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Fujimura, Yuki; Ishikawa, Norito; Kondo, Keietsu
JAEA-Technology 2024-012, 26 Pages, 2024/10
JAEA-Technology-2024-012.pdf:3.03MB
While ceramic materials exhibit high temperature strength and corrosion resistance, they are also chemically stable. Specifically, aluminum oxide (Al
O
) is recognized as one of the highly radiation resistant materials. On the other hand, the precise evaluation of irradiation damage in these materials poses a significant challenge because detecting radiation damage induced in highly radiation-resistant ceramics is difficult. The objective of this study is to evaluate irradiation-induced lattice strain using Electron BackScatter Diffraction (EBSD), a technique commonly employed for damage analysis in metals. Ion irradiation tests were conducted on AlO, a representative highly radiation-resistant ceramic, at various doses. Through lattice strain analysis using EBSD, we successfully identified irradiation-induced lattice strain in the direction parallel to the irradiation, consistent with previous XRD analysis results. Lattice strain in the direction perpendicular to the irradiation was also detected. It was observed that the lattice strain tends to increase with increasing irradiation damage. In conclusion, lattice strain analysis using EBSD proves to be an effective method for assessing the irradiation effects on ceramics.
Ogawa, Hiroaki; Ishikawa, Norito
2023-Nendo Daigaku Kenkyu Josei Gijutsu Kenkyu Hokokusho, p.123 - 134, 2024/03
Evaluation of corrosion and hydrogen embrittlement is important in the quality control of stainless steel and the development of next steel materials assuming a high-pressure hydrogen environment. Typically, a secondary ion mass spectrometer (SIMS) is used to analyze hydrogen in steel materials. The hydrogen concentration of conventional standard substance for hydrogen analysis is as small as 1wt-ppm, which has been a problem in hydrogen analysis. We use a hydrogen-implant method to create a locally higher hydrogen concentration than that of the conventional. Hydrogen concentration analysis has been evaluated using the nuclear reaction analysis (NRA) method at a tandem accelerator. We have succeeded in creating a sample with a higher hydrogen concentration of about 1,900 wt-ppm than that of the conventional in locally.
Ishikawa, Norito; Fukuda, Shoma; Nakajima, Toru; Ogawa, Hiroaki; Fujimura, Yuki; Taguchi, Tomitsugu*
Materials, 17(3), p.547_1 - 547_21, 2024/02
Times Cited Count：2 Percentile：63.37(Chemistry, Physical)Natural monoclinic zirconia (baddeleyite) was irradiated with 340-MeV Au ions, and the irradiation-induced nanostructures (i.e., ion tracks and nanohillocks) were observed using transmission electron microscopy. The diameter of the nanohillocks is approximately 10 nm, which is similar to the maximum molten region size calculated using the analytical thermal spike model. Ion tracks are imaged as strained regions that maintain their crystalline structure. The cross-sections of most of the ion tracks are imaged as parallelopiped or rectangular contrasts as large as 10 nm. These results strongly indicate that the molten region is recrystallized anisotropically, reflecting the lattice structure. Furthermore, low-density track cores are formed in the center of the ion tracks. The formation of low-density track cores can be attributed to the ejection of molten matter toward the surface.
Amekura, Hiroshi*; Chettah, A.*; Narumi, Kazumasa*; Chiba, Atsuya*; Hirano, Yoshimi*; Yamada, Keisuke*; Yamamoto, Shunya*; Leino, A. A.*; Djurabekova, F.*; Nordlund, K.*; et al.
Nature Communications (Internet), 15, p.1786_1 - 1786_10, 2024/02
Times Cited Count：2 Percentile：62.71(Multidisciplinary Sciences)Injecting high-energy heavy ions in the electronic stopping regime into solids can create cylindrical damage zones called latent ion tracks. Although these tracks form in many materials, none have ever been observed in diamond, even when irradiated with high-energy GeV uranium ions. Here we report the first observation of ion track formation in diamond irradiated with 2-9 MeV C
fullerene ions. Depending on the ion energy, the mean track length (diameter) changed from 17 (3.2) nm to 52 (7.1) nm. High resolution scanning transmission electron microscopy (HR-STEM) indicated the amorphization in the tracks, in which 
-bonding signal from graphite was detected by the electron energy loss spectroscopy (EELS).
Ishikawa, Norito
JAEA-Conf 2022-002, p.111 - 115, 2023/03
In this report, some of the research topics related to radiation damage and atomic physics researches utilizing the tandem accelerator at JAEA are introduced.
irradiated with swift heavy ions at grazing incidenceIshikawa, Norito; Fujimura, Yuki; Kondo, Keietsu; Szabo, G. L.*; Wilhelm, R. A.*; Ogawa, Hiroaki; Taguchi, Tomitsugu*
Nanotechnology, 33(23), p.235303_1 - 235303_10, 2022/06
Times Cited Count：7 Percentile：54.80(Nanoscience & Nanotechnology)A single crystal of SrTiO doped with niobium (Nb-STO) was irradiated with 200 MeV Au ions at grazing incidence. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used to study the relation between irradiation-induced change of surface topography and corresponding material property changes. As expected, multiple hillocks as high as 5-6 nm are imaged by AFM observation. It is also found that the region in between the adjacent hillocks is slightly elevated rather than depressed. Line-like contrasts along the ion paths are found in both AFM phase images and SEM images, indicating the formation of continuous ion tracks in addition to multiple hillocks. Cross-sectional transmission electron microscopy (TEM) observation shows that the ion tracks in the near-surface region are found to be relatively large, whereas buried ion tracks in the deeper region are relatively small. The results suggest that recrystallization plays an important role in the formation of small ion tracks in the deep region, whereas formation of large ion tracks in the near-surface region is likely due to the absence of recrystallization.
200 MeV ion irradiationPogrebnjak, A. D.*; Bagdasaryan, A. A.*; Horodeck, P.*; Tarelnyk, V.*; Buranich, V. V.*; Amekura, Hiroshi*; Okubo, Nariaki; Ishikawa, Norito; Beresnev, V. M.*
Materials Letters, 303, p.130548_1 - 130548_4, 2021/11
Times Cited Count：22 Percentile：79.28(Materials Science, Multidisciplinary)Positron annihilation spectroscopy (PAS) of ion-irradiated (TiZrHfNbV)N nitride which is a high-entropy alloy-based material indicates that the vacancy-defects are the dominant defects type. Although the specimens are irradiated up to 5
10
ions/cm
no amorphization or intermetallic phase formation is detected after the irradiation, demonstrating the radiation tolerance of the high-entropy alloys.
single crystal by ion irradiation; A Molecular dynamics studySasajima, Yasushi*; Kaminaga, Ryuichi*; Ishikawa, Norito; Iwase, Akihiro*
Quantum Beam Science (Internet), 5(4), p.32_1 - 32_14, 2021/11
The nano-pore formation process that occurs by supplying a thermal spike to single crystal CeO has been simulated using a molecular dynamics method. As the initial condition, high thermal energy was supplied to the atoms in a nano-cylinder placed at the center of a fluorite structure. A nano-pore was generated abruptly at around 0.3 ps after the irradiation. It grew to its maximum size at 0.5 ps, and successively it shrank during the time to 1.0 ps. The nano-pore size increased with increasing effective stopping power.
ZnSnS
thin films induced by 200 MeV Xe swift heavy ions irradiationKhoualed, M.*; Boutebakh, F. Z.*; Chettah, A.*; Amekura, Hiroshi*; Ishikawa, Norito; Ghemid, S.*; Attaf, N.*; Aida, M. S.*
Journal of Materials Science; Materials in Electronics, 32(20), p.25516 - 25527, 2021/10
Times Cited Count：4 Percentile：21.21(Engineering, Electrical & Electronic)CuZnSnS (CZTS) thin films deposited on glass substrate using spray pyrolysis technique were irradiated by 200 MeV Xe ions at different fluences. The effect of high-density electronic excitations on the properties of CZTS thin films has been examined using UV-visible spectrophotometry for optical properties, X-ray diffraction and Raman spectroscopy for structural properties. A pronounced blue-shift in the transmittance spectra edges and bandgap widening up to 2.05 eV were observed by the irradiation.
Sueyoshi, Tetsuro*; Enokihata, Ryusei*; Yamaguchi, Hiroshi*; Fujiyoshi, Takanori*; Okuno, Yasuki*; Ishikawa, Norito
IEEE Transactions on Applied Superconductivity, 31(5), p.8000305_1 - 8000305_5, 2021/08
Angular behaviors of critical current density Jc at 77 K, 1 T were investigated in YBCO films with columnar defects (CDs) tilted at small angles to the ab-plane before and after the additional introduction of CDs at different angles, where CDs were installed by heavy-ion irradiations. The enhanced Jc at 
by the initial irradiation at 
i=
85
relative to the c-axis was reduced by the additional irradiation at i=75, whereas the Jc was increased at the intermediate angle between the two irradiation angles. The addition of CDs at i=0 also lowered the Jc around , which were enhanced by the initial irradiation angles of i=80.
Ishikawa, Norito; Taguchi, Tomitsugu*; Okubo, Nariaki
Shototsu, 18(3), p.43 - 55, 2021/05
Radiation damage mechanism in ceramics irradiated with swift heavy ions has been studied by using transmission electron microscopy (TEM). We introduce how the mechanisms are unveiled by our recent TEM studies.
superconductorsSueyoshi, Tetsuro*; Enokihata, Ryusei*; Hidaka, Yuka*; Irie, Masahiro*; Fujiyoshi, Takanori*; Okuno, Yasuki*; Ishikawa, Norito
Physica C, 582, p.1353824_1 - 1353824_5, 2021/03
Times Cited Count：3 Percentile：17.60(Physics, Applied)We investigated the combined effect of flux pinning by three-directional columnar defects (CDs) in a wide field-angular range of YBaCuOy thin films, where CDs parallel to the 
-axis and CDs crossing at (=45, 60 and 80) relative to the c-axis were installed by 200 MeV Xe-ion irradiations. The three-directional CDs with 
60 form a field angular curve of critical current density Jc with a broad peak centered at magnetic field (B) parallel to the -axis, whereas the Jc shows no peaks around the crossing angles of . When the crossing angle is expanded to =80, a drastic change in the field- angular behavior of Jc is induced: there is not a large enhancement of 
around B//c. We also demonstrated that the combined configuration consisting of CDs at = 0, 45, 60 and 80 provides a uniform enhancement of over a wide angular-region.
Amekura, Hiroshi*; Toulemonde, M.*; Narumi, Kazumasa*; Li, R.*; Chiba, Atsuya*; Hirano, Yoshimi*; Yamada, Keisuke*; Yamamoto, Shunya*; Ishikawa, Norito; Okubo, Nariaki; et al.
Scientific Reports (Internet), 11(1), p.185_1 - 185_11, 2021/01
Times Cited Count：15 Percentile：70.11(Multidisciplinary Sciences)We report the track formation of 10 nm in diameter in silicon irradiated with 6 MeV C, i.e., much lower energy than the previously reported energy threshold.
Amekura, Hiroshi*; Li, R.*; Okubo, Nariaki; Ishikawa, Norito; Chen, F.*
Quantum Beam Science (Internet), 4(4), p.39_1 - 39_11, 2020/12
Evolution of depth profiles of the refractive index in YAl
O
(YAG) crystals were studied under 200 MeV Xe ion irradiation. The index changes were observed at three different depth regions; (i) a plateau near the surface between 0 and 3 
m in depth, which can be ascribed to the electronic stopping Se, (ii) a broad peak at 6 m in depth, and (iii) a sharp dip at 13 m in depth, which is attributed to the nuclear stopping Sn peak.
Ishikawa, Norito; Taguchi, Tomitsugu*; Ogawa, Hiroaki
Quantum Beam Science (Internet), 4(4), p.43_1 - 43_14, 2020/12
Amorphizable ceramics were irradiated with 200 MeV Au ions, and the as-irradiated samples were observed by transmission electron microscopy (TEM). The ion track diameter and hillock diameter are similar for all the amorphizable ceramics. For SrTiO and niobium-doped STO, 200 MeV Au ion irradiation and TEM observation were also performed. The ion track diameters in these materials are found to be markedly smaller than the hillock diameters. The ion tracks in these materials exhibit inhomogeneity, which is similar to that reported for non-amorphizable ceramics. On the other hand, the hillocks appear to be amorphous, and the amorphous feature is in contrast to the crystalline feature of hillocks observed in non-amorphizable ceramics. No marked difference is recognized between the nanostructures in STO and those in Nb-STO.
by using Poisson distribution functionYamamoto, Yuki*; Ishikawa, Norito; Hori, Fuminobu*; Iwase, Akihiro*
Quantum Beam Science (Internet), 4(3), p.26_1 - 26_13, 2020/09
The lattice constant and the magnetic state of CeO are modified by the irradiation with 200 MeV Xe ions. Under the assumption that these modifications are induced in the narrow one-dimensional region (the ion track) along the ion beam path, the dependence of the lattice constant and the saturation magnetization of CeO on the Xe ion fluence can be analyzed by using the Poisson distribution function. The analysis reveals that the lattice constant inside the ion track, which is larger than outside the ion track is not affected by the overlapping of the ion track. The present result implies that the Poisson distribution function is useful for describing the effect of ion track overlapping on the ion irradiation induced ferromagnetic state in CeO.
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：7 Percentile：30.42(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.
Okuno, Yasuki*; Ishikawa, Norito; Akiyoshi, Masafumi*; Ando, Hirokazu*; Harumoto, Masaki*; Imaizumi, Mitsuru*
Japanese Journal of Applied Physics, 59(7), p.074001_1 - 074001_7, 2020/07
Times Cited Count：3 Percentile：14.54(Physics, Applied)Performance degradation prediction for space solar cells under irradiation with low-energy electrons is greatly affected by displacement threshold energy (Ed) when a displacement damage dose (DDD) model is used. According to recent studies, the Ed of P atoms is much lower than the conventional Ed value in InP-type solar cells irradiated with low-energy electrons. This indicates that the value of Ed typically used in DDD model leads to significant error in performance degradation prediction. In this study, degradation of AlInGaP solar cells is observed after irradiation with 60 keV electrons. The results suggest that the Ed of P atoms in AlInGaP solar cells is much smaller than the conventionally used Ed value. By using the DDD model with the Ed value obtained in this study, we demonstrated that the performance degradation predicted by the DDD model agrees well with the experimental results.
and amorphizable YAlO (YAG) crystalsAmekura, Hiroshi*; Li, R.*; Okubo, Nariaki; Ishikawa, Norito; Chen, F.*
Nuclear Instruments and Methods in Physics Research B, 474, p.78 - 82, 2020/07
Times Cited Count：6 Percentile：50.34(Instruments & Instrumentation)Yttrium-aluminum-garnet (YAG) and calcium fluoride (CaF) were irradiated with 200 MeV Xe ions. YAG crystal was transformed to an amorphous phase, whereas CaF shows the non-amorphizable nature. In spite of amorphization, YAG maintained its transparency, whereas CaF markedly loses it transparency showing a broad absorption band centered at 550 nm.
and 200 MeV Xe ion irradiationLi, R.*; Narumi, Kazumasa*; Chiba, Atsuya*; Hirano, Yu*; Tsuya, Daiju*; Yamamoto, Shunya*; Saito, Yuichi*; Okubo, Nariaki; Ishikawa, Norito; Pang, C.*; et al.
Nanotechnology, 31(26), p.265606_1 - 265606_9, 2020/06
Times Cited Count：7 Percentile：35.00(Nanoscience & Nanotechnology)We report the elongation of embedded Au nanoparticles (NPs) in three different matrices under irradiations of 4 MeV C ions and 200 MeV Xe ions. Large elongation of Au NPs was observed for crystalline indium tin oxide (ITO) under both 4 MeV C and 200 MeV Xe irradiation. The ITO layer preserved the crystallinity even after large elongation was induced. This is the first report of the elongation of metal NPs in a crystalline matrix.
