label: url

en: Ultrafine Particle Removal Using Gas Cluster Ion Beam Technology

en: IEEE Transactions on Semiconductor Manufacturing


en: Modeling of Impurity Transport in Edge Plasmas and Tritium Codeposition on Plasma Facing Walls in ITER

en: Fusion Science and Technology

ja: Fusion Science and Technology


en: Molecular dynamics study on hydrocarbon interaction with plasma facing walls

en: Journal of Nuclear Materials

ja: Journal of Nuclear Materials


en: Toroidal and poloidal asymmetry in carbon deposition on gaps of plasma facing tiles


en: Monte Carlo simulation of erosion and deposition behavior on SiC-coated graphite tiles in EAST

number: No.1, Supplement


en: An EDDY/Particle-in-Cell Simulation of Erosion of Plasma Facing Walls Bombarded by a Collisional Plasma

en: To investigate the erosion of a plasma-facing wall intersecting an oblique magnetic field, we performed a kinetic particle-in-cell (PIC) simulation of magnetized plasma, in which collision processes between charged and neutral particles were taken into account. Sheath formation and local physical quantities, such as the incident angle and energy distributions of plasma ions at the wall, were examined at a plasma density of $10^{18}$ m-3, a temperature of 10 eV, and a magnetic field strength of 5 T. The erosion rate of a carbon wall was calculated using the ion--solid interaction code EDDY. At a high neutral density (${>}10^{20}$ m-3), the impact energy of the ions dropped below the threshold for physical sputtering, so that the sputtering yield was drastically decreased and wall erosion was strongly suppressed. Sputter erosion was also suppressed when the angle of the magnetic field with respect to the surface normal was sufficiently large.

en: Japanese Journal of Applied Physics

ja: Japanese Journal of Applied Physics


en: Calculation of D/XB Values of Hydrocarbon Molecules in Tokamak Edge Plasmas

en: In order to investigate the dependence of effective inverse photon-efficiency D/XB values on the plasma parameters, we have been performed calculations of effective D/XB values by Monte Carlo method. Photon fluxes are converted into particle fluxes with aid of D/XB values. A D/XB value is critical factor in the study of chemical erosion by spectroscopic measurement. In modeled tokamak edge plasma, transfer of hydrocarbon molecules (CH4, C2Hx (x = 2,4,6), C3Hy (y = 4,6,8)) and CH and C2 emissions have been simulated. The plasma temperature ranged from 1 eV to 100 eV and the plasma densities are 1018 m-3, 1019 m-3 and 1020 m-3. In the temperature region of less than 3 eV, the calculated D/XB values increase with decreasing temperature due to decreasing of emission counts. In the high temperature region (≥ 10 eV), the D/XB values increase with a rise in the temperature due to decrease of number of fragment of type CH and C2.

en: Plasma and Fusion Research

ja: Plasma and Fusion Research


en: Molecular dynamics and dynamic Monte Carlo studies of mixed materials and their impact on plasma wall interactions

en: Fusion Engineering and Design

ja: Fusion Engineering and Design


en: A coupled EDDY/PIC/ELECTRAN simulation of erosion and deposition in gaps


en: Hydrocarbon Redeposition on Plasma Facing Walls Intersecting Magnetic Field at Shallow Angles

en: In present nuclear fusion devices, hydrocarbons resulting from the chemical sputtering of carbon-based walls redeposit on other areas of the wall after transport in plasmas, forming hydrogen-rich carbon layers. A particle-in-cell calculation of a sheath region between the plasma and the wall is incorporated into the transport simulation of methane (CH4) and the fragments in the plasma. The effect of the magnetic field intersecting the wall surface at shallow angles on the redeposition characteristics is studied, taking the reflection and sticking on the wall into account. The redeposition rate is rather slowly increased with increasing angle between the magnetic field line and the surface normal, whereas it strongly depends on the plasma temperature and the sticking probability, $S$, of hydrocarbons (CHx) returning to the surface. By assuming $S = 1$, the redeposition of large molecular ions (CH3+ and CH4+) is suppressed at shallow angles ($heta > 85$°), whereas the redeposition of atomic C ions is enhanced. For zero sticking ($S = 0$), the redeposition is dominated by C ions at high temperature, whereas at low temperature, it is dominated by neutral C atoms.


en: Modelling and observations of electron beam charging of an insulator/metal bilayer and its impact on secondary electron images in defect inspection equipment

en: A self-consistent simulation of secondary electron (SE) emission and charging of a SiO(2) layer with the thickness of several tens of nanometres on Si is incorporated into a trajectory simulation of emitted SEs above the surface, the centre area of which is charged by electron beams (EBs) at the energy range from 300 to 2000 eV. In order to study the influence of the charging of an insulating layer on defect inspection, a pseudo-image is reconstructed from net SE yields calculated at each point of the SiO(2) surface locally applied the positive voltage. The image contrast between charged and uncharged areas is compared with the observation of thermally oxidized layer with the thickness of 24-106 nm on a Si wafer. The image contrast is very sensitive to the thickness of the SiO(2) layer, which is verified by both observed and calculated images. The calculated changes of the images with the layer thickness and the primary electron energy reproduce the experimental observations fairly well. This confirms a highly sensitive detection mechanism for tiny defects in insulating patterns on a metal hard mask for an EB defect inspection equipment.

en: Journal of Electron Microscopy

ja: Journal of Electron Microscopy


en: Dependency of Tritium Retention in Graphite on Temperature Control of Molecular Dynamics

en: Contributions to Plasma Physics

ja: Contributions to Plasma Physics


en: Electron Velocity Distributions at a Sheath Edge in the Presence og Secondary Electron Emission from a Metal Surface


en: Secondary electron emission in scanning Ga ion, He ion and electron microscope

en: Vacuum

ja: Vacuum


en: Analysis of the high-Z impurity transport in a Tokamak by the IMPGYRO code

en: Journal of Plasma and Fusion Research Series


en: Transport of Heavy Hydrocarbon and its Redeposition on Plasma Facing Walls

ja: Journal of Plasma and Fusion Research Series


en: An EDDY-PIC Simulation of Co-deposition of Hydrogen Isotopes on a Castellated Structure of Plasma Facing Tiles


en: Coupled IMPGYRO-EDDY simulation of tungsten impurity transport in tokamak geometry

en: Journal of Nuclear Materials


en: Numerical analysis of incident angle of heavy metal impurity to plasma facing components by IMPGYRO


en: Simulation of redeposition of carbon/hydrocarbon on a material surface with castellated structures


en: Simulation of hydrocarbon reflection from carbon and tungsten surfaces and its impact on codeposition patterns on plasma facing components


en: Kinetic modelling og impurity transport in detached plasma for integrated divertor simulation with SONIC (SOLDOR/NEUT2D/IMPMC/EDDY)

en: Nuclear Fusion

ja: Nuclear Fusion


en: Comparison of secondary electron emission in helium ion microscope with gallium ion and electron microscopes

en: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms


en: Dynamic simulation of secondary electron emission and charging up of an insulating material

en: Surface & Coatings Technology

ja: Surface & Coatings Technology


en: Comparison of carbon deposition on tungsten between molecular dynamics and dynamic Monte Carlo simulation


en: Simulation of Hydrocarbon Redeposition on Plasma Shadowed Areas

en: Contributions to Plasma Physics


en: Emission statistics of X-ray induced photoelectrons and its comparison with electron- and ion-induced electron emissions

ja: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms


en: Simulation study on image contrast and spatial resolution in helium ion microscope

en: We performed Monte Carlo simulation of helium (He) ion induced secondary electron (SE) emission in order to compare the secondary electron image characteristics between He and gallium (Ga) scanning ion microscopes (SIM) and scanning electron microscope (SEM). For 10-50 keV He ion bombardment SE yield increases gradually with increasing the atomic number, Z2, of the target, as well as for the electron bombardment. However, for 30 keV Ga ion bombardment, SE yield shows an opposite Z2 dependence. The calculated SE yield is much larger than that for both electron and Ga ion bombardment. The incident angle dependence of the SE yield approximately obeys the inverse cosine law even at high angles of 85 degrees and more. On the other hand, for electron bombardment, the incident angle dependences are much weaker for low energy and high Z2. These indicate that the image contrast on He-SIM is clearer than those of SEM. Among the electron excitations by incident He ions, recoiled target atoms and excited electrons, the first one having narrow excitation volume dominates the SE yield, so that the spatial image resolution in SIM using zero-diameter He beams with the energies of 10-50 keV is prospected to be smaller or better (<0.1 nm) than for 30 keV Ga ion and 1 keV electron beams.

en: Journal of Electron Microscopy


en: Modeling of asymmetric redeposition distribution between inner and outer regions of the W-shaped divertor in JT-60U

en: Journal of Nuclear Materials


en: Simulation of hydrocarbon redeposition in the gaps between divertor tiles


en: Monte Carlo Simulation of Hydrocarbon Redeposition on a Graphite Surface in Hydrogen Plasma

en: To investigate the hydrocarbon redeposition process on the graphite tile surface, we developed a modeling code that considers a complete set of collisional reactions in the plasma, energy- and species-dependent reflection coefficients, and fragmentation at the tile surface. The model calculations revealed local redeposition characteristics. The redeposition rate, which is the number of redeposited particles on the tile surface per launched CH4 molecule, decreases with decreasing plasma temperature due to a steep decrease in the rate coefficients for electron impact ionization at temperatures of less than 10 eV. At elevated plasma temperatures, large numbers of singly or multicharged carbon ions are redeposited because of the high sticking coefficient of the multicharged ions, which is strongly accelerated by the sheath field. The hydrogen concentration of the deposited species increases because of a decrease in the number of dissociative reactions in the plasma with decreasing plasma density. Using energy- and species-dependent sticking coefficients, low-energy ion species are reflected by the tile surface where dissociation occurs and are subsequently dissociated due to transport in the plasma; accordingly, the hydrogen concentration of deposited species is low.

en: Japanese Journal of Applied Physics


en: Dynamic Monte Carlo Simulation of Compositional and Topography Changes Induced by Ion Beam Irradiation

en: e-Journal of Surface Science and Nanotechnology


en: 大学における安全保障輸出管理 ∼徳島大学の事例を中心に∼

ja: 大学における安全保障輸出管理 ∼徳島大学の事例を中心に∼

en: CISTEC Journal

ja: CISTEC Journal

volume: Vol.No. 179


en: 大学の輸出管理における地域大学ネット枠の活動について

ja: 大学の輸出管理における地域大学ネット枠の活動について

en: CISTECジャーナル

ja: CISTECジャーナル


en: 学術安全保障を考える

ja: 学術安全保障を考える