谷池 晃 | ![]() |
タニイケ アキラ | |
大学院海事科学研究科 海事科学専攻 | |
准教授 | |
原子力工学関係 |
研究論文(学術雑誌)
研究論文(大学,研究機関等紀要)
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In order to investigate the CO2 absorption characteristics of the low- and high-density Li2TiO3 samples, X-ray diffraction (XRD), non-Rutherford backscattering spectroscopy (NRBS) and elastic recoil detection (ERD) analyses have been performed. Crystallographic structure of a sintered and CO2 exposed samples is decided by the XRD analysis, and the NRBS and ERD analyses have evaluated the amount of CO2 absorption and H content quantitatively. The CO2 absorption characteristics of the non-stoichiometric Li2TiO3 sample are investigated. It is found that the CO2 absorption rate of the non-stoichiometric Li2TiO3 sample is much larger than that of the stoichiometric sample. The Li2TiO3 sample (80%T.D.) has a good tritium release characteristics, and we find also that the sample sintered at temperatures higher than 1,428 K absorb very little CO2 under high humidity conditions. The amount of CO2 absorption of the low-density Li2TiO3 samples is found to increase with increase in the humidity. This seems to be a catalytic effect of water vapor on CO2 absorption at the Li2TiO3 surface.
Elsevier Ltd, 2018年05月01日, Nuclear Materials and Energy, 15, 164 - 168, 英語[査読有り]
研究論文(学術雑誌)
In order to investigate the CO2 absorption characteristics of the low- and high-density Li2TiO3 samples, X-ray diffraction (XRD) and non-Rutherford backscattering spectroscopy (NRBS) analyses have been performed. Crystallographic structure of a sintered sample is decided by the XRD analysis, and the NRBS analysis has evaluated the amount of CO2 absorption quantitatively. The amount of CO2 absorption of the low-density Li2TiO3 samples is increased with increase of the humidity. We find that the humidity has effect on CO2 absorption to the low-density Li2TiO3 samples. On the other hand, the high-density samples sintered at temperatures higher than 1,470 K absorb very little CO2 under high humidity conditions.
Elsevier Ltd, 2016年12月01日, Nuclear Materials and Energy, 9, 227 - 232, 英語[査読有り]
研究論文(学術雑誌)
As an energy recovery device for fast protons produced in D-3He nuclear fusion, secondary electron (SE) direct energy converter (SEDEC) was proposed in addition to traveling wave direct energy converter (TWDEC). Some protons passing through a TWDEC come into an SEDEC, where protons penetrate to a number of foil electrodes and emitted SEs are recovered. Following to a development of SE orbit control by magnetic field, dependence on incident angle of protons was examined to optimize structure of SEDEC. Based on a theoretical expectation, experiments were performed by changing incident angle of protons and variation in emission and energy recovery were measured. Both emission and energy recovery increased as the angle increased, and differences with theoretical expectation are discussed.
Japan Society of Plasma Science and Nuclear Fusion Research, 2016年, Plasma and Fusion Research, 11 (1), 2405029, 英語[査読有り]
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研究論文(研究会,シンポジウム資料等)
With an aim to improve the total efficiency of a D-(3) He nuclear fusion direct energy conversion system, a secondary electron direct energy converter (SEDEC) is proposed. The incident high-energy protons in an SEDEC penetrate a large number of foil electrodes aligned in the direction of the proton beam, and emitted secondary electrons are recovered. The results of the initial experiments showed that most of the secondary electrons flowed into anteroposterior electrodes and did not arrive at the electron collector located alongside and perpendicular to the direction of the proton beam. A magnetic field was introduced to push the electrons toward the electron collector, but it was not effective for energy recovery. This technical note analyzes the trajectories of electrons in the presence of the magnetic field and proposes and examines a revised arrangement of permanent magnets. The arrangement of the magnets along one side of the proton beam greatly improved the energy recovery; however, the recovery level was lower than that without magnets.
AMER NUCLEAR SOC, 2015年07月, FUSION SCIENCE AND TECHNOLOGY, 68 (1), 166 - 170, 英語[査読有り]
研究論文(学術雑誌)
A traveling wave direct energy converter (TWDEC) is expected to be used as an energy recovery device for fast protons produced during the D-3He nuclear fusion reaction. Some protons, however, are not fully decelerated and pass through the device. A secondary electron direct energy converter (SEDEC) was proposed as an additional device to recover the protons passing through a TWDEC. In our previous study, magnetic field was applied for efficient secondary electron (SE) collection, but the SEs were reflected close to the collector due to the magnetic mirror effect and the collection was degraded. Herein, a new arrangement of magnets is proposed to be set away from the collector, and experiments in various conditions are performed. An appropriate arrangement away from the collector resulted in the improvement of SE collection.
社団法人 プラズマ・核融合学会, 2015年03月, Plasma and Fusion Research, 10, 3405025 - 3405025, 英語[査読有り]
研究論文(学術雑誌)
A mass-flow calorimetry system has been installed to investigate the excess power phenomenon at elevated temperatures. The first trial runs with a silica-included Cu center dot Ni nano-composite sample (CNS) containing 4.1 g of Ni showed an implication of a few days lasting excess power of 5 W/g-Ni. Next, a Cu center dot Ni center dot Zr oxide nano-composite sample (CNZ4) containing 61 g of Ni has been examined to show excess power of 15 W lasting for 3 days and gradually increasing at a rate of 10 W per 3 weeks. Each corresponds to 30 eV/atom-Ni and 100 eV/atom-Ni, implying a nuclear origin of the excess energy.
INDIAN ACAD SCIENCES, 2015年02月, CURRENT SCIENCE, 108 (4), 589 - 593, 英語[査読有り]
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The ion beam graft polymerization (IBGP) method was applied to diagnosis of thin film of several tens mu m or less thickness. After a sample stacked on polyethylene film was irradiated with proton beam, polyethylene was graft-polymerized with acrylic acid monomer. From observation of the graft-polymerized polyethylene, information inside the sample are obtained. Demonstrations of the diagnosis method were conducted for a leaf sample and a polyvinyl acetate film contained some voids. Using imitation samples made of metal and polymer sheets, some characteristics of this method was obtained. This method is useful for diagnosis for voids in thin film. (C) 2015 The Authors. Published by Elsevier B.V.
ELSEVIER SCIENCE BV, 2015年, 26TH INTERNATIONAL CONFERENCE ON NUCLEAR TRACKS IN SOLIDS (ICNTS26), 80, 151 - 154, 英語[査読有り]
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Non-Rutherford backscattering spectroscopy (NRBS) for the composition analysis and X-ray diffraction (XRD) for the crystallographic structure analysis have been applied to the blanket candidate material, Li2TiO3, which is known to absorb CO2 though chemically stable. It is found that the amount of CO2 absorbed by atmospheric exposure of the low- and medium-density samples is greater than or comparable to that by dry CO2 gas exposure. By varying the density of the Li2TiO3 and composition of the ambient gas, conditions to minimize the amount of CO2 absorbed are discussed. (C) 2014 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2014年12月, JOURNAL OF NUCLEAR MATERIALS, 455 (1-3), 527 - 530, 英語[査読有り]
研究論文(学術雑誌)
A 12 x 12 pixel detector has been developed and used in a laboratory experiment for lost fast-ion diagnostics. With gamma rays in the MeV range originating from nuclear reactions Be-9(alpha, n gamma) C-12, Be-9(d, n gamma)C-12, and C-12(d, p gamma)C-13, a high purity germanium (HPGe) detector measured a fine-energy-resolved spectrum of gamma rays. The HPGe detector enables the survey of background-gamma rays and Doppler-shifted photo peak shapes. In the experiments, the pixel detector produces a gammaray image reconstructed from the energy spectrum obtained from total photon counts of irradiation passing through the detector's lead collimator. From gamma-ray image, diagnostics are able to produce an analysis of the fast ion loss onto the first wall in principle. (C) 2014 AIP Publishing LLC.
AMER INST PHYSICS, 2014年11月, REVIEW OF SCIENTIFIC INSTRUMENTS, 85 (11), 1 - 3, 英語[査読有り]
研究論文(学術雑誌)
Combined NRBS (non-Rutherford backscattering spectroscopy) and NRA (nuclear reaction analysis) methods have been applied to Li2CO3 samples with Li of various isotopic compositions. Densities of the component elements as well as the isotopic composition of Li have been determined within an error of about 10% or less. The NRBS method has also been applied to a high-density Li2TiO3 sample to investigate double-shell formation under CO2 absorption. By showing appearance of a Ti-free layer on the sample surface, usefulness of the method for investigation of the mechanism of the double-shell formation is demonstrated. (C) 2014 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2014年07月, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 331, 96 - 101, 英語[査読有り]
研究論文(学術雑誌)
Radiation graft polymerization method has been applied to make many industrial product. Ion beam graft polymerization method has been developed by Betz and many researchers, and we have also developed the method with proton whose energy is below a few MeV. Using the method, the substrate, e.g. polyethylene film, is graft-polymerized and has the graft chains near the surface. To conduct the method for some times, the structure of graft chains near the surface can be formed. When we want to produce the graft chains inside of the substrate, the graft chains near the surface are unnecessary. One of our objectives is to produce a functional polymer with a structure in the film. When the sample is irradiated in sufficiently high fluence, the sample can't be graft-polymerized in the next irradiation. Comparing the density of radicals and the number of double bond with the degree of grafting, the reason why formation of a part not grafted in high fluence irradiation was discussed. Because the number of the double bond and the allyl radicals in PE are increased for high fluence irradiation, the number of the alkyl radical as a grafting point is decreased. Moreover, the alkyl radical is not produced in following irradiation since existence of double bond and peroxy radical. (C) 2014 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2014年07月, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 331 (15), 191 - 195, 英語[査読有り]
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Charge fraction for heavy ion/neutral beams generated by the tandem accelerator was measured with MCP system.
The Japan Society of Plasma Science and Nuclear Fusion Research, 2013年08月, Plasma Fusion Res., 8 (2401087), 1 - 5, 英語[査読有り]
研究論文(学術雑誌)
The new energy recovery method using secondary electron emission has been studied in order to improve energy recovery from high energy protons of fusion products in D-He-3 nuclear fusion generation. The model experiments were performed by using the tandem electrostatic accelerator and the basic characteristics were investigated. According to our results, for penetration aluminum is better as a target material than copper, H+ is better than He2+, and higher energy beam is better which agree with numerical calculations. A qualitative characteristic of secondary electron emission dependence on beam energy was also obtained.
AMER NUCLEAR SOC, 2013年05月, FUSION SCIENCE AND TECHNOLOGY, 63 (1T), 301 - 303, 英語[査読有り]
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Non-Rutherford backscattering spectroscopy (NRBS), which allows for a greatly enhanced cross section for scattering, was used to analyze the atomic composition of Li-containing blanket material, 2.6-MeV proton beams were used as the probe beam to profile the atomic composition in the near-surface region down to about 2 μm. Li2TiO3 ceramics samples of various densities were exposed to CO2 gas at a pressure of 1 atm at room temperature in a glove box. The absorption of CO2 was observed to result in the formation of Li2CO3 on these samples in the NRBS spectra. In low and medium density samples, the density ratio of the absorbed CO2 to Li2TiO3 reached 0.5 after 1800 h and CO2 absorption showed a saturation tendency of about 1400 h. Li2TiO3 structures without CO2 were recovered by heating samples to 973 K, with a residual positive volume change of 10%. The structure appeared to have increased capacity for CO2 absorption with an expanded near-surface layer. This characteristic could present a problem in the process of tritium recovery from the blanket materials. © 2013 Elsevier B.V. All rights reserved.
2013年, Journal of Nuclear Materials, 442 (1-3), s442 - s446, 英語[査読有り]
研究論文(学術雑誌)
放射線グラフト重合法にイオンビームを応用した研究を行っている.ポリエチレンにイオンビームを照射することでラジカルが生じ,そこにモノマーを導入するとラジカルを起点としたグラフト鎖が生成する.本研究ではグラフト鎖の層をポリエチレンシート内部に作製した.
一般社団法人 日本原子力学会, 2012年, 日本原子力学会 年会・大会予稿集, 2012, 117 - 117, 日本語イオンビームを対象物(薄膜物質)に照射し、通り抜けたビームによりポリエチレン中にラジカルを生成させグラフト重合させることで、対象物の内部診断の期待ができる。そのために、厚さ方向の空孔径に対するグラフト鎖領域の違いをミクロトームによりポリエチレンをスライスすることで観測した。
一般社団法人 日本原子力学会, 2012年, 日本原子力学会 年会・大会予稿集, 2012, 118 - 118, 日本語我々はイオンビームを用いた放射線グラフト重合法に関する研究を行っている.本研究では導電性ポリマーのポリエチレン内部への導入またはゲル領域の導入を行うことで,作製したポリマーに伝導性を持たせた.本発表ではそのポリマーの導電率測定を行い,ポリマー作製時のパラメータ依存性を求めた.
一般社団法人 日本原子力学会, 2012年, 日本原子力学会 年会・大会予稿集, 2012, 116 - 116, 日本語The graft polymerization method is one of the most effective techniques to produce a new polymer with unique function. To produce the polymer, we conducted experiments on radiation graft polymerization using ion beams of several hundred keV energy. A high density polyethylene (PE) film was irradiated with H(+) beams, then, graft polymerization with monomer solution such as acrylic acid or acrylonitrile was conducted. Radicals generated by the interaction between the beam ions and the PE molecules become the starting point of the graft polymerization. Since the range in PE depends on ion energy, the density distribution of the graft chain can be controlled by the ion energy. Using a mask which restricts the ion beam incidence, PE sheets containing graft chains only in the unmasked area were obtained. Multiple ion beam graft polymerization can produce a polymer which has some functional bases at specified position. We have demonstrated the production of a polymer film with a three-dimensional structure. (C) 2011 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2011年12月, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 269 (24), 3237 - 3241, 英語[査読有り]
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Tributyltin (TBT) released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship's ballast water. The isolate (10(9.3 +/- 0.2) colony-forming units mL(-1)) adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 10(8.2). The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 10(6.8) TBT molecules is adsorbed by a single cell.
MDPI AG, 2008年10月, INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, 9 (10), 1989 - 2002, 英語[査読有り]
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The isolate, Pesudoalteromonas sp. TBT1, could grow to overcome the toxicity of tributyltin chloride (TBTCl) up to 30 mu M in the absence of Cl- in the medium until the cells reached an exponential phase of growth. The viability, however, was reduced after the cells reached a stationary phase. The degradation products, such as dibutyltin (DBT) and monobutyltin (MBT), were not detected in the growth medium, indicating that the isolate has no ability to degrade TBT into less toxic DBT and MBT. Up to about 10(7.5) TBT molecules were adsorbed by a single cell. The observation of morphological changes with an electron microscope showed that the cell surface became wrinkled after exposure to the lethal concentration of 10 mM TBTCl. These results indicate that the resistance of the isolate toward the toxicity of TBTCl is not related to the unique cell surface, which seems to play an important role in preventing the diffusion of TBTCl into the cytoplasm. (C) 2008 Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 2008年, MARINE POLLUTION BULLETIN, 57 (6-12), 877 - 882, 英語[査読有り]
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For diagnostics of confined and escaping alpha particles in burning plasma, we have proposed to apply the measurements of the gamma rays from D(alpha,gamma)Li-6 and F-19(alpha,n)(22) Na nuclear reactions and verified the validity to the diagnostics by accelerator experiments. From our experiments, we obtained the properties of the emitted gamma rays and some prospects for the diagnostics on ITER-like plasma based on their measurements. This paper discusses the spectrum properties of the emitted gamma rays and their applications to a particles diagnostics.
AMER NUCLEAR SOCIETY, 2007年02月, FUSION SCIENCE AND TECHNOLOGY, 51 (2T), 262 - 264, 英語[査読有り]
研究論文(学術雑誌)
For the diagnosis of confined alpha particles in D-T plasma, we propose the observation of 2.186 MeV gamma ray produced by D(alpha, gamma)(6) Li reaction. However, there are few nuclear data of the D(alpha, gamma)Li-6 reaction rate. Therefore, we carried out the experimental verification of the gamma ray diagnostics technique by using an accelerator. Helium ions in the energy range of 2-4 MeV were bombarded into a thick deuterated polyethylene, where the gamma ray spectrum was measured with a Ge detector. Photopeak of the 2.186 MeV gamma ray was clearly observed. From our experiment, the emission rate of the 2.186 MeV gamma ray from the D(alpha, gamma)(6) Li reaction is estimated to be 10(12)-10(13) s(-1) in the ITER typical plasma condition. So we obtained a good prospect of the gamma ray measurement as the confined alpha particle diagnostics by using a high efficiency detector. (c) 2006 American Institute of Physics.
AMER INST PHYSICS, 2006年10月, REVIEW OF SCIENTIFIC INSTRUMENTS, 77 (10), 英語[査読有り]
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To investigate possible anomaly in nuclear reactions in solids, deuterium ion irradiation of deuterated Au/Pd samples have been performed with extensive measurements of reaction products and in situ characterization of the samples including ERDA and RBS. The D(d,p)t reaction rate has been observed to become three orders of magnitude greater than the calculated one. The deuterium density distribution in the sample with a composition modified by irradiation has been observed to be peaked at a depth appreciably greater than the projectile range. We speculate that the formation of the mixed layer of An and Pd maintaining significantly high deuterium density is the key factor for the reaction rate enhancement.
WORLD SCIENTIFIC PUBL CO PTE LTD, 2006年, CONDENSED MATTER NUCLEAR SCIENCE, pp.623-634, 623 - +, 英語研究論文(国際会議プロシーディングス)
Preliminary results of experiments on D-2 gas permeation using a system (vacuum/CaO/Sr/PdDx/D-2) have shown some evidence of nuclear transmutation from Sr to Mo. The system is a little simpler than that used by Imamura et al., and has a reversed gas flow direction. The diagnostic method used to identify the elements was conventional X-ray photoelectron spectroscopy, giving the areal densities of 4.2 x 10(14) cm(-2) (Sr) and 3.3 x 10(14) cm(-2) (Mo). Extended analytical methods are now being prepared, including in situ and simultaneous particle induced X-ray emission, Rutherford backscattering spectroscopy, nuclear reaction analysis, and elastic recoil detection analyse for areal densities of transmutation elements and deuterium distribution.
WORLD SCIENTIFIC PUBL CO PTE LTD, 2006年, CONDENSED MATTER NUCLEAR SCIENCE, pp.272-277, 272 - +, 英語[査読有り]
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MeV proton beams have been successfully applied as ionizing radiation to induce graft polymerization of acrylonitrile to prepare amidoxime-type adsorbents on polyethylene film substrates. Dependence of degree of grafting (DG) on the pre-irradiation proton energy, beam current and fluence has been examined with use of FTIR absorption measurements and RBS. The DG is observed to be proportional to the deposited energy, and saturate at a fluence of the order of 10(13)cm(-2) which is more than one order of magnitude smaller than the saturation fluence for molecular hydrogen release from the substrate. It is shown that graft polymerization could be possible deep into a substrate with thickness of hundreds of gm, indicating a possibility to control distribution of functional groups with a spatial variation of the order of a micron. (C) 2003 Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 2004年02月, RADIATION PHYSICS AND CHEMISTRY, 69 (2), 171 - 178, 英語[査読有り]
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The neutron flux distributions in UTR-KINKI are comprehensively analyzed in terms of the Au activation reaction rate and compared with those calculated by SRAC-CITATION and MCNP4C. The vertical distribution at the central stringer is found to be a cosine-like one with a smaller FWHM by about 15%, which is in good agreement with both simulation results within an RMS deviation of 2.4% and 2.1 %, respectively. However. the CITATION fails to predict the horizontal distribution and humps in the vertical distribution in the fuel tank (FT) just outside the fuel meat due to low energy neutrons moderated in the H2O reflector region. It is suggested that the method of homogenization of the fuel assembly should be optimized to have satisfactory agreement with the measured distributions. On the contrary, the MCNP reproduces well the vertical distribution within the experimental uncertainty of +/-3% in the FT and the horizontal distribution within the error of +/-10%. From a little asymmetry of the distributions measured in the FT, it is implied that perturbation of the low energy neutron flux due to control rods or voids for them could be appreciable, and should be taken into account in the calculations in order to have even better agreement with the measured distributions.
ATOMIC ENERGY SOC JAPAN, 2003年05月, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 40 (5), 349 - 355, 英語[査読有り]
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To clarify characteristics of thin Li films as a plasma facing material, effect of modification of chemical composition of mum-thick deposited Li films introduced during the sample preparation and implantation with 1-keV deuterons on deuterium retention and thermal desorption properties is studied. Accelerator analysis has been employed to measure the thickness, the retention of D, H, O and C in the Li film, while thermal desorption spectroscopy has been utilized to investigate the chemical composition. The Li films exposed to moist atmosphere and subjected to D implantation show almost perfect isotope exchange from LiOH to LiOD. Carbon deposition during ion implantation is found to form a layer mixed with Li. With increasing the deposited amount of C, D-2 desorption behavior approaches that of pure C. (C) 2003 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2003年03月, JOURNAL OF NUCLEAR MATERIALS, 313, 288 - 291, 英語[査読有り]
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Degradation of a polymer under ion irradiation is investigated quantitatively. The loss of hydrogen atoms in polyethylene films under bombardment of various kinds of ions has been measured by directly monitoring recoil hydrogen atoms. Fluence dependence of the decrease in the hydrogen density is analyzed using a modified model based on that of M. P. de Jong, A. J. H. Maas, L. J. van Ijzendoorn, S. S. Klein, and M. J. A. de Voigt, J. Appl. Phys. 82, 1058 (1997). It is shown that the dependence is well explained by the present model with a hydrogen trapping reaction constant having hydrogen density dependence. It is found that the product of a bond cleavage probability squared and an ion track area is proportional to z(4)/E-3, where z and E are the atomic number and energy of the projectile, respectively. (C) 2002 American Institute of Physics.
AMER INST PHYSICS, 2002年12月, JOURNAL OF APPLIED PHYSICS, 92 (11), 6489 - 6494, 英語[査読有り]
研究論文(学術雑誌)
A novel analytical method of light element distribution in a thin film is presented. The method is based on the deuteron-induced nuclear reaction. The emission angle of the lighter product detected coincidentally with the heavier product is analyzed to deduce the depth distribution of the target atoms, while the conventional energy analysis is applied for impurities, the distributions of which are not of primary interest. Results of proof-of-principle experiments using the D(d, p)t reaction for a deuterated polyethylene (C2D4) film are described. The depth resolution is evaluated to be 0.66 +/- 0.07 mum, for 400 keV deuteron incidence in the C2D4 film. Factors limiting the resolution are discussed, and possible improvement even down to several tens of nm is concluded. The present method is applicable for microanalysis of some light elements other than deuterium contained in a film with thickness of several mum which cannot be reached by conventional heavy ion elastic recoil detection using MV accelerators. The method has another advantage that deterioration of the sample property, such as hydrogen isotope distribution, due to the probe beam irradiation can be minimized. (C) 2002 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2002年10月, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 195 (3-4), 358 - 366, 英語[査読有り]
研究論文(学術雑誌)
In order to develop short-wavelength (extreme ultra violet (XUV) or soft X-ray) laser devices of tabletop size, the characteristics of a capillary tube discharge are examined. The polyacetal (CH2O)(n) capillaries with diameter and length of 2 mm and 60 mm, respectively, are filled with methane (CH4) gas up to 5 Pa, and powered by a Marx generator pulse-forming line system. Time-integrated XUV spectra are analyzed using a flat-field grazing-incidence spectrometer equipped with a 1200 line/mm grating. Although the experimental conditions are rather different from those published, spectral shapes with the same features are obtained. The spatial distribution of the 18.2 nm transition intensity of Carbon VI and its dependence on the discharge parameters such as the capillary length, the diameter and the discharge voltage are discussed.
INST PURE APPLIED PHYSICS, 2001年02月, JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 40 (2B), 995 - 998, 英語[査読有り]
研究論文(学術雑誌)
A novel analytical method of deuterium depth distribution is presented for a film target with thickness exceeding a few mu m The method is based on the Rutherford Backscattering Spectroscopy (RBS) combined with the Elastic Recoil Detection (ERD). The scattered protons are detected coincidentally with the recoil deuterons to eliminate protons scattered by substrate and impurity atoms. Energy of the coincident protons is then analyzed to deduce the deuterium distribution. Results of proof-of-principle experiments using a deuterated polyethylene film and a deuterium implanted titanium sample are presented, and effect of multiple scattering is discussed. The present method is applicable for targets with thickness of several mu m which cannot be reached by conventional heavy-ion ERD using MV accelerators, and has an advantage that we can avoid deformation of hydrogen isotope distribution caused by irradiation of heavy ions. (C) 1999 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 1999年03月, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 149 (4), 469 - 476, 英語[査読有り]
研究論文(学術雑誌)
A dc-mode [formula omitted] source of the double charge exchange type has been developed for the purpose of application to alpha-particle measurement. Because the optimum energy for the two-step two-electron capture process in a rubidium vapor was reported to be around 6 keV, the essential point of development is extraction of an intense [formula omitted] beam at relatively low energy. As the discharge current of the [formula omitted] ion source is increased, the focusing property deteriorates, and higher electrostatic field is required for extraction. A [formula omitted] current of 0.07 mA is continuously obtained from a [formula omitted] beam extracted from a 6 mm diameter single hole. The conversion efficiency from [formula omitted] to [formula omitted] is about 2%–3% in the energy region of 5–10 keV. © 1998, American Institute of Physics. All rights reserved.
1998年01月01日, Review of Scientific Instruments, 69, 1063 - 1065For the purpose of identifying hydrogen isotope distribution in a microscopically rough surface, the geometrical effect on elastic recoil detection (ERD) spectra is examined using an optical grating base coated with a thin film of deuterated polyethylene (CD2). It is shown that the ERD spectra from such surfaces with a periodic roughness agree well with the simulation spectra using the roughness parameters determined by the simultaneous Rutherford backscattering spectroscopy (RBS) quantification of the roughness, the "Pb coating-RBS method". The microscopic structure of the sample surface is reflected well in the spectral shape. This means that the true distribution of the hydrogen isotopes in a sample could be determined by correcting the ERD spectra for the roughness. Potential applicability of the present method, Pb coating of the sample followed by simultaneous RBS-ERD analysis, to correction of ERD spectra for the surface roughness is thus demonstrated. (C) 1998 Elsevier Science B.V.
ELSEVIER SCIENCE BV, 1998年01月, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 134 (1), 98 - 106, 英語[査読有り]
研究論文(学術雑誌)
A heavy ion beam probe (HIBP) has been used as a reliable method to measure the plasma potential and its fluctuation in a magnetically confined fusion plasma. On the large helical device (LHD) an Au+ beam produced by a 3 MV tandem acceleration system will be used. It is necessary to optimize the charge fractions and minimize the energy broadening of the Au+ beam. Charge fractions can be calculated from electron loss and electron capture cross-sections. It is predicted that the optimum gas thickness for Au+ beam production is about 4 × 1014 cm-2. The broadening due to electron stripping is calculated to be several electronvolts and does not depend on the target mass. The energy straggling due to multiple collisions at the optimum target thickness can be calculated theoretically taking the lower limit of the impact parameter into account. Consequently, the total energy width of the Au+ beam produced by a tandem system might be about 100 eV. © 1997 Elsevier Science S.A.
Elsevier BV, 1997年, Fusion Engineering and Design, 34-35, 675 - 678, 英語研究論文(学術雑誌)
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A study is conducted of the feasibility of alpha particle measurement using a high energy diagnostic beam in combination with a neutral particle analyser for an ITER plasma. In order to measure alpha particles over an energy range of 0.5 to 3.5 MeV, the required beam energy is approximately 1 MeV for a 3He0 beam and 3 MeV for a 6Li0 beam, the beam current density being about 1 mA/cm2 for both cases. Among the various methods of producing such a high energy neutral beam, the acceleration of negative ions is the most favourable. Recent results of relatively small scale experiments with these negative ion sources reveal that the required current density is now attainable. Technical problems as to how to scale the ion sources used on an ITER sized experiment are also discussed for these experiments.
1995年, Nuclear Fusion, 35 (12), 1619 - 1624, 英語研究論文(学術雑誌)
A 6 MeV heavy ion beam probe (HLBP) is being designed for potential measurements on the Large Helical Device (LHD). This article describes a method to control the 3-D probing beam trajectories in the helical magnetic field, an estimate of beam attenuation and energy reduction arising from the long paths in the plasma, and a cylindrical analyzer as a candidate for the energy analyzer.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 1994年08月, IEEE TRANSACTIONS ON PLASMA SCIENCE, 22 (4), 395 - 402, 英語[査読有り]
研究論文(学術雑誌)
The feasibility of a heavy ion beam with a tandem acceleration system for plasma potential measurement has been examined. A plasma-sputter-type ion source which produces an Au-beam with an energy width as small as 6 eV and a reasonably small emittance of π mm-mrad (MeV)1/2, can be used for this purpose. Suitable target gas thickness for a charge exchange is estimated to be less than 1015atom/cm2at the 3 MV terminal voltage. © 1994 IEEE
1994年, IEEE Transactions on Plasma Science, 22 (4), 430 - 434, 英語研究論文(学術雑誌)
研究発表ペーパー・要旨(国際会議)
A successful application of the electrostatic accelerator, 1.7-MV Tandem Pelletron 5SDH-2, is demonstrated. Nuclear reaction analyses (NRA) using reactions ^7Li(p,2α) and ^6Li(d,2α) have been performed to reveal reliable isotopic abundance ratio of ^6Li/^7Li in Ni thin-film electrodes deposited on PTFE sheets which had been employed as the cathodes in electrolysis of aqueous Li_2SO_4 solution. The reliable conclusion was obtained by simultaneously analyzing Li_2CO_3 and PTFE sheets as reference samples, the former having Li with natural abundance ratio and the latter producing α particles by ^<19>F(p,α)^<16>O or ^<19>F(d,α)^<17>O reaction which could disturb the charged particle spectra to be analyzed.
神戸大学, 2008年07月, 神戸大学大学院海事科学研究科紀要, 5, 33 - 40, 日本語その他
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Two new ideas are going to be applied for the fusion product measurement, on LHD. One is a neutron emission monitor, located at the torus center, which has such a high detection efficiency that good statistics can be expected even in experiments with a hydrogen plasma, and the other is an active charge exchange neutral particle analyzing system using a high energy neutral beam. This system will be used to measure fusion reactivity of a D-He-3 plasma, and to study the confinement of alpha particles in a helical system. (C) 1997 Elsevier Science S.A.
ELSEVIER SCIENCE SA, 1997年03月, FUSION ENGINEERING AND DESIGN, 34-35, 595 - 598, 英語口頭発表(一般)
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