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Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：6 Percentile：84.97(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
NeNakamura, Takashi*; Kobayashi, Nobuyuki*; Kondo, Yosuke*; Sato, Yoshiteru*; Aoi, Nori*; Baba, Hidetada*; Deguchi, Shigeki*; Fukuda, Naoki*; Gibelin, J.*; Inabe, Naoto*; et al.
Physical Review Letters, 103(26), p.262501_1 - 262501_4, 2009/12
Times Cited Count：198 Percentile：97.53(Physics, Multidisciplinary)no abstracts in English
Ogiwara, Norio; Kanazawa, Kenichiro; Inohara, Takashi*; Wada, Kaoru*
Vacuum, 84(5), p.718 - 722, 2009/12
Times Cited Count：7 Percentile：30.19(Materials Science, Multidisciplinary)Recently turbo-molecular pumps (TMPs) have been widely used in nuclear fusion devices and sometimes in particle accelerators. Therefore, in order to use them in a quasi-static magnetic field the influence of the fields on TMPs has been exactly investigated. First of all, the influence for the two special magnetic fields has been examined: one is due to the vertical magnetic field, and the other due to the parallel component. The parallel magnetic field has no influence of the operation of the TMP. On the contrary, the driving power and the rotor temperature were largely affected by the vertical magnetic field. The eddy current loss in the vertical field increases rapidly with the field strength. It is proportional to the square of the field strength. The eddy current loss also increases as the revolution frequency, however, it has quite different dependence from the magnetic field strength. These dependences are well explained by the skin depth, which referred to the region where a localized magnetic field and current flow exists. Then we have successfully evaluated the influence of the magnetic field with an arbitrary direction by means of adding the contributions from the two magnetic components. Furthermore, from the demonstration experiment, it is generally found that the magnetic field with the symmetry around the rotor axis does not affect the operation of the TMP.
Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.
Materials Science Forum, 607, p.248 - 250, 2009/00
So far no standard procedure for the positron annihilation lifetime (PAL) technique has been established. A lack of the standards has led to difficulty in ensuring the equivalency and reliability of data from different laboratories. As a first, we conducted an interlaboratory comparison of PAL measurements for metal, polymer and silica glass with agreed procedures for data recording and analysis. The PAL data recorded at different laboratories were analyzed with a single lifetime component for the metal sample and with three components for the others, respectively. Based on the results of the reported positron and ortho-positronium lifetimes, the possible sources of the uncertainties in the PAL measurements are discussed. To reduce the effect of scattered 
rays, a lead shield was placed between the detectors. The uncertainty was significantly decreased, signifying that placing lead shields between the detectors effectively reduced the false signals due to the scattered rays.
Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.
Journal of Applied Physics, 104(2), p.026102_1 - 026102_3, 2008/07
Times Cited Count：48 Percentile：83.5(Physics, Applied)Interlaboratory comparison of positron annihilation lifetime measurements using synthetic fused silica and polycarbonate was conducted with the participation of 12 laboratories. By regulating procedures for the measurement and data analysis the uncertainties of the positron lifetimes obtained at different laboratories were significantly reduced in comparison with those reported in the past.
Kanazawa, Kenichiro; Ogiwara, Norio; Suganuma, Kazuaki; Inohara, Takashi*; Wada, Kaoru*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.391 - 393, 2008/00
no abstracts in English
Kizaki, Hiroyuki*; Wada, Shinichi*; Sako, Erika*; Sumii, Ryohei*; Waki, Satoshi*; Isari, Koji*; Sekitani, Tetsuji*; Sekiguchi, Tetsuhiro; Tanaka, Kenichiro*
Journal of Electron Spectroscopy and Related Phenomena, 144-147, p.447 - 451, 2005/06
Times Cited Count：5 Percentile：27.35(Spectroscopy)no abstracts in English
Wada, Shinichi*; Sumii, Ryohei*; Isari, Koji*; Waki, Satoshi*; Sako, Erika*; Sekiguchi, Tetsuhiro; Sekitani, Tetsuji*; Tanaka, Kenichiro*
Surface Science, 528(1-3), p.242 - 248, 2003/03
Times Cited Count：45 Percentile：84.06(Chemistry, Physical)no abstracts in English
Wada, Shinichi*; Sako, Erika*; Sumii, Ryohei*; Waki, Satoshi*; Isari, Koji*; Sekiguchi, Tetsuhiro; Sekitani, Tetsuji*; Tanaka, Kenichiro*
Nuclear Instruments and Methods in Physics Research B, 199, p.361 - 365, 2003/01
Times Cited Count：11 Percentile：59.38(Instruments & Instrumentation)no abstracts in English
Watanabe, Masayuki; Ishimori, Kenichiro; Wada, Atsushi*; Kataoka, Yumiko*; Murata, Masaki*; Shinoda, Satoshi*; Nishihara, Hiroshi*; Tsukube, Hiroshi*; Kimura, Takaumi
no journal, ,
Soft-donor extractants containing sulfur- or nitrogen-donor are applicable to the separation of trivalent actinides (An(III)) from lanthanides (Ln(III)) by solvent extraction method. We designed two ligand systems which are expected to efficiently separate An(III) from Ln(III). The one is "Oligo-pyridine" ligand containing multiple pyridine moieties. The other is "Chirality-controlled" ligand containing chiral centers in the ligand. We synthesized more than thirty ligands and found out the ability on the separation of An(III) from Ln(III). In this presentation, we will discuss about the comprehensive results on the separation ability of An(III) from Ln(III) by means of "Oligo-pyridine" and "Chirality-controlled" ligands, and the extraction equilibrium of An(III) with selected tripodal ligands in detail.
Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.
no journal, ,
So far no standard procedure for the positron annihilation lifetime (PAL) technique has been established. A lack of the standards has led to difficulty in ensuring equivalency and reliability of data from different laboratories. Recently, as a first step toward the standardization of the PAL technique, we conducted an interlaboratory comparison of PAL measurements for fused silica, polycarbonate and metal with agreed procedures for data recording and analysis. Based on the results of the reported lifetimes, possible sources of the uncertainties in the PAL measurements is probably caused by the backscattered -rays by other detectors. We succeeded to show that inserting shields between detectors can reduce the uncertainty.
Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.
no journal, ,
An interlaboratory comparison for positron annihilation lifetime measurements for pure nickel, polycarbonate (PC) and fused silica was performed. Based on the reported data of positron (for nickel) and positronium (for PC and fused silica) components, the uncertainties in the PAL measurements were estimated and their possible source was discussed.
