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Namba, Shinichi*; Hasegawa, Noboru; Kishimoto, Maki; Nishikino, Masaharu; Ishino, Masahiko; Kawachi, Tetsuya
AIP Advances (Internet), 5(11), p.117101_1 - 117101_10, 2015/11
Times Cited Count：3 Percentile：13.89(Nanoscience & Nanotechnology)To characterize the temporal evolution of ultrashort X-ray pulses emitted by laser plasmas using a pump-probe method, a magnetic bottle time-of-flight electron spectrometer is constructed. The design is determined by numerical calculations of a mirror magnetic field and of the electron trajectory in a flight tube. The performance of the spectrometer is characterized by measuring the electron spectra of xenon atoms irradiated with a laser-driven plasma X-ray pulse. In addition, as a preliminary experiment, two-color above-threshold ionization (ATI) is conducted, in which xenon atoms are simultaneously irradiated with an X-ray laser pump and an IR laser probe. The correlation in the intensity of the Auger sideband spectra and in the time delay of the two laser pulses yields an X-ray pulse width of 5.7 ps, in good agreement with the value obtained using an X-ray streak camera.
Hikino, Shinichi*; Mori, Michiyasu; Maekawa, Sadamichi
Journal of the Physical Society of Japan, 83(7), p.074704_1 - 074704_5, 2014/07
Times Cited Count：3 Percentile：28.33(Physics, Multidisciplinary)Mori, Michiyasu; Koshibae, Wataru*; Hikino, Shinichi*; Maekawa, Sadamichi
Journal of Physics; Condensed Matter, 26(25), p.255702_1 - 255702_5, 2014/06
Times Cited Count：3 Percentile：14.73(Physics, Condensed Matter)Hikino, Shinichi*; Mori, Michiyasu; Koshibae, Wataru*; Maekawa, Sadamichi
Applied Physics Letters, 100(15), p.152402_1 - 152402_3, 2012/04
Times Cited Count：5 Percentile：22.57(Physics, Applied)Hikino, Shinichi*; Mori, Michiyasu; Takahashi, Saburo; Maekawa, Sadamichi
Journal of the Physical Society of Japan, 80(7), p.074707_1 - 074707_8, 2011/07
Times Cited Count：7 Percentile：47.32(Physics, Multidisciplinary)Hikino, Shinichi*; Mori, Michiyasu; Takahashi, Saburo*; Maekawa, Sadamichi
Superconductor Science and Technology, 24(2), p.024008_1 - 024008_5, 2011/02
Times Cited Count：13 Percentile：44.66(Physics, Applied)Yogo, Akifumi; Sato, Katsutoshi; Nishikino, Masaharu; Mori, Michiaki; Teshima, Teruki*; Numasaki, Hodaka*; Murakami, Masao*; Demizu, Yusuke*; Akagi, Takashi*; Nagayama, Shinichi*; et al.
Applied Physics Letters, 94(18), p.181502_1 - 181502_3, 2009/05
Times Cited Count：110 Percentile：94.75(Physics, Applied)Namba, Shinichi*; Hasegawa, Noboru; Nishikino, Masaharu; Kawachi, Tetsuya; Kishimoto, Maki; Sukegawa, Kota; Tanaka, Momoko; Ochi, Yoshihiro; Takiyama, Ken*; Nagashima, Keisuke
Physical Review Letters, 99(4), p.043004_1 - 043004_4, 2007/07
Times Cited Count：32 Percentile：77.94(Physics, Multidisciplinary)The interaction of large Xe clusters with a soft X-ray laser pulse having a wavelength of 13.9 nm and an intensity of up to 2
10
W/cm
was investigated using a time-of-flight ion mass spectrometer. It was found that Xe
ions (which result from double Auger decay of 4d vacancies) became the dominant final ionic product with increasing cluster size and X-ray intensity. This is in contrast to the results of synchrotron radiation experiments involving free Xe atoms, in which Xe
is the dominant resultant ion species. Possible mechanisms responsible for the enhancement of the double Auger transition probability in X-ray laser and cluster interaction are discussed.
Namba, Shinichi*; Hasegawa, Noboru; Nishikino, Masaharu; Kawachi, Tetsuya; Kishimoto, Maki; Tanaka, Momoko; Nagashima, Keisuke
no journal, ,
no abstracts in English
Namba, Shinichi*; Hasegawa, Noboru; Nishikino, Masaharu; Kawachi, Tetsuya; Kishimoto, Maki; Tanaka, Momoko; Ochi, Yoshihiro; Nagashima, Keisuke; Takiyama, Ken*
no journal, ,
Kawachi, Tetsuya; Kishimoto, Maki; Kado, Masataka; Tanaka, Momoko; Hasegawa, Noboru; Ochi, Yoshihiro; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kunieda, Yuichi; et al.
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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.
Okano, Yasuaki*; Nishikino, Masaharu; Nakahara, Shogo*; Tokita, Shigeki*; Masuno, Shinichiro*; Hashida, Masaki*; Sakabe, Shuji*; Nakano, Hidetoshi*; Kawachi, Tetsuya; Nishimura, Hiroaki*; et al.
no journal, ,
The generation of monoenergetic hard X-rays more than 10 keV has attracted much attention for X-ray imaging in the field of high density physics and biomedical applications. Our group is currently developing an X-ray microbeam system to study radiobiological effects of cells as fundamental study of radiation therapy. In such applications, improvement of conversion efficiency (CE) from the driving laser to X-rays is an important issue and some approaches for efficient X-ray generation up to several keV have been proposed so far using low density, surface-structured targets, such as porous metals, velvet targets, and carbon nanotubes (CNTs), with the concepts of improvement of the laser absorption efficiency. In this work, we investigated the yields of K-alpha emission from bare and aligned CNT-array coated metal targets to take baseline data aiming to improve the CE in hard X-ray region (multi-keV to tens of keV) by adapting such kind of method.
Mori, Michiyasu; Hikino, Shinichi*; Takahashi, Saburo; Maekawa, Sadamichi
no journal, ,
Nishikino, Masaharu; Ochi, Yoshihiro; Hasegawa, Noboru; Kawachi, Tetsuya; Ishino, Masahiko; Imazono, Takashi; Tanaka, Momoko; Sato, Katsutoshi; Yamamoto, Minoru; Oba, Toshiyuki; et al.
no journal, ,
Recent Progress in the development of laser-driven plasma soft X-ray laser (XRL) and the applications are presented. In the source development, TOPAZ laser using Nd:glass zigzag slab amplifiers with 10 J, 0.1 Hz repetition-rate routinely provides the fully spatial coherent X-ray laser at 13.9 nm for the applications. The bright, coherent, and picoseconds X-ray pulse can be used in a variety of applications such as X-ray speckle measurement and interferometer for probing materials, diffraction imaging, nano-scale fabrication, radiation biology, and so on. In order to extend the use of XRLs, now we are constructing new XRL beam lines for the optical pump and XRL probe experiment.
Nishikino, Masaharu; Hasegawa, Noboru; Ochi, Yoshihiro; Kawachi, Tetsuya; Ishino, Masahiko; Imazono, Takashi; Tanaka, Momoko; Sasaki, Akira; Sato, Katsutoshi; Yamamoto, Minoru; et al.
no journal, ,
no abstracts in English
Mori, Michiyasu; Hikino, Shinichi*; Takahashi, Saburo; Maekawa, Sadamichi
no journal, ,
Mori, Michiyasu; Hikino, Shinichi*; Koshibae, Wataru*; Maekawa, Sadamichi
no journal, ,
Kawachi, Tetsuya; Sasaki, Akira; Nishikino, Masaharu; Ishino, Masahiko; Hasegawa, Noboru; Imazono, Takashi; Ochi, Yoshihiro; Tanaka, Momoko; Faenov, A. Ya.*; Pikuz, T.; et al.
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This paper reviews recent progress in the X-ray laser research in JAEA. In the source development, the polarization of the 13.9 nm laser has been investigated experimentally. The result indicates that the output beam is strongly polarized in the direction perpendicular to the target surface. In the alternative schemes toward the shorter wavelength region, intense higher-order harmonics with more than 300 eV has been observed from relativistic plasma generated with the laser intensity higher than 1E19 W/cm. Furthermore, theoretical investigations of resonantly photo-pumping scheme using intense K-alpha line and generation of 
-ray flash induced by radiation damping effect are also studied. In the application study, the surface dynamics of metal plate irradiated by an optical pulse observed by X-ray laser interferometer, surface deformation induced by a single-shot XRL exposure in which nano-scale conical structures are formed, will be reported.
Mori, Michiyasu; Hikino, Shinichi*; Koshibae, Wataru*; Maekawa, Sadamichi
no journal, ,
Mori, Michiyasu; Hikino, Shinichi*; Koshibae, Wataru*; Maekawa, Sadamichi
no journal, ,
no abstracts in English
