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high energy resolution XAFSYamamoto, Naoki*; Matsumura, Daiju; Hagihara, Yuto*; Tanaka, Kei*; Hasegawa, Yuta*; Ishii, Kenji*; Tanaka, Hirohisa*
Journal of Power Sources, 557, p.232508_1 - 232508_10, 2023/02
Times Cited Count：2 Percentile：29.01(Chemistry, Physical)
-edge to assess the U(V) electronic structure in FeUO
Yomogida, Takumi; Akiyama, Daisuke*; Ouchi, Kazuki; Kumagai, Yuta; Higashi, Kotaro*; Kitatsuji, Yoshihiro; Kirishima, Akira*; Kawamura, Naomi*; Takahashi, Yoshio*
Inorganic Chemistry, 61(50), p.20206 - 20210, 2022/12
Times Cited Count：2 Percentile：36.89(Chemistry, Inorganic & Nuclear)FeUO was studied to clarify the electronic structure of U(V) in a metal monouranate compound. We obtained the peak splitting of HERFD-XANES spectra utilizing high-energy-resolution fluorescence detection-X-ray absorption near edge structure (HERFD-XANES) spectroscopy at the U L-edge, which is a novel technique in the U(V) compounds. Theoretical calculations revealed that the peak splitting was caused by splitting the 6d orbital of U(V). Such distinctive electronic states are of major interest to researchers and engineers working in various fields, from fundamental physics to the nuclear industry and environmental sciences for actinide elements.
Al
GaO
:Ce single-crystal scintillator to neutron radiographyIsegawa, Kazuhisa; Setoyama, Daigo*; Kimura, Hidehiko*; Shinohara, Takenao
Journal of Imaging (Internet), 7(11), p.232_1 - 232_9, 2021/11
Neutron radiography is regarded as complementary to X-ray radiography in terms of transmittance through materials, but its spatial resolution is still insufficient. In order to achieve higher resolution in neutron imaging, several approaches have been adopted such as optical magnification and event centroiding, and the authors focused on modification of the scintillator in this paper. A GdAlGaO:Ce single-crystal scintillator was applied to neutron radiography for the first time and was achieved a spatial resolution of 10.5 micrometers. The results indicate that this material can be a powerful candidate for a new neutron scintillator providing a resolution in micrometer order by optimizing the optical system and increasing the scintillator luminosity.
Murai, Naoki; Fukuda, Tatsuo; Nakajima, Masamichi*; Kawamura, Mitsuaki*; Ishikawa, Daisuke*; Tajima, Setsuko*; Baron, A. Q. R.*
Physical Review B, 101(3), p.035126_1 - 035126_6, 2020/01
Times Cited Count：5 Percentile：33.01(Materials Science, Multidisciplinary)We report an inelastic X-ray scattering investigation of phonons in FeSe superconductor. Comparing the experimental phonon dispersion with density functional theory (DFT) calculations in the non-magnetic state, we found a significant disagreement between them. A better overall agreement was obtained by allowing for spin-polarization in DFT calculations, despite the absence of magnetic order in FeSe. This calculation gives a realistic approximation, at DFT level, of the disordered paramagnetic state of FeSe, in which strong spin fluctuations are present.
Nakamura, Tatsuya; Kawasaki, Takuro; To, Kentaro; Tsutsui, Noriaki; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru
Proceedings of 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2018) (Internet), 3 Pages, 2019/10
A two-dimensional scintillation neutron detector with a submillimeter spatial resolution was developed for pulsed neutron diffraction imaging at the J-PARC MLF. The detector comprised the thin, single ZnS/
LiF scintillator screen coupled with the crossed wavelength-shifting fiber array for light collection. For a high spatial resolution, the wavelength shifting fibers with diameter of 0.1 mm were used them for assembling the detector. The prototype detector that has a neutron-sensitive area of 24 
24 mm
exhibited a spatial resolution of 0.20
0.06 mm and 0.160.06 mm for x and y directions, respectively. The detector had a detection efficiency of 7
for thermal neutrons with a 
Co 
-ray sensitivity in the order of 10
. In this paper detailed detector design is presented together with experimental results using the pulsed neutron beam.
Kusano, Shogo*; Matsumura, Daiju; Ishii, Kenji*; Tanaka, Hirohisa*; Mizuki, Junichiro*
Nanomaterials (Internet), 9(4), p.642_1 - 642_14, 2019/04
Times Cited Count：7 Percentile：37.59(Chemistry, Multidisciplinary)Cui, Y.-T.*; Harada, Yoshihisa*; Niwa, Hideharu*; Oshima, Masaharu*; Hatanaka, Tatsuya*; Nakamura, Naoki*; Ando, Masaki*; Yoshida, Toshihiko*; Ishii, Kenji*; Matsumura, Daiju
NanotechJapan Bulletin (Internet), 11(4), 6 Pages, 2018/08
no abstracts in English
Nakayama, Hiromasa; Takemi, Tetsuya*
Proceedings of 18th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes (HARMO-18) (USB Flash Drive), p.843 - 847, 2017/10
We have attempted to develop a practical and quick local-scale atmospheric dispersion calculation method using an overlapping technique for plume concentration distributions in an emergency response to nuclear accidents. In order to evaluate the overlapping approach, we performed LESs of turbulent flows and plume dispersion under varying mean wind directions using the meteorological data as the model input. When compared with the simulated results under the real meteorological condition, it is shown that the concentration distribution patterns are reasonably simulated by the overlapping method. It can be concluded that the atmospheric dispersion calculation method using the overlapping technique has potential performance for emergency responses to nuclear accidents.
Kumada, Takayuki
Kagaku No Yoten Shirizu, 20, P. 71, 2017/06
no abstracts in English
high energy resolution X-ray absorption spectroscopyCui, Y.-T.*; Harada, Yoshihisa*; Niwa, Hideharu*; Hatanaka, Tatsuya*; Nakamura, Naoki*; Ando, Masaki*; Yoshida, Toshihiko*; Ishii, Kenji*; Matsumura, Daiju; Oji, Hiroshi*; et al.
Scientific Reports (Internet), 7(1), p.1482_1 - 1482_8, 2017/05
Times Cited Count：19 Percentile：49.58(Multidisciplinary Sciences)Sakai, Takuro; Yasuda, Ryo; Iikura, Hiroshi; Matsubayashi, Masahito
JPS Conference Proceedings (Internet), 11, p.020005_1 - 020005_6, 2016/11
SiTabata, Chihiro*; Inami, Toshiya; Michimura, Shinji*; Yokoyama, Makoto*; Hidaka, Hiroyuki*; Yanagisawa, Tatsuya*; Amitsuka, Hiroshi*
Philosophical Magazine, 94(32-33), p.3691 - 3701, 2014/00
Times Cited Count：16 Percentile：57.9(Materials Science, Multidisciplinary)Koike, Masato; Sano, Kazuo*
Dai-5-Han Jikken Kagaku Koza 10; Busshitsu No Kozo 2, Bunko (Ge), 10, p.106 - 153, 2005/08
The chapter provides the basic knowledge of "vacuum ultraviolet spectrometers" and "ray racing" for young scientists without reading the numerous references and is intend to be the handbook for the specialist in various related sciences when they initiate spectroscopic experiments in the vacuum ultraviolet region. The content includes the basis of diffraction gratings, Optical properties of diffraction gratings, aberration theories, diffraction efficiency theories, basis of spectrometers, vacuum ultraviolet plane grating spectrometers, vacuum ultraviolet concave grating spectrometers, soft X-ray plane grating spectrometers, soft X-ray concave grating spectrometers, basis of ray tracing, applications of ray tracing, analytic design method, hybrid design method, etc.
Kusama, Yoshinori; Ishikawa, Masao
NEW DIAMOND, 21(3), p.24 - 25, 2005/07
no abstracts in English
Ebine, Masumi; Katagiri, Masaki; Birumachi, Atsushi; Matsubayashi, Masahito; Sakasai, Kaoru; Sato, Setsuo*
Nuclear Instruments and Methods in Physics Research A, 529(1-3), p.429 - 432, 2004/08
Times Cited Count：1 Percentile：10.3(Instruments & Instrumentation)no abstracts in English
Katagiri, Masaki; Matsubayashi, Masahito; Sakasai, Kaoru; Nakamura, Tatsuya; Ebine, Masumi; Birumachi, Atsushi; Rhodes, N.*
Nuclear Instruments and Methods in Physics Research A, 529(1-3), p.313 - 316, 2004/08
Times Cited Count：13 Percentile：63.95(Instruments & Instrumentation)no abstracts in English
Koike, Masato; Namioka, Takeshi*
AIP Conference Proceedings 705, p.865 - 868, 2004/00
The high brightness soft X-ray sources have been playing an important role in frontier sciences and high technologies. Then it is often required to perform high-resolution spectroscopic measurements in the energy region of 1-10 keV by using a single instrument. Unfortunately, both the grating and the crystal spectrometer cannot meet the requirement satisfactorily, because of various problems they have in the efficiency, spectral resolution, and wavelength scanning range. To overcome these problems we have developed a conical diffraction type grating spectrometer for use in the 1-4 keV region. The spectrometer employs a toroidal mirror and a plane holographic grating to separate the imaging and dispersing functions. This spectrometer works both as monochromator and as spectrograph. In this paper, we describe details of the design and give the expected performance of the spectrometer for cases of practical interest in the use of soft X-ray synchrotron radiation and laboratory sources.
Katagiri, Masaki; Sakasai, Kaoru; Matsubayashi, Masahito; Takahashi, Hiroyuki*; Nakazawa, Masaharu*
Nuclear Instruments and Methods in Physics Research A, 513(1-2), p.374 - 378, 2003/11
Times Cited Count：3 Percentile：27.69(Instruments & Instrumentation)no abstracts in English
Terauchi, Masami*; Koike, Masato
Microscopy and Microanalysis, 9(S02), p.894 - 895, 2003/08
We have been developing a high energy-resolution soft-X-ray spectrometer for a transmission electron microscope to obtain the information of the density of states (DOS) of the valence band (occupied states) from identified small specimen areas. We have designed and produced a new grating. The new varied-line-spacing laminar-type holographic grating was designed to have a focal distance of about 50 cm. An energy resolution of about 0.7 eV is expected for X-ray energy of about 1000 eV.
Koike, Masato; Sano, Kazuo*; Gullikson, E. M.*; Harada, Yoshihisa*; Kumata, Hideki*
Review of Scientific Instruments, 74(2), p.1156 - 1158, 2003/02
Times Cited Count：24 Percentile：72.13(Instruments & Instrumentation)Laminar-type holographic grating having a groove density of 2400 lines/mm was designed and fabricated for use with a soft X-ray flat field spectrograph covering the 0.7-6 nm region. The varied-line-spaced grating pattern was generated by use of an aspheric wave-front recording system and the laminar-type grooves were formed by a reactive ion-etching method. The performance of the grating was evaluated by using a molybdenum K X-ray generator and a spectrograph with a CCD imaging detector. Also the absolute diffraction efficiencies of 0th, 1st, 2nd, and 3rd spectral orders were measured by use of the reflectometers installed at synchrotron radiation beamlines. The experimental results showed that the holographic grating indicated comparable spectral resolution and maximum first-order diffraction efficiency (
2%) at 
2 nm with a replica grating made from a mechanically ruled varied-line-spacing grating, and it also showed higher efficiency in 
1.0nm region and lower level higher order light over the whole wavelength range than the replica grating.
