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Kamiya, Junichiro; Takano, Kazuhiro; Yuza, Hiromu*; Wada, Kaoru
Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.3471 - 3474, 2021/08
The NEG coating, which has been developed in CERN, is a revolutionary technique that can make a beam pipe act as a vacuum pump by coating the getter materials with the ability to adsorb/absorb gas molecules on the beam pipe surface. The NEG materials are alloys of titanium, zirconium, and vanadium. Titanium is one of the getter materials. In high-power beam accelerators, titanium has been used as the beam pipe chamber material due to its low radioactivation characteristics. The ordinal titanium surface has no getter function because it is covered with titanium-oxide film. The new technique, which removes the titanium-oxide surface by the sputtering and makes the titanium vacuum chamber itself the vacuum pump like NEG coated chamber, has been developed. After sputtering the inner surface of the titanium chamber, we obtained clear evidence that shows the chamber acts as a vacuum pump. We have also tried to make a titanium chamber with a getter function only by baking. Dependence of the getter characteristics on the baking temperature will also be reported.
Ito, Takashi; Higemoto, Wataru; Koda, Akihiro*; Shimomura, Koichiro*
Applied Physics Letters, 115(19), p.192103_1 - 192103_4, 2019/11
Times Cited Count：8 Percentile：37.59(Physics, Applied) in high-temperature cubic phaseYoneda, Yasuhiro; Taniguchi, Hiroki*; Kitanaka, Yuki*; Noguchi, Yuji*
Ferroelectrics, 538(1), p.57 - 62, 2019/05
Times Cited Count：5 Percentile：27.39(Materials Science, Multidisciplinary)High-energy X-ray diffraction study was performed on lead titanate (PbTiO). Short-range order structure was revealed using atomic pair-distribution function (PDF) method. In the high-temperature cubic phase, there is a large deviation between local and average structure. Especially, Pb atoms deviated from the cubic lattice framework, but establish Pb-O-Pb random network.
-gas exposure at high temperaturesTakeda, Yusuke; Iida, Kiyoshi*; Sato, Shinji*; Matsuo, Tadatoshi*; Nagashima, Yasuyuki*; Okubo, Nariaki; Kondo, Keietsu; Hirade, Tetsuya
JPS Conference Proceedings (Internet), 25, p.011023_1 - 011023_3, 2019/03
In this study, we prepared samples under two different conditions, (1) 810
C, for 600 min, and (2) 850C, for 720 min. A depth-profile analysis of the surfaces of the samples is conducted through Doppler broadening (DB) measurements of positron annihilation 
rays using a slow positron beam. It was indicated that many of positrons annihilated in defects near the surface. According to the TEM image, there are nano-crystal grains near the surface and then positrons can diffuse in the grains and annihilate in defects at the grain boundaries. Furthermore, DB measurements indicated that there is a depth dependence on the chemical composition where positrons annihilate. EDS spectroscopy measurements also indicated that there is a depth dependence of impurities such as Vanadium. These results indicated change of the chemical composition at the grain boundaries.
O
Tsukada, Shinya*; Fujii, Yasuhiro*; Yoneda, Yasuhiro; Moriwake, Hiroki*; Konishi, Ayako*; Akishige, Yukikuni*
Physical Review B, 97(2), p.024116_1 - 024116_7, 2018/02
Times Cited Count：19 Percentile：65.6(Materials Science, Multidisciplinary)Uniaxial ferroelectric BaTiO with a Curie temperature 
of 743 K was investigated to clarify its paraelectric-ferroelectric phase transition behavior. The mechanism is discussed on the basis of the structure from short to long ranges determined by synchrotron X-ray diffraction and the lattice dynamics probed by Raman spectroscopy. Using a combination of experimental results and first-principles calculations, we explain the phase transition. Ti vibration of TiO
octahedral units is frozen in the ferroelectric phase and the space group changes from nonpolar 
to polar 
.
-gas exposure at high temperaturesTakeda, Yusuke; Iida, Kiyoshi*; Sato, Shinji*; Matsuo, Tadatoshi*; Nagashima, Yasuyuki*; Okubo, Nariaki; Kondo, Keietsu; Hirade, Tetsuya
Journal of Physics; Conference Series, 791(1), p.012022_1 - 012022_4, 2017/02
Times Cited Count：1 Percentile：42.05(Physics, Multidisciplinary)Titanium alloy is widely used for applications such as golf club heads and structural materials for aircrafts. The surface can be exceedingly hardened by nitriding treatment that initiates defects, but there are some difficulties on use of titanium nitride because the layer can be exfoliated by stress. Therefore, we prepared samples in two different treatment conditions, (1) 810C 600 min and (2) 850C 720 min and performed depth profile analysis of Doppler broadening of positron annihilation -rays (DB) for these samples. According to a calculation of nitrogen diffusion depth, the nitride layer should be only about 0.05-0.1
m. However, the depth profile analysis of the DB measurement indicated that the defects introduced by nitriding treatment extended to a depth of 0.5m.
irradiationYukawa, Takuji*; Inoue, Hiroyuki*; Kojima, Takao*; Iwase, Akihiro*; Taniguchi, Naoki; Tachikawa, Hirokazu*
Zairyo To Kankyo 2016 Koenshu (CD-ROM), p.359 - 362, 2016/05
The immersion tests of pure titanium were carried out in aqueous solution containing carbonate/bicarbonate with 50 mM-chloride ion under gamma irradiation. The effect of pH on general corrosion rate of titanium were studied. The experimental results showed that the concentration of hydrogen preoxide was increased with pH, and the corrosion rate increased with the hydrogen preoxide concentration. The corrosion rate in pH12 and 13 were 5 to10 times larger than those under unirradiated conditions.
on dehydrogenation of magnesium borohydride Mg(BH
)Li, H.-W.*; Matsumura, Daiju; Nishihata, Yasuo; Akiba, Etsuo*; Orimo, Shinichi*
Nihon Kinzoku Gakkai-Shi, 77(12), p.627 - 630, 2013/12
Times Cited Count：4 Percentile：27.48(Metallurgy & Metallurgical Engineering)no abstracts in English
(100) films by helium irradiationYamamoto, Shunya; Nagata, Shinji*; Takeyama, Akinori; Yoshikawa, Masahito
Nuclear Instruments and Methods in Physics Research B, 249(1-2), p.374 - 376, 2006/08
Times Cited Count：8 Percentile：50.31(Instruments & Instrumentation)no abstracts in English
Kiriyama, Hiromitsu; Yamakawa, Koichi
Laser Physics, 16(4), p.666 - 672, 2006/04
Times Cited Count：4 Percentile：23.42(Optics)no abstracts in English
TiO heated at high temperature under various conditionsHoshino, Tsuyoshi; Yasumoto, Masaru*; Tsuchiya, Kunihiko; Hayashi, Kimio; Nishimura, Hidetoshi*; Suzuki, Akihiro*; Terai, Takayuki*
Fusion Engineering and Design, 81(1-7), p.555 - 559, 2006/02
Times Cited Count：18 Percentile：76.2(Nuclear Science & Technology)no abstracts in English
films by RBS/CYamamoto, Shunya; Takeyama, Akinori; Yoshikawa, Masahito
Nuclear Instruments and Methods in Physics Research B, 242(1-2), p.377 - 379, 2006/01
Times Cited Count：9 Percentile：53.56(Instruments & Instrumentation)no abstracts in English
TiO pebbles from Li-Ti complex solutionTsuchiya, Kunihiko; Kawamura, Hiroshi; Casadio, S.*; Alvani, C.*
Fusion Engineering and Design, 75-79, p.877 - 880, 2005/11
Times Cited Count：26 Percentile：84.04(Nuclear Science & Technology)no abstracts in English
TiO under varied surface conditionOlivares, R.*; Oda, Takuji*; Oya, Yasuhisa*; Tanaka, Satoru*; Tsuchiya, Kunihiko
Fusion Engineering and Design, 75-79, p.765 - 768, 2005/11
Times Cited Count：9 Percentile：53.19(Nuclear Science & Technology)no abstracts in English
TiO under hydrogen atmosphere conditionHoshino, Tsuyoshi; Tsuchiya, Kunihiko; Hayashi, Kimio; Terai, Takayuki*; Tanaka, Satoru*; Takahashi, Yoichi*
Fusion Engineering and Design, 75-79, p.939 - 943, 2005/11
Times Cited Count：13 Percentile：65.42(Nuclear Science & Technology)no abstracts in English
TiO pebbles fabricated by indirect wet processesTsuchiya, Kunihiko; Kawamura, Hiroshi; Takayama, Tomoo*; Kato, Shigeru*
Journal of Nuclear Materials, 345(2-3), p.239 - 244, 2005/10
Times Cited Count：38 Percentile：91.02(Materials Science, Multidisciplinary)no abstracts in English
Yamazaki, Atsushi; Kotaki, Hideyuki; Daito, Izuru; Kando, Masaki; Bulanov, S. V.; Esirkepov, T. Z.; Kondo, Shuji; Kanazawa, Shuhei; Homma, Takayuki*; Nakajima, Kazuhisa; et al.
Physics of Plasmas, 12(9), p.093101_1 - 093101_5, 2005/09
Times Cited Count：70 Percentile：88.77(Physics, Fluids & Plasmas)no abstracts in English
(100) thin films by helium ion implantationYamamoto, Shunya; Nagata, Shinji*; Takeyama, Akinori; Yoshikawa, Masahito
Transactions of the Materials Research Society of Japan, 30(3), p.789 - 792, 2005/09
no abstracts in English
TiO reaction with H in thermo-chemical environment relevant to breeding blanket for fusion power plantsAlvani, C.*; Casadio, S.*; Contini, V.*; Giorgi, R.*; Mancini, M. R.*; Tsuchiya, Kunihiko; Kawamura, Hiroshi
JAERI-Review 2005-024, 28 Pages, 2005/07
JAERI-Review-2005-024.pdf:5.73MB
no abstracts in English
Sato, Satoshi; Verzilov, Y. M.; Nakao, Makoto*; Ochiai, Kentaro; Wada, Masayuki*; Nishitani, Takeo
Fusion Science and Technology, 47(4), p.1046 - 1051, 2005/05
Times Cited Count：12 Percentile：62.91(Nuclear Science & Technology)no abstracts in English
