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Journal Articles

Equilibrium and non-equilibrium charge-state distributions of 2.0 MeV/u carbon ions passing through carbon foils

Imai, Makoto*; Sataka, Masao*; Matsuda, Makoto; Okayasu, Satoru; Kawatsura, Kiyoshi*; Takahiro, Katsumi*; Komaki, Kenichiro*; Shibata, Hiromi*; Nishio, Katsuhisa

Nuclear Instruments and Methods in Physics Research B, 354, p.172 - 176, 2015/07

 Times Cited Count:12 Percentile:73.32(Instruments & Instrumentation)

Both equilibrium and non-equilibrium charge-state distributions were studied experimentally for 2.0 MeV/u carbon ions after passing through carbon foils. Measured charge-state distribution established the equilibrium at a target thickness of 10 $$mu$$g/cm$$^{2}$$ and this remained unchanged until a maximum target thickness of 98 $$mu$$g/cm$$^{2}$$. The equilibrium charge-state distribution, the equilibrium mean charge-state, and the width and skewness of the equilibrium distribution were compared with predictions using existing semi-empirical formulae as well as simulation results, including the ETACHA code. It was found that charge-state distributions, mean charge states, and distribution widths for C$$^{2+}$$, C$$^{3+}$$, and C$$^{4+}$$ incident ions merged into quasi-equilibrium values at a target thickness of 5.7 $$mu$$g/cm$$^{2}$$ in the pre-equilibrium region and evolved simultaneously to the "real equilibrium" values for all of the initial charge states, including C$$^{5+}$$ and C$$^{6+}$$ ions. Two kinds of simulation, ETACHA and solution of rate equations taking only single electron transfers into account, were used, and both of them reproduced the measured charge evolution qualitatively. The quasi-equilibrium behavior could be reproduced with the ETACHA code, but not with solution of elementary rate equations.

Journal Articles

Application of X-ray photoelectron spectroscopy to characterization of Au nanoparticles formed by ion implantation into SiO$$_{2}$$

Takahiro, Katsumi*; Oizumi, Shinnosuke*; Morimoto, Keiichi*; Kawatsura, Kiyoshi*; Isshiki, Toshiyuki*; Nishio, Koji*; Nagata, Shinji*; Yamamoto, Shunya; Narumi, Kazumasa; Naramoto, Hiroshi*

Applied Surface Science, 256(4), p.1061 - 1064, 2009/11

 Times Cited Count:8 Percentile:35.36(Chemistry, Physical)

Journal Articles

Ion-induced self-organized ripple patterns on graphite and diamond surfaces

Takahiro, Katsumi*; Ozaki, Koichi*; Kawatsura, Kiyoshi*; Nagata, Shinji*; Yamamoto, Shunya; Narumi, Kazumasa; Naramoto, Hiroshi*

Applied Surface Science, 256(4), p.972 - 975, 2009/11

 Times Cited Count:10 Percentile:44.86(Chemistry, Physical)

Journal Articles

Ion irradiation effects on amorphization and thermal crystallization in Zr-Al-Ni-Cu alloys

Nagata, Shinji*; Higashi, Seijiro*; Tsuchiya, Bun*; To, Kentaro*; Shikama, Tatsuo*; Takahiro, Katsumi*; Ozaki, Koichi*; Kawatsura, Kiyoshi*; Yamamoto, Shunya; Inoue, Aichi

Nuclear Instruments and Methods in Physics Research B, 257(1-2), p.420 - 423, 2007/04

 Times Cited Count:16 Percentile:74.96(Instruments & Instrumentation)

Structural modification and primary precipitates in the Zr$$_{55}$$Al$$_{10}$$Ni$$_{5}$$Cu$$_{30}$$ alloy films (50-100 $$mu$$m thickness) caused by radiation with 300-500 keV H, Ag, Cu and Au ions has been studied. The results of XRD indicated that a metastable primary phase was formed in the alloy by the heat treatment after ion irradiation, but no difference was observed just after the ion irradiation at room temperature. Furthermore, higher incident Au ion fluence effectively suppressed thermal precipitation of the Zr$$_{2}$$Ni type crystalline phase in the alloy. The deposited energy dependence of the precipitation behavior indicated an increase of the nucleation sites by the implanted metal atoms, simultaneously with a decrease of the growth rate by higher energy deposition density.

Journal Articles

Charge state evolution of 2MeV/u sulfur ion passing through thin carbon foil

Imai, Makoto*; Sataka, Masao; Kawatsura, Kiyoshi*; Takahiro, Katsumi*; Komaki, Kenichiro*; Shibata, Hiromi*; Sugai, Hiroyuki; Nishio, Katsuhisa

Nuclear Instruments and Methods in Physics Research B, 256(1), p.11 - 15, 2007/03

 Times Cited Count:5 Percentile:42.39(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Core level and valence band photoemission spectra of Au clusters embedded in carbon

Takahiro, Katsumi*; Oizumi, Shinnosuke*; Terai, Atsushi*; Kawatsura, Kiyoshi*; Tsuchiya, Bun*; Nagata, Shinji*; Yamamoto, Shunya; Naramoto, Hiroshi; Narumi, Kazumasa; Sasase, Masato*

Journal of Applied Physics, 100(8), p.084325_1 - 084325_6, 2006/10

 Times Cited Count:25 Percentile:65.62(Physics, Applied)

X-ray photoelectron spectroscopy (XPS) has been applied for size estimation of Au clusters formed by ion implantation into glassy carbon. The 4f and 5d XPS spectra reveal the presence of the cluster 0.7-2.5nm in diameter, depending on the Au concentration. The elationship between XPS 4f-binding energy shift and 5d splitting is determined for the Au clusters embedded in the carbon and found to be significantly different from the previous data for the ones supported on a carbon substrate. We suppose that this difference results from the effect of the environment around a cluster on Coulomb charging during photoemission at the final state.

Journal Articles

Rutherford backscattering spectrometry of electrically charged targets; Elegant technique for measuring charge-state distribution of backscattered ions

Takahiro, Katsumi*; Terai, Atsushi*; Kawatsura, Kiyoshi*; Naramoto, Hiroshi; Yamamoto, Shunya; Tsuchiya, Bun*; Nagata, Shinji*; Nishiyama, Fumitaka*

Japanese Journal of Applied Physics, Part 1, 45(3A), p.1823 - 1825, 2006/03

 Times Cited Count:2 Percentile:9.26(Physics, Applied)

It is found that the surface charging during Rutherford backscattering spectrometry (RBS) of insulating sapphire samples enables us to measure the charge-state distribution of probing ions backscattered at the sapphire surface. For Cu/Au-deposited Al$$_{2}$$O$$_{3}$$ samples, two components, higher and lower-energy ones, were resolved on both Cu and Au peaks in the RBS random spectrum. For single-crystalline Al$$_{2}$$O$$_{3}$$ samples, a double-peak structure was clearly observed on both Al and O surface peaks in the RBS aligned spectrum. The charge-state distribution can be obtained from the intensity of each component. The results obtained here are compared with previous data for the equilibrium charge-state distribution.

Journal Articles

Amorphization of carbon materials studied by X-ray photoelectron spectroscopy

Takahiro, Katsumi*; Terai, Atsushi*; Oizumi, Shinnosuke*; Kawatsura, Kiyoshi*; Yamamoto, Shunya; Naramoto, Hiroshi

Nuclear Instruments and Methods in Physics Research B, 242(1-2), p.445 - 447, 2006/01

 Times Cited Count:9 Percentile:56.05(Instruments & Instrumentation)

X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy have been applied to investigate amorphization processes by ion irradiation for various carbon materials, including highly oriented pyrolytic graphite (HOPG), isotropic graphite, glassy carbon (GC) and C$$_{60}$$ crystalline film. It is found that the asymmetry of the XPS C 1s line increases as the irradiation dose increases. The origin of the asymmetry appeared on the C 1s line is discussed. It is concluded that the asymmetry of the C 1s line is not correlated with the increase in the size of a graphitic layer, but is related with the structural disorders, such as a bond angle disorder.

Journal Articles

Charge state distribution and its equilibration of 2 MeV/u sulfur ions passing through carbon foils

Imai, Makoto*; Sataka, Masao; Kawatsura, Kiyoshi*; Takahiro, Katsumi*; Komaki, Kenichiro*; Shibata, Hiromi*; Sugai, Hiroyuki; Nishio, Katsuhisa

Nuclear Instruments and Methods in Physics Research B, 230(1-4), p.63 - 67, 2005/04

 Times Cited Count:7 Percentile:50.55(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Ejected electron spectra from highly excited states in high-energy collisions of O$$^{q+}$$ with He

Kawatsura, Kiyoshi*; Takahiro, Katsumi*; Imai, Makoto*; Sataka, Masao; Komaki, Kenichiro*; Shibata, Hiromi*

Nuclear Instruments and Methods in Physics Research B, 205, p.528 - 532, 2003/05

 Times Cited Count:4 Percentile:34.53(Instruments & Instrumentation)

Auger and Coster-Kronig electron spectra from highly excited states produced by low-energy highly charged ions with gas targets have been investigated both theoretically and experimentally. In this case, the highly excited states were formed by electron capture processes. We have studied collision processes of high-energy highly charged ions with a gas target using zero-degree electron spectroscopy at the tandem accelerator of JAERI, Tokai. In the present, we have measured Auger and C-K electron spectra from highly excited states produced by 1-3 MeV/u O$${q+}$$ (q=3-5) + He collisions, where the highly excited states in Oq+ ions were formed by electron excitation. We have compared and discussed the Auger and C-K electron spectra obtained by electron-capture and electron-excitation processes. It is found that the C-K spectra for high-energy Oq+ ions show relatively low-l states and the Auger spectra also have different structures from those for low-energy highly charged Oq+ ions.

Journal Articles

The 1s-2p resonance photoionization measurement of O$$^{+}$$ ions in comparison with an isoelectronic species Ne$$^{3+}$$

Kawatsura, Kiyoshi*; Yamaoka, Hitoshi*; Oura, Masaki*; Hayaishi, T.*; Sekioka, T.*; Agui, Akane; Yoshigoe, Akitaka; Koike, Fumihiro*

Journal of Physics B; Atomic, Molecular and Optical Physics, 35(20), p.4147 - 4153, 2002/10

 Times Cited Count:21 Percentile:66.85(Optics)

no abstracts in English

Journal Articles

Angular momentum distributions of Rydberg state electrons of Be-like sulfur produced through foil penetration

Imai, Makoto*; Sataka, Masao; Kitazawa, Shinichi; Komaki, Kenichiro*; Kawatsura, Kiyoshi*; Shibata, Hiromi*; Tawara, Hiroyuki*; Azuma, Toshiyuki*; Kanai, Yasuyuki*; Yamazaki, Y.*

Nuclear Instruments and Methods in Physics Research B, 193(1-4), p.674 - 679, 2002/06

 Times Cited Count:5 Percentile:35.97(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Comprehensive theoretical and experimental analysis of Coster-Kronig electron spectra from 64-MeV S$$^{12+}$$ ions excited through He gas and C-foil targets

Sataka, Masao; Imai, Makoto*; Kawatsura, Kiyoshi*; Komaki, Kenichiro*; Tawara, Hiroyuki*; Vasilyev, A.*; Safronova, U. I.*

Physical Review A, 65(5), p.052704_1 - 052704_11, 2002/05

 Times Cited Count:13 Percentile:53.47(Optics)

no abstracts in English

Journal Articles

Coster-Kronig electrons from the autoionizing Rydberg states of 2 MeV u$$^{-1}$$ Si$$^{5+}$$ ions excited through a thin C-foil target

Sataka, Masao; Imai, Makoto*; Kawatsura, Kiyoshi*; Komaki, Kenichiro*; Tawara, Hiroyuki*; Vasilyev, A.*; Safronova, U. I.*

Journal of Physics B; Atomic, Molecular and Optical Physics, 35(2), p.267 - 281, 2002/01

 Times Cited Count:3 Percentile:20.26(Optics)

no abstracts in English

Journal Articles

Improvement in surface roughness of nitrogen-implanted glassy carbon by hydrogen doping

Takahiro, Katsumi*; Takeshima, Naoki*; Kawatsura, Kiyoshi*; Nagata, Shinji*; Yamamoto, Shunya; Narumi, Kazumasa; Naramoto, Hiroshi

JAERI-Review 2001-039, TIARA Annual Report 2000, p.188 - 189, 2001/11

no abstracts in English

Journal Articles

Photoionization of Ne$$^{3+}$$ ions in the region of the 1${it s}$ $$rightarrow$$ 2${it p}$ autoionizing resonance

Oura, Masaki*; Yamaoka, Hitoshi*; Kawatsura, Kiyoshi*; Kimata, Junichi*; Hayaishi, T.*; Takahashi, Takehisa*; Koizumi, Tetsuo*; Sekioka, T.*; Terasawa, Michitaka*; Ito, Yo*; et al.

Physical Review A, 63(1), p.014704_1 - 014704_4, 2001/01

 Times Cited Count:15 Percentile:61.17(Optics)

no abstracts in English

Journal Articles

Chemical effect on X-ray spectra induced by multiple inner-shell ionization, 2

Kawatsura, Kiyoshi*; Takeshima, Naoki*; Terazawa, Norihisa*; Aoki, Yasushi; Yamamoto, Shunya; Nashiyama, Isamu; Narumi, Kazumasa; Naramoto, Hiroshi

JAERI-Review 99-025, TIARA Annual Report 1998, p.188 - 190, 1999/10

no abstracts in English

Journal Articles

Chemical effect on X-ray spectra induced by multiple inner-shell ionization, 2

Kawatsura, Kiyoshi*; Takeshima, Naoki*; Terazawa, Norihisa*; Aoki, Yasushi*; Yamamoto, Shunya; Nashiyama, Isamu; Narumi, Kazumasa; Naramoto, Hiroshi

JAERI-Review 99-025, TIARA Annual Report 1998, p.188 - 190, 1999/10

no abstracts in English

Journal Articles

Ejected electron spectra from highly charged oxygen ions in collisions with foils and gas atoms

Kitazawa, Shinichi; Sataka, Masao; Tawara, Hiroyuki*; Imai, Makoto*; Shibata, Hiromi*; Komaki, Kenichiro*; Azuma, Toshiyuki*; Kawatsura, Kiyoshi*; Kanai, Yasuyuki*

Atomic Collision Research in Japan, No.25, p.65 - 67, 1999/00

no abstracts in English

Journal Articles

L X-ray spectra of Fe and Cu by 0.75 MeV/u H, He, Si and Ar ion impacts

Kageyama, H.*; Kawatsura, Kiyoshi*; Takahashi, R.*; Arai, Shigeyoshi*; Kambara, Tadashi*; Oura, Masaki*; Papp, T.*; Kanai, Yasuyuki*; Awaya, Yoko*; Takeshita, Hidefumi; et al.

Nuclear Instruments and Methods in Physics Research B, 107(1-4), p.47 - 50, 1996/00

 Times Cited Count:2 Percentile:32.32(Instruments & Instrumentation)

no abstracts in English

71 (Records 1-20 displayed on this page)