Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ao, Hiroyuki; Asano, Hiroyuki; Ouchi, Nobuo; Tsubota, Naoaki; Hasegawa, Kazuo; Hirano, Koichiro; Morishita, Takatoshi; Takata, Koji*; Naito, Fujio*; Yamazaki, Yoshishige
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.552 - 554, 2010/08
The energy upgrade of the J-PARC linac was started from March 2009. In this project 20 Annular Coupled Structure (ACS) modules will be fabricated. The resonant frequency of the ACS module has to be tuned with mechanical machining before the final brazing. Therefore the test cells were fabricated to accumulate frequency tuning parameters. We fixed the final dimensions and the machining amount of the frequency tuning using these results. So far, the cell parts for the five ACS modules were tuned within 71.93 
0.05 MHz. At the moment the first ACS module is being assembled and it will be completed in autumn 2010.
Ao, Hiroyuki; Asano, Hiroyuki; Ouchi, Nobuo; Tsubota, Naoaki; Hasegawa, Kazuo; Hirano, Koichiro; Morishita, Takatoshi; Takata, Koji*; Naito, Fujio*; Yamazaki, Yoshishige
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.618 - 620, 2010/05
The mass production of the ACS (Annular-ring Coupled Structure) cavity started from March 2009 for the J-PARC linac energy upgrade from 181 MeV to 400 MeV. This upgrade project requires 18 ACS accelerating modules and two debunchers additionally within three years. The schedule is so tight that we have to optimize the fabrication process. Thus the test cells were fabricated for the all geometrical beta before the mass production to confirm the initial design and the frequency tuning procedure. This paper describes our approach for the mass production and the current status.
Fang, Z.*; Michizono, Shinichiro*; Anami, Shozo*; Yamaguchi, Seiya*; Naito, Fujio*; Fukui, Yuji*; Kawamura, Masato*; Kubota, Chikashi*; Nammo, Kesao*; Kobayashi, Tetsuya; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.1434 - 1436, 2010/05
The output energy of the J-PARC proton linac will be upgraded from 181 to 400 MeV in the next two years by adding high-b acceleration sections. The upgrade of the FPGA-based digital LLRF controller for the 400 MeV linac will be presented in this paper. This new LLRF controller works for both the 324-MHz low-b and 972-MHz high-b sections. Many functions have been added into the LLRF controller, such as (1) working for different RF systems, (2) gradually increasing the feedback gains in the feedback loop instead of fixed ones, (3) automatic chopped beam compensation, (4) automatically switching the beam loading compensation in accordance with different beam operation mode, (5) input RF-frequency tuning to match the RF cavities during RF start-up, and (6) auto-tuning of the RF cavity tuner by detecting the phase curve of the RF cavity during the field decay instead of the phase difference between the cavity input and output signals.
Ne, 
C, and 
HeAkeo, Kiyoshi*; Hamada, Nobuyuki*; Kobayashi, Yasuhiko; Funayama, Tomoo; Sakashita, Tetsuya; Akeo, Yoko*; Kawada, Kumiko*; Tsubota, Kazuo*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 114, 2007/02
no abstracts in English
Akeo, Kiyoshi*; Akeo, Yoko*; Tsubota, Kazuo*; Funayama, Tomoo; Hamada, Nobuyuki*; Kobayashi, Yasuhiko
no journal, ,
no abstracts in English
Akeo, Kiyoshi*; Akeo, Yoko*; Tsubota, Kazuo*; Funayama, Tomoo; Hamada, Nobuyuki*; Kobayashi, Yasuhiko
no journal, ,
no abstracts in English
Akeo, Kiyoshi*; Hamada, Nobuyuki*; Kobayashi, Yasuhiko; Funayama, Tomoo; Sakashita, Tetsuya; Akeo, Yoko*; Kawada, Kumiko*; Tsubota, Kazuo*
no journal, ,
no abstracts in English
Ikeda, Ryosuke; Oda, Yasuhisa; Kajiwara, Ken; Terakado, Masayuki; Aoki, Takashi; Oshima, Katsumi; Tsubota, Naoaki; Hayashibara, Masashi; Hayashi, Kazuo*; Kobayashi, Takayuki; et al.
no journal, ,
no abstracts in English
