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Teshigawara, Makoto; Ikeda, Yujiro*; Yan, M.*; Muramatsu, Kazuo*; Sutani, Koichi*; Fukuzumi, Masafumi*; Noda, Yohei*; Koizumi, Satoshi*; Saruta, Koichi; Otake, Yoshie*
Nanomaterials (Internet), 13(1), p.76_1 - 76_9, 2023/01
Times Cited Count：2 Percentile：54.89(Chemistry, Multidisciplinary)To enhance neutron intensity below cold neutrons, it is proposed that nanosized graphene aggregation could facilitate neutron coherent scattering under particle size conditions similar to nanodiamond. It might also be possible to use it in high neutron radiation conditions due to graphene's strong sp2 bonds. Using the RIKEN accelerator-driven compact neutron source and iMATERIA at J-PARC, we performed neutron measurement experiments, total neutron cross-section, and small-angle neutron scattering on nanosized graphene aggregation. The measured data revealed, for the first time, that nanosized graphene aggregation increased the total cross-sections and small-angle scattering in the cold neutron energy region, most likely due to coherent scattering, resulting in higher neutron intensities, similar to nanodiamond.
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Ma, B.*; Teshigawara, Makoto; Wakabayashi, Yasuo*; Yan, M.*; Hashiguchi, Takao*; Yamagata, Yutaka*; Wang, S.*; Ikeda, Yujiro*; Otake, Yoshie*
Nuclear Instruments and Methods in Physics Research A, 995, p.165079_1 - 165079_7, 2021/04
Times Cited Count：2 Percentile：34.88(Instruments & Instrumentation)We have optimized a cold neutron moderator to be operated at the RIKEN accelerator-driven compact neutron source. We selected a safe and easy to manage material, mesitylene, as the RANS cold moderator. An efficient moderator system was designed by studying and optimizing a coupled cold neutron moderator of mesitylene at 20 K with a polyethylene (PE) pre-moderator at room temperature in the slab geometry with Particle and Heavy Ion Transport code System (PHITS) simulations. The parameters of mesitylene and PE thickness, the reflector, and the shielding configuration were studied to increase cold neutron intensities. Consequently, an integrated cold neutron intensity of 1.15
10
n/cm
/
A at 2 m from the neutron-producing target was finally achieved, which was 12 times higher than that of the current PE moderator. The results showed attractive application prospect of mesitylene as cold neutron moderator material.
As by 320 MeV Au irradiation in single crystals and by high-pressure sintering in powder-in-tube wiresPyon, S.*; Taen, Toshihiro*; Otake, Fumiaki*; Tsuchiya, Yuji*; Inoue, Hiroshi*; Akiyama, Hiroki*; Kajitani, Hideki; Koizumi, Norikiyo; Okayasu, Satoru; Tamegai, Tsuyoshi*
Applied Physics Express, 6(12), p.123101_1 - 123101_4, 2013/12
Times Cited Count：21 Percentile：63.34(Physics, Applied)We demonstrate a large enhancement of critical current density (
) up to 1.0 10
A/cm at 5 K under self-field in (Ba,K)FeAs single crystals by irradiating 320 MeV Au ions. With the very promising potential of this material in mind, we have fabricated a (Ba,K)FeAs superconducting wire through a powder-in-tube method combined with the hot isostatic pressing technique, whose effectiveness has been proven in industrial Bi2223 tapes. The Jc in the wire at 4.2 K has reached 37 kA/cm under self-field and 3.0 kA/cm at 90 kOe. Magneto-optical imaging of the wire confirmed the large intergranular Jc in the wire core.
Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Togashi, Tadashi*; Fukami, Kenji*; et al.
Journal of Physics B; Atomic, Molecular and Optical Physics, 46(16), p.164006_1 - 164006_6, 2013/08
Times Cited Count：3 Percentile：19.06(Optics)By introducing 13th- (61.7 nm) and 15th-order harmonics (53.4 nm) of femtosecond laser pulses at 800 nm into an undulator of SCSS (SPring-8 Compact SASE Source) test accelerator at RIKEN, these harmonic pulses were amplified by a factor of more than 10 with a high contrast ratio through the interaction between accelerated electron bunches and the harmonic pulses. From numerical simulations of the amplification processes of high-order harmonic pulses in the undulator, optimum conditions of the electron bunch duration interacting with the high-order harmonic pulses were investigated for generating full-coherent and intense pulses in the extreme ultraviolet wavelength region.
Ogawa, Kanade*; Sato, Takahiro*; Matsubara, Shinichi*; Okayasu, Yuichi*; Togashi, Tadashi*; Watanabe, Takahiro*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; et al.
Proceedings of 10th Conference on Lasers and Electro-Optics Pacific Rim and 18th OptoElectronics and Communications Conference and Photonics in Switching 2013 (CLEO-PR & OECC/PS 2013) (USB Flash Drive), 2 Pages, 2013/06
no abstracts in English
Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Hara, Toru*; et al.
Proceedings of Ultrafast Optics IX (CD-ROM), 2 Pages, 2013/03
We have demonstrated free-electron laser radiation seeded by high-order harmonics in the extreme-ultraviolet region. Strong enhancement of the radiation intensity by a factor of 104 was observed with timing control of an electro-optical sampling technique.
Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Hara, Toru*; et al.
Proceedings of 11th International School and Symposium on Synchrotron Radiation in Natural Science (ISSRNS 2012), p.1 - 21, 2012/05
The 13th harmonic of a Ti:sapphire laser has been significantly amplified with the SCSS test accelerator. The temporal and spatial overlap of the electron beam and the high harmonic radiation were precisely tuned for achieving the seeded free electron laser operation. With numerical simulation the present HH-seeded FEL scheme could readily be applied to the wavelength region down to 10 nm.
Sato, Koji; Kotake, Shoji; Fujita, Yuji; Mizuno, Tomoyasu
Energy Procedia, 7, p.140 - 145, 2011/09
Times Cited Count：3 Percentile：89.42(Nuclear Science & Technology)JAEA has been implementing the FaCT project in cooperation with electric utilities toward the commercialization of fast reactor cycle system before 2050. In this FaCT project, many innovative technologies with technical challenges are actively used in order to provide significant improvements in economic competitiveness, enhancement of safety and reliability, sustainability, and nonproliferation. The work of deciding on the adoption of innovative technologies by the end of JFY2010 is in progress. This paper describes current preliminary assessment results.
Takahashi, Eiji*; Togashi, Tadashi*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Hara, Toru*; et al.
Proceedings of European Conference on Lasers and Electro-Optics and the 12th European Quantum Electronics Conference (CLEO/Europe-EQEC 2011) (CD-ROM), 1 Pages, 2011/05
We succeeded in generating the seeded free electron laser (FEL) with wavelengths of 61 nm at the SCSS test accelerator. The 13th (61 nm) harmonics generated by focusing the high peak power Ti:Sapphire laser to the Xe gas cell was directed to the undulator. This is first realization of the seeded FEL in extreme ultraviolet region.
Takahashi, Eiji*; Togashi, Tadashi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Hara, Toru*; Matsubara, Shinichi*; et al.
Proceedings of International Quantum Electronics Conference and the Pacific Rim Conference on Lasers and Electro-Optics (IQEC/CLEO Pacific Rim 2011) (CD-ROM), p.199 - 200, 2011/05
We succeeded in generating the seeded free electron laser (FEL) with wavelengths of 61 nm at the SCSS test accelerator. The 13th (61 nm) harmonics generated by focusing the high peak power Ti:Sapphire laser to the Xe gas cell was directed to the undulator. This is first realization of the seeded FEL in extreme ultraviolet region.
Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Okino, Tomoya*; Yamanouchi, Kaoru*; et al.
Optics Express (Internet), 19(1), p.317 - 324, 2011/01
Times Cited Count：96 Percentile：96.45(Optics)The 13th harmonic of a Ti:sapphire (Ti:S) laser in the plateau region was injected as a seeding source to a 250-MeV free-electron-laser (FEL) amplifier. When the amplification conditions were fulfilled, strong enhancement of the radiation intensity by a factor of 650 was observed. The random and uncontrollable spikes, which appeared in the spectra of the Self-Amplified Spontaneous Emission (SASE) based FEL radiation without the seeding source, were found to be suppressed drastically to form to a narrow-band, single peak profile at 61.2 nm. The properties of the seeded FEL radiation were well reproduced by numerical simulations. We discuss the future precept of the seeded FEL scheme to the shorter wavelength region.
Takada, Hiroshi; Maekawa, Fujio; Honmura, Shiro*; Yoshida, Katsuhiko*; Teraoku, Takuji*; Meigo, Shinichiro; Sakai, Akio*; Kasugai, Yoshimi; Kanechika, Shuji*; Otake, Hidenori*; et al.
Proceedings of ICANS-XVI, Volume 3, p.1115 - 1125, 2003/07
no abstracts in English
Matsubara, Shinichi*; Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; et al.
no journal, ,
no abstracts in English
Watanabe, Takahiro*; Aoyama, Makoto; Iwasaki, Atsushi*; Otake, Yuji*; Oshima, Takashi*; Okayasu, Yuichi*; Ogawa, Kanade*; Owada, Shigeki*; Sato, Takahiro*; Togashi, Tadashi*; et al.
no journal, ,
no abstracts in English
