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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:1 Percentile:71.47(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.
Miyai, Hiromitsu; Suzuki, Miho; Kanazawa, Hiroyuki
JAEA-Technology 2016-041, 46 Pages, 2017/03
In the Reactor Fuel Examination Facility (RFEF) of Japan Atomic Energy Agency (JAEA), Post Irradiation Examinations (PIEs) have been carried out for a long time in order to verify the reliability and the safety of the nuclear fuels irradiated in nuclear power plants. Samples for the PIEs are small and have various shapes. In order to facilitate the handling of the samples using a manipulator, the several kinds of jigs have been used for PIEs at RFEF those jigs are usually manufactured by machining process. We tried to make the jigs, which is PLA resin, with 3D printer and instead of machining process for the reduction of the manufacturing time and the improvement of the dimensional accuracy of the jig this time. It became clear that the actual dimensions of the jigs manufactured with 3D printer were roughly smaller at the concave section and larger at the convex section compared with the dimensions of the plan. So it is necessary to make a plan for the jigs after consideration of the characteristic of the 3D printer. The jigs can be applied to SEM observation, because the deposition of carbon film onto the jigs was well. And the jigs can be used to for the metallography, because the jigs were applicable without any harmful effects on polishing and etching processes.
Miyai, Hiromitsu; Suzuki, Miho; Kanazawa, Hiroyuki
Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 4 Pages, 2017/00
In the Reactor Fuel Examination Facility (RFEF) of Japan Atomic Energy Agency (JAEA), Post Irradiation Examinations (PIEs) have been carried out for a long time in order to verify the reliability and the safety of the nuclear fuels irradiated in nuclear power plants. Samples for the PIEs are small and have various shapes. In order to facilitate the handling of the samples using a manipulator, the several kinds of jigs have been used for PIEs at RFEF. Those jigs are usually manufactured by machining process. We tried to make the jigs, which is PLA resin, with 3D printer and instead of machining process for the reduction of the manufacturing time and the improvement of the dimensional accuracy of the jig this time. It became clear that the actual dimensions of the jigs manufactured with 3D printer were roughly smaller at the concave section and larger at the convex section compared with the dimensions of the plan. So it is necessary to make a plan for the jigs after consideration of the characteristic of the 3D printer. The jigs can be applied to SEM observation, because the deposition of carbon film onto the jigs was well. And the jigs can be used to for the metallography, because the jigs were applicable without any harmful effects on polishing and etching processes.
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
Kiriyama, Hiromitsu; Mori, Michiaki; Suzuki, Masayuki*; Daito, Izuru*; Okada, Hajime; Ochi, Yoshihiro; Tanaka, Momoko; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; et al.
Reza Kenkyu, 42(6), p.441 - 447, 2014/06
We describe three specific high power laser systems that are being developed in our laboratory for many applications in high field science, nonlinear optics and material processing. We report on a femtosecond petawatt-class Ti:sapphire chirped-pulse amplification laser system that can produce a pulse energy of 20 J of 40 fs pulse duration, a picosecond high intensity Yb:YAG chirped-pulse amplification laser system that can generate a pulse energy of 100 mJ of 0.5 ps pulse duration, and a nanosecond high repetition rate Nd:YAG laser system that can provide an average power of 360 W with a pulse duration of 30 ns delivered at a 1 kHz repetition rate. We discuss the basic design aspects and present the results from our experimental investigations of these laser systems.
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:61 Percentile:95.05(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:27.41(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
Kiriyama, Hiromitsu; Shimomura, Takuya; Mori, Michiaki; Nakai, Yoshiki*; Tanoue, Manabu; Kondo, Shuji; Kanazawa, Shuhei; Pirozhkov, A. S.; Esirkepov, T. Z.; Hayashi, Yukio; et al.
Applied Sciences (Internet), 3(1), p.214 - 250, 2013/03
Times Cited Count:15 Percentile:52.68(Chemistry, Multidisciplinary)This paper reviews techniques for improving the temporal contrast and spatial beam quality in an ultra-intense laser system that is based on chirped-pulse amplification (CPA). We describe the design, performance, and characterization of our laser system, which has the potential for achieving a peak power of 600 TW. We also describe applications of the laser system in the relativistically dominant regime of laser-matter interactions and discuss a compact, high efficiency diode-pumped laser system.
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.
Suzuki, Masayuki; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Ochi, Yoshihiro; Sato, Masatoshi*; Yoshii, Takehiro*; Tamaoki, Yoshinori*; Maeda, Junya*; Matsuoka, Shinichi*; et al.
AIP Conference Proceedings 1465, p.53 - 57, 2012/07
Times Cited Count:0 Percentile:0.13We have reported hundred mJ level, femtosecond pulse duration with the high temporal contrast in an OPCPA/Yb:YAG ceramic thin disk laser system at 10 Hz repetition rate. At an input laser pulse energy of 3.8 mJ from the OPCPA preamplifer the output energy of 130 mJ with spectral bandwidth of 2.5 nm has been obtained from multipass Yb:YAG ceramic thin disk amplifier, and the optical efficiency from LD energy to amplified laser pulse is 9.6%. The recompressed laser pulse duration was measured to be 450 fs. Because the compressor efficiency exceeds 73% the compressed pulse energy can potentially be as high as 95 mJ. The contrast level of this laser pulse was measured to be less than 7.210
at -150 ps. This novel laser system after further amplification using additional amplifiers can be useful for the laser-driven proton acceleration in future.
Kiriyama, Hiromitsu; Suzuki, Masayuki*; Daito, Izuru; Okada, Hajime; Ochi, Yoshihiro; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; Maeda, Junya*; Matsuoka, Shinichi*; et al.
Reza Kenkyu, 40(2), p.143 - 145, 2012/02
We demonstrate a compact, high-spatiotemporal-quality, high-intensity diode-pumped Yb:YAG thin-disk chirped-pulse amplification (CPA) laser system that incorporates a nonlinear preamplifier based on optical parametric chirped-pulse amplification (OPCPA). The stretched pulses are amplified in the OPCPA preamplifier and the following Yb:YAG main amplifier to 100 mJ at 10 Hz. The broadband amplified beam quality of 1.1 (horizontal direction) and 1.4 (vertical direction) times diffraction limited and pulse compression down to 470 fs with contrast of better than 10
have been achieved successfully.
Suzuki, Masayuki*; Kiriyama, Hiromitsu; Daito, Izuru; Ochi, Yoshihiro; Okada, Hajime; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; Maeda, Junya*; Matsuoka, Shinichi*; et al.
Applied Physics B, 105(2), p.181 - 184, 2011/11
Times Cited Count:5 Percentile:29.56(Optics)We have demonstrated an OPCPA/Yb:YAG ceramic thin disk hybrid laser system having hundred mJ level pulse energy sub-picosecond pulse duration with high temporal contrast. At an input energy of 3.8 mJ from an OPCPA preamplifier an output energy of 130 mJ was obtained from Yb:YAG ceramic thin disk amplifier. A recompressed pulse duration of 450 fs with a contrast level of less than 7.210
was obtained. The contrast level is the highest value achieved in Yb:YAG chirped pulse amplification (CPA) laser system with hundred mJ level.
Suzuki, Masayuki; Kiriyama, Hiromitsu
Reza Kenkyu, 39(8), p.649 - 651, 2011/08
no abstracts in English
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:8 Percentile:52.43(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.