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Journal Articles

Effects of OH$$^{-}$$ activity and temperature on the dissolution rate of compacted montmorillonite under highly alkaline conditions

Sawaguchi, Takuma; Tsukada, Manabu; Yamaguchi, Tetsuji; Mukai, Masayuki

Clay Minerals, 51(2), p.267 - 278, 2016/05

https://doi.org/10.1180/claymin.2016.051.2.12
 Times Cited Count：7 Percentile：24.47(Chemistry, Physical)

The dependences of the dissolution rate of compacted montmorillonite on activity of OH$$^{-}$$ (a$$_{rm OH}$$-) and temperature (T) were investigated. The dissolution rate of montmorillonite ($$R_{rm A}$$) in compacted pure montmorillonite, which was formulized as $$R_{rm A}$$ = 10$$^{4.5}$$ (a$$_{rm OH}$$-)$$^{1.3}$$ e$$^{-55000/RT}$$, was higher than that in the compacted sand-bentonite mixtures: $$R_{rm A}$$ = 3500 (a$$_{rm OH}$$-)$$^{1.4}$$ e$$^{-51000/RT}$$. The difference can be explained by considering the decrease in a$$_{rm OH}$$- in the mixtures accompanied by dissolution of accessory minerals such as quartz and chalcedony. The dissolution rate model developed for pure montmorillonite is expected to be applied to bentonite mixtures if quantification of the decrease in a$$_{rm OH}$$- is achieved somehow.

Journal Articles

R&D on a high energy accelerator and a large negative ion source for ITER

Inoue, Takashi; Taniguchi, Masaki; Morishita, Takatoshi; Dairaku, Masayuki; Hanada, Masaya; Imai, Tsuyoshi*; Kashiwagi, Mieko; Sakamoto, Keishi; Seki, Takayoshi*; Watanabe, Kazuhiro

Nuclear Fusion, 45(8), p.790 - 795, 2005/08

https://doi.org/10.1088/0029-5515/45/8/004

The R&D of a 1 MeV accelerator and a large negative ion source have been carried out at JAERI. The paper presents following progress as a step toward ITER NB system. (1) Accelerator R&D: According to success in improvement of voltage holding capability, the acceleration test of H$$^{-}$$ ions up to 1 MeV class energy is in progress. H$$^{-}$$ ion beams of 1 MeV, 100 mA class have been generated with a substantial beam current density (100 A/m$$^{2}$$), and the current density is still increasing by the ion source tuning. (2) Large ion source R&D: One of major causes that limited the NB injection performance was spatial unifomity of negative ion production in existing negative-ion based NB systems. The present study revealed that the negative ions produced in the extraction region of the source were locally destructed by fast electrons leaking through magnetic filter. Some countermeasures and their test results are also described.

Journal Articles

R&D on a high energy accelerator and a large negative ion source for ITER

Inoue, Takashi; Taniguchi, Masaki; Morishita, Takatoshi; Dairaku, Masayuki; Hanada, Masaya; Imai, Tsuyoshi*; Kashiwagi, Mieko; Sakamoto, Keishi; Seki, Takayoshi*; Watanabe, Kazuhiro

Nuclear Fusion, 45(8), p.790 - 795, 2005/08

https://doi.org/10.1088/0029-5515/45/8/004
 Times Cited Count：23 Percentile：59.63(Physics, Fluids & Plasmas)

The R&D of a 1 MeV accelerator and a large negative ion source has been carried out at JAERI for the ITER NB system. The R&D is in progress at present toward: (1) 1 MeV acceleration of H$$^{-}$$ ion beams at the ITER relevant current density of 200 A/m$$^{2}$$, and (2) improvement of uniform negative ion production over wide extraction area in large negative ion sources. Recently, H$$^{-}$$ ion beams of 1 MeV, 140 mA level have been generated with a substantial beam current density (100 A/m$$^{2}$$). In the uniformity study, it has been clarified that electron temperature in the ion extraction region is locally high ($$>$$ 1 eV), which resulted in destruction of negative ions at a high reaction rate. Interception of fast electrons leaking through a transverse magnetic field called "magnetic filter" has been found effective to lower the local electron temperature, followed by an improvement of negative ion beam profile.

JAEA Reports

R&D on high power negative ion sources and accelerators for a neutral beam injector

Inoue, Takashi

JAERI-Research 2005-006, 87 Pages, 2005/03

JAERI-Research-2005-006.pdf:10.53MB

Negative ion sources and accelerators have been developed toward the ITER neutral beam injector (NBI). According to an analysis of negative ion surface production, the "KAMABOKO" ion source has been developed maximizing its volume/surface ratio, for fast electron confinement followed by enhancement of atomic density. An "external filter" is equipped in the source, to suppress ion destruction by the fast electrons with efficient diffusion of the atoms to ion extraction region. H$$^{-}$$ ions of 300 A/m$$^{2}$$ was extracted at the pressure of 0.3 Pa. For the accelerator, vacuum insulation technology has been developed since insulation gas such as SF$$_{6}$$ is not applicable under radiation environment. Considering pressure in the accelerator (0.02$$sim$$0.2 Pa), insulation guideline has been developed for both vacuum arc and glow discharges. Reduction of electric field stress at triple junction was effective to prevent flashover along insulator surface. H$$^{-}$$ ion beams of 900 keV and 80 A/m$$^{2}$$ (total ion current: 0.11 A) were obtained for several hundred shots.

Journal Articles

Acceleration of 1 MeV, 100 mA class H$$^{-}$$ ion beams in a proof-of-principle accelerator for ITER

Inoue, Takashi; Taniguchi, Masaki; Dairaku, Masayuki; Hanada, Masaya; Kashiwagi, Mieko; Morishita, Takatoshi; Watanabe, Kazuhiro; Imai, Tsuyoshi

Review of Scientific Instruments, 75(5), p.1819 - 1821, 2004/05

https://doi.org/10.1063/1.1699507
 Times Cited Count：11 Percentile：51.25(Instruments & Instrumentation)

The paper reports progress of proof-of-principle test of negative ion accelerator for ITER. The accelerator structure is immersed in vacuum, surrounded by a FRP insulator column as the vacuum boundary. So far, the beam energy has been limited due to poor voltage holding capability of the FRP insulator column. By lowering the electric field strength at the triple junction (interface of FRP insulator, metal flange and vacuum) with large stress ring installed inside the insulator column, high voltage of 1 MV was stably sustained for more than 2 hours. In the following beam test, acceleration of 900 keV, 100 mA H$$^{-}$$ ion beam was succeeded. Although the current was lower (70 mA) at 1 MeV, the beam of this level has been stably accelerated for 6 days, 130 shots in total (each pulse length: 1 s).

Journal Articles

Cross-sections for ion production in H$$^{+}$$+H$$_{2}$$ collisions calculated with the trajectory-surface-hopping method

Ichihara, Akira; Iwamoto, Osamu; Yokoyama, Keiichi

Atomic and Plasma-Material Interaction Data for Fusion, Vol. 9, p.193 - 235, 2001/00

no abstracts in English

Journal Articles

Cross sections for the reaction H$$^{+}$$+H$$_{2}$$(v=0-14)$$rightarrow$$H+H$$_{2}^{+}$$ at low collision energies

Ichihara, Akira; Iwamoto, Osamu; Janev, R. K.*

Journal of Physics B; Atomic, Molecular and Optical Physics, 33(21), p.4747 - 4758, 2000/11

https://doi.org/10.1088/0953-4075/33/21/318
 Times Cited Count：62 Percentile：90.26(Optics)

no abstracts in English

JAEA Reports

Steering of H$$^{-}$$ ion beamlet by aperture displacement

Inoue, Takashi; Suzuki, Yasuo*; Miyamoto, Kenji; Okumura, Yoshikazu

JAERI-Tech 2000-051, 16 Pages, 2000/09

JAERI-Tech-2000-051.pdf:2.27MB

no abstracts in English

Journal Articles

Analytic cross sections for collisions of H$$^{+}$$, H$$_{2}^{+}$$, H$$_{3}^{+}$$, H, H$$_{2}$$ and H$$^{-}$$ with hydrogen molecules

Tabata, Tatsuo*; Shirai, Toshizo

Atomic Data and Nuclear Data Tables, 76(1), p.1 - 25, 2000/09

https://doi.org/10.1006/adnd.2000.0835
 Times Cited Count：79 Percentile：94.41(Physics, Atomic, Molecular & Chemical)

no abstracts in English

JAEA Reports

Steering of high energy negative ion beam and design of beam focusing/deflection compensation for JT-60U large negative ion source

Inoue, Takashi; Miyamoto, Kenji; Nagase, Akihito*; Okumura, Yoshikazu; Watanabe, Kazuhiro

JAERI-Tech 2000-023, p.27 - 0, 2000/03

JAERI-Tech-2000-023.pdf:1.18MB

no abstracts in English

Journal Articles

State-selected cross sections for ion production in the H$$^{+}$$+H$$_{2}$$ collisions

Ichihara, Akira; Iwamoto, Osamu; Yokoyama, Keiichi

Atomic Collision Research in Japan, No.25, p.28 - 29, 1999/11

no abstracts in English

JAEA Reports

Cross sections for ion production in reactions of H$$^{+}$$ with D$$_{2}$$; Effects of vibrational and rotational excited states of D$$_{2}$$

Ichihara, Akira; Iwamoto, Osamu; Yokoyama, Keiichi

JAERI-Research 98-056, 22 Pages, 1998/09

JAERI-Research-98-056.pdf:0.62MB

no abstracts in English

Journal Articles

Cyclotron

Arakawa, Kazuo

Kasokuki No Genjo To Shorai, (6), p.71 - 80, 1998/06

no abstracts in English

Journal Articles

Development of a 1MeV H$$^{-}$$ beam accelerator for neutral beam injector

Watanabe, Kazuhiro; Fujiwara, Yukio; Hanada, Masaya; Inoue, Takashi; Miyamoto, Kenji; Miyamoto, Naoki*; Okumura, Yoshikazu; Sato, Kazuyoshi

Fusion Technology 1998, 1, p.493 - 496, 1998/00

no abstracts in English

JAEA Reports

Performance evaluation on reactor power control by H$$^{infty}$$ controller with gain scaling

Ishikawa, Nobuyuki; Suzuki, Katsuo

JAERI-Research 97-038, 17 Pages, 1997/05

JAERI-Research-97-038.pdf:0.56MB

no abstracts in English

Journal Articles

Multi-stage,multi-aperture electrostatic accelerator for H$$^{-}$$ ions

Watanabe, Kazuhiro; Fujiwara, Yukio; Hanada, Masaya; Inoue, Takashi; Miyamoto, Kenji; Miyamoto, Naoki*; Ohara, Yoshihiro; Okumura, Yoshikazu

Proc. of Joint Meeting of 8th Int. Symp. on the Production and Neutralization of Negative Ions & Beams, p.179 - 186, 1997/00

no abstracts in English

Journal Articles

Recent progress of high-power negative ion beam development for fusion plasma heating

Watanabe, Kazuhiro; ; Aoyagi, Tetsuo; ; Fujiwara, Yukio; Honda, Atsushi; Inoue, Takashi; Ito, Takao; Kawai, Mikito; Kazawa, Minoru; et al.

Radiation Physics and Chemistry, 49(6), p.631 - 639, 1997/00

https://doi.org/10.1016/S0969-806X(97)00012-1
 Times Cited Count：3 Percentile：30.37(Chemistry, Physical)

no abstracts in English

JAEA Reports

Application of 2DOF controller for reactor power control; Verification by numerical simulation

Ishikawa, Nobuyuki; Suzuki, Katsuo

JAERI-Research 96-048, 50 Pages, 1996/09

JAERI-Research-96-048.pdf:1.22MB

no abstracts in English

Journal Articles

Study on ion-molecule reactions in the H$$_{3+}$$ system with the trajectory-surface-hopping model

Ichihara, Akira; Shirai, Toshizo; Yokoyama, Keiichi

Journal of Chemical Physics, 105(5), p.1857 - 1861, 1996/08

https://doi.org/10.1063/1.472047
 Times Cited Count：38 Percentile：78.01(Chemistry, Physical)

no abstracts in English

Journal Articles

Development of negative ion beam accelerators for high power neutral beam systems

Watanabe, Kazuhiro; ; Fujiwara, Yukio; Honda, Atsushi; Inoue, Takashi; Kazawa, Minoru; Kuriyama, Masaaki; Miyamoto, Kenji; Miyamoto, Naoki*; Mogaki, Kazuhiko; et al.

16th IEEE/NPSS Symp. on Fusion Engineering (SOFE '95), 1, p.642 - 645, 1996/00

no abstracts in English

37 (Records 1-20 displayed on this page)