A5056657217- Fusion materials and technologies
- Nuclear Materials and Properties
- Magnetic confinement fusion research
- Advanced materials and composites
- Vacuum and Plasma Arcs
- Ion-surface interactions and analysis
- Advanced Materials Characterization Techniques
- Metal and Thin Film Mechanics
- Nuclear Physics and Applications
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Diamond and Carbon-based Materials Research
- Nuclear reactor physics and engineering
- Catalytic Processes in Materials Science
- Radiation Detection and Scintillator Technologies
- High-Temperature Coating Behaviors
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Intermetallics and Advanced Alloy Properties
- Advanced Photocatalysis Techniques
- Minerals Flotation and Separation Techniques
- Pharmaceutical Practices and Patient Outcomes
- Industrial Vision Systems and Defect Detection
- Ionosphere and magnetosphere dynamics
- Nuclear materials and radiation effects
Saitama Medical University
2024
Social Insurance Saitama Chuo Hospital
2024
National Institute for Fusion Science
2015-2024
National Institutes of Natural Sciences
2017-2022
The Graduate University for Advanced Studies, SOKENDAI
2020-2022
Nagoya University
2011-2015
Japan External Trade Organization
2015
Kyushu University
2013
It has been found recently that low-energy helium (He) plasma irradiation to tungsten (W) leads the growth of W nanostructures on surface. The process grow nanostructure is identified as a self-growth He bubbles and potential open up new processing method. Here, we show metallic formation by exposure can occur in various metals such as, titanium, nickel, iron, so on. When conditions alter, cone arrays including nanobubbles inside are formed Different from cases, other processes than...
For the purposes of long-term use tungsten divertor walls, formation process fuzzy nanostructure induced by exposure to helium plasma was studied. In present paper, nanostructure's has been successfully reproduced new hybrid simulation method in which deformation material due pressure bubbles simulated molecular dynamics and diffusion atoms random walk based on Monte Carlo method. By results, surface height increased only when retention under steady state. It proven that growth brought about...
Abstract In order to clarify the divertor plasma-induced tungsten (W) surface modifications as well irradiation defects effect, two kinds of ITER grade W were exposed large helical device (LHD) deuterium (D) plasma at divertor-leg position. One was iron (Fe) ion irradiated produce defects, and other unirradiated W. The distributions on these clarified by scanning electron microscope (SEM) transmission microscopy (TEM). A co-deposition layer which mainly made up carbon (C) Fe formed private...
Abstract Understanding helium (He) plasma-induced tungsten (W) surface modifications, and the effect of irradiation defects on He W modifications under a real divertor environment are important for operation fusion reactors. In this study, two iron (Fe) ions pre-irradiated samples with dislocation loops voids, unirradiated were exposed to plasma at leg position Large Helical Device (LHD). The gross erosion rate 1.0×1020 atoms m-2 s-1, 9.3×1019 7.4×1019 s-1 W9, W10, W11, W12, respectively....
Tungsten was exposed to pure Ar or Ne plasmas over 1550 K at several incident ion energies. Even under the irradiation condition that tungsten nanostructure is formed by He plasma irradiation, holes/bubbles and fiberform nanostructures were not on surface exposure plasmas. In addition, results from energy dispersive X-ray spectroscopy supported facts did remain in sample. We will discuss reason for differences damage noble gas
When tungsten is exposed to a helium plasma under specific conditions, fiberform nanostructures grow from the surface, and optical properties significantly alter. It shown that absorptivity increases by irradiation visible near-infrared wavelength range. The became almost 100% near infrared range after nanostructure was formed on surface. result indicates emissivity of radiation in also irradiation. around 1550 nm 4.4 times higher than initial value, while it twice at fluence dependences...
When tungsten is exposed to a helium plasma under specific conditions, fiberform nanostructures grow from the surface, and optical properties significantly alter. It shown that absorptivity increases by irradiation visible near-infrared wavelength range. The became almost 100% near infrared range after nanostructure was formed on surface. result indicates emissivity of radiation in also irradiation. around 1550 nm 4.4 times higher than initial value, while it twice at fluence dependences...
The dendritic nanostructure was fabricated on a surface of tungsten plate by helium plasma irradiation. consisting W metal partially oxidized to form WO3 exposure air, and the resulting exhibited broad photoabsorption in range from 1 5 eV. We examined photoinduced reaction methylene blue (MB) material. It found that fully nanostructures were able promote decolorization MB under photoirradiation even with near-infrared light (< 1:55 eV), whose energy is lower than band gap WO3. rate varied...
A simple method to evaluate the thickness distribution of deposition layer formed on first wall is proposed using an innovative measurement concept optical reflection coefficient, which measured as RGB (red, green, blue) value a compact color analyzer. Analysis samples exposed plasmas during experimental campaign shows relationship between and followed by single model. The coefficient clearly indicates 10 100 nm. coefficients stainless steel plates helically twisted coil in one toroidal...
Abstract In the Wendelstein 7-X stellarator with its twisted magnetic geometry investigation of plasma wall interaction processes in 3D configurations is an important research subject. For upcoming operation phase i.e. OP1.2, three different types material probes have been installed within vessel for erosion/deposition investigations selected areas largely expected heat load levels, namely, ≤10 MW m −2 at test divertor units (TDU), ≤500 kW baffles, shields and toroidal closures ≤100...
The objective of this study is to investigate the effects neutron (n) irradiation on hydrogen isotope transport in tungsten (W). W samples were irradiated with neutrons a fission reactor and then exposed high flux deuterium (D) plasma at 563 K linear device. fraction D release increased increasing exposure time. In addition, retention n-irradiated proportion square root These observations explained by increase penetration depth filling up displacement damages acting as strong trapping sites.
The Large Helical Device (LHD) started the deuterium plasma experiment on March 7, 2017. Approximately 6.4 GBq of tritium was produced in first campaign and were utilized as tracers for investigation release behavior balance LHD vacuum vessel. To determine LHD, from vessel continually observed during period maintenance activities. exhaust rate approximately 32.8% at end experiment. After experiment, ventilated by room air activity in-vessel components observed. gradually decreased became...