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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：7 Percentile：74.40(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.
Kondo, Yasuhiro; Kitamura, Ryo; Fuwa, Yasuhiro; Morishita, Takatoshi; Moriya, Katsuhiro; Takayanagi, Tomohiro; Otani, Masashi*; Cicek, E.*; Ego, Hiroyasu*; Fukao, Yoshinori*; et al.
Proceedings of 31st International Linear Accelerator Conference (LINAC 2022) (Internet), p.636 - 641, 2022/09
The muon linac project for the precise measurement of the muon anomalous magnetic and electric dipole moments, which is currently one of the hottest issues of the elementary particle physics, is in progress at J-PARC. The muons from the J-PARC muon facility are once cooled to room temperature, then accelerated up to 212 MeV with a normalized emittance of 1.5 
mm mrad and a momentum spread of 0.1%. Four types of accelerating structures are adopted to obtain the efficient acceleration with a wide beta range from 0.01 to 0.94. The project is moving into the construction phase. We already demonstrated the re-acceleration scheme of the decelerated muons using a 324-MHz RFQ in 2017. The high-power test of the 324-MHz Interdigital H-mode (IH) DTL using a prototype cavity was performed in 2021. The fabrication of the first module of 14 modules of the 1296-MHz Disk and Washer (DAW) CCL will be done to confirm the production process. Moreover, the final design of the travelling wave accelerating structure for the high beta region is also proceeding. In this paper, the recent progress toward the realization of the world first muon linac will be presented.
Tsunoda, Naofumi*; Otsuka, Takaharu; Takayanagi, Kazuo*; Shimizu, Noritaka*; Suzuki, Toshio*; Utsuno, Yutaka; Yoshida, Sota*; Ueno, Hideki*
Nature, 587, p.66 - 71, 2020/11
Times Cited Count：67 Percentile：94.62(Multidisciplinary Sciences)no abstracts in English
Koizumi, Norikiyo; Nakajima, Hideo; Matsui, Kunihiro; Isono, Takaaki; Okuno, Kiyoshi; Takayanagi, Tadatoshi*; Kuno, Kazuo*; Senda, Ikuo*
IEEE Transactions on Applied Superconductivity, 18(2), p.475 - 478, 2008/06
Times Cited Count：16 Percentile：61.92(Engineering, Electrical & Electronic)ITER-TF coil is scaled up by about 3 times from TFMC, which was developed in ITER EDA and successfully tested in EU. New technical issues are initiated because of the scale-up. The major issues are feasibilities of high accuracy automatic winding, precise prediction of conductor elongation and/or shrinkage after heat treatment to transfer the conductor in narrow grove of radial plate. It is also necessary to develop insulation system, whose radiation resistance is enough to sustain irradiation in ITER TF coil and which enable vacuum impregnation in suitable duration, such as 24 h. The authors therefore develop one of major parts of automatic winding machine, bending roller head, and optimize TF winding shape to enable successive winding. In addition, the elongation of the TF conductors was evaluated in 
200 ppm after the heat treatment. Moreover, impregnation test of the conductor was performed. The test results indicate that it will take a several ten hours to impregnate TF double-pancake by the method developed in EDA.
Takayanagi, Tadatoshi*; Kuno, Kazuo*; Ichihara, Tadashi*; Nomoto, Kazuhiro*; Hasegawa, Mitsuru*; Koizumi, Norikiyo; Matsui, Kunihiro; Okuno, Kiyoshi
no journal, ,
no abstracts in English
Takayanagi, Tadatoshi*; Kuno, Kazuo*; Hasegawa, Mitsuru*; Koizumi, Norikiyo; Nakajima, Hideo; Hamada, Kazuya; Nunoya, Yoshihiko; Okuno, Kiyoshi
no journal, ,
no abstracts in English
