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Park, P.*; Cho, W.*; Kim, C.*; An, Y.*; Kang, Y.-G.*; Avdeev, M.*; Sibille, R.*; Iida, Kazuki*; Kajimoto, Ryoichi; Lee, K. H.*; et al.
Nature Communications (Internet), 14, p.8346_1 - 8346_9, 2023/12
Times Cited Count:0 Percentile:0.00(Multidisciplinary Sciences)Tanigawa, Hiroyasu; Ozawa, Kazumi; Morisada, Yoshiaki*; Noh, S.*; Fujii, Hidetoshi*
Fusion Engineering and Design, 98-99, p.2080 - 2084, 2015/10
Times Cited Count:10 Percentile:64.00(Nuclear Science & Technology)The vacuum plasma spray (VPS) technique has been investigated as the most practical method to form Tungsten (W) layer as a plasma facing material in fusion devices. The issues are the thermal conductivity and the strength of VPS-W, i.e., the thermal conductivity of VPS-W were significantly lower than that of the bulk W, and the hardness of VPS-W is much less than that of the bulk W. These are mainly caused by the porous structure of VPS-W. In order to solve these issues, friction stir processing (FPS) was applied on VPS-W in this study. It was suggested that FSP can contribute to significant improvement both in mechanical and thermal properties of VPS-W coating.
Nozawa, Takashi; Noh, S.; Tanigawa, Hiroyasu
Journal of Nuclear Materials, 427(1-3), p.282 - 289, 2012/08
Times Cited Count:6 Percentile:43.19(Materials Science, Multidisciplinary)A hot isostatic press (HIP) process is a key technology to fabricate a first wall with cooling channels of the fusion blanket system utilizing a reduced-activation ferritic/martensitic steel. This study aims to develop the torsion test method with a special emphasis to provide a reasonable and comprehensive method to determine interfacial shear properties of HIP joints during the torsional fracture process. Torsion test results identified that the torsion process shows yield of the base metal and following non-elastic deformation due to work hardening of the base metal. By considering this work hardening issue, we could propose a reasonable and realistic solution to determine the torsional yield shear stress and the ultimate torsional shear strength of the HIPped interface. Finally, representative torsion fracture process was identified.
Nishiuchi, Mamiko; Daido, Hiroyuki; Yogo, Akifumi; Orimo, Satoshi; Ogura, Koichi; Ma, J.-L.; Sagisaka, Akito; Mori, Michiaki; Pirozhkov, A. S.; Kiriyama, Hiromitsu; et al.
Physics of Plasmas, 15(5), p.053104_1 - 053104_10, 2008/05
Times Cited Count:45 Percentile:84.16(Physics, Fluids & Plasmas)High-flux energetic protons whose maximum energies are up to 4 MeV are generated by an intense femtosecond Titanium Sapphire laser pulse interacting with a 7.5, 12.5, and 25m thick Polyimide tape targets. The laser pulse energy is 1.7 J, duration is 34 fs, and intensity is 310Wcm. The amplified spontaneous emission (ASE) has the intensity contrast ratio of 410. The conversion efficiency from laser energy into proton kinetic energies of 3% is achieved, which is comparable or even higher than those achieved in the previous works with nanometer-thick targets and the ultrahigh contrast laser pulses (10).
Orimo, Satoshi; Nishiuchi, Mamiko; Daido, Hiroyuki; Yogo, Akifumi; Ogura, Koichi; Sagisaka, Akito; Li, Z.*; Pirozhkov, A. S.; Mori, Michiaki; Kiriyama, Hiromitsu; et al.
Japanese Journal of Applied Physics, Part 1, 46(9A), p.5853 - 5858, 2007/09
Times Cited Count:17 Percentile:54.86(Physics, Applied)A laser-driven proton beam with a maximum energy of a few MeV is stably obtained using an ultra-short and high-intensity Titanium Sapphire laser. At the same time, keV X-ray is also generated at almost the same place where protons are emitted. Here, we show the successful demonstration of simultaneous proton and X-ray projection images of a test sample placed close to the source with a resolution of 10m, which is determined from the source sizes. Although the experimental configuration is very simple, the simultaneity is better than a few hundreds of ps. A CR-39 track detector and imaging plate, which are placed as close as possible to the CR-39, are used as detectors of protons and X-ray. The technique is applicable to the precise observation of microstructures.
Daido, Hiroyuki; Sagisaka, Akito; Ogura, Koichi; Orimo, Satoshi; Nishiuchi, Mamiko; Mori, Michiaki; Ma, J.-L.; Pirozhkov, A. S.; Kiriyama, Hiromitsu; Kanazawa, Shuhei; et al.
Proceedings of 7th Pacific Rim Conference on Lasers and Electro-Optics (CLEO-PR 2007) (CD-ROM), p.77 - 79, 2007/00
We are developing a proton accelerator using an intense lasers with a focused intensity of 10 W/cm. To monitor proton energy spectra as well as plasma parameters at each laser shot, we are using real time detectors. The proton energy of MeV is stably obtained for applications.
Daido, Hiroyuki; Sagisaka, Akito; Ogura, Koichi; Orimo, Satoshi; Nishiuchi, Mamiko; Yogo, Akifumi; Mori, Michiaki; Li, Z.*; Kiriyama, Hiromitsu; Kanazawa, Shuhei; et al.
X-Ray Lasers 2006; Springer Proceedings in Physics, Vol.115, p.595 - 605, 2007/00
At present, using ultra-short high intensity lasers at APRC, JAEA Kansai photon research institute, we are developing laser driven multiple quantum beams such as protons, X-rays, electrons and THz waves. These beams are perfectly synchronized with each other. The pulse duration of each beam is lass than a pico-second. They have sharp directionality with high brightness. If we properly combined these, we have new pump-probe techniques for various applications.
Tanigawa, Hiroyasu; Ozawa, Kazumi; Morisada, Yoshiaki*; Fujii, Hidetoshi*; Noh, S.*
no journal, ,
no abstracts in English
Orimo, Satoshi; Yogo, Akifumi; Sagisaka, Akito; Ogura, Koichi; Mori, Michiaki; Pirozhkov, A. S.; Li, Z.*; Ma, J.-L.; Daido, Hiroyuki; Nakamura, Shu*; et al.
no journal, ,
Laser drive ion acceleration generated by thin foil irradiation high intensity laser and it is applications. An intense p-pol. laser was irradiated by the 45 degree incident angle on 310Wcm at 5 microns thickness copper tape target. The proton of a maximum of more 2MeV was generated, and a space spread and the propagation characteristic for energy of the were measured using CR39 with a range filter. Moreover, demonstration of simultaneous imaging by the proton beam and X-rays was measured.
Yogo, Akifumi; Ogura, Koichi; Orimo, Satoshi; Sagisaka, Akito; Takai, Mamiko; Mori, Michiaki; Pirozhkov, A. S.; Daido, Hiroyuki; Nakamura, Shu*; Shirai, Toshiyuki*; et al.
no journal, ,
no abstracts in English
Nishiuchi, Mamiko; Daito, Izuru; Ikegami, Masahiro; Mori, Michiaki; Orimo, Satoshi; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Pirozhkov, A. S.; Ma, J.*; et al.
no journal, ,
A laser-driven proton beam with a maximum energy of a few MeV is stably obtained using an ultra-short and high-intensity Titanium Sapphire laser. As compared with the proton beam from the conventional accelerator, this proton beam exhibits peculiar characteristics, such as, more than 10 protons per bunch are produced within a short pulse duration of ps at a source, resulting in a very high peak current. It also exhibits a very low transverse emittance. The proton beam has a divergence angle of 10 degrees and energy spread of 100%. It accompanies electrons and X-rays, which is produced simultaneously. Making the best use of these peculiar characteristics, many possible applications of the laser-driven proton are proposed. In order to make practical laser-driven proton beam for the applications, we carry out series of experiments. We have successfully obtained simultaneous imaging of the target with proton and X-ray or proton and electron beams. In the course of practical use of the proton beam for specific applications, characteristics above should be optimized based on the variations of the applications. For example, in order to apply the laser-driven proton beam for the proton irradiation system, such as used in the medical or the industrial applications, we should obtain focused or parallel proton beam. One of our plans to alter the orbits of the laser-driven protons from the planer tape target is using permanent quadrupole magnets.
Nishiuchi, Mamiko; Daido, Hiroyuki; Yogo, Akifumi; Orimo, Satoshi; Ogura, Koichi; Ma, J.-L.; Sagisaka, Akito; Mori, Michiaki; Pirozhkov, A. S.; Kiriyama, Hiromitsu; et al.
no journal, ,
The efficient proton beam whose maximum energy of up to 4 MeV was produced by the 50TW short pulse intensity Ti:Sap laser irradiated on the polyimide target [(CHON)n] with the thicknesses of 7.5m, 12.5m, 25m, which is transparent to the 800 nm laser. The laser parameters are energy of 1.7J, pulse width of 35fs and the intensity of 310 Wcm. The contrast of the ASE component is 410. The conversion efficiency from laser energy into the proton kinetic energy is up to 3%. This conversion efficiency is comparable or even higher than the results obtained with the same level laser ( J energy) interacts with the nano-meter level ultra thin target. In this paper we discuss on the comparison between our results and other experimental results obtained in other facilities.
Nozawa, Takashi; Noh, S.; Kishimoto, Hirotatsu*; Tanigawa, Hiroyasu
no journal, ,
A hot isostatic press (HIP) process is a key technology to fabricate a first wall with cooling channels of the fusion blanket system utilizing a reduced-activation ferritic/martensitic (RAFM) steel. A primary objective of this study is to provide a reasonable and comprehensive method to determine interfacial shear properties of HIP joints during the torsional fracture process. By considering hardening during torsional process, we could propose a reasonable and realistic solution to define the interfacial debond shear strength of the HIPed interface by torsion.
Sagisaka, Akito; Pirozhkov, A. S.; Daido, Hiroyuki; Ogura, Koichi; Orimo, Satoshi; Yogo, Akifumi; Daito, Izuru; Nishiuchi, Mamiko; Mori, Michiaki; Nashima, Shigeki*; et al.
no journal, ,
no abstracts in English