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Tamatsukuri, Hiromu; Kozawa, Tatsuya*; Mitsuda, Setsuo*; Fujihara, Masayoshi; Kinjo, Katsuki*; Nawa, Kazuhiro*; Wu, H.-C.*; Sato, Taku*; Yano, Shinichiro*
Physical Review B, 112(18), p.184115_1 - 184115_8, 2025/11
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)Costantini, J.-M.*; Guillaumet, M.*; Lelong, G.*; Ishikawa, Norito; Seo, P.*; Yasuda, Kazuhiro*
Nuclear Instruments and Methods in Physics Research B, 558, p.165567_1 - 165567_6, 2025/01
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Radiation damage is studied in ion-irradiated sintered CeO
and (Ce, Gd)O
samples. Near Infra-red (NIR) spectra measurements were carried out by using the diffuse reflectivity mode for all of these sintered samples. Samples were irradiated with 100-MeV Kr, 200-MeV Xe, and 36-MeV W ions. Four broad absorption bands centered at 3700, 4100, 6000, and 7600 cm
(i.e. 0.46, 0.51, 0.74, and 0.94 eV) are deduced from fits of the FTIR spectra for the ion-irradiated CeO and (Ce, Gd)O samples accompanied by a change in color from ivory to green. No such bands are recorded for the virgin (Ce, Gd)O samples with 5, 10, and 15 mol GdO
with an increasing amount of oxygen vacancies. Absorption bands are tentatively assigned to electronic transitions involving cerium vacancy levels in the band gap, which has been also observed under high-energy electron irradiation.
observation of radiation-induced defects in ZrN under electron irradiation in HVEMRahman, M. M.*; Yamamoto, Tomokazu*; Matsumura, Sho*; Takaki, Seiya; Takano, Masahide; Costantini, J. M.*; Yasuda, Kazuhiro*
Nuclear Instruments and Methods in Physics Research B, 549, p.165289_1 - 165289_8, 2024/04
Times Cited Count：4 Percentile：75.59(Instruments & Instrumentation)Nucleation-and-growth process of radiation-induced defects in zirconium nitride (ZrN) has been investigated 
under electron irradiation by using a high voltage transmission electron microscope (HVEM) under electron irradiation by using a high voltage transmission electron microscope (HVEM).
Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Miyashita, Konan*; Yasuda, Kazuhiro*; Oka, Toshitaka; Okada, Shinji*; Sato, Motoyasu*
JJAP Conference Proceedings (Internet), 9, p.011003_1 - 011003_7, 2023/00
Muon catalyzed fusion (
CF) is a cyclic reaction where a negatively charged muon itself acts like a catalyst of nuclear fusion between hydrogen isotopes. In the CF reaction, muon transfer from deuteron to triton and muonic molecular formation are rate-limiting processes. In this work, we have investigated the role of resonance states of muonic molecule in the CF which affects the muonic deuterium atom population. Solving simultaneous rate equations numerically by the fourth-order Runge-Kutta method, we determined the muonic molecular formation rate so that the number of fusion events reproduces a latest experimental result. It is revealed that the resonance states play a role to enhance the fusion rate by accelerating the de-excitation of the muonic atoms.
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
Times Cited Count：3 Percentile：26.10(Nuclear Science & Technology)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
Times Cited Count：3 Percentile：26.10(Nuclear Science & Technology)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.
MnO cathode in an all-solid-state thin-film battery during cyclingHikima, Kazuhiro*; Hinuma, Yoyo*; Shimizu, Keisuke*; Suzuki, Kota*; Taminato, So*; Hirayama, Masaaki*; Masuda, Takuya*; Tamura, Kazuhisa; Kanno, Ryoji*
ACS Applied Materials & Interfaces, 13(6), p.7650 - 7663, 2021/02
Times Cited Count：23 Percentile：66.16(Nanoscience & Nanotechnology)We evaluated the structural change of the cathode material LiMnO that was deposited as an epitaxial film with an (001) orientation in an all-solid-state battery. In case of the electrode with LiPO
coating. Experiments revealed a structural change to a high-capacity (activated) phase that proceeded gradually and continuously with cycling. The activated phase barely showed any capacity fading. We propose a mechanism of structural change with cycling: charging to a high voltage at a sufficiently low Li concentration typically induces irreversible transition to a phase detrimental to cycling that could, but not necessarily, be accompanied by the dissolution of Mn and/or the release of O into the electrolyte, while a gradual irreversible transition to an activated phase happens at a similar Li concentration under a lower voltage.
Constantini, J.-M.*; Seo, P.*; Yasuda, Kazuhiro*; Bhuian, AKM S. I.*; Ogawa, Tatsuhiko; Gourier, D.*
Journal of Luminescence, 226, p.117379_1 - 117379_10, 2020/10
Times Cited Count：11 Percentile：49.34(Optics)Cathodo-luminescence is used for detection of lattice defects, in particular oxygen vacancies in ceramics induced by electrons. However, how oxygen vacancy production efficiency depends on sample temperature, incoming electron flux, and electron energy was not clear. In this study, oxygen vacancies were made in the specimens of CeO by irradiation of 400-1250 keV electrons and the cathodoluminescence from thus induced vacancies were observed by photo-fiber probe combined with CCD. As the result, the dependence of luminescence intensity on specimen temperature depends on the carrier trapping frequency and luminescence efficiency while luminescence center production/annihilation speed determines the dependency on the incoming electron flux. Moreover, radiation transport calculation conducted by the particle transport simulation code PHITS indicates that the number of electrons above the defect production threshold energy is vital to explain incoming electron energy dependence.
OYoshioka, Satoru*; Tsuruta, Konosuke*; Yamamoto, Tomokazu*; Yasuda, Kazuhiro*; Matsumura, Sho*; Sugiyama, Takeharu*; Oba, Yojiro; Ishikawa, Norito; Kobayashi, Eiichi*; Okudaira, Koji*
Journal of the American Ceramic Society, 103(8), p.4654 - 4663, 2020/08
Times Cited Count：8 Percentile：29.90(Materials Science, Ceramics)X-ray absorption near edge structure (XANES) and small-angle X-ray scattering (SAXS) reveal the damaged structures in MgAlO spinel induced by swift heavy ions. SAXS indicates the formation of ion tracks with cylindrical shape with a diameter of 5 nm. XANES indicates the cationic disordering between tetrahedral and octahedral sites by the irradiation. Quantitative analysis of XANES also reveals that cations preferably occupy the octahedral sites at high fluence.
Bh in the 
Cm(
Na,5
)Bh reaction and its decay propertiesHaba, Hiromitsu*; Fan, F.*; Kaji, Daiya*; Kasamatsu, Yoshitaka*; Kikunaga, Hidetoshi*; Komori, Yukiko*; Kondo, Narumi*; Kudo, Hisaaki*; Morimoto, Koji*; Morita, Kosuke*; et al.
Physical Review C, 102(2), p.024625_1 - 024625_12, 2020/08
Times Cited Count：8 Percentile：56.07(Physics, Nuclear)Sueyoshi, Tetsuro*; Kotaki, Tetsuya*; Furuki, Yuichi*; Fujiyoshi, Takanori*; Semboshi, Satoshi*; Ozaki, Toshinori*; Sakane, Hitoshi*; Kudo, Masaki*; Yasuda, Kazuhiro*; Ishikawa, Norito
Japanese Journal of Applied Physics, 59(2), p.023001_1 - 023001_7, 2020/02
Times Cited Count：9 Percentile：38.95(Physics, Applied)We show that Xe ion irradiation with 80 MeV to GdBaCuOy-coated conductors creates different morphologies of columnar defects (CDs) depending on the irradiation angles relative to the c-axis: continuous CDs with a larger diameter are formed for oblique irradiation at 
= 45
, whereas the same ion beam at a different angle ( = 0) induces the formation of discontinuous CDs. The direction-dependent morphologies of CDs significantly affect the angular behavior of the critical current density 
.
Constantini, J.-M.*; Ogawa, Tatsuhiko; Bhuian, A. S. I.*; Yasuda, Kazuhiro*
Journal of Luminescence, 208, p.108 - 118, 2019/04
Times Cited Count：6 Percentile：29.63(Optics)Cathodo-luminescence is used for detection of lattice defects, in particular oxygen vacancies in ceramics induced by electrons. However, how oxygen vacancy production efficiency depends on sample temperature, incoming electron flux, and electron energy was not clear. In this study, oxygen vacancies were made in the specimens of AlO, ZrO:Y(Yttrium stabilized zirconia), MgAlO, and TiO by irradiation of 400-1250keV electrons and the cathodoluminescence from thus induced vacancies were observed by photo-fiber probe combined with CCD. As the result, the dependence of luminescence intensity on specimen temperature depends on the carrier trapping frequency and luminescence efficiency while luminescence center production/annihilation speed determines the dependency on the incoming electron flux. Moreover, radiation transport calculation conducted by the particle transport simulation code PHITS indicates that the number of electrons above the defect production threshold energy is vital to explain incoming electron energy dependence.
O induced by swift heavy ionsYoshioka, Satoru*; Tsuruta, Konosuke*; Yamamoto, Tomokazu*; Yasuda, Kazuhiro*; Matsumura, Sho*; Ishikawa, Norito; Kobayashi, Eiichi*
Physical Chemistry Chemical Physics, 20(7), p.4962 - 4969, 2018/02
Times Cited Count：11 Percentile：38.27(Chemistry, Physical)Cationic disorder in the MgAlO spinel induced by swift heavy ions was investigated using the X-ray absorption near edge structure. With changes in the irradiation fluences of 200 MeV Xe ions, the Mg K-edge and Al K-edge spectra were synchronously changed. The calculated spectra based on density function theory indicate that the change in the experimental spectra was due to cationic disorder between Mg in tetrahedral sites and Al in octahedral sites. These results suggest a high inversion degree to an extent that the completely random configuration is achieved in MgAlO induced by the high density electronic excitation under swift heavy ion irradiation.
in GdBCO-coated conductors with crossed columnar defects around 
planeSueyoshi, Tetsuro*; Iwanaga, Yasuya*; Fujiyoshi, Takanori*; Takai, Yosuke*; Mukaida, Masashi*; Kudo, Masaki*; Yasuda, Kazuhiro*; Ishikawa, Norito
IEEE Transactions on Applied Superconductivity, 27(4), p.8001305_1 - 8001305_5, 2017/06
Times Cited Count：9 Percentile：40.99(Engineering, Electrical & Electronic)We investigated in detail the flux pinning properties around B 
for GdBCO coated conductors with crossed columnar defects produced by heavy-ion irradiation, where the crossing angle was systematically controlled in the range from 5 to 15 relative to the ab-plane. A single peak of critical current density centered at B occurs for the crossing angle of 5, where an upward shift in can be observed compared to an unirradiated sample. As the crossing angle is larger, the peak becomes smaller and broader while maintaining the peak at B . Three peaks emerges at B and at the two irradiation angles, independently from the others.
Sueyoshi, Tetsuro*; Kotaki, Tetsuya*; Furuki, Yuichi*; Uraguchi, Yusei*; Kai, Takashi*; Fujiyoshi, Takanori*; Shimada, Yusuke*; Yasuda, Kazuhiro*; Ishikawa, Norito
IEEE Transactions on Applied Superconductivity, 25(3), p.6603004_1 - 6603004_4, 2015/06
Times Cited Count：12 Percentile：49.65(Engineering, Electrical & Electronic)To investigate the effect of discontinuity of 1-D pinning centers on the flux pinning in a wide range of magnetic field directions, discontinuous columnar defects (CDs) and continuous CDs were formed in GdBCO coated conductors using Xe-ion irradiations with 80 and 270 MeV, respectively. An overall shift upward in Jc, for the 80-MeV-irradiated sample compared to the 270-MeV-irradiated one, can be observed in every direction of magnetic field, which is more remarkable as temperature decreases. This implies a synergetic effect of the pinning interaction between the linearity and the discontinuity for the discontinuous CDs.
and EuAlNakamura, Ai*; Hiranaka, Yuichi*; Hedo, Masato*; Nakama, Takao*; Miura, Yasunao*; Tsutsumi, Hiroki*; Mori, Akinobu*; Ishida, Kazuhiro*; Mitamura, Katsuya*; Hirose, Yusuke*; et al.
JPS Conference Proceedings (Internet), 3, p.011012_1 - 011012_6, 2014/06
Takaki, Seiya*; Yasuda, Kazuhiro*; Yamamoto, Tomokazu*; Matsumura, Sho*; Ishikawa, Norito
Nuclear Instruments and Methods in Physics Research B, 326, p.140 - 144, 2014/05
Times Cited Count：45 Percentile：93.98(Instruments & Instrumentation)We have investigated atomic structure of ion tracks in CeO irradiated with 200 MeV Xe ions by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). TEM observations under inclined conditions showed continuous ion tracks with diffraction and structure factor contrast, and the decrease in the atomic density of the ion tracks was evaluated. High resolution STEM with high-angle annular dark-field (HAADF) technique showed that the crystal structure of the Ce cation column is retained at the core region of ion tracks, although the signal intensity of the Ce cation lattice is reduced over a region nm in size. Annular bright field (ABF) STEM observation has detected that the O anion column is preferentially distorted at the core region of ion tracks within a diameter of 4 nm.
irradiated with swift heavy ionsYasuda, Kazuhiro*; Eto, Motoki*; Sawada, Kenichi*; Yamamoto, Tomokazu*; Yasunaga, Kazufumi*; Matsumura, Sho*; Ishikawa, Norito
Nuclear Instruments and Methods in Physics Research B, 314, p.185 - 190, 2013/11
Times Cited Count：43 Percentile：93.03(Instruments & Instrumentation)We have investigated microstructure evolution in CeO irradiated with 210 MeV Xe ions by using transmission electron microscopy to gain the fundamental knowledge on radiation damage induced by fission fragments in nuclear fuel and transmutation target.
Nakamura, Ai*; Hiranaka, Yuichi*; Hedo, Masato*; Nakama, Takao*; Miura, Yasunao*; Tsutsumi, Hiroki*; Mori, Akinobu*; Ishida, Kazuhiro*; Mitamura, Katsuya*; Hirose, Yusuke*; et al.
Journal of the Physical Society of Japan, 82(10), p.104703_1 - 104703_10, 2013/10
Times Cited Count：44 Percentile：82.79(Physics, Multidisciplinary)Al
(R = La and Pr)Sakoda, Masahito*; Kubota, Kazuhiro*; Tanaka, Shuhei*; Matsuoka, Eiichi*; Sugawara, Hitoshi*; Matsuda, Tatsuma; Haga, Yoshinori
Journal of the Physical Society of Japan, 81(Suppl.B), p.SB011_1 - SB011_4, 2012/12
Times Cited Count：3 Percentile：25.26(Physics, Multidisciplinary)