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1,652 results on '"Ochiai, K."'

203. Radiation detector made of a high-quality polycrystalline diamond

Author

Kaneko, J.H., primary, Tanaka, T., additional, Kawamura, S., additional, Oshiki, Y., additional, Tsuji, K., additional, Katagiri, M., additional, Ochiai, K., additional, Nishitani, T., additional, Fujita, F., additional, Homma, A., additional, Sawamura, T., additional, Iida, T., additional, and Furusaka, M., additional

Published
2005
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215. Neutron Tranamission Experiment of Boron-doped Resin for the JT-60SC Neutron Shield using 2.45 Mev Neutron Source

Author

Morioka, A., primary, Sato, S., additional, Ochiai, K., additional, Sakasai, A., additional, Hori, J., additional, Yamauchi, M., additional, Nishitani, T., additional, Kaminaga, A., additional, Masaki, K., additional, Sakurai, S., additional, Hayashi, T., additional, Matsukawa, M., additional, Tamai, H., additional, and Ishida, S., additional

Published
2004
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222. 14 MEV NEUTRON IRRADIATION EFFECT ON CRITICAL CURRENT AND CRITCAL MAGNETIC FIELD OF NB3SN AND NB3AL WIRES.

Author

Nishimura, A., Takeuchi, T., Nishijima, S., Ochiai, K., Nishijima, G., Watanabe, K., and Shikama, T.

Subjects
ALUMINUM wire, MAGNETIC fields, NEUTRONS, IRRADIATION, SUPERCONDUCTIVITY
Abstract

To investigate the effect of neutron irradiation on superconducting properties, a collaboration network was established among superconducting material engineering and neutronics fields. Within the framework, irradiation test of Nb3Sn and Nb3Al wires by 14 MeV fusion neutron was planned and carried out at Fusion Neutronics Source in Japan Atomic Energy Agency. After the irradiation, critical current and critical magnetic field were measured with 28 T hybrid magnet at Institute for Metals Research in Tohoku University. The irradiation to 3.52×1020 n/m2 showed a slight increase of the critical current of the Nb3Sn wire, and the irradiation to 1.78×1021 n/m2 made the critical current appreciably larger. Regarding the critical magnetic field, no clear change was observed. In the case of Nb3Al wire, a sample irradiated to 1.78×1021 n/m2 showed no increase of the critical current below 200 A which was the limit of the power supply. As for the critical magnetic field, there was no clear improvement similar to the Nb3Sn wire. The increase of the critical current would be caused by knock-on effect of the fast neutron. [ABSTRACT FROM AUTHOR]

Published
2010
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230. 14 MeV Neutron Irradiation Effect on Superconducting Magnet Materials for Fusion Device.

Author

Nishimura, A., Hishinuma, Y., Seo, K., Tanaka, T., Muroga, T., Nishijima, S., Katagiri, K., Takeuchi, T., Shindo, Y., Ochiai, K., Nishitani, T., and Okuno, K.

Subjects
NEUTRON irradiation, IRRADIATION, NUCLEAR reactions, SUPERCONDUCTING magnets, ELECTROMAGNETS, SUPERCONDUCTORS, MAGNETIC fields, FIELD theory (Physics)
Abstract

As a large-scale plasma experimental device is planned and designed, the importance of investigations on irradiation effect of 14 MeV neutron increases and an experimental database is desired to be piled up. Recently, intense streaming of fast neutron from ports are reported and degradation of superconducting magnet performance is anticipated. To investigate the pure neutron effect on superconducting magnet materials, a cryogenic target system was newly developed and installed at Fusion Neutronics Source in Japan Atomic Energy Research Institute. Although production rate of 14 MeV neutron is not large, only 14 MeV neutron can be supplied to irradiation test without gamma ray. Copper wires, superconducting wires, glass fiber reinforced composites are irradiated and the irradiation effects are characterized. At the same time, sensors for measuring temperature and magnetic field are irradiated and their performance was investigated after irradiation. This paper presents outline of the cryogenic target system and some irradiation test results. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2006
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231. Irradiation Effect of 14 MeV Neutron on Interlaminar Shear Strength of Glass Fiber Reinforced Plastics.

Author

Nishimura, A., Hishinuma, Y., Seo, K., Tanaka, T., Muroga, T., Nishijima, S., Katagiri, K., Takeuchi, T., Shindo, Y., Ochiai, K., Nishitani, T., and Okuno, K.

Subjects
IRRADIATION, NEUTRAL beams, PARTICLE beams, NEUTRONS, GAMMA rays, ELECTROMAGNETIC waves, IONIZING radiation
Abstract

Design activity of International Thermonuclear Experimental Reactor clarifies intense neutron streaming from ports for neutral beam injectors. Energy spectrum of the streaming is very wide and 14 MeV neutron and gamma ray are the typical radiations. Large amount of glass fiber reinforced plastics will be used in a superconducting magnet system as an electric insulation material and a support structure, for such organic material is easy to manufacture, and light and cheap. In this report, effects of 14 MeV neutron and gamma ray irradiation on interlaminar shear strength and fracture mode are investigated using G-10CR small specimen of which configuration was proposed as a standard for evaluation of the interlaminar shear strength. A short beam test under three point bending was conducted at room temperature and 77 K. Neutron fluence of 3.91 × 1019 n/m2 was irradiated and the specimens did not show clear degradation of the strength. On the other hand, gamma ray irradiation of 1 MGy made the specimen weaker and 10 MGy caused delamination. Most of the specimens showed both of interlaminar cracking and bending fracture, but some specimens were fractured with irregular shear occurred on the planes connecting loading point and supporting points. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2006
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233. Development of Charged-Particle Emission DDX Spectrometer with SSD Telescope and Pencil-Beam DT Neutron Source.

Author

Murata, I., Kondo, K., Takagi, S., Miyamaru, H., Takahashi, A., Ochiai, K., and Nishitani, T.

Subjects
NEUTRON sources, RADIATION sources, NUCLEAR cross sections, COLLISIONS (Nuclear physics), SPECTROMETERS, TELESCOPES, NUCLEAR physics, PHYSICS
Abstract

A new spectrometer has been developed, including a pencil-beam 14-MeV neutron source and a telescope system with two SSDs of ΔE and E, in order to measure double differential charged-particle emission cross sections (DDXs). The spectrometer can supply quite good performance, i.e., low minimum measurable energy of below 2 MeV for alpha particles and a very high S/N ratio over 10. Highly accurate charged-particle emission DDX data can thus be expected to be measured by this spectrometer. From the test measurement for aluminum, the validity was confirmed by comparing the angular differential cross section (ADX) and the total charged-particle emission cross section with other data. Also, the measurement for beryllium has been carried out. From the result of the measurement, the acceptable agreement with the evaluation was confirmed in the energy spectrum. The precise branching ratio of the breakup nuclear reaction of beryllium is now being analyzed from the obtained DDX data. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2005
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