Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
Fusion Engineering and Design, 170, p.112712_1 - 112712_4, 2021/09
A muonic molecule which consists of two hydrogen isotope nuclei (deuteron (d) or tritium (t)) and a muon decays immediately via nuclear fusion and the muon will be released as a recycling muon, and start to find another hydrogen isotope nucleus. The reaction cycle continues until the muon ends up its lifetime of 2.2 
s. Since the muon does not participate in the nuclear reaction, the reaction is so called a muon catalyzed fusion (CF). The recycling muon has a particular kinetic energy (KE) of the muon molecular orbital when the nuclear reaction occurs. Since the KE is based on the unified atom limit where distance between two nuclei is zero. A precise few-body calculation estimating KE distribution (KED) is also in progress, which could be compared with the experimental results. In the present work, we observed recycling muons after CF reaction.
Yamashita, Takuma*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
Fusion Engineering and Design, 169, p.112580_1 - 112580_5, 2021/08
A muon () having 207 times larger mass of electron and the same charge as the electron has been known to catalyze a nuclear fusion between deuteron (d) and triton (t). These two nuclei are bound by and form a muonic hydrogen molecular ion, dt. Due to the short inter-nuclear distance of dt, the nuclear fusion, d +t
+ n + 17.6 MeV, occurs inside the molecule. This reaction is called muon catalyzed fusion (CF). Recently, the interest on CF is renewed from the viewpoint of applications, such as a source of high-resolution muon beam and mono-energetic neutron beam. In this work, we report a time evolution calculation of CF in a two-layered hydrogen isotope target.
Hirota, Takatoshi*; Nagoshi, Yasuto*; Hojo, Kiminobu*; Okada, Hiroshi*; Takahashi, Akiyuki*; Katsuyama, Jinya; Ueda, Takashi*; Ogawa, Takuya*; Yashirodai, Kenji*; Ohata, Mitsuru*; et al.
Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 9 Pages, 2021/07
=0 long-range magnetic order in centennialite CaCu
(OD)
Cl
0.6DO; A Spin-
perfect kagome antiferromagnet with 
-
-
Iida, Kazuki*; Yoshida, Hiroyuki*; Nakao, Akiko*; Jeschke, H. O.*; Iqbal, Y.*; Nakajima, Kenji; Kawamura, Seiko; Munakata, Koji*; Inamura, Yasuhiro; Murai, Naoki; et al.
Physical Review B, 101(22), p.220408_1 - 220408_6, 2020/06
Times Cited Count：6 Percentile：75.71(Materials Science, Multidisciplinary)Crystal and magnetic structures of the mineral centennialite CaCu(OD)Cl 0.6DO are investigated by means of synchrotron X-ray diffraction and neutron diffraction measurements complemented by density functional theory (DFT) and pseudofermion functional renormalization group (PFFRG) calculations. In CaCu(OD)Cl 0.6DO, Cu
ions form a geometrically perfect kagome network with antiferromagnetic . No intersite disorder between Cu and Ca ions is detected. CaCu(OD)Cl 0.6DO enters a magnetic long-range ordered state below 
= 7.2 K, and the =0 magnetic structure with negative vector spin chirality is obtained. The ordered moment at 0.3 K is suppressed to 0.58(2)B. Our DFT calculations indicate the presence of antiferromagnetic and ferromagnetic superexchange couplings of a strength which places the system at the crossroads of three magnetic orders (at the classical level) and a spin- PFFRG analysis shows a dominance of =0 type magnetic correlations, consistent with and indicating proximity to the observed =0 spin structure. The results suggest that this material is located close to a quantum critical point and is a good realization of a -- kagome antiferromagnet.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.
Science, 364(6437), p.272 - 275, 2019/04
Times Cited Count：140 Percentile：99.81(Multidisciplinary Sciences)The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
rays from neutron-induced compound states of 
LaOkudaira, Takuya*; Takada, Shusuke*; Hirota, Katsuya*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; Nagamoto, Kosuke*; Nakao, Taro*; Okada, Anju*; Sakai, Kenji; et al.
Physical Review C, 97(3), p.034622_1 - 034622_15, 2018/03
Times Cited Count：6 Percentile：62.89(Physics, Nuclear)Nagai, Takayuki; Kobayashi, Hidekazu; Sasage, Kenichi; Ayame, Yasuo; Okamoto, Yoshihiro; Shiwaku, Hideaki; Matsuura, Haruaki*; Uchiyama, Takafumi*; Okada, Yukiko*; Nezu, Atsushi*; et al.
JAEA-Research 2016-015, 52 Pages, 2016/11
JAEA-Research-2016-015.pdf:37.48MB
The local structure of waste elements in simulated waste glasses including V was estimated by using synchrotron XAFS measurement in this study. The results are as follows. (1) V has a high possibility which exists in the glass phase in the case of frit, and V can regard both samples as stable 4 coordination structure. (2) Zn, Ce, Nd, Zr, and Mo exist in the glass phase, and the difference is admitted by the percentage of Ce(III) and Ce(IV) by the composition. (3) Ru is separated from the glass phase as RuO crystalline, both of metal and oxide exist in Rh, and Pd is separated out as metal. (4) It was confirmed that the regularity of the local structure of Zr and Mo in the molten glasses retreats as a result of the XAFS measurement at high temperature. (5) The XAFS measurement of molten glasses were performed at 1200
C, so it would be possible to acquire excellent data by improving the shapes of the sample cell.
Magome, Hirokatsu; Okada, Yuji; Tomita, Kenji; Iida, Kazuhiro; Ando, Hitoshi; Yonekawa, Akihisa; Ueda, Haruyasu; Hanawa, Hiroshi; Kanno, Masaru; Sakuta, Yoshiyuki
JAEA-Technology 2015-025, 100 Pages, 2015/09
JAEA-Technology-2015-025.pdf:78.32MB
In Japan Atomic Energy Agency, in order to solve the problem in the long-term operation of a light water reactor, preparation which does the irradiation experiment of light-water reactor fuel and material was advanced. JMTR stopped after the 165th operation cycle in August 2006, and is advancing renewal of the irradiation facility towards re-operation. The material irradiation test facility was installed from 2008 fiscal year to 2012 fiscal year in JMTR. The material irradiation test facility is used for IASCC study, and that consists of mainly three equipments. This report is described performance operating test of the water environmental control facilities for IASCC study carried out 2013 fiscal year.
Nakamoto, Tatsushi*; Sugano, Michinaka*; Xu, Q.*; Kawamata, Hiroshi*; Enomoto, Shun*; Higashi, Norio*; Idesaki, Akira; Iio, Masami*; Ikemoto, Yukio*; Iwasaki, Ruri*; et al.
IEEE Transactions on Applied Superconductivity, 25(3), p.4000505_1 - 4000505_5, 2015/06
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)Recently, development of superconducting magnet system with high radiation resistance has been demanded for application in accelerator facilities such as CERN LHC. In order to realize superconducting magnet system with high radiation resistance, it is necessary to develop electrical insulator with high radiation resistance because the electrical insulator is made of organic materials whose radiation resistance is inferior to that of inorganic materials. We developed a glass fiber reinforced plastic with bismaleimide-triazine resin. The developed material showed excellent radiation resistance; the material evolved gases of 5
10 
mol/g and maintained flexural strength of 640MPa (90% of initial value).
Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Faenov, A. Y.*; Pikuz, T. A.*; Kawachi, Tetsuya; Sagisaka, Akito; Koga, J. K.; Mori, Michiaki; Kawase, Keigo*; et al.
RAL-TR-2015-025, P. 22, 2015/00
Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T. A.*; Kawachi, Tetsuya; Sagisaka, Akito; et al.
New Journal of Physics (Internet), 16(9), p.093003_1 - 093003_30, 2014/09
Times Cited Count：25 Percentile：81.51(Physics, Multidisciplinary)Kikuchi, Kenji*; Okada, Noriyuki*; Kato, Mikio*; Uchida, Hiroshi*; Saito, Shigeru
Journal of Nuclear Materials, 450(1-3), p.237 - 243, 2014/07
Times Cited Count：3 Percentile：28.59(Materials Science, Multidisciplinary)Three-dimensional atom probe techniques were applied to the investigation on the oxide scale in 12Cr ferritic-martensitic steel, HCM12A. A duplex oxide scale was formed in lead bismuth eutectic at 450-500C, during 5500 h. Samples were located 500-700 nm away from the boundary between magnetite and Fe-Cr spinel layers, while the total oxide layer thickness is 18 m. It detected super enrichment of Cr with a size of ten nm roughly, as well as depletion of Fe and enrichment of O at the same site. Surrounding the Cr super enrichment area, enrichment of Si was newly noticed due to the scanned profile of detected atom counts. It is also confirmed that Pb and Bi concentration in the observed spinel region is almost null or less than 0.01 atomic percent, which is possible detecting lowest limit.
Tokuhisa, Atsushi*; Arai, Junya*; Jochi, Yasumasa*; Ono, Yoshiyuki*; Kameyama, Toyohisa*; Yamamoto, Keiji*; Hatanaka, Masayuki*; Gerofi, B.*; Shimada, Akio*; Kurokawa, Motoyoshi*; et al.
Journal of Synchrotron Radiation, 20(6), p.899 - 904, 2013/11
Times Cited Count：4 Percentile：27.21(Instruments & Instrumentation)Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T.; Kawachi, Tetsuya; Sagisaka, Akito; et al.
AIP Conference Proceedings 1465, p.167 - 171, 2012/07
Times Cited Count：1 Percentile：49.39Esirkepov, T. Z.; Pirozhkov, A. S.; Kando, Masaki; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A.*; Pikuz, T.; Kawachi, Tetsuya; Sagisaka, Akito; et al.
AIP Conference Proceedings 1465, p.172 - 180, 2012/07
Times Cited Count：0 Percentile：0.13The bow wave induced mechanism of high-order harmonics generation was discovered using simulations and catastrophe theory. This mechanism feasibility was successfully demonstrated in 3D and 2D PIC simulations. The mechanism and the simulations explained high-order harmonics in the XUV spectral region seen in recent experiments with terawatt lasers. Development of new XUV light and X-ray source based on the high-order harmonics generation mechanism is proposed.
Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T.; Kawachi, Tetsuya; Sagisaka, Akito; et al.
Physical Review Letters, 108(13), p.135004_1 - 135004_5, 2012/03
Times Cited Count：64 Percentile：91.71(Physics, Multidisciplinary)We demonstrate a new high-order harmonic generation mechanism reaching the "water window" spectral region in experiments with multi-terawatt femtosecond lasers irradiating gas jets. A few hundred harmonic orders are resolved, giving J/sr pulses. Harmonics are collectively emitted by an oscillating electron spike formed at the joint of the boundaries of a cavity and bow wave created by a relativistically self-focusing laser in underdense plasma. The spike sharpness and stability are explained by catastrophe theory. The mechanism is corroborated by particle-in-cell simulations.
Koyama, Shinichi; Suzuki, Tatsuya*; Ozawa, Masaki*; Kurosawa, Kiyoko*; Fujita, Reiko*; Mimura, Hitoshi*; Okada, Ken*; Morita, Yasuji; Fujii, Yasuhiko*
Procedia Chemistry, 7, p.222 - 230, 2012/00
Times Cited Count：1 Percentile：60.25Adv.-ORIENT cycle strategy has been proposed as a basic concept for trinitarian research on separation, transmutation and utilization of nuclides and elements based on FBR fuel cycle. Validation of principal separation method and related safety research were performed from 2006 through 2011 as Phase I program. First, more than 90% of Cs could be recovered from the actual spent fuel [IXC(I) step]. The next is the adsorption of the platinum group metals (PGM), lanthanides, Am and Cm were separated by using a tertiary pyridine-type resin (TPR) as ion exchange steps [IXC(II, III, IV) steps]. The separated PGM metals will be supplied to the electrochemical extraction [CEE step]. As experiment for safety issues, Hastelloy-B at RT and Ta at 90C were confirmed their anti-corrosive in highly concentrated HCl media. Thermo-chemical stability for TPR was verified. Issues to be solved for next phase based on the final results of phase I program.
Koyama, Shinichi; Yamagishi, Isao; Suzuki, Tatsuya*; Ozawa, Masaki*; Fujita, Reiko*; Okada, Ken*; Tatenuma, Katsuyoshi*; Mimura, Hitoshi*; Fujii, Yasuhiko
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 8 Pages, 2011/12
Effective separation of MA and LLFP, transmutation and utilization were the main directions of Advanced OREINT Cycle project. Study for each integrant technology was concluded as first trial of the project. TPR enabled to separate MA/Ln and then Am/Cm precisely from spent fuel in HCl and HNO media. CEE method could separate the light PGM and Tc by HCl media. Recovery of Cs from simulated HLLW coul be achieved more than 90 %. In addition, the perspective for next phase was proposed.
Koyama, Shinichi; Suzuki, Tatsuya*; Mimura, Hitoshi*; Fujita, Reiko*; Kurosawa, Kiyoko*; Okada, Ken*; Ozawa, Masaki
Progress in Nuclear Energy, 53(7), p.980 - 987, 2011/09
Times Cited Count：5 Percentile：42.62(Nuclear Science & Technology)Individual basic researches of separation step were performed in the Advanced ORIENT Cycle project. High separation selectivity for Cs and Sr by novel nano adsorbents AMP-SG (D) and D18C6-MC were confirmed, respectively. TPR well adsorbed Pd and Tc in dilute HCl condition. Formation of rare metal fission product RMFP-deposit Pt electrodes from SHLLW was verified, and it was confirmed that high catalytic reactivity on electrolytic production of hydrogen. As experiment for engineering feasibility, Hastelloy-B at RT and Ta at 90C were confirmed their anti-corrosive in highly concentrated HCl media. Thermo-chemical stability for TPR was verified in either HCl or HNO media toward its practical use in the separation process. Issues to be solved for optimization based on the results of lab-scale experiment have revealed in this study.
Nagao, Keisuke*; Okazaki, Ryuji*; Nakamura, Tomoki*; Miura, Yayoi*; Osawa, Takahito; Bajo, Kenichi*; Matsuda, Shintaro*; Ebihara, Mitsuru*; Ireland, T.*; Kitajima, Fumio*; et al.
Science, 333(6046), p.1128 - 1131, 2011/08
Times Cited Count：104 Percentile：95.41(Multidisciplinary Sciences)A steroid surface materials record regolith processes and a history of cosmic-ray irradiation. Noble gas isotopes in three rocky grains from Itokawa have been determined. High concentrations of solar He, Ne, and Ar, as high as those in lunar soils, are released at variable temperatures from each sample. The isotopic compositions are essentially identical to those of solar wind but distinguishable in He relative abundance. These noble gas characteristics can be explained by repeated implantation and preferential loss of solar He by removal of weathered He-rich rim on the grain surface through friction among regolith grains on Itokawa. Residence time of regolith materials on Itokawa is alculated to be shorter than 10 Myr, suggesting that regolith materials of small asteroids would escape easily to space.
