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Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：5 Percentile：87.42(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
Yamamoto, Kazami; Kamiya, Junichiro; Saha, P. K.; Takayanagi, Tomohiro; Yoshimoto, Masahiro; Hotchi, Hideaki; Harada, Hiroyuki; Takeda, Osamu*; Miki, Nobuharu*
Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.579 - 581, 2017/05
The 3-GeV Rapid Cycling Synchrotron of Japan Proton Accelerator Research Complex aims to deliver 1-MW proton beam to the neutron target and Main Ring synchrotron. Present beam power of the Rapid Cycling Synchrotron is up to 500-kW and the higher radiation doses were concentrated in the injection area. These activations were caused by the interaction between the foil and the beam. To reduce the worker dose near the injection point, we have studied a new design of the injection scheme to secure enough space for radiation shielding and bellows. In the new system, two of four injection pulse bump magnets are replaced and we are able to ensure the additional space around the injection foil chamber. So far, new injection system seems not impossible. However, preliminary study result indicated that temperature of the duct and shielding metals would be slightly higher. The eddy current due to the shift bump magnet field generates heat. Thus we have to study details of above effect.
Yamamoto, Masanobu
Proceedings of 57th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB 2016) (Internet), p.110 - 114, 2016/08
We have been developing a longitudinal particle tracking code for a high intensity proton synchrotron, especially for the J-PARC Synchrotron. Although some longitudinal particle tracking codes exist, our code can track the particles with a wake voltage and a space charge effect, and also can calculate a beam emittance and a momentum filling factor under a multi-harmonics to evaluate the margin of a rf bucket. Furthermore, we originally have developed the calculation method of a synchronous particle, which realizes the simulation in the case that the revolution frequency of the synchronous particle is not proportional to an acceleration frequency pattern. This is useful to check an adiabaticity. We have achieved 1 MW-eq. beam acceleration at J-PARC RCS by using the code because we can calculate the optimum acceleration conditions for the high intensity beam. We will describe the basic design of the code and the simulation results for the J-PARC RCS and MR.
Sakamoto, Shinichi; Meigo, Shinichiro; Konno, Chikara; Kai, Tetsuya; Kasugai, Yoshimi; Harada, Masahide; Fujimori, Hiroshi*; Kaneko, Naokatsu*; Muto, Suguru*; Ono, Takehiro*; et al.
JAERI-Tech 2004-020, 332 Pages, 2004/03
JAERI-Tech-2004-020.pdf:17.93MB
One of the experimental facilities in Japan Proton Accelerator Research Complex (J-PARC) is the Materials and Life Science Experimental Facility (MLF), where high-intensity neutron beams and muon beams are used as powerful probes for materials science, life science and related engineering. The neutrons and muons are generated with high-intensity proton beam from 3-GeV rapid cycling synchrotron (RCS). The high-intensity proton beam has to be effectively transported, and a neutron production target and a muon production target have to be also properly irradiated. The principal design of the 3-GeV proton beam transport facility (3NBT) is systematized.
Nishizawa, Daiji*; Kinsho, Michikazu; Kanazawa, Kenichiro; Ogiwara, Norio; Saito, Yoshio*; Kubo, Tomio*; Sato, Yoshihiro*
Shinku, 47(4), p.339 - 343, 2004/02
Large aperture cylindrical beam ducts consisting of alumina ceramics will be used for the first time in the 3GeV-synchrotron of High Intensity Proton Accelerator Facility. It is necessary to evaluate roundness and straightness of ceramic ducts because we have to compensate contact area of the connected beam duct large as well as we have to compensate large enough beam aperture. We developed an apparatus of measuring roundness and straightness, and we completed data analysis method as well as measuring method. Then we are measuring and evaluating roundness and straightness of ceramic beam ducts. Now, we have newly made an ellipse ceramic duct for the 3GeV-synchrotron BM. This duct has ellipse cross-sections to satisfy with larger aperture that the beam dynamics requires. In this conference, we are going to present taken data and findings regarding form accuracy including roundness and straightness of the ellipse ceramic duct.
Yamazaki, Yoshishige
Proceedings of 2003 Particle Accelerator Conference (PAC 2003) (CD-ROM), p.576 - 580, 2003/00
The JAERI-KEK Joint Project for the High Intensity Proton Accelerator, now referred to as the J-PARC Project (Japan Proton Accelerator Research Complex), comprises a 400-MeV linac, a 3-GeV, 25-Hz Rapid-Cycling Synchrotron (RCS), and a 50-GeV Main Synchrotron (MR). In contrast to the SNS or the ESS, the J-PARC makes use of the RCS in order to produce MW-class pulsed spallation neutrons rather than a combination of the full-energy linac and the compressor ring.
Yamamoto, Masanobu; Tamura, Fumihiko; Ezura, Eiji*; Hashimoto, Yoshinori*; Mori, Yoshiharu*; Omori, Chihiro*; Schnase, A.*; Takagi, Akira*; Uesugi, Tomonori*; Yoshii, Masahito*
Proceedings of 8th European Particle Accelerator Conference (EPAC 2002), p.1073 - 1075, 2002/00
Longitudinal beam emittance should be controlled to alleviate space charge effects by rf manipulations at 3 GeV proton synchrotrons in JAERI-KEK Joint High Intensity Proton Accelerator Project. At injection, bunching factor of 0.4 will be achived by controlled longitudinal beam painting and multiplying 2nd higher harmonics. Furthermore, heavy beam loading is a severe problem, and it should be compensated by feedforward method for stable acceleration. About these themes, the scenario will be described with particle tracking simulations.
Tani, Norio; Kanazawa, Kenichiro; Shimada, Taihei; Suzuki, Hiromitsu; Watanabe, Yasuhiro; Adachi, Toshikazu*; Someya, Hirohiko*
Proceedings of 8th European Particle Accelerator Conference (EPAC 2002), p.2376 - 2378, 2002/00
The 3-GeV synchrotron proposed in the JAERI/KEK Joint Project is a rapid-cycling synchrotron (RCS), which accelerates a high-intensity proton beam from 400 MeV to 3 GeV at a repetition rate of 25 Hz. The 3-GeV synchrotron is used to produce pulsed spallation neutrons and muons. It also works as an injector for a 50-GeV synchrotron. Since the magnets for the 3-GeV synchrotron are required to have a large aperture in order to realize the large beam power of 1 MW, there is a large leakage field at an end part than a usual synchrotron magnet. In addition, 25-Hz ac field induces an eddy current in magnet components: e.g. a coil, magnet end plates and etc. We intend to use a stranded conductor as a coil conductor so that the eddy current induced in the coil can be reduced. On the other hand, the eddy current induced in the end plates is expected to be large. Therefore, it is important to investigate an effect of the large leakage field and the eddy current to the beam motion around the magnet end part. We have constructed a prototype dipole magnet and field measurement system for this purpose. This paper reports the results of the design and the preliminary test about this magnet.
