situ method for studying erosion/deposition processes at the first walls of fusion reactors. To this end, samples extracted from the divertor tiles of ASDEX Upgrade after the 2009 plasma operations were analyzed using LIBS for their composition and the results were compared with other post mortem deposition data. Quantitative depth profiles for the elemental concentrations were extracted from time-resolved LIBS spectra by applying a novel data processing method. In addition, both multiline and multispot averaging procedures were applied to reduce fluctuations in the data. The LIBS concentration profiles matched qualitatively with those given by secondary ion mass spectrometry and quantitatively with the ion-beam data. The deuterium content of the samples could be reliably determined if the surface densities were >10 17 at/cm 2 .

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LIBS for tungsten diagnostics in vacuum: Selection of analytes

Cited by 15 publications

References 8 publications

Origin of Hybrid 1T- and 2H-WS₂ Ultrathin Layers by Pulsed Laser Deposition

Origin of Hybrid 1T- and 2H-WS₂ Ultrathin Layers by Pulsed Laser Deposition

Tungsten plasma density and temperature time analysis using 1.064 $$\upmu $$m nanosecond dual-pulse laser

Development of laser induced breakdown spectroscopy for studying erosion, deposition, and fuel retention in ASDEX Upgrade

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LIBS for tungsten diagnostics in vacuum: Selection of analytes

Cited by 15 publications

References 8 publications

Origin of Hybrid 1T- and 2H-WS2 Ultrathin Layers by Pulsed Laser Deposition

Origin of Hybrid 1T- and 2H-WS2 Ultrathin Layers by Pulsed Laser Deposition

Tungsten plasma density and temperature time analysis using 1.064 $$\upmu $$m nanosecond dual-pulse laser

Development of laser induced breakdown spectroscopy for studying erosion, deposition, and fuel retention in ASDEX Upgrade

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Product

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Origin of Hybrid 1T- and 2H-WS₂ Ultrathin Layers by Pulsed Laser Deposition

Origin of Hybrid 1T- and 2H-WS₂ Ultrathin Layers by Pulsed Laser Deposition