The Experts below are selected from a list of 2580 Experts worldwide ranked by ideXlab platform
J N Brooks - One of the best experts on this subject based on the ideXlab platform.
-
erosion redeposition analysis of the iter first wall with convective and non convective plasma transport
Physics of Plasmas, 2006Co-Authors: J N Brooks, Jean Paul Allain, T D RognlienAbstract:Sputtering erosion/redeposition is analyzed for IAEA [Report GA10FDR1-01-07-13 (2001)] plasma facing components, with scrape-off layer (SOL) plasma convective radial transport and nonconvective (diffusion-only) transport. The analysis uses the UEDGE code [T .D. Rognlien et al., J. Nucl. Mater. 196, 347 (1992)] and DEGAS code [D. P. Stotler et al., Contrib. Plasma Phys. 40, 221 (2000) ] to compute plasma SOL profiles and ion and neutral fluxes to the wall, TRIM-SP code [J. P. Biersack, W. Eckstein, J. Appl. Phys. A34, 73 (1984)] to compute sputter yields, and the REDEP/WBC code package [J. N. Brooks, Fusion Eng. Des. 60, 515 (2002)] for three-dimensional kinetic modeling of Sputtered Particle transport. Convective transport is modeled for the background plasma by a radially varying outward-flow component of the fluid velocity, and for the impurity ions by three models designed to bracket existing models/data. Results are reported here for the first wall with the reference beryllium coating and an alternati...
-
modeling and analysis of surface roughness effects on sputtering reflection and Sputtered Particle transport
Journal of Nuclear Materials, 1990Co-Authors: J N Brooks, David N RuzicAbstract:The microstructure of the redeposited surface in tokamaks may affect sputtering and reflection properties and subsequent Particle transport. This subject has been studied numerically using coupled models/codes for near-surface plasma Particle kinetic transport (WBC code) and rough surface sputtering (fractal-TRIM). The coupled codes provide an overall Monte Carlo calculation of the sputtering cascade resulting from an initial flux of hydrogen ions. Beryllium, carbon, and tungsten surfaces are analyzed for typical high recycling, oblique magnetic field, divertor conditions. Significant variations in computed sputtering rates are found with surface roughness. Beryllium exhibits high D-T and self-sputtering coefficients for the plasma regime studied (T{sub e} = 30-75 eV). Carbon and tungsten sputtering is significantly lower. 9 refs., 6 figs., 1 tab.
T D Rognlien - One of the best experts on this subject based on the ideXlab platform.
-
erosion redeposition analysis of the iter first wall with convective and non convective plasma transport
Physics of Plasmas, 2006Co-Authors: J N Brooks, Jean Paul Allain, T D RognlienAbstract:Sputtering erosion/redeposition is analyzed for IAEA [Report GA10FDR1-01-07-13 (2001)] plasma facing components, with scrape-off layer (SOL) plasma convective radial transport and nonconvective (diffusion-only) transport. The analysis uses the UEDGE code [T .D. Rognlien et al., J. Nucl. Mater. 196, 347 (1992)] and DEGAS code [D. P. Stotler et al., Contrib. Plasma Phys. 40, 221 (2000) ] to compute plasma SOL profiles and ion and neutral fluxes to the wall, TRIM-SP code [J. P. Biersack, W. Eckstein, J. Appl. Phys. A34, 73 (1984)] to compute sputter yields, and the REDEP/WBC code package [J. N. Brooks, Fusion Eng. Des. 60, 515 (2002)] for three-dimensional kinetic modeling of Sputtered Particle transport. Convective transport is modeled for the background plasma by a radially varying outward-flow component of the fluid velocity, and for the impurity ions by three models designed to bracket existing models/data. Results are reported here for the first wall with the reference beryllium coating and an alternati...
Jeffrey N. Brooks - One of the best experts on this subject based on the ideXlab platform.
-
near surface Sputtered Particle transport for an oblique incidence magnetic field plasma
Physics of fluids. B Plasma physics, 1990Co-Authors: Jeffrey N. BrooksAbstract:Near‐surface Sputtered Particle transport has been analyzed numerically using models of sputtering, sheath parameters, and impurity collisions with a background D–T plasma. Tungsten and carbon sputtering was examined, for tokamak divertor plasma conditions. Redeposited ion parameters computed include the charge state, transit time, energy, and angle of incidence. A regime of operation for finite self‐sputtering of tungsten has been identified. This regime is broader than previous estimates. Results for energetically Sputtered and thermally Sputtered carbon are compared.
-
Near‐surface Sputtered Particle transport for an oblique incidence magnetic field plasma
Physics of Fluids B: Plasma Physics, 1990Co-Authors: Jeffrey N. BrooksAbstract:Near‐surface Sputtered Particle transport has been analyzed numerically using models of sputtering, sheath parameters, and impurity collisions with a background D–T plasma. Tungsten and carbon sputtering was examined, for tokamak divertor plasma conditions. Redeposited ion parameters computed include the charge state, transit time, energy, and angle of incidence. A regime of operation for finite self‐sputtering of tungsten has been identified. This regime is broader than previous estimates. Results for energetically Sputtered and thermally Sputtered carbon are compared.
Toshiaki Makabe - One of the best experts on this subject based on the ideXlab platform.
-
Predictive study of a plasma structure and function in reactive ion etcher driven by very high frequency: Validity of an extended two-dimensional relaxation continuum model
Journal of Applied Physics, 2000Co-Authors: Kazunobu Maeshige, Masao Hasebe, Yukio Yamaguchi, Toshiaki MakabeAbstract:The plasma structure and physical function of a narrow gap reactive ion etcher (RIE), consisting of capacitively coupled parallel plates driven at 100 MHz, have been predicted in a proper manner by an extended relaxation continuum model including gas flow and Sputtered Particle transport from the substrate. Monitoring the spatiotemporal excitation rate gives validity to the use of the continuum model even at 50 mTorr under higher power condition mainly maintained by an ionization multiplication of the secondary electrons ejected from the powered electrode by ion impacts. The plasma structures are testified by comparing the two-dimensional net excitation rate of Ar(3p5) with the experimental computerized tomography image. A nonvolatile Particle transport successive to the physical etching on the substrate has been predicted in the RIE under a feed gas flow.
-
tomographic imagings of a plasma structure and Sputtered Particle in a direct current magnetron discharge
IEEE Transactions on Plasma Science, 1996Co-Authors: A Itoh, Toshiaki Makabe, N Shimura, S TougoAbstract:Computer-aided tomographic imagings for optical emission and absorption have been performed by using a four-axis industrial robot. The robotic system is applied to the investigation of a dc magnetron discharge for sputtering. It enables the visualization of a three-dimensional discharge structure, and the estimation of the two-dimensional thickness of a deposited film.
G Turban - One of the best experts on this subject based on the ideXlab platform.
-
experimental and modeling study of the Sputtered Particle transport in an r f magnetron discharge
Thin Solid Films, 1999Co-Authors: F Clenet, Ph Briaud, G Lemperiere, G TurbanAbstract:The influence of the gas pressure and the RF discharge power on Sputtered Ti and W atom concentrations in r.f. magnetron sputtering has been studied. Ti and W spatial densities were experimentally determined by optical spectroscopic measurements. As the discharge pressure increases in the range of 0.667 Pa to 5.33 Pa, the sputtering species are thermalized. Consequently their densities in the discharge increase with pressure. Owing to their weaker mass value, Ti atoms are faster thermalized than W atoms. The concentrations in the plasma of Sputtered species increase quasi-linearly with the RF power as the impinging argon ion energy. Experimental results are in good agreement with those obtained with a transport model based on a Particle in cell Monte Carlo method. The simulation uses a subcosinus law for the ejection angular distribution and a Thompson's theoretical distribution of the energy for atoms Sputtered from the cathode surface. Collisions between background gas atoms and ejected species are described with a Born-Mayer interaction potential. The transport model will be useful for predicting the Sputtered atom flux on every surface in contact with the discharge.