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Takeda, Masaki; Ono, Hirokazu; Ito, Tsuyoshi*; Yotsuji, Kenji*; Fukatsu, Yuta; Sato, Tomofumi*; Tachi, Yukio
Journal of Nuclear Science and Technology, 63(9), p.1071 - 1085, 2026/09
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Tachi, Yukio; Sato, Tomofumi*; Takeda, Chizuko*; Ishidera, Takamitsu; Fujiwara, Kenso; Iijima, Kazuki
Science of the Total Environment, 724, p.138097_1 - 138097_10, 2020/07
Times Cited Count：17 Percentile：47.24(Environmental Sciences)To understand and predict radiocesium transport behaviors in the environment, sorption and fixation behaviors of radiocesium on river sediments from Ukedo and Odaka rivers around the Fukushima Daiichi Nuclear Power Plant were investigated systematically focusing on Cs sorption and fixation mechanisms and their relationship with Cs concentrations and sediment properties including clay mineralogy and organic matter.
Tachi, Yukio; Sato, Tomofumi*; Akagi, Yosuke*; Kawamura, Makoto*; Nakane, Hideji*; Terashima, Motoki; Fujiwara, Kenso; Iijima, Kazuki
Science of the Total Environment, 724, p.138098_1 - 138098_11, 2020/07
Times Cited Count：22 Percentile：55.20(Environmental Sciences)To understand and predict radiocesium transport behaviors in the environment, highly contaminated sediments from Ukedo and Odaka rivers around the Fukushima Daiichi Nuclear Power Plant were investigated systematically focusing on key factors controlling radiocesium sorption and fixation, including particle size, clay mineralogy and organic matter.
bound state in the 
C
reaction at 1.8 GeV/
Nagae, Tomofumi*; Ekawa, Hiroyuki; Hasegawa, Shoichi; Hayakawa, Shuhei; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi; Kimbara, Shinji; Nanamura, Takuya*; Naruki, Megumi; et al.
AIP Conference Proceedings 2130, p.020015_1 - 020015_9, 2019/07
Times Cited Count：14 Percentile：97.01(Physics, Nuclear)Kondo, Yasuhiro; Asano, Hiroyuki*; Chishiro, Etsuji; Hirano, Koichiro; Ishiyama, Tatsuya; Ito, Takashi; Kawane, Yusuke; Kikuzawa, Nobuhiro; Meigo, Shinichiro; Miura, Akihiko; et al.
Proceedings of 28th International Linear Accelerator Conference (LINAC 2016) (Internet), p.298 - 300, 2017/05
We have constructed a linac for development of various accelerator components at J-PARC. The ion source is same as the J-PARC linac's, and the RFQ is a used one in the J-PARC linac. The beam energy is 3 MeV and nominal beam current is 30 mA. The accelerator has been already commissioned, and the first development program, laser-charge-exchange experiment for the transmutation experimental facility, has been started. In this paper, present status of this 3-MeV linac is presented.
bound states in the C
reaction at 1.8 GeV/ in J-PARCNagae, Tomofumi*; Ekawa, Hiroyuki; Hasegawa, Shoichi; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Sugimura, Hitoshi; Tanida, Kiyoshi; et al.
Proceedings of Science (Internet), 281, p.038_1 - 038_7, 2017/05
Hirano, Koichiro; Asano, Hiroyuki; Ishiyama, Tatsuya; Ito, Takashi; Okoshi, Kiyonori; Oguri, Hidetomo; Kondo, Yasuhiro; Kawane, Yusuke; Kikuzawa, Nobuhiro; Sato, Yoshikatsu; et al.
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.310 - 313, 2016/11
We have used a beam scraper with the incident angle of 65deg to reduce the beam power deposition density in the MEBT between a 324 MHz RFQ and a 50-MeV DTL of the J-PARC linac. The 65
scraper was irradiated by the H
beam up to particle number of 1.47E22. We observed a lot of surface projections with several hundred micrometers high in the beam irradiation damage on the scraper by using the laser microscope. In order to study the limits of scrapers, we constructed a new 3 MeV linac at J-PARC. We will conduct the scraper irradiation test at the end of this year.
Naito, Fujio*; Anami, Shozo*; Ikegami, Kiyoshi*; Uota, Masahiko*; Ouchi, Toshikatsu*; Onishi, Takahiro*; Oba, Toshiyuki*; Obina, Takashi*; Kawamura, Masato*; Kumada, Hiroaki*; et al.
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1244 - 1246, 2016/11
The proton linac installed in the Ibaraki Neutron Medical Research Center is used for production of the intense neutron flux for the Boron Neutron Capture Therapy (BNCT). The linac consists of the 3-MeV RFQ and the 8-MeV DTL. Design average beam current is 10mA. Target is made of Beryllium. First neutron production from the Beryllium target was observed at the end of 2015 with the low intensity beam as a demonstration. After the observation of neutron production, a lot of improvement s was carried out in order to increase the proton beam intensity for the real beam commissioning. The beam commissioning has been started on May 2016. The status of the commissioning is summarized in this report.
Kondo, Yasuhiro; Morishita, Takatoshi; Yamazaki, Saishun; Hori, Toshihiko; Sawabe, Yuki; Chishiro, Etsuji; Fukuda, Shimpei; Hasegawa, Kazuo; Hirano, Koichiro; Kikuzawa, Nobuhiro; et al.
Physical Review Special Topics; Accelerators and Beams, 17(12), p.120101_1 - 120101_8, 2014/12
Times Cited Count：8 Percentile：47.19(Physics, Nuclear)We performed a beam test of a new radio frequency quadrupole linac (RFQ III) for the beam current upgrade of the Japan Proton Accelerator Research Complex. First, the conditioning of RFQ III was conducted, and after 20 h of conditioning, RFQ III became very stable with a nominal peak power and duty factor of 400 kW and 1.5%, respectively. An off-line beam test was subsequently conducted before installation in the accelerator tunnel. The transmission, transverse emittance, and energy spread of the 50-mA negative hydrogen beam from RFQ III were measured and compared with simulation results. The experiment and simulation results showed good agreement; therefore, we conclude that the performance of RFQ III conforms to its design.
Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10
no abstracts in English
Futatsukawa, Kenta*; Ikegami, Masanori*; Ito, Yuichi; Kikuzawa, Nobuhiro; Sato, Fumiaki; Shinozaki, Shinichi; Suzuki, Takahiro*; Chishiro, Etsuji; Hirano, Koichiro; Fang, Z.*; et al.
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1149 - 1153, 2014/06
no abstracts in English
Yoshikawa, Hideki; Kawakita, Masakazu*; Fujiwara, Kazuhiro*; Sato, Tomofumi; Asano, Takahiro*; Sasaki, Yoshito
Materials Research Society Symposium Proceedings, Vol.1475, p.617 - 622, 2012/06
Since it was suggested that the microbes have ability to generate their biofilm in deep underground condition, we examined the effects of biofilm on radionuclide migration scenario. To estimate the effect on matrix diffusion, through diffusion experiment for a biofilm of Desulfovivrio desullfuricans were performed. The effective diffusion coefficient of the biofilm was 10
m
/s order which was about ten times smaller than that in free water. It is suggesting that the microbes and biofilm will not interfere with matrix diffusion as a retardation of radionuclide in rock.
Sako, Hiroyuki; Imai, Kenichi; Sato, Susumu; Sugimura, Hitoshi; Miura, Akihiko; Maruta, Tomofumi; Kikuzawa, Nobuhiro
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 3 Pages, 2011/08
J-PARC linac has been operated at 7.2 kW since Nov. 2007. The most serious problem from SDTL (Separated-type Drift-Tube Linac) to ACS (Annular-Coupled Structure) sections is how to suppress the highest beam loss due to 
which have been generated by interactions between 
and remnant gas. Although beam loss has been measured with proportional counters, we have not succeeded to estimate absolute amplitude of . We have succeeded to reconstruct proton tracks which are generated from using scintillating fiber hodoscopes which were installed in the ACS section.
Miura, Akihiko; Sako, Hiroyuki; Yamamoto, Kazami; Kikuzawa, Nobuhiro; Maruta, Tomofumi; Sato, Susumu; Imai, Kenichi; Adachi, Satoshi; Sugimura, Hitoshi; Igarashi, Zenei*; et al.
Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.590 - 592, 2010/09
Ar-CO
gas proportional counters are employed for the measurement of beam loss in the current linac operation, but they are also sensitive to background noise of X-ray emitted from RF cavities. In SDTL section, protons, secondary hadrons and 
rays would be mainly generated as a beam loss, but it is not easy to estimate real beam loss using the proportional counter. The plastic scintillation counters with less X-ray sensitivity and 
He proportional counters with high thermal neutron sensitivity will be also employed to measure the beam loss. This paper reports the signals obtained during the beam operation using the Ar-CO gas proportional counter and the plastic scintillation counter. Finally, a measurement of emission position and angle distributions of protons due to negative hydrogen ion (H) beam loss is being planed. This plan is introduced and this result would lead to clarify the source of beam loss.
phase revealed by polarized spin-selected 1
3
absorption spectraHayashi, Hisashi*; Sato, Atsushi*; Azumi, Tomofumi*; Udagawa, Yasuo*; Inami, Toshiya; Ishii, Kenji; Garg, K. B.*
Physical Review B, 73(13), p.134405_1 - 134405_5, 2006/04
Times Cited Count：15 Percentile：54.31(Materials Science, Multidisciplinary)no abstracts in English
Ota, Ryosuke*; Mitsuyama, Kazuaki*; Tachi, Yukio; Yotsuji, Kenji*; Sato, Tomofumi*; Sato, Hisao*; Martin, A.*
no journal, ,
The radionuclide migration model representing heterogeneities in distributions of minerals and pores was developed for Grimsel granodiorite. This model was applied to quantify the impact of heterogeneities on radionuclide migration and was validated by comparing with the measured data.
Tachi, Yukio; Sato, Tomofumi; Terashima, Motoki; Takeda, Chizuko*; Fujiwara, Kenso; Iijima, Kazuki
no journal, ,
To predict the transport behaviors of radiocesium in river systems around the Fukushima Dai-ichi Nuclear Power Plant, the sorption and desorption of Cs on various types of river soils was investigated as functions of Cs concentration and reaction time. The key factors controlling the Cs transport were discussed based on types of clay minerals, organics, sorption kinetics, etc.
Sasaki, Yoshito; Asano, Takahiro*; Amano, Yuki; Sato, Tomofumi; Iwatsuki, Teruki; Yoshikawa, Hideki
no journal, ,
no abstracts in English
Terashima, Motoki; Tachi, Yukio; Sato, Tomofumi; Akagi, Yosuke*; Kawamura, Makoto*; Nakane, Hideji*; Fujiwara, Kenso; Iijima, Kazuki
no journal, ,
no abstracts in English
Sasaki, Yoshito; Asano, Takahiro*; Ise, Kotaro; Sato, Tomofumi; Murakami, Hiroaki; Amamiya, Hiroki; Amano, Yuki; Iwatsuki, Teruki; Yoshikawa, Hideki
no journal, ,
no abstracts in English
