Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Toh, Yosuke; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Kitatani, Fumito; Komeda, Masao; Maeda, Makoto; Koizumi, Mitsuo
Proceedings of INMM & ESARDA Joint Virtual Annual Meeting (Internet), 8 Pages, 2021/08
Toh, Yosuke; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Kitatani, Fumito; Komeda, Masao; Maeda, Makoto; Koizumi, Mitsuo
Proceedings of INMM 60th Annual Meeting (Internet), 7 Pages, 2019/07
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Toh, Yosuke; Koizumi, Mitsuo; Seya, Michio
Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 4 Pages, 2018/11
Nakayoshi, Akira; Suzuki, Seiya; Okamura, Nobuo; Watanabe, Masayuki; Koizumi, Kenji
Journal of Nuclear Science and Technology, 55(10), p.1119 - 1129, 2018/10
Times Cited Count：2 Percentile：20.93(Nuclear Science & Technology)Toh, Yosuke; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Kitatani, Fumito; Komeda, Masao; Maeda, Makoto; Koizumi, Mitsuo; Heyse, J.*; Paradela, C.*; et al.
Proceedings of INMM 59th Annual Meeting (Internet), 9 Pages, 2018/07
Toh, Yosuke; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Kitatani, Fumito; Komeda, Masao; Maeda, Makoto; Kureta, Masatoshi; Koizumi, Mitsuo; Seya, Michio; et al.
EUR-28795-EN (Internet), p.684 - 693, 2017/00
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Tobita, Hiroshi; Kureta, Masatoshi; Koizumi, Mitsuo; Seya, Michio
Proceedings of 2016 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2016) (Internet), 4 Pages, 2016/00
no abstracts in English
Kureta, Masatoshi; Koizumi, Mitsuo; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Seya, Michio
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12
The new program "Development of active neutron NDA techniques" has started for non-proliferation applications collaborating with EC-JRC. The final purpose of this program is to establish the measurement techniques for the high radioactive special nuclear material such as MA-Pu fuel for transmutation of minor actinide. In this program, the JAEA will conduct the R&D on active neutron non-destructive measurement techniques, DDA, NRTA, PGA/NRCA and DGS. The development plan and current status of the design study of the active neutron integrated test apparatus named "Active-N" are presented in this report.
Oguri, Hidetomo; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Yamazaki, Saishun; Takagi, Akira*; Koizumi, Isao; Ueno, Akira
JPS Conference Proceedings (Internet), 8, p.011009_1 - 011009_6, 2015/09
Yamaji, Tatsuya*; Koizumi, Yasuo; Yamazaki, Kohei*; Otake, Hiroyasu*; Hasegawa, Koji*; Onuki, Akira*; Kanamori, Daisuke*
Konsoryu Shimpojiumu 2015 Koen Rombunshu (USB Flash Drive), 2 Pages, 2015/08
Experiments of condensing counter-current two-phase flow in a vertical pipe were performed. This study was intended to examine water accumulation in the up-flow side of steam generator U-tubes of a PWR during the reflux cooling stage of a small break LOCA. It has been apprehended that the water accumulation may result in temporary core liquid level depression. The inner diameter and the length of a test flow channel used in the experiments were 18 mm and 4 m, respectively. The experiments were performed by using steam and water at 0.1 MPa. Two kinds of experiments were conducted; visualization experiments by using a transparent test section and quantitative water accumulation evaluation experiments by using a brass test section. Even if water on the inner surface of the test pipe could not flow downward at the lower portion of the test pipe, a part of water became to flow downward at the upper portion of the test pipe since steam velocity decreased because of condensation. Thus, two-phase mixture level was formed in the upper portion of the test pipe, which resulted in the water accumulation in the pipe. The model to predict the water accumulation was proposed. It predicted the water accumulation reasonably well.
Kureta, Masatoshi; Koizumi, Mitsuo; Ozu, Akira; Furutaka, Kazuyoshi; Tsuchiya, Takahiro*; Seya, Michio; Harada, Hideo; Abousahl, S.*; Heyse, J.*; Kopecky, S.*; et al.
Proceedings of 37th ESARDA Annual Meeting (Internet), p.111 - 120, 2015/08
The JAEA has just started the new program "Development of active neutron NDA techniques" collaborating with EC-JRC. The final purpose of this program is to establish the measurement techniques for the high radioactive special nuclear material such as MA-Pu fuel for transmutation of minor actinide and for nuclear security applications. In this program, JAEA will conduct the R&D on active neutron non-destructive measurement techniques, DDA, NRTA, PGA/NRCA and DGS.
Kureta, Masatoshi; Koizumi, Mitsuo; Ozu, Akira; Furutaka, Kazuyoshi; Tsuchiya, Harufumi; Seya, Michio
Proceedings of INMM 56th Annual Meeting (Internet), 9 Pages, 2015/07
The new program "Development of active neutron NDA techniques" has started for non-proliferation applications. The final purpose of this program is to establish the measurement techniques for the high radioactive special nuclear material such as MA-Pu fuel for transmutation of minor actinide. In this program, the JAEA will conduct the R&D on active neutron non-destructive measurement techniques, DDA, NRTA, PGA/NRCA and DGS in collaboration with EC-JRC.
Kondo, Yasuhiro; Morishita, Takatoshi; Yamazaki, Saishun; Hori, Toshihiko; Sawabe, Yuki; Chishiro, Etsuji; Fukuda, Shimpei; Hasegawa, Kazuo; Hirano, Koichiro; Kikuzawa, Nobuhiro; et al.
Physical Review Special Topics; Accelerators and Beams, 17(12), p.120101_1 - 120101_8, 2014/12
Times Cited Count：6 Percentile：42.9(Physics, Nuclear)We performed a beam test of a new radio frequency quadrupole linac (RFQ III) for the beam current upgrade of the Japan Proton Accelerator Research Complex. First, the conditioning of RFQ III was conducted, and after 20 h of conditioning, RFQ III became very stable with a nominal peak power and duty factor of 400 kW and 1.5%, respectively. An off-line beam test was subsequently conducted before installation in the accelerator tunnel. The transmission, transverse emittance, and energy spread of the 50-mA negative hydrogen beam from RFQ III were measured and compared with simulation results. The experiment and simulation results showed good agreement; therefore, we conclude that the performance of RFQ III conforms to its design.
Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10
no abstracts in English
Okoshi, Kiyonori; Ikegami, Kiyoshi*; Koizumi, Isao; Ueno, Akira; Takagi, Akira*; Yamazaki, Saishun; Oguri, Hidetomo
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.946 - 949, 2014/06
A J-PARC ion source driven with a LaB6 filament is being operated without any serious trouble since the restoration from the earthquake. The H
ion current from the source is routinely restricted 19 mA for the filament lifetime. In order to increase the beam power at the linac beam operation, the beam current from the ion source was increased to 22 mA. At this operation, the filament lifetime was estimated by the reduction in the filament current. According to the steep reduction in the filament current, the break of the filament was predicted. Although the filament has broken after 10 h from the steep current reduction, the beam operation was restarted 8 h later by the preparation for the exchange of new filament. At the study time for the 3 GeV synchrotron, the ion source was operated at 30 mA for 8 days.
ion source for the J-PARCKoizumi, Isao; Ueno, Akira; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Takagi, Akira*; Yamazaki, Saishun; Oguri, Hidetomo
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.920 - 923, 2014/06
In order to satisfy the J-PARC (Japan Proton Accelerator Research Complex) 2nd stage requirements the J-PARC rf-driven H ion source is under development. The source plasma is produced by an about 50 W CW 30 MHz-rf and an about 40 kW pulsed 2 MHz-rf. The Cs is installed into the plasma chamber by opening the Cs-valve between the plasma chamber and the Cs oven, which is heated to 200
240 
C. The H ion beam current is maximized by optimizing the Cs quantity depending upon the Cs-valve opening time, the PE temperature depending upon the flow rate of the air through the PE cooling plate, the AMFC by the AMFC coil current, and so on. The experimental results using the plasma chamber made of copper, which satisfied the above requirements, were reported last year. The experimental results using the plasma chamber made of stainless steel are presented in this paper. The observed several interesting differences between the two plasma chambers are also presented.
ion sourceUeno, Akira; Koizumi, Isao; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Takagi, Akira*; Yamazaki, Saishun; Oguri, Hidetomo
Review of Scientific Instruments, 85(2), p.02B133_1 - 02B133_5, 2014/02
Times Cited Count：6 Percentile：29.22(Instruments & Instrumentation)no abstracts in English
Oguri, Hidetomo; Ikegami, Kiyoshi*; Okoshi, Kiyonori; Koizumi, Isao; Takagi, Akira*; Namekawa, Yuya*; Yamazaki, Saishun; Ueno, Akira
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1081 - 1083, 2013/08
no abstracts in English
ion source for the J-PARCYamazaki, Saishun; Ueno, Akira; Namekawa, Yuya*; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Takagi, Akira*; Koizumi, Isao; Oguri, Hidetomo
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.260 - 264, 2013/08
A cesium (Cs) seeded RF-driven H ion source using an internal-antenna developed at the SNS (Spallation Neutron Source) is under development for the J-PARC (Japan Proton Accelerator Research Complex). The axial magnetic field optimization by using an axial magnetic field compensation (AMFC) coil significantly enhances the H ion beam by typically 10%. An H ion beam with a flat top duty factor of 2.5% (1 ms 
25 Hz) of 77 mA, whose about 90% (corresponding to about 70 mA) of emittance of each direction is within 1.5 
mm
mrad, is successfully extracted. During a demonstration operation over 100-hours, an H ion beam over 66 mA was successfully produced with a relatively low RF power of about 40 kW by seeding Cs for 4-minutes a day.
Shindo, Yasuhide*; Takeda, Tomo*; Narita, Fumio*; Miura, Masaya*; Watanabe, Shinya*; Koizumi, Norikiyo; Idesaki, Akira; Okuno, Kiyoshi
Cryogenics, 50(1), p.36 - 42, 2010/01
Times Cited Count：15 Percentile：52.65(Thermodynamics)This paper reports the cryogenic interlaminar shear properties of composite insulation systems for the superconducting magnet coils in the International Thermonuclear Experimental Reactor (ITER). Short beam shear tests were performed at room temperature, liquid nitrogen temperature (77 K) and liquid helium temperature (4 K) on three insulation systems consisting of woven glass fiber reinforced plastic (GFRP) composites with different polymer resins and polyimide films, and the dependence of their apparent interlaminar shear strength on the temperature and the polymer resins was discussed. A detailed observation of failed specimens was made to verify the failure mechanisms. Insulation systems subjected to 
irradiation at room temperature were also considered, and the effect of irradiation on the cryogenic interlaminar shear properties was examined.
