A5075624796- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Metal and Thin Film Mechanics
- Diamond and Carbon-based Materials Research
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Semiconductor materials and devices
- Copper Interconnects and Reliability
- Magnetic confinement fusion research
- Fusion materials and technologies
- Laser-induced spectroscopy and plasma
- Plasma Applications and Diagnostics
- Nuclear Materials and Properties
- Advancements in Photolithography Techniques
- Gas Sensing Nanomaterials and Sensors
- Gyrotron and Vacuum Electronics Research
- Catalytic Processes in Materials Science
- Silicone and Siloxane Chemistry
- Electrohydrodynamics and Fluid Dynamics
- Muon and positron interactions and applications
- Mass Spectrometry Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Graphene research and applications
- Boron and Carbon Nanomaterials Research
- Vacuum and Plasma Arcs
Physique des interactions ioniques et moléculaires
2011-2025
Aix-Marseille Université
2011-2023
Centre National de la Recherche Scientifique
2011-2021
Plasma (Russia)
2015
Eindhoven University of Technology
2012
Institut des Matériaux Jean Rouxel
2002-2007
Nantes Université
2002-2007
Laboratoire de Physique des Plasmas
2003
Laboratoire de Physique des Gaz et des Plasmas
1999-2001
Université Paris-Sud
2001
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 Negative ion production is of significant interest for materials processing and neutral beam injection (NBIs) systems magnetic confinement fusion reactors. The surface mechanism can be required high current applications. Dielectric materials, including doped diamond, are increasing as a potential alternative to low-work function metals further understanding the underpinning mechanisms needed. In this study we use photoemission yield spectroscopy, in conjunction with Fowler model...
The interaction of H atoms having relatively low average kinetic energy (∼0.025 eV) with both perfectly clean and D-covered HOPG surfaces is investigated using high resolution electron loss spectroscopy. From this study we confirm, in a controlled fashion, the presence theoretically predicted adsorption barrier since no detected for such on HOPG. Moreover, demonstrate that exposure D saturated surface to these results complete removal adatoms, further despite prediction vanish dimers para...
Since the signature of ITER treaty in 2006, a new research programme targeting emergence generation neutral beam (NB) system for future fusion reactor (DEMO Tokamak) has been underway between several laboratories Europe. The specifications required to operate NB on DEMO are very demanding: provide plasma heating, current drive and control at high level power (up 150 MW) energy (1 or 2 MeV), including performances term wall-plug efficiency (η > 60%), availability reliability. To this aim,...
In parallel to the developments dedicated ITER neutral beam (NB) system, CEA-IRFM with laboratories in France and Switzerland are studying feasibility of a new generation NB system able provide heating current drive for future DEMOnstration fusion reactor. For steady-state scenario, will have high power level wall-plug efficiency (η ∼ 60%). Neutralization energetic negative ions by photodetachment (so called photoneutralization), if feasible, appears be ideal solution meet these...
This paper deals with a study of H−/D− negative ion surface production on diamond in low pressure H2/D2 plasmas. A sample placed the plasma is negatively biased respect to potential. Upon positive impacts sample, some ions are formed and detected according their mass energy by spectrometer front sample. The experimental methods developed obtain angle distribution functions first presented. Different materials ranging from nanocrystalline single crystal layers, either doped boron or...
This work is devoted to the study of atomic oxygen recombination on a glass surface, mainly in connection with sources development. In this paper we present non-stationary model for fused silica surface. Kinetics equations atoms, taking into account heterogeneous reactions between gaseous atoms and surface (Eley-Rideal mechanisms), as well homogeneous processes involving migration adsorbed species (Langmuir-Hinshelwood are solved. Surface reaction coefficients calculated, choice numerical...
The time afterglow of a pulsed discharge is used to investigate the neutral-particle kinetics in N2-O2 low-pressure mixtures. pressure range 0.5-2 Torr at 300 K and mixture composition 0-20% oxygen. Time-resolved emission spectroscopy on N2(B), N2(C), NO(A) NO(B) employed monitor energy transfers involving metastable state N2(A). influence N(4S) O(3P) atoms accurately treated using absolute concentration measurements by time-resolved absorption VUV range. It shown that an appropriate choice...
SiO 2 is a well suited material for integrated optic applications and also attractive microelectromechanical system micro-optical electromechanical fabrication. Such optical components require deep oxide etching (several microns) subsequent high selectivity with respect to the mask. In this article, we describe influence of various process parameters (gas mixture, pressure, plasma power, residence time) on selective SiO2 Si in inductively coupled (ICP) fluorocarbon aim finding best...
The neutral gas temperature in a CF4 planar inductive discharge was measured with space and time resolution using laser-induced fluorescence of the CF radical analysis rotationally resolved excitation spectra. Strong gradients are observed temperatures as high 900 K reached at reactor center 50 mTorr power density 0.15 W/cm3. increases both pressure power, but is independent flow rate. A simple model based on global thermal energy balance proposed to explain these results. fraction injected...
The aim of this paper is to determine the atomic oxygen surface loss probability on silica under microwave plasma conditions around 133 Pa (1 Torr). A pulsed induced fluorescence technique where a main long pulse creates and shorter one re-excites atoms in time post-discharge was used. method its validity present experimental are discussed at large. found be 3% conditions, while it estimated two orders magnitude lower for not submitted plasma.
In this paper, we analyse, by the use of different plasma diagnostics, appearance potential mass spectrometry (APMS), optical emission spectroscopy (OES) and Langmuir probe measurements, a commercialized ICP source devoted to etching SiO2 using Si mask. First, influence gas composition (C2F6 mixed with H2 or CH4) residence time (varying flow rate) on rates selectivity is studied optimize process. Second, in order improve understanding mechanisms, characterized according previous discharge...
Highly oriented polycrystalline graphite (HOPG), boron-doped diamond (BDD), nanocrystalline diamond, ultra-nanocrystalline and diamond-like carbon surfaces are exposed to low-pressure hydrogen plasma in a 13.56 MHz reactor. Relative yields of surface-produced H− ions due bombardment positive from the measured by an energy analyser cum quadrupole mass spectrometer. Irrespective conditions (0.2 2 Pa), HOPG show highest yield at room temperature (RT), while high (HT), (∼3–5 times compared...
The time post discharge of a low-pressure pulsed dc in pure oxygen is used to investigate the atomic recombination on fused silica surface. With intention studying this for different surface states, we perform before each experiment wall treatment by means discharges under experimental conditions. Then, monitor decrease resolved VUV resonant absorption spectroscopy. We have shown that it possible obtain given treatment, pulse after variation decrease. attributed filling chemisorption sites....
We measure H− negative ions by means of a mass spectrometer in helicon plasma reactor. The H2 operates at low injected RF power (50–300 W), capacitive regime, under pressure conditions (between 0.4 and 1 Pa). A highly oriented pyrolytic graphite (HOPG) sample centred the expanding chamber facing nozzle placed 40 mm away is negatively biased. Negative formed on surface upon positive ion bombardment are detected according to their energy spectrometer. obtain distribution function (IDF) showing...
A graphite sample is negatively biased in a hydrogen plasma. H− ions created on the surface are accelerated by sheath toward mass spectrometer where they detected according to their energy. The ion distribution function shows two contributions: main peak followed an energetic tail. It was previously proven backscattering of positive as negative responsible for high energy In this paper we demonstrate 75% production coming from sputtering adsorbed atoms ions. threshold mechanism around 20 eV...
Boron-doped polycrystalline diamond (BDD) and highly oriented pyrolytic graphite (HOPG) surfaces were exposed to low pressure hydrogen plasma. The relative yields of surface-produced H − ions measured by an energy analyser quadrupole mass spectrometer. highest yield was obtained at 400 °C for a BDD surface room temperature HOPG surface. At ion bombardment energy, the maximum on is about 5 times higher than that surface, which has been best carbon material so far production in caesium-free...
In previous works, surface-produced negative-ion distribution-functions have been measured in H2 and D2 plasmas using graphite surfaces (highly oriented pyrolitic graphite). the present paper, we use srim software to interpret distribution-functions. For this purpose, of backscattered sputtered atoms arising due impact hydrogen ions on a-CH a-CD are calculated. The calculations confirm experimental deduction that backscattering sputtering mechanisms origin creation negative at surface. It is...
Multiwavelength Raman spectroscopy (325, 514, 633 nm) was used to analyze three different kinds of samples containing sp2 and sp3 carbons: chemical vapor deposited diamond films varying microstructure, a plasma-enhanced hydrogenated amorphous carbon film heated at 500 °C highly oriented pyrolytic graphite exposed radio-frequent deuterium plasma. We found evidence that the lower part phonon density states (PDOS) spectral region (300–900 cm−1) rises when defects are introduced in crystals can...
Thin tungsten oxide layers with thicknesses up to 250 nm have been formed on W surfaces by thermal oxidation following a parabolic growth rate. The reflectance of the in IR range 2.5–16 μm has measured showing decrease layer thickness especially at low wavelengths. Raman microscopy and x-ray diffraction show nanocrystalline WO3 monoclinic structure. Low energy deuterium plasma exposure (11 eV/D+) performed inducing phase transition, change sample colour formation bronze (DxWO3). Implantation...
The formation of NO molecules during a single plasma pulse in low-pressure dc discharge is measured using time resolved tunable diode laser absorption spectroscopy the infrared region. duration ranges from 280 µs to 16 ms and current 20 80 mA. gas pressure 133 Pa. Experimental results show that density about proportional product times duration. mechanisms are discussed. We reaction oxygen atoms with vibrationally excited nitrogen (N2(X, v > 12) + O) does not impact concentration. Numerical...