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Yoshida, Masafumi; Hanada, Masaya; Kojima, Atsushi; Kashiwagi, Mieko; Grisham, L. R.*; Hatayama, Akiyoshi*; Shibata, Takanori*; Yamamoto, Takashi*; Akino, Noboru; Endo, Yasuei; et al.
Fusion Engineering and Design, 96-97, p.616 - 619, 2015/10
Times Cited Count:12 Percentile:69.86(Nuclear Science & Technology)In JT-60 Super Advanced for the fusion experiment, 22A, 100s negative ions are designed to be extracted from the world largest ion extraction area of 450 mm 1100 mm. One of the key issues for producing such as high current beams is to improve non-uniform production of the negative ions. In order to improve the uniformity of the negative ions, a tent-shaped magnetic filter has newly been developed and tested for JT-60SA negative ion source. The original tent-shaped filter significantly improved the logitudunal uniformity of the extracted H ion beams. The logitudinal uniform areas within a 10 deviation of the beam intensity were improved from 45% to 70% of the ion extraction area. However, this improvement degrades a horizontal uniformity. For this, the uniform areas was no more than 55% of the total ion extraction area. In order to improve the horizontal uniformity, the filter strength has been reduced from 660 Gasuscm to 400 Gasuscm. This reduction improved the horizontal uniform area from 75% to 90% without degrading the logitudinal uniformity. This resulted in the improvement of the uniform area from 45% of the total ion extraction areas. This improvement of the uniform area leads to the production of a 22A H ion beam from 450 mm 1100 mm with a small amount increase of electron current of 10%. The obtained beam current fulfills the requirement for JT-60SA.
Kojima, Atsushi; Umeda, Naotaka; Hanada, Masaya; Yoshida, Masafumi; Kashiwagi, Mieko; Tobari, Hiroyuki; Watanabe, Kazuhiro; Akino, Noboru; Komata, Masao; Mogaki, Kazuhiko; et al.
Nuclear Fusion, 55(6), p.063006_1 - 063006_9, 2015/06
Times Cited Count:41 Percentile:89.45(Physics, Fluids & Plasmas)Significant progresses in the extension of pulse durations of powerful negative ion beams have been made to realize the neutral beam injectors for JT-60SA and ITER. In order to overcome common issues of the long pulse production/acceleration of negative ion beams in JT-60SA and ITER, the new technologies have been developed in the JT-60SA ion source and the MeV accelerator in Japan Atomic Energy Agency. As for the long pulse production of high-current negative ions for JT-60SA ion source, the pulse durations have been successfully increased from 30 s at 13 A on JT-60U to 100 s at 15 A by modifying the JT-60SA ion source, which satisfies the required pulse duration of 100 s and 70% of the rated beam current for JT-60SA. This progress was based on the R&D efforts for the temperature control of the plasma grid and uniform negative ion productions with the modified tent-shaped filter field configuration. Moreover, the each parameter of the required beam energy, current and pulse has been achieved individually by these R&D efforts. The developed techniques are useful to design the ITER ion source because the sustainment of the cesium coverage in large extraction area is one of the common issues between JT-60SA and ITER. As for the long pulse acceleration of high power density beams in the MeV accelerator for ITER, the pulse duration of MeV-class negative ion beams has been extended by more than 2 orders of magnitude by modifying the extraction grid with a high cooling capability and a high-transmission of negative ions. A long pulse acceleration of 60 s has been achieved at 70 MW/m (683 keV, 100 A/m) which has reached to the power density of JT-60SA level of 65 MW/m.
Akino, Noboru; Endo, Yasuei; Hanada, Masaya; Kawai, Mikito*; Kazawa, Minoru; Kikuchi, Katsumi*; Kojima, Atsushi; Komata, Masao; Mogaki, Kazuhiko; Nemoto, Shuji; et al.
JAEA-Technology 2014-042, 73 Pages, 2015/02
According to the project plan of JT-60 Super Advanced that is implemented as an international project between Japan and Europe, the neutral beam (NB) injectors have been disassembled. The disassembly of the NB injectors started in November, 2009 and finished in January, 2012 without any serious problems as scheduled. This reports the disassembly activities of the NB injectors.
Yoshida, Masafumi; Hanada, Masaya; Kojima, Atsushi; Kashiwagi, Mieko; Grisham, L. R.*; Akino, Noboru; Endo, Yasuei; Komata, Masao; Mogaki, Kazuhiko; Nemoto, Shuji; et al.
Review of Scientific Instruments, 85(2), p.02B314_1 - 02B314_4, 2014/02
Times Cited Count:15 Percentile:54.93(Instruments & Instrumentation)Non-uniformity of the negative ion beams in the JT-60 negative ion source was improved by modifying an external magnetic field to a tent-shaped magnetic field for reduction of the local heat loads in the source. Distributions of the source plasmas (H ions and H atoms) of the parents of H ions converted on the cesium covered plasma grids were measured by Langmuir probes and emission spectroscopy. Beam intensities of the H ions extracted from the plasma grids were measured by IR camera from the back of the beam target plate. The tent-shaped magnetic field prevented the source plasmas to be localized by B grad B drift of the primary electrons emitted from the filaments in the arc chamber. As a result, standard derivation of the H ions beams was reduced from 14% (the external magnetic field) to 10% (the tent-shaped magnetic field) without reduction of an activity of the H ion production.
Yoshida, Masafumi; Hanada, Masaya; Kojima, Atsushi; Inoue, Takashi; Kashiwagi, Mieko; Grisham, L. R.*; Akino, Noboru; Endo, Yasuei; Komata, Masao; Mogaki, Kazuhiko; et al.
Plasma and Fusion Research (Internet), 8(Sp.1), p.2405146_1 - 2405146_4, 2013/11
Distributions of H and H in the source plasmas produced at the end-plugs of JT-60 negative ions source were measured by Langmuir probes and emission spectroscopy in order to experimentally investigate the cause of lower density of the negative ions extracted from end-plugs in the source. Densities of H and H in end-plugs of the plasma grid in the source were compared with those in the center regions. As a result, lower density of the negative ion at the edge was caused by lower beam optics due to lower and higher density of the H and H.
Ohshima, Yasuhiro; Hanaoka, Hirofumi*; Tominaga, Hideyuki*; Kanai, Yoshikatsu*; Kaira, Kyoichi*; Yamaguchi, Aiko*; Nagamori, Shushi*; Oriuchi, Noboru*; Tsushima, Yoshito*; Endo, Keigo*; et al.
Annals of Nuclear Medicine, 27(4), p.314 - 324, 2013/05
Times Cited Count:15 Percentile:49.72(Radiology, Nuclear Medicine & Medical Imaging)Achmad, A.*; Hanaoka, Hirofumi*; Yoshioka, Hiroki*; Yamamoto, Shinji*; Tominaga, Hideyuki*; Araki, Takuya*; Ohshima, Yasuhiro; Oriuchi, Noboru*; Endo, Keigo*
Cancer Science, 103(3), p.600 - 605, 2012/03
Times Cited Count:25 Percentile:55.59(Oncology)Sato, Soichi; Endo, Noboru; Fukuda, Kazuhito; Morita, Yasuji
Journal of Nuclear Science and Technology, 49(2), p.182 - 188, 2012/02
Times Cited Count:10 Percentile:60.07(Nuclear Science & Technology)Electrochemical oxidation method, to oxidize nitrosyl ruthenium to the tetra-oxide and then to remove ruthenium to the gas phase, was studied to separate Ru from the high-level liquid waste (HLLW). We carried out the experiments to clarify the effects following fundamental conditions to the electric oxidation, which are (a) electrolyte temperature, (b) presence of promoter elements, (c) evaporation or reflux of condensed phase and (d) using or not using of diaphragm at counter electrode. We found the fast oxidation conditions as follows; (1) higher temperature; 95C, (2) Ce coexistence; 3000 ppm and (3) usage of a diaphragm for counter electrode. However evaporation or reflux conditions do not directly affect the electrochemical oxidation efficiency. Electric oxidation rate was increased 3 times compared with 25C, without Ce and diaphragm for counter electrode.
Ohshima, Yasuhiro; Hanaoka, Hirofumi*; Watanabe, Shigeki; Sugo, Yumi; Watanabe, Satoshi; Tominaga, Hideyuki*; Oriuchi, Noboru*; Endo, Keigo*; Ishioka, Noriko
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 91, 2012/01
Hanada, Masaya; Kojima, Atsushi; Tanaka, Yutaka; Inoue, Takashi; Watanabe, Kazuhiro; Taniguchi, Masaki; Kashiwagi, Mieko; Tobari, Hiroyuki; Umeda, Naotaka; Akino, Noboru; et al.
Fusion Engineering and Design, 86(6-8), p.835 - 838, 2011/10
Times Cited Count:13 Percentile:69.42(Nuclear Science & Technology)Neutral beam (NB) injectors for JT-60 Super Advanced (JT-60SA) have been designed and developed. Twelve positive-ion-based and one negative-ion-based NB injectors are allocated to inject 30 MW D beams in total for 100 s. Each of the positive-ion-based NB injector is designed to inject 1.7 MW for 100s at 85 keV. A part of the power supplies and magnetic shield utilized on JT-60U are upgraded and reused on JT-60SA. To realize the negative-ion-based NB injector for JT-60SA where the injection of 500 keV, 10 MW D beams for 100s is required, R&Ds of the negative ion source have been carried out. High-energy negative ion beams of 490-500 keV have been successfully produced at a beam current of 1-2.8 A through 20% of the total ion extraction area, by improving voltage holding capability of the ion source. This is the first demonstration of a high-current negative ion acceleration of 1 A to 500 keV. The design of the power supplies and the beamline is also in progress. The procurement of the acceleration power supply starts in 2010.
Hanada, Masaya; Kojima, Atsushi; Inoue, Takashi; Watanabe, Kazuhiro; Taniguchi, Masaki; Kashiwagi, Mieko; Tobari, Hiroyuki; Umeda, Naotaka; Akino, Noboru; Kazawa, Minoru; et al.
AIP Conference Proceedings 1390, p.536 - 544, 2011/09
Times Cited Count:7 Percentile:84.66(Physics, Atomic, Molecular & Chemical)no abstracts in English
Ohshima, Yasuhiro; Hanaoka, Hirofumi*; Watanabe, Shigeki; Sugo, Yumi; Watanabe, Satoshi; Tominaga, Hideyuki*; Oriuchi, Noboru*; Endo, Keigo*; Ishioka, Noriko
Nuclear Medicine and Biology, 38(6), p.857 - 865, 2011/08
Times Cited Count:14 Percentile:47.14(Radiology, Nuclear Medicine & Medical Imaging)Endo, Hitoshi; Mayumi, Koichi*; Osaka, Noboru*; Ito, Kozo*; Shibayama, Mitsuhiro*
Polymer Journal, 43(2), p.155 - 163, 2011/02
Times Cited Count:9 Percentile:29.81(Polymer Science)Polyrotaxane (PR) possesses a supramolecular structure in which cyclic molecules are threaded into an axial polymer. In this study, the static structure of PR dissolved in a good solvent was investigated using contrast variation small-angle neutron scattering. The conformation of the axial linear polymer and the alignment of cyclic molecules within the axial polymer were evaluated quantitatively with the help of a detailed derivation of scattering theory. The decomposed partial scattering functions of the cyclic molecules and the axial polymer and the cross-correlation between cyclic molecules and an axial polymer strongly supported the idea that the alignment of cyclic molecules threaded on the axial polymer is random. On the basis of experimental observation, the entropic origin of the stiffening of PR due to the array of cyclic molecules is discussed.
Paudyal, P.*; Paudyal, B.*; Hanaoka, Hirofumi*; Oriuchi, Noboru*; Iida, Yasuhiko*; Yoshioka, Hiroki*; Tominaga, Hideyuki*; Watanabe, Satoshi; Watanabe, Shigeki; Ishioka, Noriko; et al.
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 108, 2011/01
Hanada, Masaya; Akino, Noboru; Endo, Yasuei; Inoue, Takashi; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; Komata, Masao; Kojima, Atsushi; Mogaki, Kazuhiko; et al.
Journal of Plasma and Fusion Research SERIES, Vol.9, p.208 - 213, 2010/08
A large negative ion source with an ion extraction area of 110 cm 45 cm has been developed to produce 500 keV, 22 A D ion beams required for JT-60 Super Advanced. To realize the JT-60SA negative ion source, the JT-60 negative ion source has been modified and tested on the negative-ion-based neutral beam injector on JT-60U. A 500 keV H ion beam has been produced at 3 A without a significant degradation of beam optics. This is the first demonstration of a high energy negative ion acceleration of more than one-ampere to 500 keV in the world. The beam current density of 90 A/m is being increased to meet 130 A/m of the design value for JT-60SA by tuning the operation parameters. A long pulse injection of 30 s has been achieved at a injection D power of 3 MW. The injection energy, defined as the product of the injection time and power, reaches 80 MJ by neutralizing a 340 keV, 27 A D ion beam produced with two negative ion sources.
Paudyal, P.*; Paudyal, B.*; Hanaoka, Hirofumi*; Oriuchi, Noboru*; Iida, Yasuhiko*; Yoshioka, Hiroki*; Tominaga, Hideyuki*; Watanabe, Satoshi; Watanabe, Shigeki; Ishioka, Noriko; et al.
Cancer Science, 101(4), p.1045 - 1050, 2010/04
Times Cited Count:38 Percentile:66.31(Oncology)Iida, Yasuhiko*; Hanaoka, Hirofumi*; Watanabe, Satoshi; Watanabe, Shigeki; Ishioka, Noriko; Yoshioka, Hiroki*; Yamamoto, Shinji*; Paudyal, P.*; Paudyal, B.*; Higuchi, Tetsuya*; et al.
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 108, 2009/12
Hanaoka, Hirofumi*; Tominaga, Hideyuki*; Yamada, Keiichi*; Paudyal, P.*; Iida, Yasuhiko*; Watanabe, Shigeki; Paudyal, B.*; Higuchi, Tetsuya*; Oriuchi, Noboru*; Endo, Keigo*
Annals of Nuclear Medicine, 23(6), p.559 - 567, 2009/08
Times Cited Count:17 Percentile:48.42(Radiology, Nuclear Medicine & Medical Imaging)Iida, Yasuhiko*; Hanaoka, Hirofumi*; Paudyal, P.*; Paudyal, B.*; Watanabe, Satoshi; Ishioka, Noriko; Watanabe, Shigeki; Matsuhashi, Shimpei; Yoshioka, Hiroki*; Higuchi, Tetsuya*; et al.
JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 114, 2008/11
Iida, Yasuhiko*; Hanaoka, Hirofumi*; Katabuchi, Tatsuya*; Watanabe, Shigeki; Ishioka, Noriko; Watanabe, Satoshi; Matsuhashi, Shimpei; Higuchi, Tetsuya*; Oriuchi, Noboru*; Endo, Keigo*
JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 128, 2008/03