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Journal Articles

Demonstration of a kicker impedance reduction scheme with diode stack and resistors by operating the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Shobuda, Yoshihiro; Harada, Hiroyuki; Saha, P. K.; Takayanagi, Tomohiro; Tamura, Fumihiko; Togashi, Tomohito; Watanabe, Yasuhiro; Yamamoto, Kazami; Yamamoto, Masanobu

Physical Review Accelerators and Beams (Internet), 26(5), p.053501_1 - 053501_45, 2023/05

 Times Cited Count:0 Percentile:0.02(Physics, Nuclear)

At the Rapid Cycling Synchrotron (RCS) in Japan Proton Accelerator Research Complex (J-PARC), theoretical predictions have indicated that the kicker-impedance would excite the beam-instability. A 1 MW beam with large emittance can be delivered to the Material and Life Science Experimental Facility (MLF) through suppression of the beam instabilities by choosing the appropriate machine parameters. However, we require other high-intensity and high-quality smaller emittance beams (than the 1 MW beam) for the Main Ring (MR). Hence, we proposed a scheme for suppressing the kicker-impedance by using prototype diodes and resistors, thereby demonstrating the effect on the kicker impedance reduction. However, the J-PARC RCS must be operated with a repetition rate of 25 Hz, which urged us to consider special diodes that are tolerant to heating. After developments, we have demonstrated that the special diodes with resistors can suppress the beam instability by reducing the kicker impedance. Enhanced durability of the prototype diodes and resistors for the 25 Hz operation was also realized. Moreover, the new diodes and the resistors have negligible effect on the extracted beam from the RCS. From a simulation point of view, the scheme can be employed for at least 5 MW beam operation within the stipulated specifications.

Journal Articles

Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

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:3 Percentile:80.29(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.

Journal Articles

Reduction of the kicker impedance maintaining the performance of present kicker magnet at RCS in J-PARC

Shobuda, Yoshihiro; Irie, Yoshiro*; Takayanagi, Tomohiro; Togashi, Tomohito; Yamamoto, Masanobu; Yamamoto, Kazami

Journal of Physics; Conference Series, 1067, p.062007_1 - 062007_8, 2018/10

 Times Cited Count:2 Percentile:68.57

The present four-terminal kicker at the Rapid Cycling Synchrotron (RCS) at the Japan Proton Accelerator Research Complex (J-PARC) has the power-saving benefit due to the doubled excitation currents by shorting two-terminals. On the other hand, beam instabilities are excited by the kicker impedances. In this report, we describe a scheme to reduce the kicker impedances using diodes (nonlinear devices) with resistors, while retaining the benefit of the doubled kicker excitation currents.

Journal Articles

Reducing the beam impedance of the kicker at the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Shobuda, Yoshihiro; Chin, Y. H.*; Hayashi, Naoki; Irie, Yoshiro*; Takayanagi, Tomohiro; Togashi, Tomohito; Toyama, Takeshi*; Yamamoto, Kazami; Yamamoto, Masanobu

Physical Review Accelerators and Beams (Internet), 21(6), p.061003_1 - 161003_15, 2018/06

 Times Cited Count:4 Percentile:36.63(Physics, Nuclear)

no abstracts in English

Journal Articles

Coupled bunch instability and its cure at J-PARC RCS

Shobuda, Yoshihiro; Saha, P. K.; Hotchi, Hideaki; Harada, Hiroyuki; Takayanagi, Tomohiro; Tamura, Fumihiko; Tani, Norio; Togashi, Tomohito; Toyama, Takeshi*; Watanabe, Yasuhiro; et al.

Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.2946 - 2949, 2017/05

no abstracts in English

Journal Articles

Progress of injection energy upgrade project for J-PARC RCS

Hayashi, Naoki; Harada, Hiroyuki; Horino, Koki; Hotchi, Hideaki; Kamiya, Junichiro; Kinsho, Michikazu; Saha, P. K.; Shobuda, Yoshihiro; Takayanagi, Tomohiro; Tani, Norio; et al.

Proceedings of 4th International Particle Accelerator Conference (IPAC '13) (Internet), p.3833 - 3835, 2014/07

no abstracts in English

Journal Articles

Operation and current status of injection, extraction, kicker magnet and the power supply for J-PARC 3 GeV RCS

Watanabe, Masao; Hayashi, Naoki; Shobuda, Yoshihiro; Suganuma, Kazuaki; Takayanagi, Tomohiro; Togashi, Tomohito; Toyama, Takeshi*

Proceedings of 3rd International Particle Accelerator Conference (IPAC '12) (Internet), p.3629 - 3631, 2012/05

Stable operation is required for RCS at J-PARC. In the kicker system at extraction section of RCS, there had been many troubles for unstable operation of the thyratrons switches of the power supply just after 25 pps operation started in February 2009. However, the operation was improved by handling thyratrons in appropriate manner in October 2010. After the grate earthquake on 11 March 2011, injection and extraction magnets, power supplies, cables and bus-duct were checked. The results of the measurements and the checks were all not in the problem. We have to reach extraction beam power of 1 MW in RCS in the near future. Kicker impedance is most severe among other impedance sources. The matching resistor and newly developed diodes are connected at the power supply to reduce the impedance. We confirmed that reduced voltages and stable operation of accelerator.

JAEA Reports

Present status of chemical analysis of uranyl nitrate solution used for the criticality experiments in NUCEF

Haga, Takahisa*; Gunji, Kazuhiko; Fukaya, Hiroyuki; Sonoda, Takashi; Sakazume, Yoshinori; Sakai, Yutaka; Niitsuma, Yasushi; Togashi, Yoshihiro; Miyauchi, Masakatsu; Sato, Takeshi; et al.

JAERI-Tech 2004-005, 54 Pages, 2004/02

JAERI-Tech-2004-005.pdf:2.06MB

Criticality experiments using uranyl nitrate solution fuel are being conducted at STACY (the Static Experiment Critical Facility) and TRACY (the Transient Experiment Critical Facility) in NUCEF (the Nuclear Fuel Cycle Safety Engineering Research Facility). Chemical analyses of the solution have been carried out to take necessary data for criticality experiments, for treatment and control of the fuel, and for safeguards purpose at the analytical laboratory placed in NUCEF. About 300 samples are analyzed annually that provide various kinds of data, such as uranium concentration, isolation acid concentration, uranium isotopic composition, concentration of fission product (FP) nuclides, tri-butyl phosphoric acid (TBP) concentration, impurities in the solution fuel and so on. This report summarizes the analytical methods and quality management of the analysis for uranyl nitrate solution relating to the criticality experiments.

Journal Articles

Analysis of a uranium solution for evaluating the total number of fissions in the JCO criticality accident in Tokai-mura

Uchiyama, Gunzo; Watanabe, Kazuo; Miyauchi, Masakatsu; Togashi, Yoshihiro; Nakahara, Yoshinori; Fukaya, Hiroyuki; Inagawa, Jun; Suzuki, Daisuke; Sonoda, Takashi; Kono, Nobuaki; et al.

Journal of Radiation Research, 42(Suppl.), p.S11 - S16, 2001/10

no abstracts in English

JAEA Reports

Annual report on analysis work in NUCEF in fiscal year 1998

Togashi, Yoshihiro; Miyauchi, Masakatsu; Sonobe, Tamotsu; Niitsuma, Yasushi; Nakajima, Takayuki; Haga, Takahisa*; Tanoue, Takahiro; Fukaya, Hiroyuki; Sonoda, Takashi; Sakazume, Yoshinori; et al.

JAERI-Tech 2000-032, p.25 - 0, 2000/03

JAERI-Tech-2000-032.pdf:1.45MB

no abstracts in English

JAEA Reports

Cause finding experiments and environmental analysis on the accident of the fire and explosion in TRP bituminization facility

Fujine, Sachio; Murata, Mikio; Abe, Hitoshi; Takada, Junichi; Tsukamoto, Michio; Miyata, Teijiro*; Ida, Masaaki*; Watanabe, Makio; Uchiyama, Gunzo; Asakura, Toshihide; et al.

JAERI-Research 99-056, p.278 - 0, 1999/09

JAERI-Research-99-056.pdf:22.73MB

no abstracts in English

JAEA Reports

Long-term stability of hybrid K-edge/K-XRF densitometer

Sonoda, Takashi; Togashi, Yoshihiro; Miyauchi, Masakatsu; Okazaki, Shuji*

JAERI-Tech 99-043, 16 Pages, 1999/05

JAERI-Tech-99-043.pdf:1.86MB

no abstracts in English

Journal Articles

Decommissioning of nuclear facilities in Japan

Togashi, Yoshihiro; *; *

IMechE Conf. Trans., Int. Conf. on Nuclear Decommissioning, 0, p.29 - 39, 1995/00

no abstracts in English

JAEA Reports

Thermal durability of modified synroc material as reactor fuel matrix

; Kanazawa, Hiroyuki; Togashi, Yoshihiro; ; Nishino, Yasuharu; ; Nakata, Masahito; Amano, Hidetoshi;

JAERI-Research 94-008, 20 Pages, 1994/08

JAERI-Research-94-008.pdf:1.8MB

no abstracts in English

Journal Articles

$$alpha$$-decay damage effects in curium-doped titanate ceramic containing sodium-free high-level nuclear waste

; ; M.W.A.Stewart*; Tsuboi, Takashi; *; E.R.Vance*; K.P.Hart*; Togashi, Yoshihiro; Kanazawa, Hiroyuki; C.J.Ball*; et al.

Journal of the American Ceramic Society, 77(9), p.2255 - 2264, 1994/00

 Times Cited Count:30 Percentile:80.45(Materials Science, Ceramics)

no abstracts in English

JAEA Reports

Adherent behavior of radioactive volatile substance on canister

Togashi, Yoshihiro;

JAERI-M 93-077, 12 Pages, 1993/03

JAERI-M-93-077.pdf:0.54MB

no abstracts in English

Journal Articles

Aging effects on curium-doped titanate ceramic containing sodium-bearing high-level nuclear waste

; ; K.P.Hart*; *; E.R.Vance*; Tamura, Yukito; Togashi, Yoshihiro; White, T. J.*

Journal of the American Ceramic Society, 75(2), p.392 - 400, 1992/02

 Times Cited Count:25 Percentile:76.01(Materials Science, Ceramics)

no abstracts in English

JAEA Reports

Adherent behavior of simulated waste glass to canisters

Togashi, Yoshihiro; *;

JAERI-M 91-177, 9 Pages, 1991/11

JAERI-M-91-177.pdf:0.47MB

no abstracts in English

Journal Articles

Self-irradiation damage of a curium-doped titanate ceramic containing sodium-rich high-level nuclear waste

; ; *; White, T. J.*; *; Togashi, Yoshihiro; ; ; D.M.Levins*;

Journal of the American Ceramic Society, 73(11), p.3433 - 3441, 1990/11

 Times Cited Count:10 Percentile:56.08(Materials Science, Ceramics)

no abstracts in English

Journal Articles

Well-type NaI(Tl) spectrometry for quantitative analysis of $$^{244}$$Cm leached from curium-doped Synroc

; Togashi, Yoshihiro; ; *; Tamura, Yukito;

Applied Radiation and Isotopes, 41(9), p.839 - 845, 1990/09

no abstracts in English

22 (Records 1-20 displayed on this page)