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Nishino, Saki; Tsuboi, Masatoshi; Okada, Jumpei; Saegusa, Yu; Omori, Kazuki; Yasuo, Kiyoshi; Seshimo, Kazuyoshi; Domura, Kazuyuki; Yamamoto, Masahiko
Nihon Hozen Gakkai Dai-17-Kai Gakujutsu Koenkai Yoshishu, p.541 - 548, 2021/07
no abstracts in English
Tanaka, Taiki*; Narikiyo, Yoshihiro*; Morita, Kosuke*; Fujita, Kunihiro*; Kaji, Daiya*; Morimoto, Koji*; Yamaki, Sayaka*; Wakabayashi, Yasuo*; Tanaka, Kengo*; Takeyama, Mirei*; et al.
Journal of the Physical Society of Japan, 87(1), p.014201_1 - 014201_9, 2018/01
Times Cited Count：18 Percentile：74.47(Physics, Multidisciplinary)Excitation functions of quasielastic scattering cross sections for the 
Ca + 
Pb, 
Ti + Pb, and Ca + 
Cm reactions were successfully measured by using the gas-filled recoil-ion separator GARIS. Fusion barrier distributions were extracted from these data, and compared with the coupled-channels calculations. It was found that the peak energies of the barrier distributions for the Ca + Pb and Ti + Pb systems coincide with those of the 2n evaporation channel cross sections for the systems, while that of the Ca + Cm is located slightly below the 4n evaporation ones. This results provide us helpful information to predict the optimum beam energy to synthesize superheavy nuclei.
pre-concentration of Sr from large volume of freshwater sample using Powdex resinTomita, Jumpei; Yamamoto, Masayoshi*; Nozaki, Teo; Tanimura, Yoshihiko*; Oishi, Tetsuya
Journal of Environmental Radioactivity, 146, p.88 - 93, 2015/08
Times Cited Count：12 Percentile：35.16(Environmental Sciences)Yamamoto, Masayoshi*; Tomita, Jumpei
Onsen Kagaku, 64(4), p.388 - 401, 2015/03
no abstracts in English
Shiga, Hideaki*; Taki, Junichi*; Washiyama, Koshin*; Yamamoto, Jumpei*; Kinase, Sakae; Okuda, Koichi*; Kinuya, Seigo*; Watanabe, Naoto*; Tonami, Hisao*; Koshida, Kichiro*; et al.
PLOS ONE (Internet), 8(2), p.e57671_1 - e57671_8, 2013/02
Times Cited Count：18 Percentile：68.67(Multidisciplinary Sciences)Kashiwagi, Mieko; Taniguchi, Masaki; Kojima, Atsushi; Dairaku, Masayuki; Hanada, Masaya; Hemsworth, R. S.*; Mizuno, Takatoshi*; Takemoto, Jumpei; Tanaka, Masanobu*; Tanaka, Yutaka*; et al.
Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03
At JAEA, a multi-aperture multi-grid accelerator has been developed for the ITER neutral beam system. A target is H
ion beam acceleration of 0.5 A (200 A/m
) at 1 MeV. In real accelerators, it was found that the voltage holding was about a half of that obtained in an ideal small electrode. After applying necessary gap length and radii of edges of grid supports to lower local electric field concentrations, the accelerator succeeded in sustaining 1 MV for 4000 s. As a result, beam parameters were increased to 879 keV, 0.36 A (157 A/m) at perveance matched condition from 796 kV, 0.32 A (140 A/m) reported in FEC2008. In the beam acceleration, the beamlet deflections due to magnetic field and space charge repulsion caused direct interceptions, that resulted in limitations in the beam energy and current. Compensation of these beamlet deflections has been tested applying aperture offset and field shaping plate, which were examined in a three-dimensional beam analysis.
Yamamoto, Masanori; Watanabe, Kazuhiro; Yamanaka, Haruhiko; Takemoto, Jumpei; Yamashita, Yasuo*; Inoue, Takashi
JAEA-Technology 2010-029, 60 Pages, 2010/08
JAEA-Technology-2010-029.pdf:10.49MB
A power supply for the ITER Neutral Beam Injector (NBI) is a DC ultra-high voltage (UHV) power supply to accelerate negative ion beams of 40 A up to an energy of 1 MeV. Japan Atomic Energy Agency as the Japan Domestic Agency for ITER contributes procurement of dc -1 MV main components such as step-up -1 MV transformers rectifiers, a high voltage deck 2, a -1 MV insulating transformer, a transmission line, a surge reduction system and equipments for site test. Design of the surge suppression in the NBI power supply is one of the key issues to obtain the stable injector performance. This report describes the design study using EMTDC code on the surge suppression by optimizing the core snubber and additional elements in the -1 MV power supply. The results show that the input energy from the stray capacitance to the accelerator at the breakdown can be reduced to about 25 J that is smaller than the design criteria of 50 J for the ITER NBI.
Watanabe, Kazuhiro; Yamamoto, Masanori; Takemoto, Jumpei; Yamashita, Yasuo*; Dairaku, Masayuki; Kashiwagi, Mieko; Taniguchi, Masaki; Tobari, Hiroyuki; Umeda, Naotaka; Sakamoto, Keishi; et al.
Nuclear Fusion, 49(5), p.055022_1 - 055022_5, 2009/05
Times Cited Count：28 Percentile：70.93(Physics, Fluids & Plasmas)Japan Atomic Energy Agency as the Japan Domestic Agency (JADA) for ITER contributes procurement of dc -1 MV ultra-high voltage (UHV) components such as a dc -1 MV generator, a transmission line and a -1 MV insulating transformer for the ITER NBI power supply. Inverter frequency of 150 Hz in the -1 MV power supply and major circuit parameters have been proposed and adopted in the ITER NBI. The dc UHV insulation at the multi-layer insulation structure of the transformer for a long pulse up to 3600 s has been designed with electric field simulation. Based on the simulation overall dimensions of the dc UHV components have been finalized. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J which satisfies the design criteria of the total 50 J at -1 MV breakdown.
Watanabe, Kazuhiro; Yamamoto, Masanori; Takemoto, Jumpei; Yamashita, Yasuo*; Dairaku, Masayuki; Kashiwagi, Mieko; Taniguchi, Masaki; Tobari, Hiroyuki; Umeda, Naotaka; Sakamoto, Keishi; et al.
Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 7 Pages, 2008/10
The JADA contributes procurement of DC -1 MV ultra-high voltage (UHV) components such as a -1 MV DC generator, a transmission line and a -1 MV insulating transformer. The DC UHV insulation has been carefully analyzed since DC long pulse insulation is quite different from conventional AC insulation. The insulation structure has been designed and the overall dimensions of the DC UHV components have been finalized. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J which satisfies the design criteria of the total 50 J at -1 MV breakdown. From these studies, major technical issues were considered and the functional technical specifications of the UHV components have been developed for the procurement by the JADA.
Endo, Satoru*; Tomita, Jumpei*; Tanaka, Kenichi*; Yamamoto, Masayoshi*; Fukutani, Satoshi*; Imanaka, Tetsuji*; Sakaguchi, Aya*; Amano, Hikaru; Kawamura, Hidehisa*; Kawamura, Hisao*; et al.
Radiation and Environmental Biophysics, 47(3), p.359 - 365, 2008/07
Times Cited Count：5 Percentile：21.04(Biology)Dolon village located about 60 km from the border of the Semipalatinsk Nuclear Test Site is known to be heavily contaminated by the first USSR atomic bomb test in August 1949. Soil samples around Dolon were taken in October 2005 in an attempt to evaluate internal thyroid dose arising from incorporation of radioiodine isotopes (mainly 
I). Iodine-129 in soil was measured by using the technique of Accelerator Mass Spectrometry. From the relationship between 
I and 
Cs (corrected for background and decay from 1949 to 2005) accumulated levels, the background level of I and the I/Cs ratio around Dolon were estimated to be (6.4 
0.4) 
10
atoms m
and 0.25 0.16, respectively. This I/Cs ratio is almost similar to the fission yield ratio for 
Pu fast fission (0.24).
Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro; Okamura, Masahiro*; Jameson, R. A.*; Hattori, Toshiyuki*; Hayashizaki, Noriyosu*; Sakakibara, Kazuhiko*; Takano, Jumpei*; Yamamoto, Kazuo*; Iwata, Yoshiyuki*; et al.
Review of Scientific Instruments, 77(3), p.03B305_1 - 03B305_4, 2006/03
Times Cited Count：12 Percentile：52.29(Instruments & Instrumentation)Acceleration of a 17mA 100keV/u C
ion beam has been successfully achieved with an RFQ linac by means of "Direct injection scheme". The Direct injection scheme is a new scheme for injecting an ion beam from a laser ion source to the RFQ linac without a low energy beam transport line to avoid a beam loss due to the space charge effect. The high current C beam is required for single turn injection to a synchrotron to reduce the size of synchrotron magnets. The high current C beam produced by an ion source with a Nd-YAG laser was injected to the RFQ linac by the Direct injection scheme. It has been proved experimentally that the fully-stripped carbon ion beam with a current more than 10mA can be accelerated by the RFQ linac.
Okamura, Masahiro*; Kashiwagi, Hirotsugu; Sakakibara, Kazuhiko*; Takano, Jumpei*; Hattori, Toshiyuki*; Hayashizaki, Noriyosu*; Jameson, R. A.*; Yamamoto, Kazuo*
Review of Scientific Instruments, 77(3), p.03B303_1 - 03B303_3, 2006/03
Times Cited Count：10 Percentile：47.11(Instruments & Instrumentation)We have been studying a new heavy-ion production technique called "direct plasma injection scheme", DPIS, since 2000. A new radio frequency quadrupole "RFQ" designed especially for the DPIS was commissioned in 2004 and very intense carbon beam was successfully obtained, reaching more than 60 mA accelerated current from the RFQ. Most of the contents of the accelerated beam was carbon 4+ as verified by beam analysis.
Kashiwagi, Hirotsugu; Okamura, Masahiro*; Jameson, R. A.*; Hattori, Toshiyuki*; Hayashizaki, Noriyosu*; Sakakibara, Kazuhiko*; Takano, Jumpei*; Yamamoto, Kazuo*; Iwata, Yoshiyuki*; Fujimoto, Tetsuya*
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.182 - 184, 2005/07
The carbon beam from a Nd-YAG laser ion source was accelerated successfully by an RFQ linac using Direct injection scheme. The "Direct injection scheme" is the way to inject an ion beam to the RFQ linac without a low energy beam transport line to avoid space charge effect due to a high intensity beam from the laser ion source. About 30mA of a carbon beam was detected by a faraday cup just behind the RFQ linac.
Takemoto, Jumpei; Watanabe, Kazuhiro; Yamamoto, Masanori; Inoue, Takashi; Sakamoto, Keishi; Yamashita, Yasuo*
no journal, ,
no abstracts in English
Tomita, Jumpei; Abe, Takuya; Sakaguchi, Aya*; Miyata, Yoshiki*; Nagao, Seiya*; Yamamoto, Masayoshi*
no journal, ,
no abstracts in English
Tomita, Jumpei; Miyata, Yoshiki*; Hama, Katsuhiro; Sakaguchi, Aya*; Nagao, Seiya*; Yamamoto, Masayoshi*
no journal, ,
no abstracts in English
