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Journal Articles

Behavior of Sm in the boron cage of Sm-doped $$R$$B$$_{6}$$ ($$R$$ =Yb, La) observed by multiple-wavelength neutron holography

Uechi, Shoichi*; Oyama, Kenji*; Fukumoto, Yohei*; Kanazawa, Yuki*; Happo, Naohisa*; Harada, Masahide; Inamura, Yasuhiro; Oikawa, Kenichi; Matsuhra, Wataru*; Iga, Fumitoshi*; et al.

Physical Review B, 102(5), p.054104_1 - 054104_10, 2020/08

 Times Cited Count:0 Percentile:100(Materials Science, Multidisciplinary)

Journal Articles

Comparison between Monte Carlo simulation and measurement with a 3D polymer gel dosimeter for dose distributions in biological samples

Furuta, Takuya; Maeyama, Takuya*; Ishikawa, Kenichi*; Fukunishi, Nobuhisa*; Fukasaku, Kazuaki*; Takagi, Shu*; Noda, Shigeho*; Himeno, Ryutaro*; Hayashi, Shinichiro*

Physics in Medicine & Biology, 60(16), p.6531 - 6546, 2015/08

 Times Cited Count:8 Percentile:50.08(Engineering, Biomedical)

Low reproducibility of dose distribution in inhomogeneous regions such as soft matter near bones is known with the simple dose analysis currently adopted in treatment planning of particle cancer therapy. Therefore a treatment planning system based on Monte Carlo simulation having better accuracy is highly desired. In order to assess the simulation accuracy of a Monte Carlo simulation code in situations closely related to medical application, we performed a comparison of dose distribution in a biological sample obtained by experiment and that by simulation. In particular, we irradiate a carbon beam on a biological sample composed of fresh chicken meat and bones, with a PAGAT gel dosimeter placed behind it, and compare the complex dose distribution in the gel dosimeter created by the beam passing through the inhomogeneous sample. Monte Carlo simulation using PHITS code was conducted by reconstructing the biological sample from its computed tomography images. The simulation accurately reproduced the experimental distal edge structure of the dose distribution with an accuracy under about 2 mm.

Journal Articles

Beam position monitor system of J-PARC RCS

Hayashi, Naoki; Kawase, Masato; Hatakeyama, Shuichiro; Hiroki, Seiji; Saeki, Riuji; Takahashi, Hiroki; Teruyama, Yuzo*; Toyokawa, Ryoji*; Arakawa, Dai*; Hiramatsu, Shigenori*; et al.

Nuclear Instruments and Methods in Physics Research A, 677, p.94 - 106, 2012/06

 Times Cited Count:7 Percentile:43.25(Instruments & Instrumentation)

A beam position monitor (BPM) system at J-PARC RCS is described. The J-PARC RCS is a rapid-cycling proton synchrotron and its designed beam power is 1 MW. A diameter of the BPM detector is larger than 250 mm, however the system has to measure the beam position very accurately. The system should work not only for the high intensity but also for lower intensity. There are 54 BPM around the ring and most of them are placed inside steering magnets because of quite limited space. The BPM detector is an electro static type and it has four electrodes, and a pair of electrode gives a good linear response with diagonal cut shape to detect the charge center precisely. The signal processing unit, which is equipped with 14-bit 40 MSPS ADC and 600 MHz DSP, has been developed. They are controlled via shared memory space and EPICS. It is capable to record full 25 Hz pulse data for averaged mode and it could also store whole waveform data for further analysis, like turn-by-turn position calculation.

Journal Articles

Beam commissioning and operation of the Japan Proton Accelerator Research Complex 3-GeV rapid cycling synchrotron

Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Kazami; Yamamoto, Masanobu; Yoshimoto, Masahiro; et al.

Progress of Theoretical and Experimental Physics (Internet), 2012(1), p.2B003_1 - 2B003_26, 2012/00

 Times Cited Count:12 Percentile:35.61(Physics, Multidisciplinary)

The J-PARC 3-GeV RCS is a high-power pulsed proton driver aiming at 1 MW output beam power. The RCS was beam commissioned in October 2007 and made available for user operation in December 2008 with an output beam power of 4 kW. Since then, the output beam power of the RCS has been steadily increasing as per progressions of beam tuning and hardware improvements. So far, the RCS has successfully achieved high-intensity beam trials of up to 420 kW at a low-level intensity loss of less than 1%, and the output beam power for the routine user program has been increased to 210 kW. The most important issues in increasing the output beam power are the control and minimization of beam loss to maintain machine activation within the permissible level. This paper presents the recent progress in the RCS beam power ramp-up scenario, with particular emphasis on our efforts for beam loss issues.

Journal Articles

Upgrade of the transport monitoring system of nuclear materials

Uchida, Shinichi; Yuasa, Wataru; Hayashi, Akihiko; Inose, Shoichi; Ouchi, Yuichiro; Asakawa, Kenichi*; Uchikoshi, Yuta*

Kaku Busshitsu Kanri Gakkai (INMM) Nippon Shibu Dai-32-Kai Nenji Taikai Rombunshu (Internet), 7 Pages, 2011/11

JAEA has developed a TMS which can monitor the movement of nuclear material convoys to make safe and proper transport of nuclear materials. The TMS mainly consists of the location information monitoring system to monitor the location of the convoys and the visual information monitoring system to survey around the convoys. The TMS can send information in real-time to the TCC located at the shipper site. The JAEA has operated the TMS for ground transportation of MOX fuels since 2005, and the JAEA solved visual control problems that were observed during the operational experience and upgraded the system by adding the automatic communication control system, etc. In the case of emergency during transport, the TMS can send much more detailed visual information of the accident site to the TCC, which is useful for planning and executing an effective response. This paper reports the overview of the upgraded TMS and its effectiveness.

Journal Articles

Development of prototype YAG laser amplifier for the edge Thomson scattering system in ITER

Hatae, Takaki; Hayashi, Toshimitsu; Yatsuka, Eiichi; Kajita, Shin*; Yoshida, Hidetsugu*; Fujita, Hisanori*; Nakatsuka, Masahiro*; Yahagi, Kenichi*; Shinobu, Katsuya*; Ono, Takehiro; et al.

Journal of Plasma and Fusion Research SERIES, Vol.9, p.253 - 258, 2010/08

Journal Articles

Online monitoring of the H0 dump beam current during user operation of J-PARC RCS

Hatakeyama, Shuichiro; Saha, P. K.; Yoshimoto, Masahiro; Yamamoto, Kazami; Hayashi, Naoki; Sato, Kenichiro*

Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.1013 - 1015, 2010/08

In J-PARC (Japan Proton Accelerator Research Complex), the negative hydrogen ions (H$$^{-}$$) accelerated by LINAC are converted to protons (H$$^{+}$$) by the Charge Stripping Foil before injecting into RCS (Rapid Cycling Synchrotron). About 99.7% of H$$^{-}$$ are stripped it's two electrons by the 1st foil. The rest of H0 and H$$^{-}$$ are converted to H$$^{+}$$ by 2nd and 3rd foils and abandoned into H0 dump. Monitoring of the fraction of beam current into the H0 dump gives useful information for the stable beam supply during accelerator user's operation. This report describes the method of online monitoring to estimate the beam current of the H0 dump line.

Journal Articles

The Data acquisition system of beam position monitors in J-PARC main ring

Hatakeyama, Shuichiro; Hayashi, Naoki; Arakawa, Dai*; Hashimoto, Yoshinori*; Hiramatsu, Shigenori*; Odagiri, Junichi*; Sato, Kenichiro*; Tejima, Masaki*; Tobiyama, Makoto*; Toyama, Takeshi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2698 - 2700, 2010/05

The Data Acquisition System of Beam Position Monitors (BPMs) in J-PARC Main Ring are consist of 186 Linux-based Data Processing Circuits (BPMCs) and 12 EPICS IOCs. They are important tool to see the COD and turn-by-turn beam positions. This report describes the process of the data reconstruction which include how the various calibration constants are applied.

Journal Articles

Shot-by-shot beam position monitor system for beam transport line from RCS to MR in J-PARC

Tejima, Masaki*; Arakawa, Dai*; Hashimoto, Yoshinori*; Sato, Kenichiro*; Toyama, Takeshi*; Yamamoto, Noboru*; Hayashi, Naoki; Hanamura, Kotoku*

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.978 - 980, 2010/05

To maintain the beam orbit of beam transport line from RCS to MR in J-PARC (3-50BT), 14 beam position monitors (BPMs) were installed. Their signals gathered in the local control building (D01) have been measured by using 14 digitizing oscilloscopes. The data acquisition system have a performance of shot-by-shot measurement.

Journal Articles

Performance of the main ring BPM during the beam commissioning at J-PARC

Toyama, Takeshi*; Arakawa, Dai*; Hiramatsu, Shigenori*; Igarashi, Susumu*; Lee, S.*; Matsumoto, Hiroshi*; Odagiri, Junichi*; Tejima, Masaki*; Tobiyama, Makoto*; Hashimoto, Yoshinori*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.981 - 983, 2010/05

Experiences of operating BPM's during beam commissioning at the J-PARC MR are reported. The subjects are: (1) bug report, statistics and especially the effect of a beam duct step, (2) position resolution estimation ($$<$$30 micrometers with 1 sec averaging), (3) beam based alignment.

Journal Articles

Dynamics of ion internal transport barrier in LHD heliotron and JT-60U tokamak plasmas

Ida, Katsumi*; Sakamoto, Yoshiteru; Yoshinuma, Mikiro*; Takenaga, Hidenobu; Nagaoka, Kenichi*; Hayashi, Nobuhiko; Oyama, Naoyuki; Osakabe, Masaki*; Yokoyama, Masayuki*; Funaba, Hisamichi*; et al.

Nuclear Fusion, 49(9), p.095024_1 - 095024_9, 2009/09

 Times Cited Count:26 Percentile:25.52(Physics, Fluids & Plasmas)

Dynamics of ion internal transport barrier (ITB) formation and impurity transport both in the Large Helical Device (LHD) heliotron and JT-60U tokamak are described. Significant differences between heliotron and tokamak plasmas are observed. The location of the ITB moves outward during the ITB formation regardless of the sign of magnetic shear in JT-60U and the ITB becomes more localized in the plasma with negative magnetic shear. In LHD, the low Te/Ti ratio ($$<$$ 1) of the target plasma for the high power heating is found to be necessary condition to achieve the ITB plasma and the ITB location tends to expand outward or inward depending on the condition of the target plasmas. Associated with the formation of ITB, the carbon density tends to be peaked due to inward convection in JT-60U, while the carbon density becomes hollow due to outward convection in LHD. The outward convection observed in LHD contradicts the prediction by neoclassical theory.

Journal Articles

New synthesis method of advanced lithium titanate with Li$$_{4}$$TiO$$_{4}$$ additives for ITER-TBM

Hoshino, Tsuyoshi; Kato, Kenichi*; Natori, Yuri*; Nakamura, Mutsumi*; Sasaki, Kazuya*; Hayashi, Kimio; Terai, Takayuki*; Tatenuma, Katsuyoshi*

Fusion Engineering and Design, 84(2-6), p.956 - 959, 2009/06

 Times Cited Count:35 Percentile:6.79(Nuclear Science & Technology)

Li$$_{2}$$TiO$$_{3}$$ is one of the most promising candidates among the proposed solid breeder materials for fusion reactors. Addition of H$$_{2}$$ to inert sweep gas has been proposed for enhancing the release of bred tritium from breeder material. However, the mass of Li$$_{2}$$TiO$$_{3}$$ was found to decrease with time in the hydrogen atmosphere. This mass change indicates that the oxygen content of the sample decreased, suggesting the change from Ti$$^{4+}$$ to Ti$$^{3+}$$. In order to control the mass change at the time of high temperature use, the development of lithium titanate which has Li$$_{4}$$TiO$$_{4}$$ additive is expected to be effective.

Journal Articles

Toyocamycin specifically inhibits auxin signaling mediated by SCF$$^{TIR1}$$ pathway

Hayashi, Kenichiro*; Kamio, Shuichi*; Ono, Yutaka; Townsend, L.*; Nozaki, Hiroshi*

Phytochemistry, 70(2), p.190 - 197, 2009/01

 Times Cited Count:20 Percentile:43.11(Biochemistry & Molecular Biology)

Journal Articles

Status of JT-60SA tokamak under the EU-JA broader approach agreement

Matsukawa, Makoto; Kikuchi, Mitsuru; Fujii, Tsuneyuki; Fujita, Takaaki; Hayashi, Takao; Higashijima, Satoru; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Ide, Shunsuke; Ishida, Shinichi; et al.

Fusion Engineering and Design, 83(7-9), p.795 - 803, 2008/12

 Times Cited Count:15 Percentile:25.93(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Corrosion rate of parent and weld materials of F82H and JPCA steels under LBE flow with active oxygen control at 450 and 500 $$^{circ}$$C

Kikuchi, Kenji; Kamata, Kinya*; Ono, Mikinori*; Kitano, Teruaki*; Hayashi, Kenichi*; Oigawa, Hiroyuki

Journal of Nuclear Materials, 377(1), p.232 - 242, 2008/06

 Times Cited Count:14 Percentile:27.98(Materials Science, Multidisciplinary)

Corrosion behavior of F82H and JPCA was studied in the circulating LBE loop. Those are candidate materials of Japanese ADS beam windows. Maximum temperatures were kept to 450 and 500 $$^{circ}$$C with 100 $$^{circ}$$C constant temperature difference. Main flow velocity was 0.4 to 0.6 m/s in every case. Oxygen concentration was controlled to 2$$sim$$4$$times$$10$$^{-5}$$ mass% although there was an exception. Testing time durations were 500 to 3000 hrs. Round bar type specimens were put in the circular tube of the loop. Electron beam welded joint in the middle part of specimens were also studied. Optical micrograph, electron micrograph, X-ray element analyses and X-ray diffraction were investigated. Consequently for a long-term behavior a linear law is recommended to predict corrosion in the ADS beam design.

JAEA Reports

Thermal hydraulic design of the mercury target vessel

Haga, Katsuhiro; Wakui, Takashi; Kogawa, Hiroyuki; Harada, Masahide; Futakawa, Masatoshi; Hayashi, Kenichi*; Nakamura, Koji*

JAEA-Technology 2008-033, 40 Pages, 2008/05

JAEA-Technology-2008-033.pdf:4.9MB

JAEA has completed the mercury target system as the spallation neutron source of J-PARC project, which has the power of the world highest level of 1MW. The basic design of the flow channel and structure of the mercury target vessel was carried out by JAEA, and the detail design, parts fabrication and assembling has been carried out by the vendor from 2003. Taking these fabrication designs and assembling conditions into consideration, the final performance evaluation of the mercury target vessel was carried out in view of thermal hydraulics. The general thermal hydraulic analyses code, STAR-CD, was used, and the three dimensional thermal hydraulic analyses were carried out taking the nuclear heating and the heat transportation into consideration. As results, it was confirmed that the mercury target vessel fulfills the design requirements such as the fluid inlet velocity, the maximum temperature of fluid, the maximum temperature of the vessel, the pressure drop of fluid, etc.

Journal Articles

Active core structure of terfestatin A, a new specific inhibitor of auxin signaling

Hayashi, Kenichiro*; Yamazoe, Atsushi*; Ishibashi, Yuki*; Kusaka, Naoyuki*; Ono, Yutaka; Nozaki, Hiroshi*

Bioorganic & Medicinal Chemistry, 16(9), p.5331 - 5344, 2008/05

 Times Cited Count:19 Percentile:45.44(Biochemistry & Molecular Biology)

The auxins, plant hormones, regulate many aspects of the growth and development of plants. Terfestatin A (TrfA), a novel auxin signaling inhibitor, was identified in a screen of ${it Streptomyces sp}$. F40 extracts for inhibition of the expression of an auxin-inducible gene. However, the mode of action of TrfA has not been elucidated. To identify the active core structure, 25 derivatives of TrfA were synthesized and their inhibitory activities against auxin-inducible gene expression were evaluated. The structure-activity relationships revealed the essential active core structure of TrfA, 3-butoxy-4-methylbiphenyl-2,6-diol, which will lead to the design of biotin-tagged active TrfA.

Journal Articles

Thermal-hydraulic experiment on beam window for developing the accelerator-driven transmutation system

Hayashi, Kenichi*; Ono, Mikinori*; Kikuchi, Kenji; Tokunaga, Noriya*; Kitano, Teruaki*; Oigawa, Hiroyuki

Nippon Genshiryoku Gakkai Wabun Rombunshi, 7(1), p.44 - 57, 2008/03

Accelerator driven nuclear transmutation system aims at transmuting minor actinides and long-lived fission products to stable or short-lived nuclei. A design study of proton beam window, which is an interface component between accelerator and nuclear reactor. Thermal-hydraulic experiment of the beam window was done. Two experiments were conducted: one was particle image velocimetry measurement around the beam window in flowing water and the other was temperature measurement at the beam window under flowing lead bismuth. Numerical simulation was also done to validate the beam window model for design work. Results show that heat transfer characteristics of the beam widow averaged in space and with time under flowing lead bismuth was formulized by the experimental equation. Numerical simulation model can estimate the mean heat transfer coefficient. However, a local heat transfer coefficient was not stable: it fluctuates with time and even in space, especially around stagnation point.

Journal Articles

The Status of the J-PARC RCS beam monitor system

Hayashi, Naoki; Hiroki, Seiji; Saha, P. K.; Saeki, Riuji; Toyokawa, Ryoji*; Yamamoto, Kazami; Yoshimoto, Masahiro; Arakawa, Dai*; Hiramatsu, Shigenori*; Lee, S.*; et al.

Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.243 - 245, 2008/00

The J-PARC RCS has been beam commissioned since fall 2007. During such a short period, the following items have been established. Establishment of the injection orbit, beam circulation, acceleration up to 3GeV, optics parameters measurements and it achieved 50 kW beam power (4$$times$$10$$^{12}$$ ppb). The beam monitor system has an important role for smooth beam commissioning. This paper describes the status of the beam monitor system, BPM, Injection monitors, IPM, current monitor, tune meter and BLM of the RCS.

Journal Articles

Introduction to plasma fusion energy

Takamura, Shuichi*; Kado, Shinichiro*; Fujii, Takashi*; Fujiyama, Hiroshi*; Takabe, Hideaki*; Adachi, Kazuo*; Morimiya, Osamu*; Fujimori, Naoji*; Watanabe, Takayuki*; Hayashi, Yasuaki*; et al.

Kara Zukai, Purazuma Enerugi No Subete, P. 164, 2007/03

no abstracts in English

70 (Records 1-20 displayed on this page)