Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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：6 Percentile：84.97(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.
Maebara, Sunao; Sukegawa, Keiichi*; Tadano, Shuya*; Kasugai, Atsushi; Suzuki, Hiromitsu; Abe, Kazuhiko*; Oku, Ryuji*; Sugimoto, Masayoshi
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1140 - 1142, 2015/09
For the IFMIF/EVEDA accelerator prototype RFQ linac, the operation frequency of 175MHz was selected to accelerate a large current of 125mA. The driving RF power of 1.28MW by 8 RF input couplers has to be injected to the RFQ cavity for CW operation mode. For each RF input coupler, nominal RF power of 160kW and maximum transmitted RF power of 200kW are required. For this purpose, an RF input coupler with cooling functions was designed, based on a 6 1/8 inch co-axial waveguide, and the RF coupler was manufactured by way of trial. For the trial RF coupler, high-power tests using a high voltage standing wave on a high-Q load circuit wave were carried out, and a 200kW-14 sec CW operation were performed after four days of RF aging. No RF contact defects, unnecessary low-Q value and extraordinary outgassing were observed. This report describes the high-power tests of the RF input coupler.
Takahashi, Hiroki; Maebara, Sunao; Kojima, Toshiyuki; Narita, Takahiro; Tsutsumi, Kazuyoshi; Sakaki, Hironao; Suzuki, Hiromitsu; Sugimoto, Masayoshi
Fusion Engineering and Design, 89(9-10), p.2066 - 2070, 2014/10
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Maebara, Sunao; Antonio, P.*; Ichikawa, Masahiro; Takahashi, Hiroki; Suzuki, Hiromitsu; Sugimoto, Masayoshi
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.561 - 563, 2014/06
no abstracts in English
Takahashi, Hiroki; Kojima, Toshiyuki; Narita, Takahiro; Maebara, Sunao; Sakaki, Hironao; Suzuki, Hiromitsu
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.724 - 727, 2014/06
no abstracts in English
Takahashi, Hiroki; Maebara, Sunao; Sakaki, Hironao; Ichikawa, Masahiro; Suzuki, Hiromitsu; Sugimoto, Masayoshi
Progress in Nuclear Science and Technology (Internet), 4, p.261 - 263, 2014/04
An development of accelerator-based neutron irradiation facility is planning to develop materials for a demonstration fusion reactor. To obtain a 14 MeV neutron energy using the neutron-generating D-Li stripping reaction, an injection into liquid lithium flow by a 40 MeV deuteron beam is employed in IFMIF design concept. In the acceleration of deuteron beam, the activation due to the beam loss is critical issue. The activation analyses for the air in an accelerator vault are carried out by PHITS code and DCHAIN code using the experimental data for deuteron induced thick target neutron yield at 5 MeV and 9 MeV for source term.
Knaster, J.*; Arbeiter, F.*; Cara, P.*; Favuzza, P.*; Furukawa, Tomohiro; Groeschel, F.*; Heidinger, R.*; Ibarra, A.*; Matsumoto, Hiroshi*; Mosnier, A.*; et al.
Nuclear Fusion, 53(11), p.116001_1 - 116001_18, 2013/11
Times Cited Count：63 Percentile：94.24(Physics, Fluids & Plasmas)The IFMIF/EVEDA project under the Broader Approach Agreement between Japan and EU aims at allowing a rapid construction phase of IFMIF in due time. The three main facilities, (1) the Accelerator Facility, (2) the Target Facility and (3) the Test Facility, are the subject of validation activities that include the construction of either full scale prototypes or smartly devised scaled down facilities that will allow a straightforward extrapolation to IFMIF needs. The installation of a Linac of 1.125 MW (125 mA and 9 MeV) of deuterons started in March 2013 in Rokkasho. The world largest liquid Li test loop is running in Oarai with an ambitious experimental programme for the years ahead. A full scale high flux test module that will house 
1000 small specimens developed jointly in Europe and Japan has been constructed in Germany together with its He gas loop. A full scale medium flux test module to carry out on-line creep measurement has been constructed in Switzerland.
Maebara, Sunao; Palmieri, A.*; Mereu, P.*; Ichikawa, Masahiro; Takahashi, Hiroki; Comunian, M.*; Suzuki, Hiromitsu; Pisent, A.*; Sugimoto, Masayoshi
Fusion Engineering and Design, 88(9-10), p.2740 - 2743, 2013/10
Times Cited Count：3 Percentile：25.73(Nuclear Science & Technology)Takahashi, Hiroki; Maebara, Sunao; Sakaki, Hironao; Suzuki, Hiromitsu; Sugimoto, Masayoshi
JAEA-Conf 2013-002, p.109 - 112, 2013/10
Shimada, Taihei; Nomura, Masahiro; Tamura, Fumihiko; Yamamoto, Masanobu; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Toda, Makoto*; Yoshii, Masahito*; Schnase, A.*; et al.
Proceedings of 4th International Particle Accelerator Conference (IPAC '13) (Internet), p.2750 - 2752, 2013/06
no abstracts in English
Shimada, Taihei; Suzuki, Hiromitsu; Yamamoto, Masanobu; Schnase, A.; Toda, Makoto*; Omori, Chihiro*; Hara, Keigo*; Hasegawa, Katsushi*; Nomura, Masahiro; Tamura, Fumihiko; et al.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1143 - 1145, 2012/08
The RF cavities of J-PARC 3 GeV synchrotron use 198 MA cores. Buckling occurred in some cores since the operation starting on the October of 2007. We have measured the inner diameters of the cores as a part of the investigation to determine the cause of the buckling when the cavities were disassembled for maintenance. We noticed that deformations of the inner shapes of the cores related to its manufacturing process and that inner diameters change over year were not measured in the most of the cores without buckled cores. Furthermore, the effective manufacturing process of cores to avoid the buckling has be established. We are going to replace old type cores with new type cores in shutdown periods in summer every year.
Nomura, Masahiro; Yamamoto, Masanobu; Schnase, A.; Shimada, Taihei; Suzuki, Hiromitsu; Tamura, Fumihiko; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Toda, Makoto*; et al.
Nuclear Instruments and Methods in Physics Research A, 623(3), p.903 - 909, 2010/11
Times Cited Count：9 Percentile：54.21(Instruments & Instrumentation)We have been operating ten RF cavities loaded with magnetic alloy cores in J-PARC 3 GeV RCS since September 2007. During 3 years operation, we detected three times the impedance reductions of RF cavities resulting from the buckling of MA cores. To find out the origin of the MA core buckling, we evaluated the thermal stress inside the MA cores in operation and studied the relationship between the MA core buckling and core structure. We figured out that the MA core buckling was caused by the thermal stress that was enhanced due to the impregnation with low viscosity epoxy resin.
Shimada, Taihei; Yamamoto, Masanobu; Nomura, Masahiro; Schnase, A.; Tamura, Fumihiko; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Toda, Makoto*; Suzuki, Hiromitsu; et al.
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.549 - 551, 2010/08
The beam pipes of the RF acceleration section in the J-PARC RCS have a large aperture (247 mm) in order to handle a high power proton beam of 1 MW with acceptable loss. When we disassemble and later reassemble the test cavity in between the high power test runs for the MA cores, it is quite hard work to take out, and reinstall the beam pipe. Therefore, instead of using an original beam pipe, risking that it becomes unusable for accelerator operation due to scratches or discharges, we developed a light weight dummy beam pipe and dedicated copper connection parts for the acceleration gaps, which are easy to take apart and to assemble. Accordingly, the copper parts, which are used to connect the acceleration gaps to the cavity tanks for the installed cavity systems were redesigned, so that the time required for assembly or disassembly is reduced. This is especially important, as the cavities in the accelerator tunnel are in a high radiation environment caused by high power RCS operation.
Sugimoto, Masayoshi; Garin, P.*; Vermare, C.*; Shidara, Hiroyuki; Kimura, Haruyuki; Suzuki, Hiromitsu; Ohira, Shigeru; Okumura, Yoshikazu; Mosnier, A.*; Facco, A.*; et al.
Kasokuki, 7(2), p.110 - 118, 2010/07
International Fusion Materials Irradiation Facility (IFMIF) is an accelerator-based neutron irradiation facility dedicated for development of fusion materials. Engineering Validation and Engineering Design Activities (EVEDA) phase of IFMIF project has been initiated in June 2007 and a prototype of the IFMIF accelerator (40 MeV - 125 mA CW Deuteron) is under construction in Rokkasho, Aomori. The target of the prototype is 9 MeV - 125 mA CW beam operation, which is full scale prototyping up to the first tank of superconducting linac section. In this report, the major technical specifications and issues of this extremely high-power machine are overviewed and expected results through operation in future are summarized.
Schnase, A.; Tamura, Fumihiko; Koseki, Tadashi*; Tomizawa, Masahito*; Toyama, Takeshi*; Yoshii, Masahito*; Omori, Chihiro*; Nomura, Masahiro; Yamamoto, Masanobu; Toda, Makoto*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.1446 - 1448, 2010/05
Tamura, Fumihiko; Schnase, A.; Yoshii, Masahito*; Omori, Chihiro*; Yamamoto, Masanobu; Nomura, Masahiro; Toda, Makoto*; Suzuki, Hiromitsu; Shimada, Taihei; Hara, Keigo*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.1443 - 1445, 2010/05
The wide-band RF cavities in the J-PARC RCS are operated in the dual-harmonic operation, in which each single cavity is driven by a superposition of the fundamental and the second harmonic RF signals. By the dual-harmonic operation large amplitude second harmonic signals for the bunch shape manipulation are generated without extra cavities. The phase control of the second harmonic RF is a key for the bunch shape manipulation. The fundamental RF signal is controlled by the phase feedback loop to damp the dipole oscillation. The second harmonic is locked to the phase of the vector-sum phase of the fundamental RF signals. We present the system detail and the performance in the beam operation of the RCS.
Nomura, Masahiro; Schnase, A.; Shimada, Taihei; Suzuki, Hiromitsu; Tamura, Fumihiko; Yamamoto, Masanobu; Ezura, Eiji*; Omori, Chihiro*; Hara, Keigo*; Hasegawa, Katsushi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3723 - 3725, 2010/05
We have been operating the RF cavities loaded with MA cores with a high field gradient of more than 20 kV/m since October 2007. We have been measuring the RF cavity impedance at the shutdown periods, and we detected the impedance reductions of RCS RF cavities on January and June 2009. Taking out the RF cavities from the beam line and opening them, we found that many of cores showed a buckling at the inner radius. We report the detail of condition of MA cores and the relation between the impedance reduction and core condition.
Shimada, Taihei; Yamamoto, Masanobu; Nomura, Masahiro; Schnase, A.; Tamura, Fumihiko; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Toda, Makoto*; Yoshii, Masahito*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3717 - 3719, 2010/05
Several magnetic alloy cores of the RF cavities, which are installed in the 3 GeV rapid cycling synchrotron (RCS) of J-PARC have shown buckling after about two years operation. To find the reason, why the local deformation happened, we made a test setup. There we heat up MA cores in air by 500 kHz RF and measure the thermal deformation in order to collect information about the buckling process. The results obtained by comparing the expansion of cores made by different production methods are reported.
Tamura, Fumihiko; Yamamoto, Masanobu; Yoshii, Masahito*; Omori, Chihiro*; Nomura, Masahiro; Schnase, A.; Toda, Makoto*; Suzuki, Hiromitsu; Shimada, Taihei; Hara, Keigo*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.366 - 368, 2010/03
For stable acceleration of the high intensity proton beams, increasing the bunching factor by the longitudinal painting is essentially important to reduce the space-charge tune shift. The momentum offset injection method and applying the second harmonic RF are employed for the longitudinal painting in the J-PARC RCS. We employ wide band magnetic alloy (MA) cavities to realize the dual-harmonic operation, in which each cavity is driven by the superposition of the fundamental and the second harmonic RF signals. By the dual-harmonic operation we can generate the large amplitude second harmonic RF without extra cavities for the second harmonic. We report the beam test results of the longitudinal painting.
Schnase, A.; Omori, Chihiro*; Tamura, Fumihiko; Ezura, Eiji*; Hara, Keigo*; Hasegawa, Katsushi*; Nomura, Masahiro; Shimada, Taihei; Suzuki, Hiromitsu; Takagi, Akira*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1077 - 1079, 2010/03
