Actively-cooled plasma electrode for long pulse operations in a cesium-seeded negative ion source

Fujiwara, Yukio; Watanabe, Kazuhiro; Okumura, Yoshikazu; Trainham, R.*; Jacquot, C.*

Review of Scientific Instruments, 76(1), p.013501_1 - 013501_5, 2005/01

https://doi.org/10.1063/1.1823611

A new actively-cooled plasma electrode has been developed for long pulse operation in a cesium-seeded negative ion source. To keep the electrode temperature at about 300 C, which is optimum range of temperature to enhance cesium effects, the electrode cooling structure has been designed using three-dimensional numerical simulation assuming that the heat flux from the source plasma was 15 W/cm. Water cooling tubes were brazed to the plasma electrode substrate with spacers made of stainless steel which acts as a thermal resistance. The fabricated plasma electrode has been tested in a cesium-seeded volume negative ion source called Kamaboko source. The temperature of the electrode reached 280 C for the arc power of 41 kW, which is operating condition required for producing D- beams with current densities exceeding 20 mA/cm. It was demonstrated that the actively-cooled plasma electrode is applicable to long pulse operations, meeting the temperature requirement for optimizing the surface-production process of negative ions in the cesium seeded ion source.

Experimental studies of microbial acclimation to condition of geological disposal system

*; *

JNC TJ8400 2002-034, 78 Pages, 2002/02

JNC-TJ8400-2002-034.pdf:0.35MB

TRU waste is disposed of deep underground by packed in cement compounds as engineering barrier material. One of negative effects to this disposal system is supposed to be ability of microbial degradation of organic compounds. This disposal system might be exposed to high alkali condition by cement compounds. For estimating the quantity of degradation of organic compounds under high alkali conditions, asphalt (blown asphalt) that is the major ingredient of TRU waste was used for the microbial acclimation test to high alkali condition and degradation test. After microbial were collected as water samples from three different conditions, those were cultured with asphalt as carbon source for acclimation under high alkali conditions. These acclimated microbial were used for vial and plate test measuring degradation rate of asphalt at high alkali condition. Estimation items were ICs, TOCs, groups and cell count of microbial from vial test, and also, quantity of asphalt degradation and cell count of microbial from plate test. Furthermore, the genetic information of microbial was analyzed with the DGGE method and those sequencing data. The result shows that microbial might degrade asphalt under high alkali condition like pH 12.5, and it was less asphalt degradation rate in anaerobic than in aerobic condition.

A Frame-cooled plasma grid for long pulse operations in a cesium-seeded volume negative ion source

Fujiwara, Yukio; Okumura, Yoshikazu; Watanabe, Kazuhiro; Trainham, R.*; Jacquot, C.*

Review of Scientific Instruments, 73(2), p.298 - 304, 2002/02

https://doi.org/10.1063/1.1435845

no abstracts in English

Beamlet-beamlet interaction in a multi-aperture negative ion source

Fujiwara, Yukio; Hanada, Masaya; Okumura, Yoshikazu; Watanabe, Kazuhiro; Kawai, Kenichi*

Review of Scientific Instruments, 71(8), p.3059 - 3064, 2000/08

https://doi.org/10.1063/1.1305515

no abstracts in English

Hydrogen negative ion beam acceleration in a multiaperture five-stage electrostatic accelerator

Watanabe, Kazuhiro; Fujiwara, Yukio; Hanada, Masaya; Kashiwagi, Mieko; Kitagawa, Tadashi*; Miyamoto, Kenji; Morishita, Takatoshi; Okumura, Yoshikazu; Takayanagi, Tomohiro; Taniguchi, Masaki

Review of Scientific Instruments, 71(2), p.1231 - 1233, 2000/02

https://doi.org/10.1063/1.1150434

no abstracts in English

Experimental study on the influence of radiation on high-voltage insulation gases

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

JAERI-Research 99-071, p.33 - 0, 1999/12

JAERI-Research-99-071.pdf:1.18MB

no abstracts in English

Beamlet interaction in multi-aperture negative ion source

Fujiwara, Yukio; Hanada, Masaya; Kawai, Kenichi*; *; Miyamoto, Kenji; Okumura, Yoshikazu; Watanabe, Kazuhiro

JAERI-Research 99-013, 32 Pages, 1999/02

JAERI-Research-99-013.pdf:1.51MB

no abstracts in English

Development of a multiaperture, multistage electrostatic accelerator for hydrogen negative ion beams

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

Review of Scientific Instruments, 69(2), p.986 - 988, 1998/02

https://doi.org/10.1063/1.1148619

no abstracts in English

Experimental study on beamlet interaction in high current negative ion source

Fujiwara, Yukio; Kawai, Kenichi*; Hanada, Masaya; *; Miyamoto, Kenji; Okumura, Yoshikazu; Watanabe, Kazuhiro

Dai-9-Kai Ryushisen No Sentanteki Oyo Gijutsu Ni Kansuru Shimpojiumu (BEAMS1998), 6 Pages, 1998/00

no abstracts in English

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