A5038182531- Fusion materials and technologies
- Nuclear Materials and Properties
- Magnetic confinement fusion research
- Advanced Chemical Physics Studies
- Nuclear Physics and Applications
- Metal and Thin Film Mechanics
- Graphene research and applications
- Ion-surface interactions and analysis
- Spectroscopy and Laser Applications
- Mass Spectrometry Techniques and Applications
- Advanced Materials Characterization Techniques
- Nuclear reactor physics and engineering
- Catalytic Processes in Materials Science
- Plasma Diagnostics and Applications
- Quantum, superfluid, helium dynamics
- Laser-induced spectroscopy and plasma
- Superconducting Materials and Applications
- Diamond and Carbon-based Materials Research
- Laser Material Processing Techniques
- Spectroscopy and Quantum Chemical Studies
- Cold Fusion and Nuclear Reactions
- Laser-Plasma Interactions and Diagnostics
- Nuclear materials and radiation effects
- Atmospheric Ozone and Climate
- Semiconductor Lasers and Optical Devices
Physique des interactions ioniques et moléculaires
2015-2024
Aix-Marseille Université
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Institut de Recherche sur la Fusion par Confinement Magnétique
2020-2024
CEA Cadarache
2024
IBM (Canada)
2015-2016
Plasma (Russia)
2015
École Polytechnique Fédérale de Lausanne
2007-2010
École Polytechnique
2004-2006
Laboratoire de Physique des Interfaces et des Couches Minces
2005-2006
Abstract In 2021 JET exploited its unique capabilities to operate with T and D–T fuel an ITER-like Be/W wall (JET-ILW). This second major campaign (DTE2), after DTE1 in 1997, represented the culmination of a series enhancements—new fusion diagnostics, new injection capabilities, refurbishment plant, increased auxiliary heating, in-vessel calibration 14 MeV neutron yield monitors—as well as significant advances plasma theory modelling community. DTE2 was complemented by sequence isotope...
Newly available, powerful infrared laser sources enable the preparation of intense molecular beams quantum-state prepared and aligned molecules for gas/surface reaction dynamics experiments. We present a stereodynamics study chemisorption vibrationally excited methane on (100) surface nickel. Using linearly polarized excitation C-H stretch modes two isotopologues [CH4(nu3) CD3H(nu1)], we methane's angular momentum vibrational transition dipole moment in laboratory frame. An increase...
The provision of a particle and power exhaust solution which is compatible with first-wall components edge-plasma conditions key area present-day fusion research mandatory for successful operation ITER DEMO. work package plasma-facing (WP PFC) within the European programme complements laboratory experiments, i.e. in linear plasma devices, electron ion beam loading facilities, studies performed toroidally confined magnetic such as JET, ASDEX Upgrade, WEST etc. connection both groups done via...
Abstract WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up 1000 s. In support of ITER operation and DEMO conceptual activities, key missions are: (i) qualification high heat flux plasma-facing components integrating both technological physics aspects relevant particle exhaust conditions, particularly for the monoblocks foreseen divertor; (ii) integrated steady-state at confinement, with a focus on power issues. During phase...
Quantum state-resolved sticking coefficients on Pt(111) and Ni(111) surfaces have been measured for CH4 excited to the first overtone of antisymmetric C-H stretch (2nu3) at well-defined kinetic energies in range 10-90 kJ/mol. The ground-state reactivity is approximately 3 orders magnitude lower than 10-64 kJ/mol, reflecting a difference barrier height 28+/-6 2nu3 excitation increases its by more 4 Ni(111), whereas increase 2 magnitude. We discuss observed differences ground state methane...
The knowledge of optical properties tungsten at high temperatures is crucial importance in fields such as nuclear fusion and aerospace applications. are well known room temperature, but little has been done between 300 K 1000 the visible near-infrared domains. Here, we investigate temperature dependence reflectivity from ambient to (<1000 K) 500–1050 nm spectral range, a region where interband transitions make strong contribution. Experimental measurements, performed via spectroscopic system...
Reflection absorption infrared spectroscopy (RAIRS) was used to probe for vibrational bond-selectivity in the dissociative chemisorption of three partially deuterated methane isotopologues on a Pt(111) surface. While combination incident translational energy and thermal excitation produces nearly statistical distribution C-H C-D bond cleavage products, we observe that laser an active stretch normal mode leads highly selective dissociation CHD3, CH2D2, CH3D. Our results show redistribution...
Abstract ITER will operate with a tungsten divertor, material featuring surface morphology changes when exposed to helium plasmas, in particular the formation of so called fuzz under specific conditions. Investigating interactions between plasma facing components and plasmas tokamak environment is therefore key point consolidate predictions for divertor performance lifetime. To this end, dedicated campaign was performed full WEST tokamak, cumulating ∼2000 s repetitive L mode discharges. It...
The state-resolved reaction probability of ${\text{CH}}_{4}$ on $\text{Pt}(110)\text{\ensuremath{-}}(1\ifmmode\times\else\texttimes\fi{}2)$ was measured as a function translational energy for four vibrational eigenstates comprising different amounts C-H stretch and bend excitation. Mode-specific reactivity is observed both between states from polyads isoenergetic belonging to the same polyad ${\text{CH}}_{4}$. For stretch/bend combination states, efficacy activation be higher than either...
We present a stereodynamics study of the dissociative chemisorption vibrationally excited methane on (100), (110), and (111) planes nickel single crystal surface. Using linearly polarized infrared excitation antisymmetric C–H stretch normal mode vibration (ν3), we aligned angular momentum amplitude CH4(ν3) in laboratory frame measured alignment dependence state-resolved reactivity CH4 for ν3 = 1, J 0–3 quantum states over range incident translational energies. For all three surfaces studied,...
Simulations of deuterium (D) atom exposure in self-damaged polycrystalline tungsten at 500 K and 600 are performed using an evolution the MHIMS (migration hydrogen isotopes materials) code which a model to describe interaction D with surface is implemented. The surface-energy barriers for both temperatures determined analytically steady-state analysis. desorption energy per from 0.69 ± 0.02 eV 0.87 0.03 K. These values good agreement ab initio calculations as well experimental determination...
Density Functional Theory studies show that in tungsten a mono vacancy can contain up to 6 Hydrogen Isotopes (HIs) at 300K with detrapping energies varying the number of HIs vacancy.Using these predictions, multi trapping rate equation model has been built and used thermal desorption spectrometry (TDS) experiments performed on single crystal after deuterium ions implantation.Detrapping obtained from adjust temperature TDS spectrum observed experimentally are good agreement DFT values within...
Fusion fuel retention (trapping) and release (desorption) from plasma-facing components are critical issues for ITER any future industrial demonstration reactors such as DEMO. Therefore, understanding the fundamental mechanisms behind of hydrogen isotopes in first wall divertor materials is necessary. We developed an approach that couples dedicated experimental studies with modelling at all relevant scales, microscopic elementary steps to macroscopic observables, order build a reliable...
Abstract Surface and near-surface morphology evolution of helium-irradiated tungsten due to thermal cycling up the ITER-relevant temperature 1350 K was studied using electron microscopy positron annihilation spectroscopy techniques. Holes at surface bubbles in recrystallized polycrystalline samples were created by 75 eV helium plasma irradiation with fluence 3 × 10 23 He m −2 1073 K. Subsequent annealing experiments combined a detailed analysis investigate shape density changes holes respect...
The reactivity of methane (CH(4)) on Pt(110)-(1 x 2) has been studied by quantum state-resolved surface measurements. Ground state reaction probabilities, S(0)(v=0) congruent with S(0)(laser-off), as well probabilities S(0)(2nu(3)), for CH(4) excited to the first overtone antisymmetric C-H stretch (2nu(3)) have measured at incident translational energies in range 4-64 kJ/mol. We observe S(0)(2nu(3)) be up three orders magnitude higher than S(0)(v=0), demonstrating significant vibrational...
Abstract We performed a direct comparison of deuterium retention and release from tungsten in presence or absence oxygen impurities. A single crystal W(110) was used to prepare with four different surface states: its native oxide, atomically clean, covered half monolayer atoms, three fourths atoms. For D ion fluence 3 × 10 21 + m −2 implanted at 300 K, highest the lowest atoms intermediate for clean surface. This counterintuitive result is explained by localization these samples. occurs...
We report the design and characterization of a new molecular-beam/surface-science apparatus for quantum state-resolved studies gas/surface reaction dynamics combining optical state-specific reactant preparation in molecular beam by rapid adiabatic passage with detection surface-bound products reflection absorption infrared spectroscopy (RAIRS). RAIRS is non-invasive spectroscopic technique that enables online monitoring buildup on target surface during deposition beam. The product uptake...
Hydrogen functionalization of graphene by exposure to vibrationally excited H2 molecules is investigated combined scanning tunneling microscopy, high-resolution electron energy loss spectroscopy, X-ray photoelectron spectroscopy measurements, and density functional theory calculations. The measurements reveal that dissociatively adsorb on Ir(111) resulting in nanopatterned hydrogen structures. Calculations demonstrate the presence Ir surface below lowers dissociative adsorption barrier...
Plasma-facing materials for next generation fusion devices, like ITER and DEMO, will be submitted to intense fluxes of light elements, notably He H isotopes (HI). Our study focuses on tritium (T) retention a wide range W samples: first, different types were investigated distinguish the impact pristine original structure retention, from W-coated samples ITER-grade pure various annealing manufacturing procedures, along with monocrystalline reference. Then, He-D irradiated studied investigate...
The impact of helium (He) plasma exposure with He fluxes relevant for ITER and WEST on the near-surface microstructure polycrystalline tungsten (W) is investigated by coupling transmission electron microscopy (TEM) analysis thermal desorption spectrometry (TDS) measurements. samples were exposed in PSI-2 linear device to 75 eV ions up fluence 3 × 1023 m−2 surface temperature range 1053–1073 K. obtained bubbles–enriched W are subsequently probed sequences low flux 250 deuterium (D) ion...
The pre-fusion power operation (PFPO) phase of ITER, as described in the ITER research plan with Staged Approach2, includes both hydrogen (H) and helium (He) plasma operations. In preparation for PFPO, WEST JET ran He campaigns to study plasma-wall interactions a tungsten environment. included back-and-forth transition between H or deuterium (D) allowing assessment achievable content well accessible wall reservoirs respective species. changeovers tokamak pulses fixed divertor configuration....
Abstract Rate equation modelling is performed to simulate <?CDATA ${\mathrm{D_2}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi mathvariant="normal">D</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> and ${\mathrm{D_2}}+{\mathrm{D}_2^+}$?> <mml:mo>+</mml:mo> <mml:msubsup> </mml:msubsup> exposure of the ${\mathrm{W}(110)}$?> mathvariant="normal">W</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mn>110</mml:mn>...