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Abe, Mitsushi*; Bae, S.*; Beer, G.*; Bunce, G.*; Choi, H.*; Choi, S.*; Chung, M.*; da Silva, W.*; Eidelman, S.*; Finger, M.*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(5), p.053C02_1 - 053C02_22, 2019/05
Times Cited Count：196 Percentile：99.40(Physics, Multidisciplinary)This paper introduces a new approach to measure the muon magnetic moment anomaly 
and the muon electric dipole moment (EDM) 
at the J-PARC muon facility. The goal of our experiment is to measure 
and using an independent method with a factor of 10 lower muon momentum, and a factor of 20 smaller diameter storage-ring solenoid compared with previous and ongoing muon g-2 experiments with unprecedented quality of the storage magnetic field. Additional significant differences from the present experimental method include a factor of 1000 smaller transverse emittance of the muon beam (reaccelerated thermal muon beam), its efficient vertical injection into the solenoid, and tracking each decay positron from muon decay to obtain its momentum vector. The precision goal for is a statistical uncertainty of 450 parts per billion (ppb), similar to the present experimental uncertainty, and a systematic uncertainty less than 70 ppb. The goal for EDM is a sensitivity of 
e
cm.
Oshima, Katsumi; Oda, Yasuhisa; Takahashi, Koji; Terakado, Masayuki; Ikeda, Ryosuke; Hayashi, Kazuo*; Moriyama, Shinichi; Kajiwara, Ken; Sakamoto, Keishi
JAEA-Technology 2015-061, 65 Pages, 2016/03
JAEA-Technology-2015-061.pdf:24.28MB
In JAEA, an ITER relevant control system for ITER gyrotron was developed according to Plant Control Design Handbook. This control system was developed based on ITER CODAC Core System and implemented state machine control of gyrotron operation system, sequential timing control of gyrotron oscillation startup, and data acquisition. The operation of ITER 170 GHz gyrotron was demonstrated with ITER relevant power supply configuration. This system is utilized for gyrotron operation test for ITER procurement. This report describes the architecture of gyrotron operation system, its basic and detailed design, and recent operation results.
Takahashi, Koji; Abe, Ganji; Kajiwara, Ken; Oda, Yasuhisa; Isozaki, Masami; Ikeda, Ryosuke; Sakamoto, Keishi; 2 of others*
Fusion Engineering and Design, 96-97, p.602 - 606, 2015/10
Times Cited Count：7 Percentile：45.00(Nuclear Science & Technology)The recent physics analysis reveals that there is the potential to more than double the drive current at the range of 
= 0.4
0.6 if a beam steering direction can be modified from toroidal to poloidal. However, the change of steering direction has a significant impact on the design of the Equatorial EC Launcher (EL), especially, mm-wave propagation and blanket shield modules (BSMs) and a knock-on effect impacting the internal shield structure. The EL has three sets of mm-wave beam row and each is composed of eight waveguide lines and a quasi-optical transmission region that is formed a steering and fixed mirror, locating in front of the waveguide outlet. It has been successfully performed that the outstanding configuration of the mirrors is developed, the mirror actuator is changed from the push-pull to pneumatic concept and the modification of the internal shield structure is minimized as much as possible. This creative modification ensures that both mm-wave beams from the middle and bottom row pass through the same BSM opening and then, the feasible and reliable design of BSMs can be carried out. The nuclear analysis of this design modification shows that the residual dose rate at the launcher back end is reduced by 20%. This paper summarizes that the possible solution of the mm-wave design modification enhancing the off axis current drive functionality is developed and ensures the effective mm-wave propagation, feasible design of the EL BSMs and nuclear shield structure.
Schrech, S.*; Aiello, G.*; Meier, A.*; Strauss, D.*; Ikeda, Ryosuke; Oda, Yasuhisa; Sakamoto, Keishi; Takahashi, Koji; Scherer, T.*
Fusion Engineering and Design, 96-97, p.593 - 596, 2015/10
Times Cited Count：11 Percentile：60.62(Nuclear Science & Technology)Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Ikeda, Ryosuke; Oda, Yasuhisa; Wada, Kenji; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; et al.
Proceedings of 40th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz 2015) (USB Flash Drive), 3 Pages, 2015/08
A gyrotron for electron cyclotron heating and current drive (ECH/CD) has been developed for JT-60SA (Super-Advanced). In high-power, long-pulse operations, oscillations of 1 MW/100 s have been demonstrated at both 110 GHz and 138 GHz, for the first time. These results fully satisfied the requirements for JT-60SA. Moreover, it was experimentally shown that the higher power operation at each frequency is expected to be acceptable for this gyrotron from the viewpoint of heat load at the cavity resonator, collector, and stray radiation absorbers. An oscillation at 82 GHz, which is an additional frequency, has been demonstrated up to 2 s at the output power of 0.4 MW, so far. High power experiments toward higher power of 1.5 MW (110/138 GHz) and 1 MW (82 GHz) are ongoing.
Kobayashi, Takayuki; Moriyama, Shinichi; Yokokura, Kenji; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Hoshino, Katsumichi; et al.
Nuclear Fusion, 55(6), p.063008_1 - 063008_8, 2015/06
Times Cited Count：28 Percentile：75.05(Physics, Fluids & Plasmas)A gyrotron enabling high-power, long-pulse oscillations at both 110 GHz and 138 GHz has been developed for electron cyclotron heating (ECH) and current drive (CD) in JT-60SA. Oscillations of 1 MW for 100 s have been demonstrated at both frequencies, for the first time as a gyrotron operating at two frequencies. The optimization of the anode voltage, or the electron pitch factor, using a triode gun was a key to obtain high power and high efficiency at two frequencies. It was also confirmed that the internal losses in the gyrotron were sufficiently low for expected long pulse operation at the higher power level of 1.5 MW. Another important result is that an oscillation at 82 GHz, which enables to use fundamental harmonic waves in JT-60SA while the other two frequencies are used as second harmonics waves, was demonstrated up to 0.4 MW for 2 s. These results of the gyrotron development significantly contribute to enhancing operation regime of the ECH/CD system in JT-60SA.
Oda, Yasuhisa; Oshima, Katsumi; Nakamoto, Takashi*; Hashimoto, Yasunori*; Yamamoto, Tsuyoshi; Hayashi, Kazuo*; Ikeda, Yukiharu; Ikeda, Ryosuke; Kajiwara, Ken; Takahashi, Koji; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 90(7), p.365 - 373, 2014/07
no abstracts in English
Hiraishi, Masatoshi*; Iimura, Soshi*; Kojima, Kenji*; Yamaura, Junichi*; Hiraka, Haruhiro*; Ikeda, Kazutaka*; Miao, P.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Miyazaki, Masanori*; et al.
Nature Physics, 10(4), p.300 - 303, 2014/04
Times Cited Count：115 Percentile：94.86(Physics, Multidisciplinary)Ikeda, Ryosuke; Kajiwara, Ken; Oda, Yasuhisa; Takahashi, Koji; Aoki, Takashi; Oshima, Katsumi; Tsubota, Naoaki; Kobayashi, Takayuki; Moriyama, Shinichi; Sakamoto, Keishi
no journal, ,
no abstracts in English
Ikeda, Ryosuke; Kajiwara, Ken; Oda, Yasuhisa; Takahashi, Koji; Kobayashi, Takayuki; Moriyama, Shinichi; Sakamoto, Keishi
no journal, ,
TE
mode gyrotron has advantages for multi-frequency oscillation. Oscillations of 170 GHz, 137 GHz and 104 GHz at TE, TE
and TE
modes, respectively are excited by varying the magnetic field strength. In high power experiments, the output power, the oscillation efficiency and the electric efficiency for 170 GHz, 137 GHz and 104 GHz oscillation achieved 1.2 MW / 27% / 43%, 810 kW / 25% / 40% and 720 kW / 25% / 38%. In long pulse operation, 900 kW / 100 s, 800 kW / 224 s and 650 kW / 433 s for 170 GHz oscillation are obtained. HE
mode purity of 91%, 88% and 95% for 170 GHz, 137 GHz and 104 GHz oscillation is obtained at the exit of a 40 m transmission line.
Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; Takahashi, Koji; et al.
no journal, ,
Developments of a dual frequency (110 GHz and 138 GHz) electron cyclotron heating and current drive system for JT-60SA are required. In a long pulse operation of a dual-frequency gyrotron, oscillations of 1 MW for 10 s at both frequencies were obtained, so far. Out gas in the gyrotron has been decreased shot by shot, and conditioning of the gyrotron is in progress. Oscillation efficiencies of higher than 30% were obtained for both frequencies. Measured internal diffraction loss was almost the same level of the previously developed 110 GHz long pulse gyrotron. From the above results, it is expected that further pulse length expansion is possible by continuing conditioning operations. Moreover, optical characteristics of an antenna, which is used to inject high-power millimeter waves into tokamak, was confirmed for dual frequency operation. It was found that the beam width for the 138 GHz wave is narrower than that for the 110 GHz wave.
Oda, Yasuhisa; Oshima, Katsumi; Ikeda, Ryosuke; Kajiwara, Ken; Takahashi, Koji
no journal, ,
no abstracts in English
Oda, Yasuhisa; Ikeda, Ryosuke; Kajiwara, Ken; Takahashi, Koji; Sakamoto, Keishi
no journal, ,
Ikeda, Ryosuke; Kajiwara, Ken; Oda, Yasuhisa; Takahashi, Koji; Kobayashi, Takayuki; Moriyama, Shinichi; Sakamoto, Keishi
no journal, ,
no abstracts in English
Kobayashi, Takayuki; Isayama, Akihiko; Hiranai, Shinichi; Sawahata, Masayuki; Terakado, Masayuki; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; et al.
no journal, ,
An original design of the toroidal injection angle range of electron cyclotron waves in JT-60SA was -15 degree to +15 degree for effective use of 110 GHz wave. However, the modification of the toroidal angle range has been discussed since the frequency of 138 GHz is considered to be a second frequency by the use of a dual frequency gyrotron. We report newly calculated available steering range of the launcher on both poloidal and toroidal angles with and without tilting angle of the second mirror, which is considered to obtain large toroidal injection angle. Moreover calculated beam divergences for various curvature radiuses of the first and second mirrors are shown. The decision of the target injection angle range for JT-60SA initial plasma will be made by the JT-60SA physics team by taking into account the above calculation results.
Moriyama, Shinichi; Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Hinata, Jun; Sato, Yoshikatsu; Yokokura, Kenji; Hoshino, Katsumichi; et al.
no journal, ,
no abstracts in English
Oda, Yasuhisa; Ikeda, Ryosuke; Kajiwara, Ken; Oshima, Katsumi; Hayashi, Kazuo*; Takahashi, Koji; Sakamoto, Keishi; Purohito, D.*; Henderson, M.*
no journal, ,
no abstracts in English
Oshima, Katsumi; Oda, Yasuhisa; Hashimoto, Yasunori*; Hayashi, Kazuo*; Ikeda, Ryosuke; Kajiwara, Ken; Takahashi, Koji; Sakamoto, Keishi
no journal, ,
In the ITER gyrotron development activity, the local control system for ITER gyrotron has been carried out using the ITER CODAC Core system. This control system is composed of Fast controller and Slow controller. The former has a role to control the gyrotron oscillation, timing control, data acquisition, etc. The later has a role to manage the operation phase shift, machine protection and alarm management, etc. Using this prototype system, we succeeded the gyrotron oscillation and 5 kHz power modulation.
Ikeda, Ryosuke; Oda, Yasuhisa; Kajiwara, Ken; Takahashi, Koji; Kobayashi, Takayuki; Moriyama, Shinichi; Sakamoto, Keishi
no journal, ,
Long pulse gyrotrons for ITER are under development. At present, output power of 1.2 MW for 2 s pulse operation and long pulse operation of 1000 s at 0.5 MW were achieved in experiments of TE31,11 mode gyrotron. Moreover, a transmission efficiency of 91% was obtained in 40 m transmission experiment. Recently, development of TE31,9 mode gyrotron was started. 1 MW with oscillation efficiency of 33% was realized in 1 ms operation without depressed collector voltage. And, 0.61 MW with total electric efficiency 51 % was achieved in 10 s operation with depressed collector voltage.
Ikeda, Ryosuke; Kajiwara, Ken; Oda, Yasuhisa; Takahashi, Koji; Kobayashi, Takayuki; Moriyama, Shinichi; Sakamoto, Keishi
no journal, ,
TE mode gyrotron has advantages for multi-frequency oscillation. Triple frequency of 170 GHz, 137 GHz and 104 GHz pass through a diamond disk window without a reflection lose and are radiated toward the same direction without moving a final mirror in the gyroton. In short pulse experiments (
5s), the output power, the oscillation efficiency and the electric efficiency for 170 GHz, 137 GHz and 104 GHz oscillation achieved 1.2 MW/27%/43%, 810 kW/25%/40% and 720 kW/25%/38%. In long pulse operation, pulse length reached 100s with 870 kW output power for 170 GHz oscillation. HE11 mode purity measured at the MOU exit was 94.5%, 93% and 92% for 170 GHz, 137 GHz and 104 GHz oscillation. By building precisely a transmission line, the purity of 91%, 88% and 95%, respectively is obtained at the exit of the long transmission line (35 m).
