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Meigo, Shinichiro; Oi, Motoki; Fujimori, Hiroshi*
Physical Review Accelerators and Beams (Internet), 23(6), p.062802_1 - 062802_24, 2020/06
Times Cited Count：3 Percentile：36.4(Physics, Nuclear)As hadron accelerators for such as the ADS and spallation neutron source achieve increasing beam power, damage to targets is becoming increasingly severe. To mitigate this damage, nonlinear beam optics based on octupole magnets is attractive. Nonlinear optics can decrease the beam-focusing hazard due to failure of the rastering magnet. As a side effect of nonlinear optics, the beam size is known to expand drastically compared with linear optics. Nonlinear effects have been studied via a simplified filament model that ignores beam-divergence spread at the octupole magnet. In this study, a new generalized model is proposed for application to an octupole magnet, regardless of the filament-model approximation. It is found that the transverse distribution obtained by beam tracking can be specified by the introduction of only two parameters, namely the normalized octupole strength of 
and the 
of the phase advance. To achieve the two antagonistic requirements of reduction of the beam-peak density and minimization of the beam loss, the transverse distribution is surveyed for a large range of beam position. It is found that a bell-shaped distribution with 
1 and 
3 can satisfy requirements. This result is applied to beam transport in the spallation neutron source at J-PARC. The calculation result given by the present model shows good agreement with the experimental data, and the peak current density is reduced by 50% compared with the linear-optics case.
Taguchi, Shigeo; Miyauchi, Hironari*; Horigome, Kazushi; Yamamoto, Masahiko; Kuno, Takehiko
Bunseki Kagaku, 67(11), p.681 - 686, 2018/11
In thermal ionization mass spectrometry, de-gassing is one of the important treatments to release impurities of filaments and to minimize the influence of background. In this work, the effect of the surface change in the tungsten filament induced by the conductively heating treatment on uranium isotopic (
U/
U) measurement has been investigated. It was found that the conductively heating treatment of the filament has the effect of smoothing the surface of the filament and also has the effect of improving the deposition of the sample on the filament surface. As a result of either these effects, the precision of uranium isotopic (U/U) measurement was improved.
-ion source for the High-Intensity Proton Accelerator (J-PARC)Oguri, Hidetomo; Ueno, Akira; Namekawa, Yuya*; Ikegami, Kiyoshi*
Review of Scientific Instruments, 77(3, Part2), p.03A517_1 - 03A517_3, 2006/03
Times Cited Count：5 Percentile：29.76(Instruments & Instrumentation)The J-PARC Project was started in 2001 as a joint project carried out by JAERI and KEK. At the first stage of the J-PARC, the linac will accelerate the H- ion beam current of 30 mA with a duty factor of 1.25 %. The J-PARC H- ion source driven with a LaB6 filament has regularly delivered more than 35 mA beam with a duty factor of 0.9 % without resorting to cesium. Although the operated duty factor is about 1/3 of the requirement, the filament is not replaced for a half year. At the J-PARC, the lifetime of the tungsten (W) filament was measured by using another H- ion source, which can produce a 72 mA with cesium seeded. The experimental results showed that there is a possibility of the W filament satisfying the lifetime of more than 500 hours, which is J-PARC requirement. We consider the W driven plasma ion source is one of the candidates for the J-PARC source. At present, we are performing the beam test of the cesium free ion source driven with W. We will present the experimental data of the beam test in this conference.
Matsumoto, Fumiko*; Makino, Koji*; Maeda, Kayo*; Patzelt, H.*; Maeda, Yuichiro*; Fujiwara, Satoru
Journal of Molecular Biology, 342(4), p.1209 - 1221, 2004/09
Times Cited Count：19 Percentile：29.79(Biochemistry & Molecular Biology)Regulation of skeletal and cardiac muscle contraction is associated with the thin filament-based proteins, troponin C (TnC), TnI, TnT, tropomyosin, and actin. Knowledge of 
structures of these proteins is indispensable for elucidating the molecular mechanism of this Ca
-sensitive regulation. Here the structure of TnC within the thin filaments was investigated with neutron scattering, combined with selective deuteration and the contrast matching technique. Deuterated TnC was prepared, reconstituted into the native thin filaments, and neutron scattering patterns of these reconstituted thin filaments containing deuterated TnC were measured under the condition where non-deuterated components were rendered 'invisible' to neutrons. The obtained scattering curves arising only from deuterated TnC were analyzed by model calculations using the Monte Carlo method. The results showed that upon binding of Ca, radius of gyration of TnC changed from 23 AA to 24 AA , and the radial position of TnC within the thin filament changed from 53 AA to 49 AA .
Oguri, Hidetomo; Namekawa, Yuya*
JAERI-Tech 2004-053, 35 Pages, 2004/07
JAERI-Tech-2004-053.pdf:1.33MB
The high intensity proton accelerator facility project (J-PARC) aims to pursue frontier science in materials science, nuclear physics and nuclear technology, using an accelerator complex at the highest beam power in the world. An H ion source for the project is required to produce a beam current of 
60 mA and an emittance of 
0.20 
mm.mrad with a duty factor of 2.5 %. In addition, the ion source must be run for 500 h continuously without maintenance. As a result of the beam test, the beam current and the emittance of 72 mA and 0.15 mm.mrad were achieved in the Cs seeded operation, respectively. Because a lifetime of the filament cathode is one of the main restrictions for the maintenance cycle, we started to perform a filament lifetime test. As the result of the test, we succeeded for 258 h arc operation at the arc power of 30 kW with the duty factor of 3 %. Moreover, the results showed that there is a possibility of achievement 800 h lifetime by change the connection between filament and arc power supply and the optimization of the filament shape.
Oguri, Hidetomo; Namekawa, Yuya*
Proceedings of 28th Linear Accelerator Meeting in Japan, p.153 - 155, 2003/00
no abstracts in English
Umeda, Naotaka; Akino, Noboru; Ebisawa, Noboru; Grisham, L. R.*; Hikida, Shigenori*; Honda, Atsushi; Ito, Takao; Kawai, Mikito; Kazawa, Minoru; Kusaka, Makoto*; et al.
Fusion Technology, 39(2-Part2), p.1135 - 1139, 2001/03
no abstracts in English
plasma methodOkoshi, Kiyonori; Saito, Yuichi; Kamiya, Tomihiro; Sakai, Takuro; Tajima, Satoshi
Review of Scientific Instruments, 71(2), p.1174 - 1176, 2000/02
Times Cited Count：0 Percentile：0.01(Instruments & Instrumentation)no abstracts in English
Tamura, Koji; Oba, Hironori; Shibata, Takemasa
JAERI-Tech 99-050, 8 Pages, 1999/07
no abstracts in English
Tamada, Masao; Omichi, Hideki; *
Thin Solid Films, 260, p.168 - 173, 1995/00
Times Cited Count：16 Percentile：68.01(Materials Science, Multidisciplinary)no abstracts in English
Tamada, Masao; Hosoi, Fumio; Omichi, Hideki; *
Denshi Joho Tsushin Gakkai Gijutsu Kenkyu Hokoku, 0(25), p.45 - 49, 1994/06
no abstracts in English
Tamada, Masao; Omichi, Hideki; *
Thin Solid Films, 251, p.36 - 39, 1994/00
no abstracts in English
Hosono, Fumikazu*; Sugimoto, Makoto; Tsukamoto, Hideo*; Oshikiri, Masayuki*; Hanawa, Hiromi*; Seki, Shuichi*; *; Koizumi, Norikiyo; Isono, Takaaki; Takahashi, Yoshikazu; et al.
IEEE Transactions on Applied Superconductivity, 3(1), p.535 - 538, 1993/03
Times Cited Count：1 Percentile：23.77(Engineering, Electrical & Electronic)no abstracts in English
Ogiwara, Norio; ; *
Vacuum, 44(5-7), p.661 - 663, 1993/00
Times Cited Count：13 Percentile：58.74(Materials Science, Multidisciplinary)no abstracts in English
Fujiwara, Satoru; Matsuo, Tatsuhito; Yamada, Takeshi*; Shibata, Kaoru
no journal, ,
no abstracts in English
