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Journal Articles

Structure and magnetic properties of Fe nanoparticles in amorphous silica implanted with Fe ions and effect of subsequent energetic heavy ion irradiation

Iwase, Akihiro*; Fukuda, Kengo*; Saito, Yuichi*; Okamoto, Yoshihiro; Semboshi, Satoshi*; Amekura, Hiroshi*; Matsui, Toshiyuki*

Journal of Applied Physics, 132(16), p.163902_1 - 163902_10, 2022/10

 Times Cited Count:0 Percentile:0(Physics, Applied)

Amorphous SiO$$_{2}$$ samples were implanted with 380 keV Fe ions at room temperature. After implantation, some of the samples were irradiated with 16 MeV Au ions. magnetic properties were investigated using a SQUID magnetometer, and the morphology of the Fe-implanted SiO$$_{2}$$ samples was examined using transmission electron microscopy and X-ray absorption spectroscopy (EXAFS and XANES), which showed that the size of Fe nanoparticles was increasing The size of Fe nanoparticles increased with increasing Fe implantation amount; some of the Fe nanoparticles consisted of Fe oxides, and the valence and structure of Fe atoms became closer to that of metallic $$alpha$$-Fe with increasing Fe injection amount. The magnetization-field curve of the sample implanted with a small amount of Fe was reproduced by Langevin's equation, suggesting that the Fe nanoparticles behave in a superparamagnetic manner. In addition, when a large amount of Fe was implanted, the magnetization-magnetic field curve shows a ferromagnetic state. These magnetic property results are consistent with the X-ray absorption results. Subsequent 16 MeV Au irradiation crushed the Fe nanoparticles, resulting in a decrease in magnetization.

Journal Articles

Nitrogen K-edge X-ray absorption near edge structure of pyrimidine-containing nucleotides in aqueous solution

Shimada, Hiroyuki*; Minami, Hirotake*; Okuizumi, Naoto*; Sakuma, Ichiro*; Ukai, Masatoshi*; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro*; Saito, Yuji

Journal of Chemical Physics, 142(17), p.175102_1 - 175102_9, 2015/05


 Times Cited Count:10 Percentile:40.9(Chemistry, Physical)

JAEA Reports

Development of a "scroll pump operation status monitoring system(SCP-MS)" for use at a synchrotron radiation beamline

Yamaoka, Shingo; Shimizu, Yuka*; Fukuda, Yoshihiro*; Shobu, Takahisa; Konishi, Hiroyuki

JAEA-Technology 2014-027, 21 Pages, 2014/08


At SPring-8 synchrotron radiation beamlines, it is essential to maintain a vacuum between the radiation source and the experimental station. This is achieved by using scroll pumps and turbo molecular pumps. However, scroll pump malfunctions have been reported at BL22XU. Since many of the pumps are located inside radiation-shielding hutches, malfunctions often go un-noticed. As a result, operations can continue despite the malfunction. To facilitate the early detection of scroll pump malfunctions, we have developed a "scroll pump operating status monitoring system (SCP-MS)". The system simultaneously measures motor current and vacuum pressure at the scroll pump. It is possible to monitor pumps from outside of the shielding hutch, something which was not possible until now. The (SCP-MS) has been installed to monitor scroll pumps in actual operation, to monitor the change of the motor current value and vacuum pressure. We report on the detail of the system.

Journal Articles

Nitrogen K-edge X-ray absorption near edge structure (XANES) spectra of purine-containing nucleotides in aqueous solution

Shimada, Hiroyuki*; Fukao, Taishi*; Minami, Hirotake*; Ukai, Masatoshi*; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro*; Saito, Yuji

Journal of Chemical Physics, 141(5), p.055102_1 - 055102_8, 2014/08

 Times Cited Count:15 Percentile:53.72(Chemistry, Physical)

Journal Articles

Structural changes of nucleic acid base in aqueous solution as observed in X-ray absorption near edge structure (XANES)

Shimada, Hiroyuki*; Fukao, Taishi*; Minami, Hirotake*; Ukai, Masatoshi*; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro*; Saito, Yuji

Chemical Physics Letters, 591, p.137 - 141, 2014/01

 Times Cited Count:8 Percentile:31.36(Chemistry, Physical)

Journal Articles

Observation of cleavage in DNA and nucleotides following oxygen $$K$$-shell ionization by measuring X-ray absorption near edge structure

Fujii, Kentaro; Fukuda, Yoshihiro; Yokoya, Akinari

International Journal of Radiation Biology, 88(12), p.888 - 894, 2012/12

 Times Cited Count:3 Percentile:25.94(Biology)

Journal Articles

Unpaired electron species in thin films of calf-thymus DNA molecules induced by nitrogen and oxygen K-shell photoabsorption

Oka, Toshitaka; Yokoya, Akinari; Fujii, Kentaro; Fukuda, Yoshihiro; Ukai, Masatoshi*

Physical Review Letters, 109(21), p.213001_1 - 213001_5, 2012/11

 Times Cited Count:12 Percentile:60.59(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Nanomodification of gold surface by picosecond soft X-ray laser pulse

Norman, G.*; Starikov, S.*; Stegailov, V.*; Fortov, V.*; Skobelev, I.*; Pikuz, T.; Faenov, A.*; Tamotsu, Satoshi*; Kato, Yoshiaki*; Ishino, Masahiko; et al.

Journal of Applied Physics, 112(1), p.013104_1 - 013104_8, 2012/07

 Times Cited Count:41 Percentile:83.31(Physics, Applied)

Journal Articles

Performance upgrade in the JAEA actinide science beamline BL23SU at SPring-8 with a new twin-helical undulator

Saito, Yuji; Fukuda, Yoshihiro; Takeda, Yukiharu; Yamagami, Hiroshi; Takahashi, Sunao*; Asano, Yoshihiro*; Hara, Toru*; Shirasawa, Katsutoshi*; Takeuchi, Masao*; Tanaka, Takashi*; et al.

Journal of Synchrotron Radiation, 19(3), p.388 - 393, 2012/05

 Times Cited Count:93 Percentile:96.95(Instruments & Instrumentation)

The soft X-ray beamline BL23SU at SPring-8 has undergone an upgrade with a twin-helical undulator of in-vacuum type to enhance the experimental capabilities of the end stations. The new light source with a fast helicity-switching operation allows not only the data throughput but also the sensitivity in X-ray magnetic circular dichroism (XMCD) to be improved. The operational performance and potential are described by presenting XMCD results of paramagnetic $$beta$$-US$$_{2}$$ measured with a 10 T superconducting magnet.

Journal Articles

Quasi-monochromatic pencil beam of laser-driven protons generated using a conical cavity target holder

Nishiuchi, Mamiko; Pirozhkov, A. S.; Sakaki, Hironao; Ogura, Koichi; Esirkepov, T. Z.; Tanimoto, Tsuyoshi; Kanasaki, Masato; Yogo, Akifumi; Hori, Toshihiko; Sagisaka, Akito; et al.

Physics of Plasmas, 19(3), p.030706_1 - 030706_4, 2012/03

 Times Cited Count:6 Percentile:26.93(Physics, Fluids & Plasmas)

A 7 MeV proton beam collimated to 16 mrad containing more than $$10^6$$ particles is experimentally demonstrated by focusing a 2J, 60 fs pulse of a Ti:sapphire laser onto targets of different materials and thicknesses placed in a millimeter scale conical holder. The electric potential induced on the target holder by laser-driven electrons accelerates and dynamically controls a portion of a divergent quasi-thermal proton beam originated from the target, producing a quasi-monoenergetic "pencil" beam.

Journal Articles

Evaluation of ZnO fast scintillator spatial resolution using the FZP-focused X-ray laser

Tanaka, Momoko; Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Sakai, Kohei*; Sarukura, Nobuhiko*; Nishikino, Masaharu; Oba, Toshiyuki; Kaihori, Takeshi; Ochi, Yoshihiro; et al.

JAEA-Conf 2011-001, p.126 - 128, 2011/03

The spatial resolution of hydrothermal method grown zinc oxide (ZnO) scintillator was evaluated using X-ray laser focused with Fresnel zone plate. The fluorescence image of the ZnO scintillator was measured to be less than 10um using CCD camera coupled with a Schbartzchild expander mirror. The availability of large size ZnO crystal up to 3-inch is quite attractive for future lithography and imaging applications.

Journal Articles

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Journal Articles

EPR study of radiation damage to DNA irradiated with synchrotron soft X-rays around nitrogen and oxygen K-edge

Yokoya, Akinari; Fujii, Kentaro; Fukuda, Yoshihiro; Ukai, Masatoshi*

Radiation Physics and Chemistry, 78(12), p.1211 - 1215, 2009/12

 Times Cited Count:5 Percentile:36.83(Chemistry, Physical)

To obtain detailed insights into the physicochemical mechanism of DNA damage induction, "in situ" measurement of electron paramagnetic resonance (EPR) signal from DNA constituent nucleobases, guanine and adenine, has been performed in a vacuum using monochromatic synchrotron soft X-rays. We found that short-lived unpaired electron species arise only during irradiation to the evaporated thin film on a surface. The EPR spectrum of the short-lived species significantly depends on the photon energy irradiated, and the spin concentration obtained from the EPR spectra shows a similar fine structure to the X-ray photoabsorption spectra. For the adenine sample, the spin concentration alters strikingly by water absorption on the sample surface. Trapping of photo- or Auger electrons into a newly generated potential in the nucleobases as the consequence of photoelectric effect is suggested as mechanisms of the induction of the short-lived species.

JAEA Reports

A Laboratory X-ray measurement system of the crystallinity of single crystal for the synchrotron radiation optics

Kiriyama, Koji; Mitsui, Takaya; Fukuda, Yoshihiro

JAEA-Technology 2009-035, 24 Pages, 2009/07


Single crystal for experiment using by synchrotron radiation X-ray is needed to have high quality and performance as optics element. Therefore, quantitative estimation of performance of the single crystal must be done before the experiment. Precise X-ray optics system has been developed at JAEA/Quantum Beam Science Directorate/Synchrotron Radiation Unit at SPring-8. This system can measure small sample that is less than 0.01 mm in size, and have resolving ability of sample rotation that is less than 0.01 degree. And, scanning of sample, it is possible to measure distribution of quality at sample surface. For example, single crystal of FeBO$$_{3}$$ which was measured by this system have been installed in synchrotron radiation M$"o$ssbauer spectroscopy using Doppler-shifted 14.4 keV single line $$^{57}$$Fe-M$"o$ssbauer radiation.

JAEA Reports

Installation of nonstop absorption measurement system in JAEA soft X-ray beamline BL23SU at SPring-8

Fukuda, Yoshihiro; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Kobayashi, Keisuke*

JAEA-Technology 2007-007, 23 Pages, 2007/03


We have introduced a "Nonstop absorption measurement system" into the XMCD station of BL23SU at SPring-8. This system allows us to shorten the measuring time by about 1/10 in comparison to conventional one. We report on the detail of the system.

JAEA Reports

Installation of refocusing mirrors in JAEA soft X-ray beamline BL23SU at SPring-8

Fukuda, Yoshihiro; Saito, Yuji; Yokoya, Akinari; Teraoka, Yuden

JAEA-Technology 2007-002, 35 Pages, 2007/03


JAEA(Japan Atomic Energy Agency) have newly introduced refocusing toroidal mirrors to upgrade a surface chemistry and biophysical spectroscopy stations of BL23SU (JAEA Actinide Science) in SPring-8. We demonstrate significant improvements in the efficiency of experiments. We report on the detail of the systems.

Journal Articles

Gated multiple-sampling and tracking proportional chamber; New detector system for nuclear astrophysical study with radioactive nuclear beams

Hashimoto, Takashi; Ishiyama, Hironobu*; Ishikawa, Tomoko*; Kawamura, Takashi*; Nakai, Koji*; Watanabe, Yutaka*; Miyatake, Hiroari; Tanaka, Masahiko*; Fuchi, Yoshihide*; Yoshikawa, Nobuharu*; et al.

Nuclear Instruments and Methods in Physics Research A, 556(1), p.339 - 349, 2006/01

 Times Cited Count:32 Percentile:89.16(Instruments & Instrumentation)

A new type of three dimensional tracking and proportional gas counter has been developed. Adopting a gating-grid system, performance of the detector becomes stable under the injection rate of charged particles less than 4$$times$$10$$^4$$ pps. It is a useful detection system for astrophysical experiments using radioactive nuclear beams, since the efficiency is so high as 100 %.

Oral presentation

Recent progress in X-ray laser research in JAEA

Kawachi, Tetsuya; Kishimoto, Maki; Kado, Masataka; Tanaka, Momoko; Hasegawa, Noboru; Ochi, Yoshihiro; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kunieda, Yuichi; et al.

no journal, , 

Recent progress in X-ray laser research in Japan Atomic Energy Agency is reviewed. Using the nickel-like silver soft X-ray laser at the wavelength of 13.9 nm, the application experiments have been conducted in the research fields such as material science, high-density plasma diagnostics, XRL ablation, XRL imaging using single-shot holography and atomic physics. The repetition rate of the XRL beam has been improved from each 10-20 minutes to 0.1 Hz by using new driver laser system with Nd: glass zigzag slab amplifier, and we are now constructing new beam line for the pump-probe measurement of the surface phase-transition by the method of X-ray laser interferometer. In the research activity on the extension of the wavelength region of the X-ray lasers, firstly, the demonstration of novel coherent X-ray generation by "flying mirror" technique is reported. The second is theoretical investigation of the resonance photo-pumping scheme toward water-window region.

Oral presentation

Present status of soft X-ray magnetic circular dichroism at SPring-8 BL23SU

Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fukuda, Yoshihiro; Yamagami, Hiroshi

no journal, , 

no abstracts in English

Oral presentation

Single-shot focal spot image of EUV laser using a ZnO scintillator

Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Takatori, Satoru*; Estacio, E.*; Cadatal, M.*; Sarukura, Nobuhiko*; Nishimura, Hiroaki*; Mima, Kunioki*; Tanaka, Momoko; et al.

no journal, , 

We have observed the single shot, focused image of a EUV laser through the emission of a ZnO scintillator. An estimated EUV laser focal spot size of 50$$times$$88 micrometer is reasonable considering the long focal length of the spherical mirror. This work reports a feasible method to perform single-shot beam diagnostics for EUV laser sources using a ZnO crystal scintillator. Furthermore, since the ZnO fluorescence is at 380 nm wavelength, the imaging optics for the diagnostics can all be placed outside the vacuum chamber; thereby making experiments less cumbersome. Having a capability in fast and efficient beam profiling of EUV laser sources with acceptable resolving power is very important in future lithography applications.

39 (Records 1-20 displayed on this page)