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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

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

Matrix-material dependence on the elongation of embedded gold nanoparticles induced by 4 MeV C$$_{60}$$ and 200 MeV Xe ion irradiation

Li, 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:1 Percentile:24.67(Nanoscience & Nanotechnology)

We report the elongation of embedded Au nanoparticles (NPs) in three different matrices under irradiations of 4 MeV C$$_{60}$$ ions and 200 MeV Xe ions. Large elongation of Au NPs was observed for crystalline indium tin oxide (ITO) under both 4 MeV C$$_{60}$$ 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.

Journal Articles

Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment

Ino, Kohei*; Hernsdorf, A. W.*; Konno, Yuta*; Kozuka, Mariko*; Yanagawa, Katsunori*; Kato, Shingo*; Sunamura, Michinari*; Hirota, Akinari*; Togo, Yoko*; Ito, Kazumasa*; et al.

ISME Journal, 12(1), p.31 - 47, 2018/01

 Times Cited Count:30 Percentile:93.55(Ecology)

In this study, we found the dominance ofanaerobic methane-oxidizing archaea in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock.

Journal Articles

Age and speciation of iodine in groundwater and mudstones of the Horonobe area, Hokkaido, Japan; Implications for the origin and migration of iodine during basin evolution

Togo, Yoko*; Takahashi, Yoshio*; Amano, Yuki; Matsuzaki, Hiroyuki*; Suzuki, Yohei*; Terada, Yasuko*; Muramatsu, Yasuyuki*; Ito, Kazumasa*; Iwatsuki, Teruki

Geochimica et Cosmochimica Acta, 191, p.165 - 186, 2016/10

 Times Cited Count:13 Percentile:60.45(Geochemistry & Geophysics)

Iodine distribution, speciation, and isotope ratio ($$^{129}$$I/$$^{127}$$I) in both rock and groundwater phases were determined to investigate long-term migration of iodine in diatomaceous and siliceous shale. It was suggested that I$$^{-}$$ is released to the ground water during the progress of the maturation of organic matter. Dissociated I$$^{-}$$ could move toward the surface because of the upward water flow driven by the compaction during burial diagenetic process. Thus, iodine rich brine is created by integration of iodine released from underlying formations. Because of low affinity of I$$^{-}$$ to solid phase, released I$$^{-}$$ remains in solution phase, and the concentration of the iodine in the solution has been possibly increasing during sedimentation history.

Journal Articles

Deep microbial life in high-quality granitic groundwater from geochemically and geographically distinct underground boreholes

Ino, Kohei*; Konno, Yuta*; Kozuka, Mariko*; Hirota, Akinari*; Togo, Yoko*; Fukuda, Akari*; Komatsu, Daisuke*; Tsunogai, Urumu*; Tanabe, Akifumi*; Yamamoto, Satoshi*; et al.

Environmental Microbiology Reports (Internet), 8(2), p.285 - 294, 2016/04

 Times Cited Count:18 Percentile:67.66(Environmental Sciences)

To understand the subsurface biosphere, borehole investigation was conducted for 300-m deep granitic rocks at the Mizunami underground research laboratory, Japan. The initial biomass was the highest with the flourish of aerobic H$$_{2}$$-oxidizing Hydrogenophaga spp., whereas an uncultivated lineage of the phylum Nitrospirae became predominant after three years with decreasing biomass. The common occurrence of many species of Nitrospirae and Chlorobi phyla at the geographically distinct sites and the exclusive detection of their phylogenetically related environmental sequences from deep groundwaters and terrestrial hot springs, suggest that these bacteria are indigenous and potentially adapted to the deep terrestrial subsurface.

Journal Articles

Temperature of thermal spikes in amorphous silicon nitride films produced by 1.11 MeV C$$_{60}^{3+}$$ impacts

Kitayama, Takumi*; Nakajima, Kaoru*; Suzuki, Motofumi*; Narumi, Kazumasa; Saito, Yuichi; Matsuda, Makoto; Sataka, Masao*; Tsujimoto, Masahiko*; Isoda, Shoji*; Kimura, Kenji*

Nuclear Instruments and Methods in Physics Research B, 354, p.183 - 186, 2015/07

 Times Cited Count:2 Percentile:22.25(Instruments & Instrumentation)

Journal Articles

Biogeochemical signals from deep microbial life in terrestrial crust

Suzuki, Yohei*; Konno, Yuta*; Fukuda, Akari*; Komatsu, Daisuke*; Hirota, Akinari*; Watanabe, Katsuaki*; Togo, Yoko*; Morikawa, Noritoshi*; Hagiwara, Hiroki; Aosai, Daisuke*; et al.

PLOS ONE (Internet), 9(12), p.e113063_1 - e113063_20, 2014/12

 Times Cited Count:9 Percentile:36.08(Multidisciplinary Sciences)

We present multi-isotopic evidence of microbially mediated sulfate reduction in a granitic aquifer, a representative of the terrestrial crust habitat. Deep groundwater of meteoric origin was collected from underground boreholes drilled into the Cretaceous Toki granite, central Japan. A large sulfur isotopic fractionation of 20-60 permil diagnostic to microbial sulfate reduction is associated with the investigated groundwater containing sulfate below 0.2 mM. In contrast, a small carbon isotopic fractionation ($$<$$ 30 permil) is not indicative of methanogenesis. Our results demonstrate that the deep biosphere in the terrestrial crust is metabolically active and playing a crucial role in the formation of reducing groundwater even under low energy fluxes.

Journal Articles

Sputtering of SiN films by 540 keV C$$_{60}$$$$^{2+}$$ ions observed using high-resolution Rutherford backscattering spectroscopy

Nakajima, Kaoru*; Morita, Yosuke*; Kitayama, Takumi*; Suzuki, Motofumi*; Narumi, Kazumasa; Saito, Yuichi; Tsujimoto, Masahiko*; Isoda, Shoji*; Fujii, Yoshikazu*; Kimura, Kenji*

Nuclear Instruments and Methods in Physics Research B, 332, p.117 - 121, 2014/08

 Times Cited Count:7 Percentile:55.77(Instruments & Instrumentation)

Journal Articles

Transmission secondary ion mass spectrometry using 5 MeV C$$_{60}$$$$^{+}$$ ions

Nakajima, Kaoru*; Nagano, Kengo*; Suzuki, Motofumi*; Narumi, Kazumasa; Saito, Yuichi; Hirata, Koichi*; Kimura, Kenji*

Applied Physics Letters, 104(11), p.114103_1 - 114103_4, 2014/03

 Times Cited Count:5 Percentile:26.55(Physics, Applied)

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

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:0 Percentile:0.01(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.

Journal Articles

Time-of-flight secondary ion mass spectrometry with energetic cluster ion impact ionization for highly sensitive chemical structure characterization

Hirata, Koichi*; Saito, Yuichi; Chiba, Atsuya; Yamada, Keisuke; Narumi, Kazumasa

Nuclear Instruments and Methods in Physics Research B, 314, p.39 - 42, 2013/11

 Times Cited Count:3 Percentile:29.69(Instruments & Instrumentation)

Journal Articles

Surface effect on ion track formation in amorphous Si$$_{3}$$N$$_{4}$$ films

Morita, Yosuke*; Nakajima, Kaoru*; Suzuki, Motofumi*; Narumi, Kazumasa; Saito, Yuichi; Ishikawa, Norito; Hojo, Kiichi; Tsujimoto, Masahiko*; Isoda, Shoji*; Kimura, Kenji*

Nuclear Instruments and Methods in Physics Research B, 315, p.142 - 145, 2013/11

 Times Cited Count:8 Percentile:59.34(Instruments & Instrumentation)

Journal Articles

Transmission properties of C$$_{60}$$ ions through micro- and nano-capillaries

Tsuchida, Hidetsugu*; Majima, Takuya*; Tomita, Shigeo*; Sasa, Kimikazu*; Narumi, Kazumasa; Saito, Yuichi; Chiba, Atsuya; Yamada, Keisuke; Hirata, Koichi*; Shibata, Hiromi*; et al.

Nuclear Instruments and Methods in Physics Research B, 315, p.336 - 340, 2013/11

 Times Cited Count:3 Percentile:29.69(Instruments & Instrumentation)

Journal Articles

Quantitative evaluation of charge state for internuclear distance of constituent ions dissociated from C$$_2^+$$ ion moving in a solid

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

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 161, 2013/01

An average charge of the constituent ions resulting from the foil-induced dissociation of cluster ions is smaller than that of monatomic ions at the same speed. It is considered that such a charge reduction effect in cluster ion bombardments depend strongly on the internuclear distance between constituent ions moving in a solid. However, there are few reports in which average charges of the constituent ions had been quantitatively evaluated in terms of their internuclear distance increasing by the screened Coulomb repulsion. Therefore, we developed a method which evaluate quantitatively the average charge for internuclear distance of constituent ions in solid through the measurements of the divergence angle of the constituent ions after foil penetration. The achieved results are approximately equal to the theoretical value derived from model considering the cluster effect in average charge.

Journal Articles

Reduction of charging effects on negative secondary ion TOF mass spectra of PMMA using cluster ion impacts

Hirata, Koichi*; Saito, Yuichi; Chiba, Atsuya; Yamada, Keisuke; Narumi, Kazumasa; Kamiya, Tomihiro

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 165, 2013/01

Journal Articles

Ion induced luminescence from sapphire irradiated with swift cluster ion beams; Cluster ion size and energy dependences

Shibata, Hiromi*; Saito, Yuichi; Chiba, Atsuya; Yamada, Keisuke; Narumi, Kazumasa; Taguchi, Mitsumasa

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 162, 2013/01

Journal Articles

Electronic stopping power connected with average charge reduction for swift carbon cluster ions in carbon

Kaneko, Toshiaki*; Ihara, Kosuke*; Kono, Maasa*; Saito, Yuichi; Chiba, Atsuya; Narumi, Kazumasa

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 164, 2013/01

Journal Articles

Visualization of a single cluster particle track in polystyrene films

Asano, Atsushi*; Takano, Katsuyoshi*; Chiba, Atsuya; Saito, Yuichi; Marui, Hiromi*; Omichi, Masaaki*; Maeyoshi, Yuta*; Honsho, Yoshito*; Saeki, Akinori*; Yamada, Keisuke; et al.

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 163, 2013/01

Journal Articles

Cluster effect on damage accumulation in a Si crystal bombarded with 10-540-keV C$$_{60}$$ ions

Narumi, Kazumasa; Naramoto, Hiroshi*; Yamada, Keisuke; Chiba, Atsuya; Saito, Yuichi; Maeda, Yoshihito

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 166, 2013/01

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186 (Records 1-20 displayed on this page)