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Yamaguchi, Kenji; Udono, Haruhiko*
International Journal of Hydrogen Energy, 32(14), p.2726 - 2729, 2007/09
Times Cited Count：14 Percentile：35.39(Chemistry, Physical)no abstracts in English
O
/YAG eutectic composite using synchrotron and neutron diffractionSuzuki, Hiroshi; Waku, Yoshiharu*; Nakagawa, Narihito*; Akita, Koichi*; Moriai, Atsushi; Morii, Yukio
Journal of Neutron Research, 15(2), p.113 - 120, 2007/06
The residual stress in only YAG phase was measured on the surface of the AlO-YAl
O
(YAG) eutectic composite(AlO/YAG MGC) using the low energy synchrotron X-rays. The residual stresses in plane stress condition were significantly different between top and side surfaces of the specimen. Therefore, an anisotropic triaxial residual stress probably exists within the MGC. The residual stress within the MGC was also measured using a neutron diffraction. The residual stress in the YAG phase rose from compression in the solidification direction to tension in perpendicular direction. The residual stress in the AlO phase was anisotropic compression and there was no tension in all directions. This anisotropic residual stress could be explained by the crystallographic anisotropy of thermal expansion in the AlO phase. However, both phase stresses were not balanced, so that it is expected that there would be the stress distribution in MGC sample used in this study.
Xe-higher fullerenes by ion implantationWatanabe, Satoshi; Katabuchi, Tatsuya*; Ishioka, Noriko; Matsuhashi, Shimpei; Muramatsu, Hisakazu*
Journal of Radioanalytical and Nuclear Chemistry, 272(3), p.467 - 469, 2007/06
Times Cited Count：1 Percentile：10.65(Chemistry, Analytical)no abstracts in English
Hatsukawa, Yuichi; Miyamoto, Yutaka; Toh, Yosuke; Oshima, Masumi; Gharaie, M. H. M.; Goto, K.*; Toyoda, K.*
Journal of Radioanalytical and Nuclear Chemistry, 272(2), p.273 - 276, 2007/05
Times Cited Count：12 Percentile：61.50(Chemistry, Analytical)In this study, using neutron activation analysis with multi-parameter coincidence method which was developed at Japan Atomic Energy Agency (JAEA), a non-destructive, ultra-high sensitive multi-elemental determination has been realized. The multi-parameter coincidence method is carried out with an array of 19 germanium detectors, GEMINI-II. Using this system, very weak 
-rays emitted from trace amounts of elements can be detected. The iridium concentration has been determined by means of the neutron activation analysis with multi-parameter coincidence method for Cuban sediment samples across the K/T boundary strata.
LiF scintillator sheetsKatagiri, Masaki; Nakamura, Tatsuya; Ebine, Masumi; Birumachi, Atsushi; Sato, Setsuo*; Shooneveld, E. M.*; Rhodes, N. J.*
Nuclear Instruments and Methods in Physics Research A, 573(1-2), p.149 - 152, 2007/04
Times Cited Count：20 Percentile：76.23(Instruments & Instrumentation)no abstracts in English
Nakamura, Tatsuya; Tanaka, Hiroki; Yamagishi, Hideshi; Soyama, Kazuhiko; Aizawa, Kazuya; Ochi, Atsuhiko*; Tanimori, Toru*
Nuclear Instruments and Methods in Physics Research A, 573(1-2), p.187 - 190, 2007/04
Times Cited Count：9 Percentile：55.05(Instruments & Instrumentation)We have been developing a neutron imaging gas detector with a high spatial resolution and with a high temporal response for the neutron scattering instruments at the pulsed neutron source in the Japan proton accelerator research complex. The gas detector system with individual read-outs was developed to meet the requirements for the instruments for neutron reflectometry or for small angle neutron scattering. The performances of the prototype detector using a multi-wire (MW) or micro-strip (MS) detector head were evaluated using a collimated neutron beam, and we confirmed the MS detector exhibiting a spatial resolution of 1.5 mm and a pulse-pair resolution of about 100 ns with a gas pressure of 6 atm helium with a mixture of 30% CF
. The performances for the MS detector were also evaluated up to the total gas pressure of 8 atm.
Kinsho, Michikazu; Saito, Yoshio*; Kabeya, Zenzaburo*; Ogiwara, Norio
Vacuum, 81(6), p.808 - 811, 2007/02
Times Cited Count：7 Percentile：28.99(Materials Science, Multidisciplinary)It was success to develop alumina ceramics vacuum ducts for the 3GeV-RCS of J-PARC at JAERI. There are two types of alumina ceramics vacuum ducts needed, one being 1.5m-long duct with a circular cross section of 378 mm inner diamater for use in the quadrupole magnet, the other being 3.5m-long and bending 15 degrees, with a race-track cross section for use in the dipole magnet. These ducts could be manufactured by joining several duct segments of 0.8 m in length by brazing. The alumina ceramics ducts have copper stripes on the outside surface of the ducts to reduce the duct impedance. The radio-frequency shield is designed as a high frequency pass filter, where eddy currents cannot be generated. In this shield one end of each strope is connected to a titanium flange with a capacitor to interrupt the eddy current loop. With this, the impedance of the duct with the radio-frequency shield was reduced within an allowable desgin limit. In order to reduce emission of secondary electrons when protons or electrons strike the surface, TiN film is coated on the inside surface of the ducts.
Yamamoto, Kazami; Shibata, Takeo*; Ogiwara, Norio; Kinsho, Michikazu
Vacuum, 81(6), p.788 - 792, 2007/02
Times Cited Count：15 Percentile：49.65(Materials Science, Multidisciplinary)The J-PARC 3GeV Rapid-Cycling Synchrotron (RCS) is required to provide 1MW pulsed protons to the spallation neutron target and the 50 GeV main ring. Since the acceleration period is set at a repetition rate of 25Hz, the eddy current effect due to such rapid repetition magnetic field is a big issue (i.e. the perturbation of the magnetic field and the heating owing to the ohmic loss) in the metal duct. Therefore, we choose the ceramics duct in the magnets in order to avoid the eddy current effect. But the total secondary electron emission yield (SEY) from the ceramics surface is larger than the metal one. In order to reduce these undesirable electron emitted from the chamber surface, Titanium Nitride (TiN) is coated on the inside surface of the chambers. We measured SEY from TiN coating surface with various conditions. We further investigated Diamond Like Carbon coating to search the possibility of another coating. The results of these measurements are shown.
Idesaki, Akira; Sugimoto, Masaki; Yoshikawa, Masahito; Tanaka, Shigeru; Narisawa, Masaki*; Okamura, Kiyohito*; Ito, Masayoshi*
Journal of Materials Science, 42(1), p.130 - 135, 2007/01
Times Cited Count：3 Percentile：13.50(Materials Science, Multidisciplinary)We have synthesized minute SiC products from polyvinylsilane (PVS), which is a liquid organosilicon polymer, with radiation curing. Since there is a close relationship between the properties of obtained SiC products and pyrolysis condition, it is important to investigate the ceramization process of PVS in order to find out the optimum pyrolysis condition. In this paper, the ceramization process of the PVS cured by -ray irradiation at room temperature was investigated by gas analysis, thermogravimetric analysis, density measurement, and so on. It was found that the ceramization of -ray cured PVS starts above 500K, and that drastic organic-inorganic conversion occurs in the temperature range of 700-1100K. According to the results of the changes of mass and density, it was found that the volume shrinkage of PVS during the curing and pyrolysis processes is 80%. The SiC obtained by pyrolysis at 1573K showed the density of 2.50g/cm
and microvickers hardness of 31.6GPa.
Fukuda, Yuji; Yamakawa, Koichi
Progress in Ultrafast Intense Laser Science II, p.231 - 251, 2007/00
To better understand a fundamental aspect of the laser cluster interaction, we have carried out systematic investigations of X-ray radiation properties of high-density and high-temperature cluster plasma, created by the action of superintense laser irradiation. The interrelationship between the X-ray radiation properties and ion kinetic energies has been for the first time examined by the simultaneous measurements of X-ray radiation spectra and ion energy spectra. Time scale and mechanism of X-ray emission process have been discussed based on a time-dependent plasma kinetics model. Moreover, in order to demonstrate the practical capability of X-rays thus produced, the pulse X-ray diffraction has been examined from Si crystal with this source.
Koga, J. K.; Bulanov, S. V.; Esirkepov, T. Z.
Ultrafast Optics V, p.143 - 148, 2007/00
When a high irradiance laser interacts with a high energy electron, radiation damping effects can become large. In this paper we show via numerical integration of the equations of motion that a high energy electron can be stopped and accelerated by a laser pulse strong enough. Very high electron energies can be achieved over a relatively short distance.
Sagisaka, Akito; Utsumi, Takayuki*; Daido, Hiroyuki; Ogura, Koichi; Orimo, Satoshi; Takai, Mamiko; Hayashi, Yukio; Mori, Michiaki; Yogo, Akifumi; Kado, Masataka; et al.
Journal of Plasma Physics, 72(6), p.1281 - 1284, 2006/12
Times Cited Count：0 Percentile：0.00(Physics, Fluids & Plasmas)no abstracts in English
Koga, J. K.; Esirkepov, T. Z.; Bulanov, S. V.
Journal of Plasma Physics, 72(6), p.1315 - 1318, 2006/12
Times Cited Count：13 Percentile：39.83(Physics, Fluids & Plasmas)With the advent of high intensity short pulse lasers it has become possible to achieve extremely high intensities. When such laser pulses interact with high energy electron beams, radiation damping, which is usually small, can become large. We examine the effects of radiation damping on the backscattered Thomson radiation numerically and analytically. Using parameters comparable to the laser and microtron here at APRC we find that the overall spectrum is downshifted and that the overall amplitude of the radiation is smaller than in the case with no damping.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Osakabe, Toyotaka; Sato, Taku*; Nakajima, Kenji; Arai, Masatoshi
Physica B; Condensed Matter, 385-386(2), p.1236 - 1239, 2006/11
Times Cited Count：9 Percentile：39.97(Physics, Condensed Matter)Performance of a neutron guide has been studied for the Cold Neutron Double-Chopper Spectrometer (CNDCS) proposed for the spallation neutron source at J-PARC. This spectrometer is dedicated to inelastic neutron scattering studies in vast research fields in an energy range of 
80 meV. In order to detect weak inelastic signals, increasing neutron flux on sample with suppressing background at detector is very important. Installing a neutron guide is a well-known solution to these problems, because it can deliver much more neutrons to sample, and it can also cut off unwanted fast neutrons when installed in a curved layout. The performance of a neutron guide is much affected by its geometry. We have studied efficiency of the beam transport by a supermirror-coated guide designed for the CNDCS with conventional geometries such as straight, curved and tapered, as well as with advanced geometries such as ballistic, parabolic and elliptical. Energy dependence of gain in intensity, and beam distributions in space and angle obtained by Monte Carlo simulation will be discussed.
Maruyama, Ryuji; Yamazaki, Dai; Ebisawa, Toru*; Hino, Masahiro*; Soyama, Kazuhiko
Physica B; Condensed Matter, 385-386(2), p.1256 - 1258, 2006/11
Times Cited Count：28 Percentile：71.69(Physics, Condensed Matter)Neutron supermirror has become an important device to transport, bending and focusing a neutron beam. We have developed it using ion beam sputtering (IBS) instrument since it enables us to produce good quality layers with high density and small grain size. We have also investigated ion-polishing technique, which suppresses the interface roughness of multilayers. We have now installed new IBS instrument with effective deposit area of 500 mm in diameter for the realization of supermirror guide and bender with large effective critical angle. In this presentation, the performance of the supermirrors fabricated with it and the future development of neutron optical devices using supermirrors will be discussed.
Ohara, Takashi; Kurihara, Kazuo; Tamada, Taro; Tanaka, Ichiro*; Niimura, Nobuo*; Kuroki, Ryota
Physica B; Condensed Matter, 385-386(2), p.1049 - 1051, 2006/11
Times Cited Count：0 Percentile：0.00(Physics, Condensed Matter)Our group has two single crystal neutron diffractometers, called BIX-3 and BIX-4, in the JRR-3 reactor-hall at JAERI. Although these diffractometers were designed for bio-macromolecules, these can be used for diffraction measurement of small organic molecules by changing the wavelength of incident neutron beam from 2.9 
to 1.5 . Since both BIX-3 and 4 has a large neutron imaging plate as a detector, they can efficiently collect the Bragg reflections of organic crystal which has relatively large unit cell, the longest value of cell dimension is 50 and typical value is 20 
30 . In typical measurement, the crystal size is 1 3 mm, the measurement time is 1 2 weeks and the minimum 
-value is 0.8 . In addition, the large imaging plate also makes the efficient measurements of fiber diffraction possible. In this presentation, we introduce the performance of BIX-3 and 4 as diffractometers for small organic molecules.
Oku, Takayuki; Yamada, Satoru; Sasao, Hajime*; Suzuki, Junichi; Shinohara, Takenao*; Hirota, Katsuya*; Ikeda, Kazuaki*; Tsuzaki, Tsuyoshi*; Kiyanagi, Yoshiaki*; Furusaka, Michihiro*; et al.
Physica B; Condensed Matter, 385-386(2), p.1225 - 1228, 2006/11
Times Cited Count：10 Percentile：42.77(Physics, Condensed Matter)We have developed a magnetic neutron lens based on an extended Halbach-type permanent sextupole magnet with magnet pieces of NEOMAX-44H, -35EH and high saturation magnetization material, permendule. The aperture size of the magnet is 35 mm in diameter and the magnet length is 2,400 mm. The magnet generates a sextupole magnetic field 
with a gradient coefficient 
=10,600 T/m
inside the aperture, where 
is a distance from the magnet center axis. To prevent neutrons from hitting and reflecting at the inner surface of the magnet, the surface is covered with cadmium (Cd) sheets and also Cd pinhole slits with size of 30 mm in diameter are positioned in series inside the magnet aperture, resulting in the effective diameter of 30 mm. The neutron focusing property of the magnet is investigated by using pulsed polarized neutrons. The obtained results are discussed with the precise simulation results. Its application to the focusing-geometry small-angle neutron scattering experiments is also discussed.
Hoshikawa, Akinori; Igawa, Naoki; Yamauchi, Hiroki; Ishii, Yoshinobu
Physica B; Condensed Matter, 385-386(Part 1), p.567 - 570, 2006/11
Times Cited Count：1 Percentile：6.05(Physics, Condensed Matter)no abstracts in English
Ce
CuO
(x=0, 0.075, and 0.15) studied by Resonant inelastic X-ray scatteringIshii, Kenji; Tsutsui, Kenji*; Endo, Yasuo*; Toyama, Takami*; Maekawa, Sadamichi*; Hoesch, M.; Kuzushita, Kaori; Inami, Toshiya; Tsubota, Masami; Yamada, Kazuyoshi*; et al.
AIP Conference Proceedings 850, p.403 - 404, 2006/09
We report a resonant inelastic X-ray scattering (RIXS) study of charge excitations in the electron-doped high-
superconductor Nd
Ce
CuO. The intraband and interband excitations across the Fermi energy are separated for the first time by tuning the experimental conditions properly to measure charge excitations at low energy. A dispersion relation with 
-dependent width emerges clearly in the intraband excitation, while the intensity of the interband excitation is concentrated around 2 eV near the zone center. The experimental results are consistent with theoretical calculation of the RIXS spectra based on the Hubbard model.
Cu
O
studied by resonant inelastic X-ray scatteringIshii, Kenji; Tsutsui, Kenji*; Endo, Yasuo*; Toyama, Takami*; Kuzushita, Kaori; Inami, Toshiya; Owada, Kenji; Maekawa, Sadamichi*; Masui, Takahiko*; Tajima, Setsuko*; et al.
AIP Conference Proceedings 850, p.445 - 446, 2006/09
Mott gap excitations in the optimally doped high- superconductor YBaCuO ( = 93 K) have been studied by the resonant inelastic X-ray scattering method. Anisotropic spectra in the 
-plane are observed in a twin-free crystal. The excitation from the one-dimensional CuO chain is enhanced at 2 eV near the zone boundary of the 
direction, while the excitation from the CuO plane is broad at 1.5-4 eV and almost independent of the momentum transfer. Theoretical calculation based on the one-dimensional and two-dimensional Hubbard model reproduces the observed spectra when different values of the on-site Coulomb energy are assumed. The Mott gap of the CuO chain site is found to be much smaller than that of the CuO plane site.
