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Miura, Yasufumi*; Suzuki, Kenji*; Morooka, Satoshi; Shobu, Takahisa
Quantum Beam Science (Internet), 8(1), p.1_1 - 1_14, 2024/03
Li, H.*; Liu, Y.*; Zhao, W.*; Liu, B.*; Tominaga, Aki; Shobu, Takahisa; Wei, D.*
International Journal of Plasticity, 165, p.103612_1 - 103612_20, 2023/06
Times Cited Count:2 Percentile:78.7(Engineering, Mechanical)In order to clarify the strength properties of Co-free maraging steel, tensile experiment using high energy synchrotron X-ray diffraction was performed. Diffraction profiles from the martensitic and austenitic phases were obtained, and their strength and width were observed to vary as loading. Analysis of the diffraction profiles showed that the content of martensite in the as-aged material decreased slowly at low stress levels and decreased rapidly at high stress levels. On the other hand, the austenite phase in the as-solution materials was significantly transformed the martensite phase as the stress increased. It was clarified to be responsible for their respective strength properties.
Shiwaku, Hideaki; Marushita, Motoharu*
JAEA-Research 2022-015, 39 Pages, 2023/05
We designed the hard X-ray undulator beamline BL22XU, which is dedicated to Japan Atomic Energy Research Institute (JAERI) at SPring-8 (now Japan Atomic Energy Agency (JAEA)). BL22XU is used for XAFS (X-ray Absorption Fine Structure) analysis experiments to develop separation and extraction materials for radioactive waste treatment and to elucidate their chemical behavior, magnetic research experiments using a diffractometer, and experiments under extreme conditions using a high-pressure press and a diamond anvil cell. The available X-ray energy range was set from 3 to 70 keV. To design the optics of the beamline, the reflectivity of the mirrors, the diffraction width of the monochromatic crystal, and the absorptance of the Be window were calculated. In addition, ray tracing was performed to optimize the materials for optics, dimensions, and location. The delay time of the ADL (Acoustic Delay Line) was also examined to ensure the safety in the use of radioactive materials. The operation of BL22XU "JAEA Actinide Science I" has already started. By collaborating BL22XU and BL23SU "JAEA Actinide Science II," which uses a soft X-ray undulator as a light source, we solve the problems to promote nuclear sciences. Since the monochromator was upgraded in 2018-2019, initial planning and measured data are documented here again.
Iyota, Muneyoshi*; Matsuda, Tomoki*; Sano, Tomokazu*; Shigeta, Masaya*; Shobu, Takahisa; Yumoto, Hirokatsu*; Koyama, Takahisa*; Yamazaki, Hiroshi*; Semba, Yasunori*; Ohashi, Haruhiko*; et al.
Journal of Manufacturing Processes, 94, p.424 - 434, 2023/05
Times Cited Count:3 Percentile:57.26(Engineering, Manufacturing)Yamazaki, Yasuhiro*; Shinomiya, Keisuke*; Okumura, Tadaharu*; Suzuki, Kenji*; Shobu, Takahisa; Nakamura, Yuiga*
Quantum Beam Science (Internet), 7(2), p.14_1 - 14_12, 2023/05
Suzuki, Kenji*; Miura, Yasufumi*; Shiro, Ayumi*; Toyokawa, Hidenori*; Saji, Choji*; Shobu, Takahisa; Morooka, Satoshi
Zairyo, 72(4), p.316 - 323, 2023/04
Im, S.*; Jee, H.*; Suh, H.*; Kanematsu, Manabu*; Morooka, Satoshi; Choe, H.*; Nishio, Yuhei*; Machida, Akihiko*; Kim, J.*; Lim, S.*; et al.
Construction and Building Materials, 365, p.130034_1 - 130034_18, 2023/02
Times Cited Count:6 Percentile:70.19(Construction & Building Technology)Hirano, Tatsumi*; Maeda, Takehiro*; Murata, Tetsuyuki*; Yamaki, Takahiro*; Matsubara, Eiichiro*; Shobu, Takahisa; Shiro, Ayumi*; Yasuda, Ryo*; Takamatsu, Daiko*
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(1), p.49 - 57, 2023/02
Tamura, Fumihiko; Omori, Chihiro*; Yoshii, Masahito*; Tomizawa, Masahito*; Toyama, Takeshi*; Sugiyama, Yasuyuki*; Hasegawa, Katsushi*; Kobayashi, Aine*; Okita, Hidefumi
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.175 - 178, 2023/01
J-PARC MR delivers high intensity proton beams to the neutrino experiment. Eight bunches with high peak currents are extracted from the MR by the extraction kicker, therefore the neutrino beam has the similar structure. Intermediate Water Cherenkov Detector (IWCD) will be installed for the future experiments and the IWCD requires a time structure with low peaks. We consider bunch manipulation at flattop of the MR for reducing the peak current. It should be quickly done to avoid the significant loss of the beam power. The beam gap for the kicker rise time must be kept. We propose a non-adiabatic bunch manipulation using the multiharmonic rf voltage. The longitudinal impedance in the MR can affect the beam stability. The feasibility of the manipulation is discussed by using the longitudinal simulations.
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.
Yamamoto, Masanobu; Nomura, Masahiro; Okita, Hidefumi; Shimada, Taihei; Tamura, Fumihiko; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Sugiyama, Yasuyuki*; Yoshii, Masahito*
Proceedings of 13th International Particle Accelerator Conference (IPAC 22) (Internet), p.1336 - 1338, 2022/06
In order to accelerate a high intensity beam in the RCS, a large amplitude of the rf current is provided by a tube amplifier to compensate a heavy beam loading. Tetrode vacuum tubes are used in the RCS, and the control grid voltage enters into a positive region to feed such a large rf current. The positive grid biasing affects the waveform of the control grid voltage; it is deformed due to the induced control grid current under the condition of the multi-harmonic rf driving. Furthermore, the DC bias voltage drop on the control grid is observed because of the exceeding the capability for the control grid power supply. We describe the influence of the positive grid biasing in the RCS.
Nakanoya, Takamitsu; Kamiya, Junichiro; Yoshimoto, Masahiro; Takayanagi, Tomohiro; Tani, Norio; Kotoku, Hirofumi*; Horino, Koki*; Yanagibashi, Toru*; Takeda, Osamu*; Yamamoto, Kazami
JAEA-Technology 2021-019, 105 Pages, 2021/11
Since a user operation startup, the 3 GeV synchrotron accelerator (Rapid-Cycling Synchrotron: RCS) gradually reinforced the beam power. As a result, the surface dose rate of the apparatus located at the beam injection area of the RCS, such as the magnet, vacuum chambers, beam monitors, etc., increases year by year. The beam injection area has many apparatuses which required manual maintenance, so reducing worker's dose is a serious issue. To solve this problem, we have organized a task force for the installation of the shield. The task force has aimed to optimize the structure of the radiation shield, construct the installation procedure with due consideration of the worker's dose suppression. As the examination result of the shield design, we have decided to adopt removal shielding that could be installed quickly and easily when needed. We carried out shield installation work during the 2020 summer maintenance period. The renewal work required to install the shielding has been carried out in a under high-dose environment. For this reason, reducing the dose of workers was an important issue. So, we carefully prepared the work plan and work procedure in advance. During the work period, we implemented various dose reduction measures and managed individual dose carefully. As a result, the dose of all workers could be kept below the predetermined management value. We had installed removal shielding at the beam injection area in the 2020 summer maintenance period. We confirmed that this shield can contribute to the reduction of the dose during work near the beam injection area. It was a large-scale work to occupy the beam injection area during almost of the summer maintenance period. However, it is considered very meaningful for dose suppression in future maintenance works.
Nakanoya, Takamitsu; Kamiya, Junichiro; Yoshimoto, Masahiro; Takayanagi, Tomohiro; Tani, Norio; Kotoku, Hirofumi*; Horino, Koki*; Yanagibashi, Toru*; Takeda, Osamu*; Yamamoto, Kazami
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.238 - 242, 2021/10
Since a user operation startup, the 3GeV synchrotron accelerator (Rapid-Cycling Synchrotron: RCS) gradually reinforced the beam power. As a result, the surface dose rate of the apparatus located at the beam injection area of the RCS increases year by year. The beam injection area has many apparatuses which required manual maintenance, so reducing worker's dose is a serious issue. To solve this problem, we have decided to adopt removal shielding that could be installed quickly and easily when needed. We carried out shield installation work during the 2020 summer maintenance period. The installation work of the shield has been carried out in a under high-dose environment. For this reason, reducing the dose of workers was an important issue. So, we carefully prepared the work plan and work procedure in advance. During the work period, we implemented various dose reduction measures and managed individual dose carefully. As a result, the dose of all workers could be kept below the predetermined management value. We had installed removal shielding at the beam injection area in the 2020 summer maintenance period. We confirmed that this shield can contribute to the reduction of the dose during work near the beam injection area.
Yamamoto, Masanobu; Okita, Hidefumi; Nomura, Masahiro; Shimada, Taihei; Tamura, Fumihiko; Furusawa, Masashi*; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Sugiyama, Yasuyuki*; et al.
Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.1884 - 1886, 2021/08
Tetrode vacuum tubes in J-PARC RCS are used under a reduced filament voltage condition compared with the rating value to prolong the tube lifetime. For the first time after 60,000 hour of operation in the RCS, one tube has reached the end of its life in 2020. Therefore, the reduced filament voltage works well because the tube has been running beyond an expected lifetime suggested by the tube manufacturer. However, the reduced filament voltage decreased the electron emission from the filament. Although the large amplitude of the anode current is necessary for the high intensity beam acceleration to compensate a wake voltage, a solid-state amplifier to drive a control grid circuit almost reaches the output power limit owing to the poor electron emission from the filament. We changed the filament voltage reduction rate from 15% to 5%. The required power of the solid-state amplifier was fairly reduced, whereas the accelerated beam power remained the same. We describe the measurement results of the vacuum tube parameters in terms of the filament voltage tuning.
Shobu, Takahisa; Shiro, Ayumi*; Muramatsu, Toshiharu*
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 9(5), p.318 - 323, 2021/08
Laser welding has already been put into practical use for various metal materials because the irradiation area is very small and the control is easy. In this study, we evaluated strain, stress, deformation, etc. near the processing affected area by high-energy synchrotron radiation X-ray diffraction method, which is one of the problems of laser welding of different materials that are expected to be put into practical use. As a result of internal deformation measurement of the bonding of dissimilar materials of copper and iron, it was confirmed that the copper side with a high coefficient of linear expansion was hardly deformed, strong tensile strain on the iron side, and a plastic deformation region on the heat-affected zone. In addition, a retained austenite phase, which is thought to be caused by the mixture of copper, was observed in the plastic deformation region of iron, and further problems were clarified in the evaluation of material strength in the mixed metallic materials.
Inami, Toshiya*; Shobu, Takahisa; Ishii, Kenji*
IEEE Transactions on Magnetics, 57(3, Part 2), p.6400105_1 - 6400105_5, 2021/03
Times Cited Count:0 Percentile:0(Engineering, Electrical & Electronic)Yamamoto, Masanobu; Furusawa, Masashi*; Hara, Keigo*; Hasegawa, Katsushi*; Nomura, Masahiro; Omori, Chihiro*; Shimada, Taihei; Sugiyama, Yasuyuki*; Tamura, Fumihiko; Yoshii, Masahito*
JPS Conference Proceedings (Internet), 33, p.011022_1 - 011022_6, 2021/03
A Tetrode vacuum tubes (Thales TH589) are used in the J-PARC ring rf system. The operation has started in 2007, and the total operation time is more than 50,000 hours. There is no tube which reaches the end of life except an initial failure in the 3 GeV synchrotron. TH589 has a thoriated tungsten filament and it is carburized to suppress an evaporation of the thorium. The resistance of the filament decreases through the decarburization process after the filament operation has started. The tube constructor suggests that reduced filament voltage up to 10% compared with the rated value is effective to suppress the decarburization. However, the filament current increases even though the voltage is kept constant due to the resistance reduction, and it is observed that an increment of the power dissipation promotes the decarburization. This means that keeping the filament voltage constant is not enough; keeping the power dissipation constant is necessary to prolong the tube life time, and we employ a procedure to decrease the current regularly.
Yamanaka, Kenta*; Kuroda, Asumi*; Ito, Miyu*; Mori, Manami*; Bian, H.*; Shobu, Takahisa; Sato, Shigeo*; Chiba, Akihiko*
Additive Manufacturing, 37, p.101678_1 - 101678_12, 2021/01
Times Cited Count:23 Percentile:86.72(Engineering, Manufacturing)Hayashi, Makoto*; Shobu, Takahisa
Residual Stress, p.100 - 132, 2021/00
Structural materials may undergo fatigue fracture or stress corrosion cracking during use. One of the causes is the residual stress generated by heat treatment and processing in the manufacturing process of structural materials. There are various methods for measuring the residual stress. This book introduces measurement techniques using ultrasonic and magnetic methods, starting with laboratory X-rays, synchrotron radiation X-rays, and neutrons. In addition, we will outline examples of measurement of residual stress due to processing and welding of various materials, measurement examples of actual machines, change behavior of residual stress due to static and repeated loads, and evaluation methods of fatigue remaining life based on the change behavior.
Sugano, Michinaka*; Machiya, Shutaro*; Shobu, Takahisa; Shiro, Ayumi*; Kajiwara, Kentaro*; Nakamoto, Tatsushi*
Superconductor Science and Technology, 33(8), p.085003_1 - 085003_10, 2020/08
Times Cited Count:5 Percentile:33.01(Physics, Applied)