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Takada, Hiroshi; Haga, Katsuhiro; Teshigawara, Makoto; Aso, Tomokazu; Meigo, Shinichiro; Kogawa, Hiroyuki; Naoe, Takashi; Wakui, Takashi; Oi, Motoki; Harada, Masahide; et al.
Quantum Beam Science (Internet), 1(2), p.8_1 - 8_26, 2017/09
At the Japan Proton Accelerator Research Complex (J-PARC), a pulsed spallation neutron source provides neutrons with high intensity and narrow pulse width to promote researches on a variety of science in the Materials and life science experimental facility. It was designed to be driven by the proton beam with an energy of 3 GeV, a power of 1 MW at a repetition rate of 25 Hz, that is world's highest power level. A mercury target and three types of liquid para-hydrogen moderators are core components of the spallation neutron source. It is still on the way towards the goal to accomplish the operation with a 1 MW proton beam. In this paper, distinctive features of the target-moderator-reflector system of the pulsed spallation neutron source are reviewed.
Shinto, Katsuhiro; Sene, F.*; Ayala, J.-M.*; Bolzon, B.*; Chauvin, N.*; Gobin, R.*; Ichimiya, Ryo; Ihara, Akira; Ikeda, Yukiharu; Kasugai, Atsushi; et al.
Review of Scientific Instruments, 87(2), p.02A727_1 - 02A727_3, 2016/02
Times Cited Count:8 Percentile:39.15(Instruments & Instrumentation)Kai, Tetsuya; Harada, Masahide; Teshigawara, Makoto; Watanabe, Noboru; Kiyanagi, Yoshiaki*; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research A, 550(1-2), p.329 - 342, 2005/09
Times Cited Count:18 Percentile:74.92(Instruments & Instrumentation)Neutronic study was performed on coupled hydrogen moderators to maximize time-integrated and pulse-peak intensities of slow neutrons when a large number of beams was required. The total increased with the number of beams, although the average decreased due to a reflector-missing by the beam extraction holes in the reflector. At a large beam extraction angle (25 degree), the spatial distribution of the vector-flux of neutrons was undesirable for a rectangular shape moderator. As an alternative we proposed a cylindrical shape one, resulting in a much improved spatial distribution. In addition, neutronic performance was calculated as a function of the diameter, indicating the optimal diameter was about 140 mm. The cylindrical one gave higher pulse-peak intensities with narrower pulse widths without penalty in time-integrated intensities and pulse decay characteristics, providing a more uniform angle-dependence. Some explanations are given for the difference in the pulse characteristics between the two. We decided to adopt the cylindrical one for the Japanese spallation neutron source.
Mironov, M. I.*; Khudoleev, A. V.*; Kusama, Yoshinori
Plasma Physics Reports, 30(2), p.164 - 168, 2004/02
Times Cited Count:0 Percentile:0.02(Physics, Fluids & Plasmas)High-energy charge-exchange diagnostics can determine the distribution function of fast atoms produced via the neutralization of hydrogen ions by hydrogen-like impurity ions. Deriving the distribution function requires to know the composition and spatial distribution of the target ions in a plasma. A charge-exchange target forms as a result of the interaction between impurity nuclei and beam atoms. Depending on the arrangement of heating beams with respect to the diagnostics, it is necessary to calculate their trajectories. A model which takes into account elementary processes resulting in the ionization equilibrium of the ions of impurities in a specific tokamak configuration is proposed. The model is applied to the JT-60U plasma. Mechanisms for the formation of charge-exchange atomic flows are considered. The relative contributions of different heating injectors to the charge-exchange flow are estimated. Based on the calculated results, a method is proposed for local measurements of the ion distribution function with a stationary analyzer.
Nakamura, Hirofumi; Hayashi, Takumi; Kakuta, Toshiya*; Suzuki, Takumi; Nishi, Masataka
Journal of Nuclear Materials, 297(3), p.285 - 291, 2001/09
Times Cited Count:17 Percentile:74.85(Materials Science, Multidisciplinary)The isotope effect on the implantation-driven permeation of pure tritium (T) and deuterium (D) through nickel was investigated, respectively. The rate-determining processes of backward flow at the upstream surface and permeation at the down-stream surface were found to be as follows: recombination on up-stream surface and diffusion at down-stream side in a lower temperature region, whereas recombination on both surfaces in a higher temperature region for T and D, respectively. The diffusion coefficients of T and D derived by analyzing the obtained transient data of permeation in the lower temperature region were in good agreement with literature data of deuterium. The obtained activation energy of diffusion for T and D suggested the tendency of mass dependence. The surface recombination coefficients for both isotopes were also derived and showed in good agreement with literature data. As a result, the experimental results indicated the surface recombination could be attributed to the isotope effect of the permeation between T and D rather than the diffusion.
*; Nakamura, Kazuyuki; Okumura, Yoshikazu; Shinto, Katsuhiro*
Dai-4-Kai Ryushisen No Sentanteki Oyo Gijutsu Ni Kansuru Shimpojiumu, p.19 - 22, 1993/00
no abstracts in English
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Radiation Physics and Chemistry, 29(4), p.295 - 301, 1987/04
no abstracts in English
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Radiation Physics and Chemistry, 27(2), p.153 - 155, 1986/00
no abstracts in English
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Radiation Physics and Chemistry, 27(2), p.147 - 151, 1986/00
no abstracts in English
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JAERI-M 84-224, 69 Pages, 1985/01
no abstracts in English
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Radiation Physics and Chemistry, 26(6), p.715 - 721, 1985/00
no abstracts in English
; Ohara, Yoshihiro; ;
JAERI-M 84-098, 23 Pages, 1984/05
no abstracts in English
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JAERI-M 83-126, 113 Pages, 1983/08
no abstracts in English
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J.Chem.Soc.,Faraday Trans.,I, 79, p.1973 - 1986, 1983/00
no abstracts in English
JAERI-M 82-192, 95 Pages, 1982/12
no abstracts in English
; Araki, Masanori; ; ; ; ; ; Matsuda, Shinzaburo; ; *; et al.
Review of Scientific Instruments, 53(12), p.1864 - 1869, 1982/00
Times Cited Count:20 Percentile:87.85(Instruments & Instrumentation)no abstracts in English
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JAERI-M 9856, 131 Pages, 1981/12
no abstracts in English
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JAERI-M 8569, 146 Pages, 1979/11
no abstracts in English
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JAERI-M 7949, 111 Pages, 1978/10
no abstracts in English
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JAERI-M 7355, 85 Pages, 1977/10
no abstracts in English
Hotta, Hiroshi; ; ;
Radiat.Res., 63(1), p.24 - 31, 1975/01
Times Cited Count:6no abstracts in English