Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 212

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Latent ion tracks were finally observed in diamond

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

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$$_{60}$$ 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 $$pi$$-bonding signal from graphite was detected by the electron energy loss spectroscopy (EELS).

Journal Articles

High-sensitive XANES analysis at Ce L$$_{2}$$-edge for Ce in bauxites using transition-edge sensors; Implications for Ti-rich geological samples

Li, W.*; Yamada, Shinya*; Hashimoto, Tadashi; Okumura, Takuma*; Hayakawa, Ryota*; Nitta, Kiyofumi*; Sekizawa, Oki*; Suga, Hiroki*; Uruga, Tomoya*; Ichinohe, Yuto*; et al.

Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02

 Times Cited Count:1 Percentile:34.31(Chemistry, Analytical)

no abstracts in English

Journal Articles

A Storm-induced flood and associated nearshore dispersal of the river-derived suspended $$^{137}$$Cs

Uchiyama, Yusuke*; Tokunaga, Natsuki*; Azuma, Kohei*; Kamidaira, Yuki; Tsumune, Daisuke*; Iwasaki, Toshiki*; Yamada, Masatoshi*; Tateda, Yutaka*; Ishimaru, Takashi*; Ito, Yukari*; et al.

Science of the Total Environment, 816, p.151573_1 - 151573_13, 2022/04

 Times Cited Count:5 Percentile:71.31(Environmental Sciences)

no abstracts in English

Journal Articles

Structural changes in pH-responsive gelatin/hydroxypropyl methylcellulose phthalate blends aimed at drug-release systems

Nogami, Satoshi*; Kadota, Kazunori*; Uchiyama, Hiromasa*; Arima-Osonoi, Hiroshi*; Iwase, Hiroki*; Tominaga, Taiki*; Yamada, Takeshi*; Takata, Shinichi; Shibayama, Mitsuhiro*; Tozuka, Yuichi*

International Journal of Biological Macromolecules, 190, p.989 - 998, 2021/11

JAEA Reports

Development of the desalting method for gross alpha activity determination (Contract research)

Koike, Yuko; Yamada, Ryohei; Nagaoka, Mika; Nakano, Masanao; Ono, Yosuke; Suitsu, Yuichi

JAEA-Technology 2021-011, 39 Pages, 2021/08

JAEA-Technology-2021-011.pdf:1.56MB

In the Analyzed Liquid Treatment Facility of Japan Nuclear Fuel Co., Ltd. (JNFL) MOX Fuel Fabrication Plant (J-MOX), the interfere by salts with the analysis of gross alpha activity concentration analysis will be caused during the treatment process. Therefore, JNFL devised the desalting method using a solid-phase extraction chromatography. Japan Atomic Energy Agency carried out the experimental study to confirm the validity of this desalting method for the treatment liquid based on the contract with JNFL. This study consists of three experiments as follows: Step 1 - Selection of an optical solid-phase extraction agent, Step 2 - Evaluation of variation optical solid-phase extraction agent, and Step 3 - Application of the imitation liquid waste. The result of Step 1 determined the solid-phase extraction agent (InertSep ME-2) and the optimum condition (aspiration method by manifold (about 5-10 mL/min), 3M nitric acid as eluent, pH: 5, and no adjustment of ionic valence). Then, the result of Step 2 and 3 made sure the validation of this method by obtaining over 70% recovery for the imitation liquid waste sample of the Analyzed Liquid Treatment Facility of J-MOX.

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

 Times Cited Count:30 Percentile:96.87(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

Ion tracks in silicon formed by much lower energy deposition than the track formation threshold

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:10 Percentile:75.98(Multidisciplinary Sciences)

We report the track formation of 10 nm in diameter in silicon irradiated with 6 MeV C$$_{60}$$, i.e., much lower energy than the previously reported energy threshold.

Journal Articles

Self-organization of zonal flows and isotropic eddies in toroidal electron temperature gradient driven turbulence

Kawai, Chika*; Idomura, Yasuhiro; Ogawa, Yuichi*; Yamada, Hiroshi*

Physics of Plasmas, 27(8), p.082302_1 - 082302_11, 2020/08

 Times Cited Count:1 Percentile:6.61(Physics, Fluids & Plasmas)

Self-organization in the toroidal electron temperature gradient driven (ETG) turbulence is investigated based on a global gyrokinetic model in a weak magnetic shear configuration. Because of global profile effects, toroidal ETG modes with higher toroidal mode number n are excited at the outer magnetic surfaces, leading to strong linear wave dispersion. The resulting anisotropic wave turbulence boundary and the inverse energy cascade generate the self-organization of zonal flows, which is the unique mechanism in the global gyrokinetic model. The self-organization is confirmed both in the decaying turbulence initialized by random noises and in the toroidal ETG turbulence. It is also shown that the self-organization process generates zonal flows and isotropic eddies depending on a criterion parameter, which is determined by the ion to electron temperature ratio and the turbulence intensity.

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

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:233 Percentile:99.74(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.

Journal Articles

Application of a communication-avoiding generalized minimal residual method to a gyrokinetic five dimensional Eulerian code on many core platforms

Idomura, Yasuhiro; Ina, Takuya*; Mayumi, Akie; Yamada, Susumu; Matsumoto, Kazuya*; Asahi, Yuichi*; Imamura, Toshiyuki*

Proceedings of 8th Workshop on Latest Advances in Scalable Algorithms for Large-Scale Systems (ScalA 2017), p.7_1 - 7_8, 2017/11

A communication-avoiding generalized minimal residual (CA-GMRES) method is applied to the gyrokinetic toroidal five dimensional Eulerian code GT5D, and its performance is compared against the original code with a generalized conjugate residual (GCR) method on the JAEA ICEX (Haswell), the Plasma Simulator (FX100), and the Oakforest-PACS (KNL). The CA-GMRES method has $$sim 3.8times$$ higher arithmetic intensity than the GCR method, and thus, is suitable for future Exa-scale architectures with limited memory and network bandwidths. In the performance evaluation, it is shown that compared with the GCR solver, its computing kernels are accelerated by $$1.47times sim 2.39times$$, and the cost of data reduction communication is reduced from $$5%sim 13%$$ to $$sim1%$$ of the total cost at 1,280 nodes.

Journal Articles

Measurements and analyses of the distribution of the radioactivity induced by the secondary neutrons produced by 17-MeV protons in compact cyclotron facility

Matsuda, Norihiro; Izumi, Yuichi*; Yamanaka, Yoshiyuki*; Gando, Toshiyuki*; Yamada, Masaaki*; Oishi, Koji*

EPJ Web of Conferences, 153, p.07001_1 - 07001_6, 2017/09

 Times Cited Count:0 Percentile:0.03

Journal Articles

Uniaxial strain dependence of the critical current of DI-BSCCO tapes

Osamura, Kozo*; Machiya, Shutaro*; Hampshire, D. P.*; Tsuchiya, Yoshinori*; Shobu, Takahisa; Kajiwara, Kentaro*; Osabe, Goro*; Yamazaki, Kohei*; Yamada, Yuichi*; Fujikami, Jun*

Superconductor Science and Technology, 27(8), p.085005_1 - 085005_11, 2014/08

 Times Cited Count:27 Percentile:74.87(Physics, Applied)

Journal Articles

Magnetic and electronic properties of (LaMnO$$_3$$)$$_5$$(SrMnO$$_3$$)$$_5$$ superlattice revealed by resonant soft X-ray scattering

Kubota, Masato; Yamada, Hiroyuki*; Nakao, Hironori*; Okamoto, Jun*; Yamasaki, Yuichi*; Sawa, Akihito*; Murakami, Yoichi*

Japanese Journal of Applied Physics, 53(5S1), p.05FH07_1 - 05FH07_5, 2014/05

 Times Cited Count:2 Percentile:8.89(Physics, Applied)

Journal Articles

Antiferromagnetic order of the Co$$^{2+}$$ high-spin state with a large orbital angular momentum in La$$_{1.5}$$Ca$$_{0.5}$$CoO$$_{4}$$

Okamoto, Jun*; Nakao, Hironori*; Yamasaki, Yuichi*; Wadachi, Hiroki*; Tanaka, Arata*; Kubota, Masato; Horigane, Kazumasa*; Murakami, Yoichi*; Yamada, Kazuyoshi*

Journal of the Physical Society of Japan, 83(4), p.044705_1 - 044705_6, 2014/04

 Times Cited Count:8 Percentile:55.49(Physics, Multidisciplinary)

Journal Articles

Coulomb explosion process in collision of a swift cluster ion with gas target

Chiba, Atsuya; Narumi, Kazumasa; Yamada, Keisuke; Matoba, Shiro; Saito, Yuichi

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 167, 2014/03

Coulomb explosion caused in an early phase affects the subsequent process significantly in the interaction of a swift cluster ion with a material, so it is considered that the Coulomb explosion is one of the most important phenomena on understanding the mechanisms of the irradiation effects on the cluster ion bombardment. In experiments, charge states and spatial distributions of C$$_{2}$$$$^{+}$$ constituent ions dissociated by the collision with an atom in a gas target were measured on the event-by-event basis. After the trajectory analysis of the constituent ions using a simulation model, it turned out that the interatomic distance of the constituent ions grows approximately 1.5 times as long as the ground state, before they dissociate.

Journal Articles

Status report on technical developments of electrostatic accelerators

Yamada, Keisuke; Saito, Yuichi; Ishii, Yasuyuki; Matoba, Shiro; Chiba, Atsuya; Yokoyama, Akihito; Usui, Aya; Sato, Takahiro; Okubo, Takeru; Uno, Sadanori

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 159, 2014/03

no abstracts in English

Journal Articles

Operation of electrostatic accelerators

Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Usui, Aya; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Nara, Takayuki; et al.

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 179, 2014/03

Three electrostatic accelerators at TIARA were operated on schedule in fiscal year 2012 except changing its schedule by cancellations of users. The yearly operation time of the 3 MV tandem accelerator, the 400 kV ion implanter and the 3MV single-ended accelerator were in the same levels as the ordinary one, whose operation time totaled to 2,073, 1,847 and 2,389 hours, respectively. The tandem accelerator had no trouble, whereas the ion implanter and the single-ended accelerator stopped by any troubles for one day and four days, respectively. The molecular ion beam of helium hydride was generated by the ion implanter, because the users required irradiation of several cluster ions in order to study the effect of irradiation. As a result, its intensity of beam was 50 nA at 200 kV. The ion beam of tungsten (W) at 15 MeV was accelerated by the tandem accelerator, whose intensity was 20 nA at charge state of 4+, because of the request from a researcher in the field of nuclear fusion.

Journal Articles

Development of microwave ion source for industrial applications

Takahashi, Nobuaki*; Murata, Hirohiko*; Mitsubori, Hitoshi*; Sakuraba, Junji*; Soga, Tomohiro*; Aoki, Yasushi*; Kato, Takanori*; Saito, Yuichi; Yamada, Keisuke; Ikenaga, Noriaki*; et al.

Review of Scientific Instruments, 85(2), p.02C306_1 - 02C306_3, 2014/02

 Times Cited Count:2 Percentile:11.31(Instruments & Instrumentation)

Journal Articles

Production of fullerene ions by combining of plasma sputtering with laser ablation

Yamada, Keisuke; Saito, Yuichi; Yokota, Wataru

Review of Scientific Instruments, 85(2), p.02A920_1 - 02A920_3, 2014/02

 Times Cited Count:1 Percentile:5.83(Instruments & Instrumentation)

Journal Articles

Quantitative evaluation of charge-reduction effect in cluster constituent ions passing through a foil

Chiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Yamada, Keisuke; Kaneko, Toshiaki*

Nuclear Instruments and Methods in Physics Research B, 315, p.81 - 84, 2013/11

 Times Cited Count:1 Percentile:11.56(Instruments & Instrumentation)

The average charge of the constituent ions resulting from foil-induced dissociation of cluster ion is smaller than that of the single ion passing through the foil at same speed. This charge reduction effect is one of the most important phenomena for understanding the interaction of cluster ions with electrons in a solid, and the theories suggested that it strongly depends on the internuclear distance of the constituent ions. However, the relationship between the internuclear distance and the charge state has still not been shown quantitatively. We developed a method to evaluate the relationship by analyzing the divergence angle of the constituent ions after foil penetration using Coulomb explosion imaging technique. As a result for 6-MeV C$$_{2}$$$$^{+}$$, it was shown quantitatively that the charge reduction effect decreases with increasing the internuclear distance of the constituent ion in the solid.

212 (Records 1-20 displayed on this page)