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Journal Articles

Phase transition and domain formation in ferroaxial crystals

Hayashida, Takeshi*; Uemura, Yohei*; Kimura, Kenta*; Matsuoka, Satoshi*; Hagihara, Masato; Hirose, Sakyo*; Morioka, Hitoshi*; Hasegawa, Tatsuo*; Kimura, Tsuyoshi*

Physical Review Materials (Internet), 5(12), p.124409_1 - 124409_10, 2021/12

Journal Articles

Quasifree neutron knockout reaction reveals a small $$s$$-Orbital component in the Borromean nucleus $$^{17}$$B

Yang, Z. H.*; Kubota, Yuki*; Corsi, A.*; Yoshida, Kazuki; Sun, X.-X.*; Li, J. G.*; Kimura, Masaaki*; Michel, N.*; Ogata, Kazuyuki*; Yuan, C. X.*; et al.

Physical Review Letters, 126(8), p.082501_1 - 082501_8, 2021/02

 Times Cited Count:10 Percentile:98.7(Physics, Multidisciplinary)

A quasifree ($$p$$,$$pn$$) experiment was performed to study the structure of the Borromean nucleus $$^{17}$$B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for $$1s_{1/2}$$ and $$0d_{5/2}$$ orbitals, and a surprisingly small percentage of 9(2)% was determined for $$1s_{1/2}$$. Our finding of such a small $$1s_{1/2}$$ component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in $$^{17}$$B. The present work gives the smallest $$s$$- or $$p$$-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of $$s$$ or $$p$$ orbitals is not a prerequisite for the occurrence of a neutron halo.

Journal Articles

Verification of dose estimation of Auger electrons emitted from Cu-64 using a combination of FNTD measurements and Monte Carlo simulations

Kusumoto, Tamon*; Matsuya, Yusuke; Baba, Kentaro*; Ogawara, Ryo*; Akselrod, M. S.*; Harrison, J.*; Fomenko, V.*; Kai, Takeshi; Ishikawa, Masayori*; Hasegawa, Sumitaka*; et al.

Radiation Measurements, 132, p.106256_1 - 106256_4, 2020/03

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

Internal radiation therapy with Cu-64 concentrates energy deposition in tumor cells by virtue of released Auger electrons with low energy. In our previous study, we have attached the solutions at the surface of Fluorescent Nuclear Track Detector (FNTD) and succeeded in measuring the absorbed doses of Auger electrons registered in FNTD. However, because there are several types of radiation emitted from the source, i.e., beta rays, positron etc., the contribution degree of Auger electron to energy concentration remain uncertain. In this study, we quantitatively analyzed the spatial dose distribution in the FNTD based on Monte Carlo simulation with PHITS and GEANT4, and evaluated high dose deposited by Auger electrons. The dose distribution calculated by the PHITS code is exactly equivalent to that by Geant4. Also, the simulations are well agreement with experimental results. If the contribution of Auger electrons is ignored, the significantly high absorbed dose proximal to the source is not properly reduced. These findings demonstrate that Auger electrons work very effectively to kill cancer cells proximal to Cu-64 source while minimizing damage effects on normal cells distal to the source.

Journal Articles

Observation of surface modification of multi-layered mirror induced by soft X-ray laser pulse

Nishikino, Masaharu; Ishino, Masahiko; Ichimaru, Satoshi*; Hatayama, Masatoshi*; Hasegawa, Noboru; Kawachi, Tetsuya

Reza Gakkai Dai-483-Kai Kenkyukai Hokoku; Tanhacho Ryoshi Bimu Hassei To Sono Oyo, p.25 - 28, 2015/12

X-ray ablation has been recently achieved using plasma soft X-ray lasers (SXRLs), laser plasma soft X-rays, and X-ray free electron lasers. In order to study the interactions between picosecond SXRL beams and material and multi-layered structure surfaces were irradiated with SXRL pulse. Following irradiation, the substrate surface was observed using a scanning electron microscope and an atomic force microscope. The surface modifications caused by the SXRL beam were clearly seen. The multi-layered mirror is the important component for the EUV lithography. Then, we have started the damage test of multi-layered structure, and the surface modifications caused by the SXRL pulse irradiations were confirmed.

Journal Articles

Exciting possibilities of soft X-ray emission spectroscopy as chemical state analysis in EPMA and FESEM

Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Terauchi, Masami*; Koike, Masato; Kawachi, Tetsuya; Imazono, Takashi; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; et al.

Microscopy and Microanalysis, 20(Suppl.3), p.684 - 685, 2014/08

A novel wavelength dispersive soft X-ray emission spectrometer (SXES) having a X-ray energy range of 50-210 eV has been developed. One feature is that the SXES is parallel detection of the signals so that it can be used like a conventional energy dispersive spectrometer. The other is a high energy resolution, which is about 0.2 eV at Al-L comparable to those revealed by XPS and EELS. These features enable us to obtain meaningful information about chemical bonding in various bulk samples. The SXES can detect Li-K emission spectrum. In the case of an anode electrode of a lithium ion battery (LIB), two types of lithium peaks are observed: one lower energy peak at 50 eV and the other higher energy peak at 54 eV. It was found that the former peak corresponds to the amount of charging, whereas the latter corresponds to the metallic state of lithium.

Journal Articles

Nano-meter size modification of metal surfaces induced by soft X-ray laser single pulse

Ishino, Masahiko; Faenov, A.*; Tanaka, Momoko; Pikuz, T.; Tamotsu, Satoshi*; Hasegawa, Noboru; Nishikino, Masaharu; Starikov, S. V.*; Stegailov, V. V.*; Norman, G.*; et al.

X-Ray Lasers 2012; Springer Proceedings in Physics, Vol.147, p.121 - 124, 2014/00

 Times Cited Count:0 Percentile:0

Journal Articles

An Extension of detectable energy-range of SXES spectrometer for electron microscopes

Terauchi, Masami*; Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Koike, Masato; Kawachi, Tetsuya; Imazono, Takashi; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; et al.

JAEA-Conf 2013-001, p.77 - 80, 2013/09

We have been developing a soft X-ray emission spectroscopy (SXES) instrument for electron microscopes (TEM, EPMA/SEM) with an extension of detectable energy range to 50-4000 eV. An introduction of valence electron spectroscopy with microscopy will supply fruitful information on bonding electrons, which cannot be obtained by EELS and EDS. For extend the lowest (or highest) detection energy upto 50 eV (or 4000 eV), a new laminar-type varied-line-spacing (VLS) grating, JS50XL, (or JS4000) has designed and manufactured. JS50XL and JS4000 having 1200 and 2400 lines/mm as well as coated by Au and a new multilayer-structure of W/B$$_{4}$$C for a wide-band energy region of 2000-3800 eV, respectively. Those gratings were installed and tested in a SXES spectrometer attached to a TEM. The extension in lowest detection energy was confirmed by Mg-L emission (JS50XL). The energy resolution was 0.2 eV at Fermi edge of 49.5 eV. It can be also seen a sharp Fermi edge for Li-K emission spectrum of metal-Li. The high energy resolution was confirmed by Te-La emission at 3.8 keV (JS4000). The full width at half maximum of the peak was 27 eV. The detection energy range was successfully extended by using the two new VLS-gratings.

Journal Articles

Development and applications of a new soft X-ray emission spectrometer for electron probe microanalysis and/or nanoanalysis

Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Koike, Masato; Kawachi, Tetsuya; Imazono, Takashi; Hasegawa, Noboru; Terauchi, Masami*; Koeda, Masaru*; Nagano, Tetsuya*; et al.

JAEA-Conf 2013-001, p.13 - 15, 2013/09

A very unique high performance soft X-ray emission spectrometer (SXES) has successfully been developed which can be attached not only to transmission electron microscopes (TEMs), but also to scanning electron microscopes (SEMs) as well as electron probe microanalyzers (EPMAs). To extend the analyzed energy ranges, a newly designed laminar-type varied-line-spacing (VLS) grating JS50XL, for a lower energy range, 50-170 eV, and a multilayered VLS grating JS4000, for a higher energy range, 2000-4000 eV, have been developed and installed to this spectrometer. Application software has also been developed for a commercial use of SXES in several fields such as battery materials, steel and alloys, and electron devices. The appearance of this spectrometer attached to EPMA and a few results acquired are shown in the following figures. This development has been conducted as one of the projects of Collaborative Development of Innovative Seeds (Practicability verification stage) by Japan Science and Technology Agency.

Journal Articles

Development of an objective flat-field spectrograph for electron microscopic soft X-ray emission spectrometry in 50-4000 eV

Imazono, Takashi; Koike, Masato; Kawachi, Tetsuya; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; Sasai, Hiroyuki*; Oue, Yuki*; Yonezawa, Zeno*; Kuramoto, Satoshi*; et al.

Proceedings of SPIE, Vol.8848, p.884812_1 - 884812_14, 2013/09

 Times Cited Count:7 Percentile:95.63

We have developed an objective soft X-ray flat-field spectrograph to be able to attach to electron microscopes. This spectrograph has two attractive features. One is that it is designed to cover a wide energy range of 50-4000 eV by using four varied-line-spacing holographic gratings optimized for 50-200 eV, 155-350 eV, 300-2200 eV, and 2000-4000 eV. They can be accommodated in the single spectrograph. The other is a newly invented W/B$$_4$$C multilayer coating covering the 2000-4000 eV range. It can enhance the diffraction efficiency above a practical level of $$sim1$$% at a constant incidence angle in the whole energy range.

Journal Articles

Nano-meter scale modifications on material surfaces induced by soft X-ray laser pulse irradiations

Ishino, Masahiko; Faenov, A.*; Tanaka, Momoko; Tamotsu, Satoshi*; Pikuz, T.; Hasegawa, Noboru; Nishikino, Masaharu; Inogamov, N.*; Skobelev, I.*; Fortov, V.*; et al.

Proceedings of SPIE, Vol.8849, p.88490F_1 - 88490F_8, 2013/09

 Times Cited Count:2 Percentile:76.86

Journal Articles

Chemical State Mapping via soft X-rays using a Wavelength Dispersive Soft X-ray Emission Spectrometer with High Energy Resolution

Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Terauchi, Masami*; Koike, Masato; Kawachi, Tetsuya; Imazono, Takashi; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; et al.

Microscopy and Microanalysis, 19(Suppl.2), p.1258 - 1259, 2013/08

A new wavelength dispersive soft X-ray emission spectrometer (WD-SXES) consisting of newly developed diffraction gratings has been developed for soft X-ray emission spectroscopy. The WD-SXES with two types of diffraction gratings nominally covering an energy range between 50 and 210 eV has been installed to electron probe X-ray microanalyzers, JEOL JXA-8100, for commercial use. The energy resolution of this WD-SXES is nominally 0.3 eV, which is one order of magnitude better than that of conventional WDSs with layered dispersion elements. It is to be noted that the corresponding edge of Al$$_{2}$$B is shifted to higher energy side by about 1 eV. One of the energy range was selected from 72 to 73.5 eV whereas the other was from 73.5 to 75 eV. The contrast in the former map is reversed in the later map as expected even though the energy difference between two maps is only 1.5 eV. The study confirms the high potential for the characterization especially for chemical state mapping.

Journal Articles

A New grating X-ray spectrometer for 2-4 keV enabling a separate observation of In-L$$beta$$ and Sn-L$$alpha$$ emissions of indium tin oxide

Terauchi, Masami*; Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Koike, Masato; Kawachi, Tetsuya; Imazono, Takashi; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; et al.

Microscopy, 62(3), p.391 - 395, 2013/06

 Times Cited Count:10 Percentile:62.95(Microscopy)

A new multilayer-coated varied line-spaced grating, JS4000, was fabricated and tested for extending the upper limit of a grating X-ray spectrometer for electron microscopy. This grating was designed for 2-3.8 keV at a grazing incidence angle of 1.35 deg. It was revealed that this new multilayer structure enables us to take soft-X-ray emission spectra continuously from 1.5 keV to 4 keV at the same optical setting. The full-width at half maximum of Te-L$$alpha$$$$_{1,2}$$ (3.8 keV) emission peak was 27 eV. Sn-L$$alpha$$ (3444 eV) and In-L$$beta$$$$_{1}$$ (3487 eV) peaks, which cannot be resolved by a widely used energy-dispersive X-ray spectrometer.

Journal Articles

Crystal morphology-dependent graft polymerization in poly(ether ether ketone) films

Hasegawa, Shin; Takahashi, Shuichi*; Iwase, Hiroki*; Koizumi, Satoshi; Onuma, Masato*; Maekawa, Yasunari

Polymer, 54(12), p.2895 - 2900, 2013/05

 Times Cited Count:9 Percentile:30.77(Polymer Science)

Radiation-induced graft polymerization of sulfo-containing styrene derivatives into crystalline poly(ether ether ketone) (PEEK) substrates was carried out to prepare thermally and mechanically stable polymer electrolyte membranes based on an aromatic hydrocarbon polymer, so-called "super-engineering plastics". Graft polymerization of the sulfo-containing styrene, ethyl 4-styrenesulfonate (E4S) into PEEK substrates with degrees of crystallinity (DC) of 11 - 26% gradually progressed, achieving a grafting degree of more than 50% after 72 hours, whereas graft polymerization of the substrates with DC above 26% did not proceed. When morphological change in these films were measured by SAXS, PEEK films with DC larger than 26% showed a new peak at d=14 nm, corresponding to lamella structure. Thus, the suppression of graft polymerization of PEEK films with DC above 26% was due to obstruct of monomer diffusion by the formation of the oriented lamella structure.

Journal Articles

Development of a flat-field spectrograph with a wide-band multilayer grating and prefocusing mirror covering 2-4 keV

Imazono, Takashi; Koike, Masato; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; Sasai, Hiroyuki*; Oue, Yuki*; Yonezawa, Zeno*; Kuramoto, Satoshi*; Terauchi, Masami*; et al.

Journal of Physics; Conference Series, 425(15), p.152008_1 - 152008_4, 2013/03

 Times Cited Count:2 Percentile:74.44

We have developed a flat-field spectrograph equipped with a wide-band multilayer grating and prefocusing mirror for the 2-4 keV range. To realize a spectrograph without any mechanical movement, the multilayer has a newly invented layer structure to uniformly enhance the diffraction efficiency (or reflectivity) of the grating (or prefocusing mirror) at a fixed angle of incidence in the whole energy region. The multilayer structure consisting of W and B$$_4$$C layers has been deposited by ion beam sputtering method on a varied-line-spacing laminar-type holographic grating. Also the same multilayer has been done on a spherical substrate. The average diffraction efficiency (or reflectivity) of the multilayer grating (or spherical mirror) is in excess of 3% at 88.65$$^circ$$ (or 4% at 88.00$$^circ$$) in the 2.1-3.8 keV range. The throughput of the spectrograph with multilayer optics can be evaluated to be 2-5000 times higher than that with conventional optics coated by a gold layer.

Journal Articles

Observations of surface modifications induced by the multiple pulse irradiation using a soft picosecond X-ray laser beam

Ishino, Masahiko; Faenov, A. Ya.*; Tanaka, Momoko; Tamotsu, Satoshi*; Hasegawa, Noboru; Nishikino, Masaharu; Pikuz, T.; Kaihori, Takeshi*; Kawachi, Tetsuya

Applied Physics A, 110(1), p.179 - 188, 2013/01

 Times Cited Count:24 Percentile:73.94(Materials Science, Multidisciplinary)

Journal Articles

Development of a soft X-ray diffractometer for a wideband multilayer grating with a novel layer structure in the 2-4 keV range

Imazono, Takashi; Koike, Masato; Kawachi, Tetsuya; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; Sasai, Hiroyuki*; Oue, Yuki*; Yonezawa, Zeno*; Kuramoto, Satoshi*; et al.

AIP Conference Proceedings 1465, p.33 - 37, 2012/07

 Times Cited Count:5 Percentile:87.84

Journal Articles

Interaction of soft X-ray laser pulse radiation with aluminum surface; Nano-meter size surface modification

Ishino, Masahiko; Faenov, A.*; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Tamotsu, Satoshi*; Pikuz, S.*; Inogamov, N. A.*; Zhakhovsky, V. V.*; Skobelev, I.*; et al.

AIP Conference Proceedings 1465, p.236 - 240, 2012/07

 Times Cited Count:2 Percentile:66.99

We irradiated the focusing soft X-ray laser pulses having a wavelength of 13.9 nm and the duration of 7 ps to aluminum surface. After the irradiation process, the irradiated surface was observed with a scanning electron microscope. The surface modifications caused by soft X-ray laser single pulse exposure were clearly seen. In addition, it was found that the conical structures having around 100 nm in diameters were formed in the shallow features. The nano-meter size modified surface structures on aluminum induced by the soft X-ray laser pulse is interesting as the newly surface structure. Hence, the soft X-ray laser beam would be a candidate for a tool of micromachining. We also provide a thermomechanical modeling of the soft X-ray laser interaction with aluminum briefly to explain the surface modification.

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:36 Percentile:82.87(Physics, Applied)

Journal Articles

Laminar and blazed type holographic gratings for a versatile soft X-ray spectrograph attached to an electron microscope and their evaluation in the 50-200 eV range

Imazono, Takashi; Koike, Masato; Kawachi, Tetsuya; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; Sasai, Hiroyuki*; Oue, Yuki*; Yonezawa, Zeno*; Kuramoto, Satoshi*; et al.

Applied Optics, 51(13), p.2351 - 2360, 2012/05

 Times Cited Count:10 Percentile:50.59(Optics)

Laminar and blazed types holographic varied-line-spacing spherical gratings for use in a versatile soft X-ray flat-field spectrograph attached to an electron microscope are designed, fabricated, and evaluated. The absolute diffraction efficiencies of laminar (or blazed) master and replica gratings at 86.00$$^circ$$ incidence evaluated by synchrotron radiation show over 5% (or 8%) in the 50-200 eV range with the maxima of 22% (or 26-27%). Also the resolving power evaluated by a laser produced plasma source is in excess of 700 at the energy near the ${it K}$ emission spectrum of lithium ($$sim$$55 eV) for all gratings. Moreover, the ${it K}$ emission spectrum of metallic Li with high spectral resolution is successfully observed with the spectrograph attached to a transmission electron microscope.

Journal Articles

Surface modifications of metals induced by soft X-ray laser pulse irradiations

Ishino, Masahiko; Faenov, A. Y.*; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Tamotsu, Satoshi*; Pikuz, T.; Oba, Toshiyuki*; Kaihori, Takeshi; Kawachi, Tetsuya

Journal of Laser Micro/Nanoengineering, 7(2), p.147 - 151, 2012/05

 Times Cited Count:5 Percentile:31.02(Nanoscience & Nanotechnology)

We irradiated the soft X-ray laser (SXRL) pulses having a wavelength of 13.9 nm, the duration time of 7 ps to aluminum (Al), copper (Cu) and gold (Au) surfaces. After the irradiation processes of SXRL beam with laser flux of $$sim$$14 mJ/cm$$^{2}$$ for Al case and of $$sim$$21 mJ/cm$$^{2}$$ for Cu and Au cases, the modified surfaces were observed with the visible microscope, the scanning electron microscope, and the atomic force microscope. The surface modifications caused by the SXRL irradiations were clearly seen on the surfaces, and it was found that the conical structures having around 100 nm in diameters were formed on the Al surface under a single pulse shot. The conical structures were formed in the features with the average depth of about 40 nm, and this value was in accordance with the attenuation length of the SXRL beam for Al. The modified structure on Al surface induced by SXRL pulse irradiations is different from those of Cu and Au surfaces. The modified structure formed on Al surface induced by the SXRL pulse exposure is interesting as the newly structure. Hence, the SXRL beam would be a candidate for a tool of micromachining, which enable to fabricate of three dimensional structures with nano-meter size on Al surface.

172 (Records 1-20 displayed on this page)