Dependence of LIBS spectra on the surface composition and morphology of W/Al coatings

Laan, M.; Hakola, A.; Paris, P.; Piip, K.; Aints, M.; Jõgi, Indrek; Kozlova, J.; Mändar, Hugo; Lungu, C.P.; Poroşnicu, C.; Grigore, E.; Ruset, C.; Kolehmainen, Jukka; Tervakangas, Sanna

doi:10.1016/j.fusengdes.2017.03.173

Cited by 9 publications

(9 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Laser induced breakdown spectroscopy (LIBS) has been shown to be a promising method for the in-situ fuel retention monitoring in tokamaks [20][21][22][23][24][25] and linear plasma devices [26][27][28][29]. However, the line intensities in LIBS spectra depend not only on the coating composition but also on morphology and crystalline phase content [30][31][32]. Besides the spectral lines intensities, the determination of the deuterium retention in the plasma-facing components requires the knowledge of ablation rates of the investigated materials which also depends on the coating properties [32,33].…”

Section: Introductionmentioning

confidence: 99%

“…However, the line intensities in LIBS spectra depend not only on the coating composition but also on morphology and crystalline phase content [30][31][32]. Besides the spectral lines intensities, the determination of the deuterium retention in the plasma-facing components requires the knowledge of ablation rates of the investigated materials which also depends on the coating properties [32,33]. These coating properties may be further changed by the exposure of coatings to high plasma fluxes [26,34,35].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

LIBS study of ITER relevant tungsten–oxygen coatings exposed to deuterium plasma in Magnum-PSI

Jõgi

Paris

Laan

et al. 2021

Journal of Nuclear Materials

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

LIBS study of ITER relevant tungsten–oxygen coatings exposed to deuterium plasma in Magnum-PSI

Jõgi

Paris

Laan

et al. 2021

Journal of Nuclear Materials

View full text Add to dashboard Cite

“…The other factor was the re‐deposition of ablated material into the crater. The central part of the crater reaches the interface first, and the change in intensity occurs gradually . The slow decay of W signals after N = 50 was caused by elemental self‐absorption as more plasma is confined in crater with increasing depth.…”

Section: Resultsmentioning

confidence: 99%

“…In Figure A, the AAR increases as the fluence increases. The AAR also depends on spot radius, power density, coating thickness, the nature of material, and pulse width . LIBS technique could also be used to remove the deposited material on the substrate by keeping the fluence higher than the ablation threshold value of the coating and lower than ablation threshold of substrate.…”

Section: Resultsmentioning

confidence: 99%

Depth profiling of tungsten coating layer on CuCrZr alloy using LIBS approach

Imran

Sun

Liu

et al. 2018

Surface & Interface Analysis

View full text Add to dashboard Cite

Laser induced breakdown spectroscopy (LIBS) was employed to find the depth profile of W-coated CuCrZr alloy. Cathodic arc deposition method was applied to produce tungsten coating on the CuCrZr alloy. The LIBS measurements were carried out by using a Nd:YAG laser at its fundamental wavelength (1064 nm) with various fluences.The spectral intensity emitted from laser induced plasma of the coating material was investigated for both elemental and depth-profile analyses in terms of linear correlation coefficient. Other surface characterization techniques (scanning electron microscopy and energy dispersive X-ray) were also used to determine morphology and elemental composition. It is observed that nonuniform radial energy distribution of Gaussian laser beam caused gradual decay of spectral lines of the coating and rise of substrate lines. The results indicate that the spectral intensity from W coating was higher than that from the bulk material at same laser fluence. The high-resolution in-depth profile was achieved at low fluence. This study demonstrates that LIBS is a promising technique for the depth-profiling analysis of W coating of EAST-like material and can be used to determine the material erosion and impurity deposition on plasma facing components. KEYWORDS cathodic arc deposition, CuCrZr alloy, depth profile, LIBS, W-coating 1 | INTRODUCTION Metallic coatings for various applications, like plasma facing material, wear and corrosion resistance, and protection against erosion, have great importance and are in a high demand both in technology and industry. 1 Many types of coating are used to improve mechanical, optical, thermal, electrical, chemical, and magnetic properties of the substrate. Many applications in industry require in-depth characterization of coated layers with thickness from nanometre to tens of micrometre. 2 The plasma facing components (PFCs) used in fusion devices have to operate under highly aggressive environment. The coatings deposition produced on PFCs have to protect them from high heat flux plasm particles in order to improve their performance in long pulse operations. However, some materials are eroded as high heat flux strike with wall components and redeposited as an impurity on PFCs which changed the surface composition. 3-5 Moreover, the exposure of PFCs to high-energy particles fluxes changes the surface crystallinity and causes the change in ablation threshold value. In EAST tokamak, the ITER-like W mono-blocks were used in upper divertor target. The divertor baffle and dome were made of W/CuCrZr (W plates on CuCrZr alloy). 6,7 A reliable technique is required to measure the depth profile of erosion and impurity deposition on surface modification which could perform in the tokamak-like environment for in-situ analysis and give the entire information of elemental composition.Laser induced breakdown spectroscopy (LIBS) is a promising multi-element analytical technique for in-situ analysis of the chemical composition of components inside the vacuum vessel of fusion devices. [8][9][10...

show abstract

“…Ablation rate /laser fluence 60-160 nm/pulse (W) 7 J/cm 2 [54] 400-800 nm/pulse (porous W-Al) 7 J/cm 2 [54] 250-500 nm/pulse (columnar W-O) 15-20 J/cm 2 [39,55] 210 nm/pulse (W-N-D) 66 J/cm 2 [28] Operational press. range H isotope distinguishability 1 bar N2 or air [28] Quality: high till 100 mbar N2 [23] At 1 bar Ar [22] Distinguishable at long delays with low S/N ratio Highest operational press.…”

Section: Table 1 Sp-libsmentioning

confidence: 99%

Monitoring of tritium and impurities in the first wall of fusion devices using a LIBS based diagnostic

Meiden¹,

Almaviva²,

Butikova³

et al. 2021

Nucl. Fusion

View full text Add to dashboard Cite

Laser-induced breakdown spectroscopy (LIBS) is one of the most promising methods for quantitative in-situ determination of fuel retention in plasma-facing components (PFCs) of magnetically confined fusion devices like ITER and JET. In this article, the current state of understanding in LIBS development for fusion applications will be presented, based on a complete review of existing results and complemented with newly obtained data. The work has been performed as part of a research programme, set up in the EUROfusion Consortium, to address the main requirements for ITER: (a) quantification of fuel from relevant surfaces with high sensitivity, (b) the technical demonstration to perform LIBS with a remote handling system and (c) accurate detection of fuel at ambient pressures relevant for ITER. For the first goal, the elemental composition of ITER-like deposits and proxies to them, including deuterium (D) or helium (He) containing W–Be, W, W–Al and Be–O–C coatings, was successfully determined with a typical depth resolution ranging from 50 up to 250 nm per laser pulse. Deuterium was used as a substitute for tritium (T) and in the LIBS experiments deuterium surface densities below 1016 D/cm2 could be measured with an accuracy of ∼30%, confirming the required high sensitivity for fuel-retention investigations. The performance of different LIBS configurations was explored, comprising LIBS systems based on single pulse (pulse durations: ps–ns) and double pulse lasers with different pulse durations. For the second goal, a remote handling application was demonstrated inside the Frascati-Tokamak-Upgrade (FTU), where a compact, remotely controlled LIBS system was mounted on a multipurpose deployer providing an in-vessel retention monitor system. During a shutdown phase, LIBS was performed at atmospheric pressure, for measuring the composition and fuel content of different area of the stainless-steel FTU first wall, and the titanium zirconium molybdenum alloy tiles of the toroidal limiter. These achievements underline the capability of a LIBS-based retention monitor, which complies with the requirements for JET and ITER operating in DT with a beryllium wall and a tungsten divertor. Concerning the capabilities of LIBS at pressure conditions relevant for ITER, quantitative determination of the composition of PFC materials at ambient pressures up to 100 mbar of N2, the D content could be determined with an accuracy of 25%, while for atmospheric pressure conditions, an accuracy of about 50% was found when using single-pulse lasers. To improve the LIBS performance in atmospheric pressure conditions, a novel approach is proposed for quantitative determination of the retained T and the D/T ratio. This scenario is based on measuring the LIBS plume emission at two different time delays after each laser pulse. On virtue of application of a double pulse LIBS system, for LIBS application at N2 atmospheric pressure the distinguishability of the spectra from H isotopes could be significantly improved, but further systematic research is required.

show abstract

Dependence of LIBS spectra on the surface composition and morphology of W/Al coatings

Cited by 9 publications

References 10 publications

LIBS study of ITER relevant tungsten–oxygen coatings exposed to deuterium plasma in Magnum-PSI

LIBS study of ITER relevant tungsten–oxygen coatings exposed to deuterium plasma in Magnum-PSI

Depth profiling of tungsten coating layer on CuCrZr alloy using LIBS approach

Monitoring of tritium and impurities in the first wall of fusion devices using a LIBS based diagnostic

Contact Info

Product

Resources

About