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Tamura, Jun; Kondo, Yasuhiro; Morishita, Takatoshi; Naito, Fujio*; Otani, Masashi*; Nemoto, Yasuo*
Journal of Physics; Conference Series, 1350, p.012080_1 - 012080_6, 2019/12
Times Cited Count：0 Percentile：0.06(Physics, Particles & Fields)In the Japan Proton Accelerator Research Complex (J-PARC) linac, negative hydrogen beams are accelerated from 190 MeV to 400 MeV by Annular-ring Coupled Structure (ACS) cavities. The RF input coupler of the ACS21 cavity, which is the twenty-first (the last) accelerating cavity in the order of beam acceleration, had a comparatively larger Voltage Standing Wave Ratio (VSWR) value than the other ACS cavities. Therefore, we designed and manufactured a rectangular waveguide which has a capacitive iris to adjust the coupling factor of the ACS21 cavity. By making use of the summer maintenance period in 2018, we installed the newly manufactured waveguide to the cavity. Consequently, the VSWR of the ACS21 was successfully decreased to the target value which leads to the critical coupling under the nominal accelerating condition with 50-mA peak beam current.
Ao, Hiroyuki; Ueno, Akira; Morishita, Takatoshi; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.332 - 334, 2005/07
The first ACS module consists of two 5-cells ACS tanks and a 5-cells bridge cavity for the buncher module. Three RF tuners are installed to the bridge cavity for fine RF tuning. An operating frequency should be tuned to 972 MHz within the fine-tuning range before a brazing process in a factory. The tuning procedure has been studied with RF simulation analysis and cold-model measurements for ACS and bridge cells. This paper describes RF tuning results, fabrication status and related development items.
Ao, Hiroyuki; Morishita, Takatoshi; Ueno, Akira; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*; Paramonov, V.*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.2684 - 2686, 2005/00
J-PARC Linac starts with 180-MeV SDTL temporary, and it is upgraded to 400-MeV with 21 ACS (Annular Coupled Structure) modules and two ACS bunchers and two debunchers. First buncher module is under fabrication, and second buncher and a few accelerating modules are also planed until FY2006. The first ACS module consists of two 5-cell ACS tanks and a 5-cell bridge cavity for the buncher module. Three RF tuners are installed to the bridge cavity for fine RF tuning. An operating frequency should be tuned to 972 MHz within the fine-tuning range before a brazing process in a factory. The tuning procedure has been studied with RF simulation analysis and cold-model measurements for ACS and bridge cells. This paper describes RF tuning results, fabrication status and related development items.
Takada, Shoji
Nuclear Engineering and Design, 233(1-3), p.185 - 195, 2004/10
Times Cited Count：6 Percentile：40.63(Nuclear Science & Technology)Experiments are carried out to investigate the effects of the natural convection of superheated gas as well as of the stand pipes on the temperature distributions of the components and the heat removal performance in the water-cooling panel system for the MHTGR for decay heat removal, and to verify the design and evaluation methods. The numerical results of the code THANPACST2 are compared with the experimental data to verify the numerical methods and axi-symmetric model proposed, which can simulate the three-dimensional configuration of the stand pipes on the upper head of the pressure vessel by using porous body cells. The experiments revealed that temperatures increased with elevation on the upper head, because the stand pipes restrict radiation heat transfer to the upper cooling panel and reduce the heat transfer area on the upper head which was superheated by natural convection of helium gas in the pressure vessel. The numerical methods were able to closely duplicate the pattern of the rising temperature profile with elevation around the top of the upper head.
Ao, Hiroyuki; Akikawa, Hisashi; Ueno, Akira; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*; Noguchi, Shuichi*; Hayashizaki, Noriyosu*; Paramonov, V.*
Proceedings of 22nd International Linear Accelerator Conference (LINAC 2004), p.75 - 77, 2004/00
The J-PARC (Japan Proton Accelerator Research Complex) LINAC will be commissioned with energy of 181-MeV using 50-keV ion source, 3-MeV RFQ, 50-MeV DTL and 181-MeV SDTL (Separated DTL) on September 2006. It is planed to be upgraded by using a 400-MeV ACS (Annular Coupled Structure), which is a high-beta structure most suitable for the J-PARC, in a few years from the commissioning. The first ACS type cavity, which will be used as the first buncher between the SDTL and the ACS, is under fabrication. Detailed design and tuning procedure of ACS cavities has been studied with RF simulation analysis and cold-model measurements. The results of cold-model measurements, fabrication status, and related development items are described in this paper.
Akikawa, Hisashi; Ao, Hiroyuki; Hayashizaki, Noriyosu*
Proceedings of 28th Linear Accelerator Meeting in Japan, p.242 - 243, 2003/08
no abstracts in English
Ao, Hiroyuki; Akikawa, Hisashi
Proceedings of 28th Linear Accelerator Meeting in Japan, p.239 - 241, 2003/08
This paper shows the design and development status of the bridge coupler for the ACS (Annular Coupled Structure) in the J-PARC Linac. The half-scale models were fabricated, and RF measurement results are compared with numerical analysis.
Takada, Tomoyuki; Miyoshi, Yoshinori; Katakura, Junichi
JAERI-Tech 2003-036, 80 Pages, 2003/03
JAERI-Tech-2003-036.pdf:3.67MB
In order to perform accuracy evaluation of the critical calculation by the combination of multi-group constant library MGCL and 3-dimensional Monte Carlo code KENO-IV among critical safety evaluation code system JACS, benchmark calculation was carried out from 1980 in 1982. Some cases where the neutron multiplication factor calculated in the heterogeneous system in it was less than 0.95 were seen. In this report, it re-calculated by considering the cause about the heterogeneous system of the U+Pu nitric acid solution systems containing the neutron poison shown in JAERI-M 9859. The present study has shown that the keff value less than 0.95 given in JAERI-M 9859 is caused by the fact that the water reflector below a cylindrical container was not taken into consideration in the KENO-IV calculation model. By taking into the water reflector, the KENO-IV calculation gives a keff value greater than 0.95 and a good agreement with the experiment.
Ao, Hiroyuki; Akikawa, Hisashi; Hayashizaki, Noriyosu*
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.365 - 367, 2003/00
The first J-PARC ACS cavity is under fabrication. Aluminum and OFC test cells were fabricated and tested for RF properties. This paper discusses the RF measurement setup, comparing the measurements and analyses, and the outlook for the next step.
Ao, Hiroyuki; Hayashizaki, Noriyosu*; Paramonov, V.*
Proceedings of 2003 Particle Accelerator Conference (PAC 2003) (CD-ROM), p.2826 - 2828, 2003/00
An Annular Coupled Structure (ACS) has been developed for upgrade of a J-PARC (Japan Proton Accelerator Research Complex) linac from 180 MeV to 400 MeV. Although install area is prepared for the ACS cavities at an initial construction, it will be used as a beam-transport line temporarily. Aluminum and copper models were fabricated for RF properties confirmation based on an initial design, and for final optimization. RF measurement procedure of the ACS structure was also studied thorough the R&D process. Many items should be considered for mass production; schedule, handling parts, utilities, and so on. The measurement results of models and some fabrication status are presented.
Ao, Hiroyuki; Hayashizaki, Noriyosu*; Paramonov, V.*
Proceedings of 21st International Linear Accelerator Conference, p.82 - 84, 2003/00
Annular Coupled Structure (ACS) has been developed for the 190-400MeV coupled-cavity linac of the JAERI/KEK joint project. Design optimization of the ACS cavity has nearly been completed using 2D and 3D codes. In parallel with the numerical analyses, half-scale aluminum models were fabricated to confirm the numerical results. The cold-model tests also aim to finish the detailed design taking mass production procedures into account. Especially, the machining and the tuning procedures are examined in detail from the viewpoint of cost reduction and quality management. The results of the model tests are presented with those of other recent R&D works on ACS, which include fabrication R&D performed with full-scale models.
Ao, Hiroyuki; Hayashizaki, Noriyosu*
Proceedings of 27th Linear Accelerator Meeting in Japan, p.195 - 197, 2002/08
The fabrication status of Annular Coupled Structure (ACS) which was adopt for the 200-400MeV part of the injector linac is presented. The RF test of half-scale aluminum model is proceeding for high-power model fabrication. This result shows that the ACS structure has sensitivity to the RF contact with cavity and short-plates for RF measurement, and that the flatness of contact surface should be finished carefully. We also mention the error distribution of half-scale model frequencies and the RF properties about real scale aluminum models of buncher cavities.
Nibe, Nobuaki; Shimakawa, Yoshio; ; Hayafune, Hiroki; ; ;
JNC TN9400 2000-074, 388 Pages, 2000/06
JNC-TN9400-2000-074.pdf:13.32MB
Large sized sodium-cooled fast breeder reactors of large-size are being studied and have been operated in Japan and many countries. ln this feasibility study, evaluation was made on technical feasibinty for design concepts or 1 loop type and 3 pool types, specially from the viewpoint of improvement of economical competence. The design concepts include the ideas of cost reduction measures such as large-scaled components, reduction of loop number and integration of components on the basic of utilization of sodium characteristics. From the results of the evaluation, it may be possible for all the concepts to attain the economical target of 200 thousands yen per kilowatt, though further confirmation should be made for technical feasibility of those concepts. ln addition, the following items were listed up as further cost-reduction measures. (1)Higher temperature cooling system and steam cycle efficiency (2)Shortening of construction term (3)Reduction of safety systems by using measuring instruments with high performmce (4)Adoption of SG-ACS
Ishizuki, Shigeru*; Ogasawara, Shinobu*; Kawai, Wataru*; Nemoto, Toshiyuki*; Kume, Etsuo; Adachi, Masaaki*; Kawasaki, Nobuo*; Yatake, Yoichi*
JAERI-Data/Code 2000-018, p.217 - 0, 2000/03
JAERI-Data-Code-2000-018.pdf:6.35MB
no abstracts in English
Takada, Shoji; *; Inagaki, Yoshiyuki; Sudo, Yukio
Nihon Kikai Gakkai Rombunshu, B, 65(635), p.303 - 311, 1999/07
no abstracts in English
Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Sudo, Yukio
Journal of Nuclear Science and Technology, 36(5), p.413 - 423, 1999/05
Times Cited Count：2 Percentile：21.18(Nuclear Science & Technology)no abstracts in English
Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Sudo, Yukio
Nihon Kikai Gakkai Rombunshu, B, 65(633), p.248 - 254, 1999/05
no abstracts in English
Murazaki, Minoru*;
JAERI-Data/Code 99-019, 103 Pages, 1999/03
JAERI-Data-Code-99-019.pdf:3.69MB
no abstracts in English
Suyama, Kenya; Komuro, Yuichi; Takada, Tomoyuki*; Kawasaki, Hiromitsu*; Ouchi, Keisuke*
JAERI-Data/Code 98-004, 172 Pages, 1998/02
JAERI-Data-Code-98-004.pdf:4.47MB
no abstracts in English
Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Sudo, Yukio
Transactions of the American Nuclear Society, 79, p.160 - 161, 1998/00
no abstracts in English
