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Journal Articles

Electronic structures of ferromagnetic CeAgSb$$_{2}$$; Soft X-ray absorption, magnetic circular dichroism, and angle-resolved photoemission spectroscopies

Saito, Yuji; Fujiwara, Hidenori*; Yamaguchi, Takashi*; Nakatani, Yasuhiro*; Mori, Takeo*; Fuchimoto, Hiroto*; Kiss, Takayuki*; Yasui, Akira*; Miyawaki, Jun*; Imada, Shin*; et al.

Journal of the Physical Society of Japan, 85(11), p.114713_1 - 114713_7, 2016/11

 Times Cited Count:7 Percentile:41.41(Physics, Multidisciplinary)

We report on the electronic structures of ferromagnetic CeAgSb$$_{2}$$ using soft X-ray absorption (XAS), magnetic circular dichroism (XMCD), and angle-resolved photoemission (ARPES) spectroscopies. The Ce $$M_{4,5}$$ XAS spectra show very small satellite structures, reflecting a strongly localized character of the Ce 4${it f}$ electrons. The linear dichroism effects in the Ce $$M_{4,5}$$ XAS spectra demonstrate the ground-state Ce 4${it f}$ symmetry of $$Gamma$$$$_{6}$$, the spatial distribution of which is directed along the ${it c}$-axis. Nevertheless, ARPES spectra at the Ce 3$$d$$-4$$f$$ resonance show the momentum dependence of the intensity ratio between Ce 4$$f^{1}_{5/2}$$ and 4$$f^{1}_{7/2}$$ peaks in a part of the Brillouin zone, suggesting the non negligible momentum-dependent hybridization effect between the Ce 4${it f}$ and the conduction electrons. This is associated with the moderate mass enhancement in CeAgSb$$_{2}$$.

Journal Articles

Submicron scale image observation with a grazing incidence reflection-type single-shot soft X-ray microscope

Baba, Motoyoshi*; Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Minami, Yasuo*; Takei, Ryota*; Yamagiwa, Mitsuru; Kawachi, Tetsuya; Suemoto, Toru

Japanese Journal of Applied Physics, 53(8), p.080302_1 - 080302_4, 2014/08

 Times Cited Count:8 Percentile:58.15(Physics, Applied)

A grazing incidence reflection-type soft X-ay microscope, using a Fresnel zone plate and a soft X-ray laser with wavelength 13.9 nm and pulse width 7 ps, was developed. Submicron size groove structures made on a Pt film were clearly captured at a single shot exposure, with spatial resolution of about 360 nm. A wide field view of 100 $$mu$$m square was secured under the Kohler illumination. This microscope also had a large depth of focus of more than 100 $$mu$$m and was proven to have a sufficient performance for observing surface morphological changes.

Journal Articles

Yields of strand breaks and base lesions induced by soft X-rays in plasmid DNA

Yokoya, Akinari; Fujii, Kentaro; Ushigome, Takeshi; Shikazono, Naoya; Urushibara, Ayumi; Watanabe, Ritsuko

Radiation Protection Dosimetry, 122(1-4), p.86 - 88, 2006/12

 Times Cited Count:10 Percentile:39.34(Environmental Sciences)

We have studied yields of DNA damages induced by soft X-rays obtained from a conventional soft X-ray machine in a LET region between $$gamma$$-rays and ultrasoft X-rays. Practically soft X-rays with a broad energy spectrum emitted from a target of heavy metal, such as tungsten, have been widely used not only for radiobiological experiments but also for medical application such as mammography. Radiation weighting factors for these soft X-rays have been assigned to be 1 by ICRP. However, the fraction of a large number of low energy photons in the spectrum (below several tens keV) provided by bremsstrahlung is expected to be more effective for DNA damage induction than $$gamma$$-rays since low energy photo- and Auger electrons predominantly ejected in consequence of a photoelectric effect can produce dense clusters of ionization/excitation on DNA molecules. We have examined the yield of DNA strand breaks induced by white soft X-rays (150 kVp, tungsten target). Yields of base lesions revealed by base excision repair enzymes will be also presented.

Journal Articles

Polarizance of a synthetic mica crystal polarizer and the degree of linear polarization of an undulator beamline at 880eV evaluated by the rotating-analyzer method

Imazono, Takashi; Hirono, Toko*; Kimura, Hiroaki*; Saito, Yuji; Ishino, Masahiko; Muramatsu, Yasuji*; Koike, Masato; Sano, Kazuo*

Review of Scientific Instruments, 76(12), p.126106_1 - 126106_4, 2005/12

 Times Cited Count:14 Percentile:42.18(Instruments & Instrumentation)

Polarizance of a reflection-type polarizer made with a synthetic mica (fluorophlogopite) single crystal was evaluated at the photon energy of 880 eV by means of the rotating-analyzer method in conjunction with the evaluation of the degree of linear polarization of the insertion beamline, SPring-8 BL23SU, featuring an APPLE-2 type variably polarizing undulator. When the undulator was tuned to the horizontal linear polarization mode, the maximum reflectances for s- and p-polarization for a symmetric Bragg reflection of synthetic mica(002) were 2.6% and 0.013%, respectively, at incident angles of near 45$$^circ$$. Our analysis based on the rotating-analyzer method gave the polarizance of the polarizer of at least 0.997 $$pm$$ 0.002 and the degree of linear polarization of 0.993 $$pm$$ 0.004 in the linear polarization mode.

Journal Articles

Resonant O K$$alpha$$ emission spectroscopy of layered manganate La$$_{1.2}$$Sr$$_{1.8}$$Mn$$_{2}$$O$$_{7}$$

Agui, Akane; K$"a$$"a$mbre, T.*; S${aa}$the, C.*; Nordgren, J.*; Usuda, Manabu; Saito, Tomohiko*; Moritomo, Yutaka*

Journal of Electron Spectroscopy and Related Phenomena, 144-147, p.589 - 592, 2005/06

 Times Cited Count:1 Percentile:93.92(Spectroscopy)

Current research in the perovskite and layered perovskite-type manganese oxides has expanded to include the study of electronic and magnetic properties such as the colossal magnetoresistance (CMR), orbital ordering and charge ordering. The O K$$alpha$$ soft X-ray emission and absorption spectra (XES and XAS) of La$$_{1.2}$$Sr$$_{1.8}$$Mn$$_{2}$$O$$_{7}$$ were measured at selected excitation energies in order to investigate the electronic structure. The measurements were carried out by using a soft X-ray emission spectrometer at beamline BW3 at HASYLAB, Germany. The dependence of O K$$alpha$$ XES on excitation-energy was observed. It is attributed the different site of oxygen ions.

Journal Articles

Resonant Mn $$L$$ Emission spectra of layered manganite La$$_{1.2}$$Sr$$_{1.8}$$Mn$$_{2}$$O$$_{7}$$

Agui, Akane; Butorin, S. M.*; K$"a$$"a$mbre, T.*; S${aa}$the, C.*; Saito, Tomohiko*; Moritomo, Yutaka*; Nordgren, J.*

Journal of the Physical Society of Japan, 74(6), p.1772 - 1776, 2005/06

 Times Cited Count:5 Percentile:61.35(Physics, Multidisciplinary)

no abstracts in English

JAEA Reports

Study of beam fluctuation of high speed variably-polarizing undulator APPLE-2 in 2001 Dec.-2002 Nov.

Nakatani, Takeshi; Agui, Akane; Yoshigoe, Akitaka; Tanaka, Hitoshi*; Takao, Masaru*; Takeuchi, Masao*; Matsushita, Tomohiro*; Aoyagi, Hideki*

JAERI-Tech 2005-027, 29 Pages, 2005/05

JAERI-Tech-2005-027.pdf:5.14MB

We measured the orbit fluctuation caused by APPLE-2 type undulator (ID23) installed in the SPring-8 storage ring by using the developed real time measurement system of electron and photon beam position monitors. We quantitatively found two characteristic fluctuations correlating with the ID23 motion by wavelet transform which is a kind of frequency analysis. One originates from the variation of error field during the ID drive. The other originates from the stray magnetic field leaked from the servomotors for the phase drive. Using these results, we tried to get rid of the effect of error fields on the beam orbit by the precise feed-forward correction table and the stray field shield. Consequently we succeeded in suppressing the orbit fluctuation down to sub-micron during the gap drive, which is observed by photon beam position monitors installed in downstream 20m from each light source point.

Journal Articles

Ultrafast X-ray absorption spectroscopy of laser-excited materials

Koike, Masato

JAERI-Conf 2005-004, p.15 - 18, 2005/04

Advanced Light Source (ALS) Beamline 6.0 is designed for X-ray absorption spectroscopy with femtosecond X-ray pulses generated by the bunch "slicing" technique. Soft and hard X-ray branch lines will cover a wide photon energy range from 120 eV to 10 keV. A soft X-ray spectrograph will collect absorption spectra dispersively. The application of laminar gratings to dispersive X-ray absorption spectroscopy in the photon energy range 2- 8 keV has been investigated.

Journal Articles

Admixture of excited states and ground states of a Eu$$^{3+}$$ ion in Eu$$_{3}$$Fe$$_{5}$$O$$_{12}$$ by means of magnetic circular dichroism

Mizumaki, Masaichiro*; Uozumi, Takayuki*; Agui, Akane; Kawamura, Naomi*; Nakazawa, Makoto*

Physical Review B, 71(13), p.134416_1 - 134416_8, 2005/04

 Times Cited Count:13 Percentile:48.07(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Performance of a reflection-type polarizer by use of muscovite mica crystal in the soft X-ray region of 1 keV

Imazono, Takashi; Ishino, Masahiko; Koike, Masato; Kimura, Hiroaki*; Hirono, Toko*; Sano, Kazuo*

Review of Scientific Instruments, 76(2), p.023104_1 - 023104_4, 2005/02

 Times Cited Count:13 Percentile:44.18(Instruments & Instrumentation)

To develop the polarizer functioning in the soft X-ray region of 1 keV, the polarization performance of muscovite mica has been investigated theoretically with simulation code based on dynamical theory. As the result of calculation, muscovite mica is found to be promising candidate as a reflection-type polarizer with the reflectivity for s-polarization of 0.03 at approximately 0.9 keV at the angle of incidence of 45$$^circ$$. In order to verify the polarization performance of muscovite mica experimentally, a symmetric Bragg reflection measurement of muscovite mica(002) was carried out using a linearly polarized undulator radiation. As the result, the maximum reflectivity for s-polarization and the extinction ratio of muscovite mica were approximately 0.018 and 200 at 878 eV, respectively. This result indicates that muscovite mica works as a practical polarizer in the soft X-ray region.

Journal Articles

Study of interdiffused layers in the surface and interfaces of multilayers by total-reflection soft-X-ray fluorescence spectroscopy

Imazono, Takashi; Yanagihara, Mihiro*

Photon Factory News, 22(3), p.18 - 22, 2004/11

Using soft-X-ray fluorescence spectroscopy with photon incidence at a critical angle of total reflection, it was made clear that SiO$$_2$$ existed within a depth of a few nanometers from the surface of Fe/Si multilayers. It was generated by oxidation of the interdiffused Fe$$_3$$Si layer nearest to the topmost Fe layer. Consequently, the Fe$$_3$$Si layer was found to decrease in thickness. This result suggests that the total-reflection soft-X-ray fluorescence spectroscopy is fairly useful to analyze the chemical state of elements to a depth of a few nanometers from the surface.

Journal Articles

Soft-X-ray high-resolution photoemission study on the valence transitions in YbInCu$$_{4}$$

Sato, Hitoshi*; Yoshikawa, Kunta*; Hiraoka, Koichi*; Arita, Masashi*; Fujimoto, Koji*; Kojima, Kenichi*; Muro, Takayuki*; Saito, Yuji; Sekiyama, Akira*; Suga, Shigemasa*; et al.

Physical Review B, 69(16), p.165101_1 - 165101_6, 2004/04

 Times Cited Count:31 Percentile:21.74(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Ion desorption from DNA components irradiated with 0.5 keV ultrasoft X-ray photons

Fujii, Kentaro; Akamatsu, Ken; Yokoya, Akinari

Radiation Research, 161(4), p.435 - 441, 2004/04

 Times Cited Count:14 Percentile:59.77(Biology)

Positive ion desorption from thin films of DNA components, 2-deoxy-D-ribose, thymine, thymidine (dThd), and thymidine 5' -monophosphate (dTMP) has been investigated in the oxygen K-edge excitation region using synchrotron ultrasoft X-rays (538 eV). The mass patterns of dThd and dTMP, especially that of dTMP, were similar to that of 2-deoxy-D-ribose, indicating that a number of ions were generated at the sugar site, even in the nucleotide molecule. It is therefore it is predicted that the sugar is a more fragile site than the thymine base.

Journal Articles

Characterization of carbon films on the Japanese smoked roof tile "Ibushi-Kawara" by high-resolution soft X-ray spectroscopy

Muramatsu, Yasuji; Motoyama, Muneyuki*; Denlinger, J. D.*; Gullikson, E. M.*; Perera, R. C. C.*

Japanese Journal of Applied Physics, Part 1, 42(10), p.6551 - 6555, 2003/10

 Times Cited Count:5 Percentile:74.5(Physics, Applied)

Carbon films on Japanese smoked roof tile "Ibushi-Kawara" were characterized by high-resolution soft X-ray spectroscopy using synchrotron radiation. By comparing the soft X-ray emission and absorption spectra of Kawara with the reference carbon compounds, it was determined that the carbon films on Kawara consist of mostly carbon-black-like sp2 carbon atoms and that the surface also contains polyethylene-like sp3 carbon atoms. The take-off/incident-angle dependence on the X-ray emission/absorption spectra of Kawara implies that the carbon-black-like sp2 carbon atoms partially form a layer structure parallel to the basal clay plane. From the take-off-angle dependence of the p/s-peak intensity ratio in the X-ray emission spectra, the layer ordering of the carbon films is estimated to be 50% of highly oriented pyrolytic graphite (HOPG). Therefore, the metallic oxidized color and durability are due to the layer structure and the random structure that connects the layer-structured clusters, respectively.

JAEA Reports

Study of closed orbit distortion from high speed phase switching of variably-polarizing undulator APPLE-2 in 2001 March-June

Nakatani, Takeshi; Tanaka, Hitoshi*; Takao, Masaru*; Agui, Akane; Yoshigoe, Akitaka; Takeuchi, Masao*; Aoyagi, Hideki*; Okuma, Haruo*

JAERI-Tech 2003-048, 29 Pages, 2003/05

JAERI-Tech-2003-048.pdf:1.14MB

no abstracts in English

Journal Articles

First results from the actinide science beamline BL23SU at SPring-8

Saito, Yuji; Nakatani, Takeshi*; Matsushita, Tomohiro*; Agui, Akane; Yoshigoe, Akitaka; Teraoka, Yuden; Yokoya, Akinari

Nuclear Instruments and Methods in Physics Research A, 474(3), p.253 - 258, 2001/12

 Times Cited Count:72 Percentile:2.26(Instruments & Instrumentation)

The present performance of a soft X-ray bealmine BL23SU at SPring-8 is described. The resolving power realized on a varied-line-spacing plane grating monochromator connected to a was estimated to be better than 10000 at 400 eV and 6500 at 867 eV. In addition, reasonable photon flux of more than 10$$^{11}$$ photons/sec/100mA/0.02% b.w. is available in the energy range of 0.5-1.8 keV at experimental stations.

Journal Articles

Soft X-ray emission spectroscopy employing CCD camera

Sasaki, Teikichi; Chugan, Nobuhiko*

Hyomen Kagaku, 22(10), p.43 - 50, 2001/10

no abstracts in English

Journal Articles

Soft X-ray absorption spectra of ilmenite family

Agui, Akane; Mizumaki, Masaichiro*; Saito, Yuji; Matsushita, Tomohiro*; Nakatani, Takeshi*; Fukaya, Atsuko*; Torikai, Eiko*

Journal of Synchrotron Radiation, 8(2), p.907 - 909, 2001/03

 Times Cited Count:9 Percentile:48.51(Instruments & Instrumentation)

no abstracts in English

JAEA Reports

Control software of a variably polarizing undulator (APPLE type) for SX beamline in the SPring-8

Hiramatsu, Yoichi*; Shimada, Taihei*; Miyahara, Yoshikazu*

JAERI-Tech 99-082, p.274 - 0, 1999/12

JAERI-Tech-99-082.pdf:7.81MB

no abstracts in English

Journal Articles

Single- and double-strand breaks in solid pBR322 DNA induced by ultrasoft X-rays at photon energies of 388, 435 and 573eV

Yokoya, Akinari; Watanabe, Ritsuko*; Hara, Takehiro*

Journal of Radiation Research, 40(2), p.145 - 158, 1999/00

 Times Cited Count:47 Percentile:18.4(Biology)

no abstracts in English

31 (Records 1-20 displayed on this page)