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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; Hasegawa, Kazuo; Kinsho, Michikazu; Oguri, Hidetomo; Hayashi, Naoki; Yamazaki, Yoshio; Naito, Fujio*; Yoshii, Masahito*; Toyama, Takeshi*
JPS Conference Proceedings (Internet), 33, p.011016_1 - 011016_7, 2021/03
The Japan Proton Accelerator Research Complex (J-PARC) is a multipurpose facility for scientific experiments. The accelerator complex consists of a 400-MeV Linac, a 3-GeV Rapid-Cycling Synchrotron (RCS) and a 30-GeV Main Ring synchrotron (MR). The RCS delivers a proton beam to the neutron target and MR, and the MR delivers the beams to the neutrino target and the Hadron Experimental Facility. The first operation of the neutron experiments began in December 2008. Following this, the user operation has been continued with some accidental suspensions. These suspensions include the recovery work due to the Great East Japan Earthquake in March 2011 and the radiation leak incident at the Hadron Experimental Facility. In this report, we summarize the major causes of suspension, and the statistics of the reliability of J-PARC accelerator system is analyzed. Owing to our efforts to achieve higher reliability, the Mean Time Between Failure (MTBF) has been improved.
Hasegawa, Kazuo; Kinsho, Michikazu; Oguri, Hidetomo; Yamamoto, Kazami; Hayashi, Naoki; Yamazaki, Yoshio; Naito, Fujio*; Yoshii, Masahito*; Toyama, Takeshi*; Yamamoto, Noboru*; et al.
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1235 - 1239, 2019/07
After the summer shutdown in 2018, the J-PARC restarted user operation in late October. While beam power to the Materials and Life Science Experimental Facility (MLF) was 500 kW as before the summer shutdown, linac beam current was increased from 40 to 50 mA. Operation of the Main Ring (MR) was suspended due to the modification and/or maintenance of the Superkamiokande (neutrino detector) and Hadron experimental facility. The user operation was resumed in the middle of February for the Hadron experimental facility at 51 kW. But on March 18, one of the bending magnets in the beam transport line to the MR had a failure. It was temporary recovered and restored beam operation on April 5, but the failure occurred again on April 24 and the beam operation of the MR was suspended. In the fiscal year of 2018, the availabilities for the MLF, neutrino and hadron facilities are 94%, 86%, and 74%, respectively.
Hasegawa, Kazuo; Kinsho, Michikazu; Oguri, Hidetomo; Yamamoto, Kazami; Hayashi, Naoki; Yamazaki, Yoshio; Naito, Fujio*; Yoshii, Masahito*; Yamamoto, Noboru*; Koseki, Tadashi*
Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1317 - 1321, 2018/08
After the summer shutdown in 2017, the J-PARC restarted user operation in late October. The Materials and Life Science Experimental Facility (MLF) used a spare target and the beam power was limited to 150-200kW. The target was replaced with a new one in the summer shutdown. The beam power was for user operation gradually increased from 300 kW to 500 kW. We have successfully demonstrated 1MW 1hour operation in July 2018. The beam power for the neutrino experimental facility (NU) was 440 kW to 470 kW. The beam was delivered to the hadron experimental facility (HD) from January to February in 2018. The repetition rate of the main ring was shortened from 5.52 to 5.20 seconds, the beam power was increased from 44 to 50 kW. From March 2018, we delivered to the NU at 490 kW stably. In the fiscal year of 2017, the availabilities for the MLF, NU and HD are 93%, 89% and 66%, respectively.
Hasegawa, Kazuo; Hayashi, Naoki; Oguri, Hidetomo; Yamamoto, Kazami; Kinsho, Michikazu; Yamazaki, Yoshio; Naito, Fujio; Koseki, Tadashi; Yamamoto, Noboru; Yoshii, Masahito
Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.1038 - 1040, 2018/06
Hasegawa, Kazuo; Kinsho, Michikazu; Oguri, Hidetomo; Yamamoto, Kazami; Hayashi, Naoki; Yamazaki, Yoshio; Naito, Fujio*; Hori, Yoichiro*; Yamamoto, Noboru*; Koseki, Tadashi*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1317 - 1321, 2017/12
After the summer shutdown in 2016, the J-PARC restarted user operation late in October for the neutrino experiments (NU) and early in November for the materials and life science experimental facility (MLF). The beam power for the NU was 420 kW in May 2016, but increased to 470 kW in February 2017 thanks to the change and optimization of operation parameters. For the hadron experimental facility (HD), we started beam tuning in April, but suspended by a failure of the electro static septum. After the treatment, we delivered beam at the power of 37 kW. We delivered beam at 150kW for the MLF. In the fiscal year of 2016, the linac, the 3 GeV synchrotron (RCS) and the MLF were stable and the availability was high at 93%. On the contrary, the main ring has several failures and the availabilities were 77% and 84% for NU and HD, respectively.
Hasegawa, Kazuo; Hayashi, Naoki; Oguri, Hidetomo; Yamamoto, Kazami; Kinsho, Michikazu; Yamazaki, Yoshio; Naito, Fujio*; Koseki, Tadashi*; Yamamoto, Noboru*; Hori, Yoichiro*
Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.2290 - 2293, 2017/06
The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a 30 GeV Main Ring Synchrotron (MR). We have taken many hardware upgrades such as front end replacement and energy upgrade at the linac, vacuum improvement, collimator upgrade, etc. The beam powers for the neutrino experiment and hadron experiment from the MR have been steadily increased by tuning and reducing beam losses. The designed 1 MW equivalent beam was demonstrated and user program was performed at 500 kW from the RCS to the neutron and muon experiments. We have experienced many failures and troubles, however, to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented.
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
Yamamoto, Kazami; Kato, Shinichi*; Harada, Hiroyuki; Yoshimoto, Masahiro; Yamazaki, Yoshio; Hayashi, Naoki; Saha, P. K.; Hotchi, Hideaki; Kinsho, Michikazu
Progress in Nuclear Science and Technology (Internet), 4, p.243 - 246, 2014/04
The most important issue in a high-intensity proton accelerator is achieving low beam loss operation in order to keep the accelerator tunnel in a hands-on-maintenance condition. To achieve such a condition, a collimation system was designed and installed in the Japan Proton Accelerator Research Complex (J-PARC) 3GeV Rapid Cycling Synchrotron (RCS). The experimental results indicated that the RCS collimation system performs well enough such that nearly all the ring components are maintained in good condition. However, as the beam power increased, unexpected losses downstream of the injection foil increased. Therefore, an additional collimator was installed that successfully reduced such unexpected losses.
Saha, P. K.; Yoshimoto, Masahiro; Yamazaki, Yoshio; Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Yamamoto, Kazami; Kinsho, Michikazu; Irie, Yoshiro*
Journal of Radioanalytical and Nuclear Chemistry, 299(2), p.1041 - 1046, 2014/02
Times Cited Count：4 Percentile：30.8(Chemistry, Analytical)Saha, P. K.; Harada, Hiroyuki; Hayashi, Naoki; Horino, Koki; Hotchi, Hideaki; Kinsho, Michikazu; Takayanagi, Tomohiro; Tani, Norio; Togashi, Tomohito; Ueno, Tomoaki; et al.
Physical Review Special Topics; Accelerators and Beams, 16(12), p.120102_1 - 120102_11, 2013/12
Times Cited Count：4 Percentile：32.87(Physics, Nuclear)Saha, P. K.; Harada, Hiroyuki; Hatakeyama, Shuichiro; Hayashi, Naoki; Hotchi, Hideaki; Kinsho, Michikazu; Okabe, Kota; Saeki, Riuji; Yamamoto, Kazami; Yamazaki, Yoshio; et al.
Proceedings of 2nd International Beam Instrumentation Conference (IBIC 2013) (Internet), p.239 - 242, 2013/12
Yoshimoto, Masahiro; Saha, P. K.; Yamazaki, Yoshio; Kawase, Masato; Saeki, Riuji; Hayashi, Naoki; Yamamoto, Kazami; Hotchi, Hideaki; Ishiyama, Tatsuya; Kinsho, Michikazu; et al.
Journal of Physics; Conference Series, 417, p.012073_1 - 012073_6, 2013/03
Times Cited Count：4 Percentile：75.62(Materials Science, Coatings & Films)The HBC foil are installed in the J-PARC RCS for the charge-exchange H
beam injection. In order to examine the characteristics of the HBC foils, beam studies for the HBC foil were carried out from the viewpoint of foil's life time and the beam survival rate due to foils. According to the compromise between charge-exchange efficiency and foil scattering beam loss, we optimized the foils thickness for user operation. The long-term observation during the user operation as well as the HBC foil endurance test for its life time evaluation was carried out. Even after one year was operation, there was no deterioration of the stripping foil.
Mo-
Tc domestic production with high-density MoO
pellets by (n,
) reactionTsuchiya, Kunihiko; Tanase, Masakazu*; Takeuchi, Nobuhiro*; Kobayashi, Masaaki*; Hasegawa, Yoshio*; Yoshinaga, Hideo*; Kaminaga, Masanori; Ishihara, Masahiro; Kawamura, Hiroshi
Proceedings of 5th International Symposium on Material Testing Reactors (ISMTR-5) (Internet), 10 Pages, 2012/10
As one of effective uses of the JMTR, JAEA has a plan to produce Mo by (n, ) method, a parent nuclide of Tc. In case of Japan, the supplying of Mo depends only on imports from foreign countries. The R&D on production method of Mo -Tc has been performed with Japanese industrial users under the cooperation programs. The main R&D items for the production are (1) Fabrication of irradiation target such as the sintered MoO pellets, (2) Separation and concentration of Tc by the solvent extraction from Mo solution, (3) Examination of Tc solution for a medicine, and (4) Mo recycling from Mo generator and solution. In this paper, the status of the R&D is introduced for the production of Mo -Tc.
Hayashi, Naoki; Harada, Hiroyuki; Hotchi, Hideaki; Kamiya, Junichiro; Saha, P. K.; Shobuda, Yoshihiro; Takayanagi, Tomohiro; Tani, Norio; Yamamoto, Kazami; Yamamoto, Masanobu; et al.
Proceedings of 3rd International Particle Accelerator Conference (IPAC '12) (Internet), p.3921 - 3923, 2012/05
The injection energy upgrade from 181 to 400 MeV for J-PARC RCS is planned in 2013. One power supply was replaced and using for a normal operation. An IGBT chopper type power supply which has larger switching noise will be changed to a capacitor bank type. New injection system allows the center injection with 400 MeV and switching painting area. As further steps for the leakage field, it begins to diminish the effect from the beam transport line. A quadrupole corrector system is designed and fabricated to compensate the beta beat due to the injection bump as the first step. Two profile monitors will be modified to correct position systematic errors and third one is going to be installed at dispersion free section. It is important to minimize kicker impedance lower, which may cause the beam instability. A diode, which has high reverse breakdown voltage and works with lower forward voltage, has been developed. Using this new diode, an experiment shows the impedance becomes lower.
Hayashi, Naoki; Hotchi, Hideaki; Kamiya, Junichiro; Saha, P. K.; Takayanagi, Tomohiro; Yamamoto, Kazami; Yamamoto, Masanobu; Yamazaki, Yoshio
Proceedings of 2nd International Particle Accelerator Conference (IPAC 2011) (Internet), p.2730 - 2732, 2011/09
The J-PARC RCS is a high beam power Rapid-Cycling Synchrotron (RCS). The original designed injection energy is 400 MeV, although presently it is 181 MeV, and its beam power is limited to 0.6 MW. Works to recover the Linac energy are ongoing and injection magnets power supplies upgrade for two bump and new knob are required in the RCS. In order to achieve 1 MW designed beam power, new instrumentation, like quadrupole corrector or to reduce kicker impedance, are also planned simultaneously. Activities related injection energy recovery in the J-PARC RCS are presented.
Fe
O
F
(x 
0.44)Tsujimoto, Yoshihiro*; Yamaura, Kazunari*; Hayashi, Naoaki*; Kodama, Katsuaki; Igawa, Naoki; Matsushita, Yoshitaka*; Katsuya, Yoshio*; Shirako, Yuichi*; Akaogi, Masaki*; Muromachi, Eiji*
Chemistry of Materials, 23(16), p.3652 - 3658, 2011/08
Times Cited Count：27 Percentile：61(Chemistry, Physical)Topotactic reaction of the Ruddlesden-Popper phase SrFeO
(
0.18) with polytetrafluoroethylene yields a highly fluorinated phase SrFeOF (x 0.44), compared with SrFeO
F
prepared by the reaction of SrFeO and F gas. Structure analyses based on powder neutron diffraction, synchrotron powder diffraction, and 
Fe M
ssbauer spectroscopy measurements demonstrate that the new oxyfluoride perovskite has no anion deficiencies and adopts the tetragonal structure (space group 
4/
) with lattice constants 
= 3.87264(6) 
and 
= 21.3465(6) at room temperature. The fluoride ions preferentially occupy the terminal apical anion sites with oxide ions in a disordered manner, which results in square pyramidal coordination around iron.
Hayashi, Naoki; Hotchi, Hideaki; Kamiya, Junichiro; Saha, P. K.; Takayanagi, Tomohiro; Yamamoto, Kazami; Yamamoto, Masanobu; Yamazaki, Yoshio
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.306 - 308, 2011/08
The J-PARC RCS is a high beam power Rapid-Cycling Synchrotron (RCS). The original designed injection energy is 400MeV, although presently it is 181MeV, and its beam power is limited to 0.6MW. Works to recover the Linac energy are ongoing and injection magnets power supplies upgrade are required in the RCS. In order to achieve 1MW designed beam power, new instrumentation is also planned simultaneously. Activities related injection energy recovery in the J-PARC RCS is presented.
Takayanagi, Tomohiro; Ueno, Tomoaki; Hayashi, Naoki; Yamazaki, Yoshio; Kinsho, Michikazu
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.584 - 586, 2010/08
In the bump system of the J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid Cycling Synchrotron), the performance improvement according to upgrade of the Linac (Linear Accelerator) to 400 MeV beam is planned. Both of the increase of the power supply capacity and the improvement of the setting accuracy of the output current are required. Moreover, the operating point that the vibration of the current ripple resonates with betatron tune was clarified. Therefore, the present level of the current ripple is necessary to decrease to half or less. The development of the pulse power supply system that solves the problems of the current ripple is required.
resolutionShimizu, Noriko*; Sugiyama, Shigeru*; Maruyama, Mihoko*; Takahashi, Yoshinori*; Adachi, Motoyasu; Tamada, Taro; Hidaka, Koshi*; Hayashi, Yoshio*; Kimura, Toru*; Kiso, Yoshiaki*; et al.
Crystal Growth & Design, 10(7), p.2990 - 2994, 2010/06
Times Cited Count：11 Percentile：71.95(Chemistry, Multidisciplinary)We report crystal growth of human immunodeficiency virus 1 protease (HIV PR) in a complex with its inhibitor KNI-272 by six different methods. Comparative analysis indicates that top-seeded solution growth (TSSG) and TSSG combined with the floating and stirring technique (TSSG-FAST) are efficient strategies for rapidly obtaining large single crystals and effectively preventing polycrystallization of the seed crystal. Neutron diffraction analysis confirmed that the crystalobtained by TSSG is a high-quality single crystal. Furthermore, crystal shape was observed to be influenced by solution flow, suggesting that the degree of supersaturation significantly affects the crystal growth direction of HIV PR complex. This finding implies that the shape of the HIV PR complex crystal might be controlled by the solution flow rate.
