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Takahashi, Hiroki; Narita, Takahiro; Usami, Hiroki; Sakaki, Hironao; Kojima, Toshiyuki*
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.756 - 759, 2015/09
no abstracts in English
Otosaka, Shigeyoshi; Nakanishi, Takahiro; Suzuki, Takashi; Sato, Yuhi; Narita, Hisashi*
Environmental Science & Technology, 48(21), p.12595 - 12602, 2014/11
Times Cited Count：22 Percentile：57.17(Engineering, Environmental)From August 2011 to July 2013, a sediment trap was deployed at 100 km east of the Fukushima Daiichi Nuclear Power Plant and sinking particles were collected. Sinking flux of 
Cs decreased over time with seasonal fluctuation. The Cs fluxes were mainly affected by two principal modes. One was a rapid sinking of radiocesium-bound particles (moderate mode). This mode was dominant especially in the early post-accident stage, and was presumed to establish the distribution of radiocesium in the offshore seabed. Another was the secondary transport of particles attributed to turbulence near the seabed and was observed in winter (turbulence mode). Although the latter process would not drastically change the distribution of sedimentary radiocesium, attention should be paid as this key process redistributing the accident-derived radiocesium may cumulatively affect the long-term distribution.
Takahashi, Hiroki; Maebara, Sunao; Kojima, Toshiyuki; Narita, Takahiro; Tsutsumi, Kazuyoshi; Sakaki, Hironao; Suzuki, Hiromitsu; Sugimoto, Masayoshi
Fusion Engineering and Design, 89(9-10), p.2066 - 2070, 2014/10
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Takahashi, Hiroki; Narita, Takahiro; Nishiyama, Koichi; Usami, Hiroki; Sakaki, Hironao; Kasugai, Atsushi; Kojima, Toshiyuki*
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.799 - 802, 2014/10
no abstracts in English
Takahashi, Hiroki; Kojima, Toshiyuki; Narita, Takahiro; Maebara, Sunao; Sakaki, Hironao; Suzuki, Hiromitsu
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.724 - 727, 2014/06
no abstracts in English
-ray and neutron area monitoring system of linear IFMIF prototype accelerator buildingTakahashi, Hiroki; Kojima, Toshiyuki; Narita, Takahiro; Tsutsumi, Kazuyoshi; Maebara, Sunao; Sakaki, Hironao; Nishiyama, Koichi
Fusion Engineering and Design, 88(9-10), p.2736 - 2739, 2013/10
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)For radiation safety of the Linear IFMIF Prototype Accelerator, -ray and neutron area monitoring system are designed. This system monitors and records the measured data by using both a supervisory board in the access room and central control system. The interlock signals are sent to Personnel Protection System (PPS) and Machine Protection System (MPS) when the integrated dose value exceeds a threshold value. After receiving them, the PPS and the MPS immediately inhibit the beam operation for secure radiation safety. This monitoring system is designed to achieve a high reliability for data transfer using hardwired interlock signals and the performance of data communication between area monitoring system and control system.
Takahashi, Hiroki; Kojima, Toshiyuki; Narita, Takahiro; Sakaki, Hironao; Komukai, Satoshi*
Proceedings of 3rd International Particle Accelerator Conference (IPAC '12) (Internet), p.3972 - 3974, 2012/07
Control System for LIPAc realizes the remote control and monitoring and data acquisition by use of EPICS. For the validations of each subsystem performance and the activity of IFMIF Accelerator design, it is very important data obtained by commissioning of LIPAc and each subsystem. To certainly archive the important data for LIPAc and to efficiently search the LIPAc data, for design and validation, we started developing Data Acquisition System (DAC) based on Relational Database (RDB) has been developed. The first design for DAC of LIPAc is configured (1) using PostgreSQL for RDB and (2) several RDB for data archiving to ensure the data archive performance and to consider the increasing data amount. In addition, (3) only one RDB for data search is included in DAC and users can search the data via this RDB. In this way, several RDB for DAC can behave only one RDB against users. In this article, the development status of DAC for LIPAc is presented.
Takahashi, Hiroki; Kojima, Toshiyuki; Tsutsumi, Kazuyoshi; Narita, Takahiro; Nishiyama, Koichi; Sakaki, Hironao; Maebara, Sunao
Proceedings of 2nd International Particle Accelerator Conference (IPAC 2011) (Internet), p.1734 - 1736, 2011/09
Control system for the IFMIF/EVEDA prototype accelerator consists of six subsystems; Central Control System (CCS), Local Area Network (LAN), Personnel Protection System (PPS), Machine Protection System (MPS), Timing System (TS) and Local Control System (LCS). The Prototype Accelerator provides the deuteron beam with the beam power more than 1 MW, and this control system is required the high reliability and usability to perform various operation modes for beam commissioning. To satisfy these requirements, we are developing mainly PPS, MPS and TS at the beginning. This paper presents the status of hardware development of the PPS, MPS and TS.
Narita, Takahiro; Kojima, Toshiyuki; Tsutsumi, Kazuyoshi; Takahashi, Hiroki; Sakaki, Hironao
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.673 - 676, 2010/08
no abstracts in English
Takahashi, Hiroki; Kojima, Toshiyuki; Tsutsumi, Kazuyoshi; Narita, Takahiro; Sakaki, Hironao; Maebara, Sunao
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2695 - 2697, 2010/05
Control System for IFMIF accelerators consists of the six subsystems; Central Control System (CCS), Local Area Network (LAN), Personnel Protection System (PPS), Machine Protection System (MPS), Timing System (TS) and Local Control System (LCS). The subsystems have been designed and their test benches been fabricated at JAEA. The IFMIF accelerator prototype provides a deuteron beam with the power more than 1 MW, which is as same as that in cases of J-PARC and SNS. In the control system, MPS and TS with high performance and precision are strongly required to avoid the radio-activation of the accelerator components. The prototypes of the MPS and TS are testing in conjunction with the injector test starting at CEA/Saclay from autumn in 2010. These results will feedback the design and the fabrication of the control components. This paper presents the development status of the TS modules and EPICS drivers for TS and MPS, and the prospects to apply them to the Injector test.
Kaneko, Fusae*; Tanaka, Masahito*; Narita, Satoru*; Kitada, Tomo*; Matsui, Takahiro*; Nakagawa, Kazumichi*; Agui, Akane; Fujii, Kentaro; Yokoya, Akinari
Journal of Electron Spectroscopy and Related Phenomena, 144-147, p.291 - 294, 2005/06
Times Cited Count：19 Percentile：65.31(Spectroscopy)no abstracts in English
Shinto, Katsuhiro; Ohira, Shigeru; Kikuchi, Takayuki; Kubo, Takashi; Yonemoto, Kazuhiro; Kasuya, Kenichi; Maebara, Sunao; Takahashi, Hiroki; Kojima, Toshiyuki; Tsutsumi, Kazuyoshi; et al.
no journal, ,
no abstracts in English
Otosaka, Shigeyoshi; Suzuki, Takashi; Nakanishi, Takahiro; Narita, Hisashi*; Kato, Yoshihisa*
no journal, ,
Between August 2011 and July 2012, sinking particles were collected with a sediment trap deployed at 100 km east of the Fukushima Daiichi Nuclear Power Plant. Concentration of 
Cs in sinking particles varied between 5 and 415 Bq/kg and was highest on December 2011. In this period, sinking particles predominantly consisted of lithogenic particles and the highest carbon/nitrogen ratio was observed, indicating resuspension of seabed sediment in the near-shore regions. From these results, it can be inferred that accident-derived radiocesium in the near-shore seabed was transported to the offshore region and increased Cs concentration in sinking particles.
Nishiyama, Koichi; Takahashi, Hiroki; Sakaki, Hironao; Narita, Takahiro; Kojima, Toshiyuki*; Knaster, J.*; Marqueta, A.*
no journal, ,
The development of IFMIF(International Fusion Material Irradiation Facility) to generate a 14 MeV source of neutrons with the spectrum of DT fusion reactions is indispensable to qualify suitable materials for the First Wall of the nuclear vessel in fusion power plants. As part of IFMIF validation activities, LIPAc (Linear IFMIF Prototype Accelerator) facility, currently under installation at Rokkasho (Japan), will accelerate a 125 mA CW and 9 MeV deuteron beam with a total beam power of 1.125 MW. The Machine Protection System (MPS) of LIPAc provides an essential interlock function of stopping the beam in case of anomalous beam loss or other hazardous situations. High speed processing is necessary to achieve properly the MPS main goal. This high speed processing of the signals, distributed alongside the accelerator facility, is based on FPGA (Field Programmable Gate Array) technology. This paper describes the basis of FPGA use in the accelerator interlock system through the development of LIPAc.
