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Journal Articles

Key factors controlling radiocesium sorption and fixation in river sediments around the Fukushima Daiichi Nuclear Power Plant, 1; Insights from sediment properties and radiocesium distributions

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:13 Percentile:58.17(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.

Journal Articles

Key factors controlling radiocesium sorption and fixation in river sediments around the Fukushima Daiichi Nuclear Power Plant, 2; Sorption and fixation behaviors and their relationship to sediment properties

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:9 Percentile:44.38(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.

Journal Articles

Observation of a $$Xi$$ bound state in the $$^{12}$$C$$(K^-, K^+)$$ reaction at 1.8 GeV/$$c$$

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:11 Percentile:98.36

Journal Articles

A 3 MeV linac for development of accelerator components at J-PARC

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.

Journal Articles

Observation of $$Xi$$ bound states in the $$^{12}$$C$$(K^-,K^+)X$$ reaction at 1.8 GeV/$$c$$ in J-PARC

Nagae, 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

Journal Articles

Development of beam scrapers using a 3-Mev linac at J-PARC

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$$^{circ}$$ 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.

Journal Articles

Beam commissioning of the linac for iBNCT

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.

Journal Articles

Beam test of a new radio frequency quadrupole linac for the Japan Proton Accelerator Research Complex

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:6 Percentile:43.07(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.

Journal Articles

Present status of J-PARC linac

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

Journal Articles

Upgrade of power supply system for RF-chopper at J-PARC Linac

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

Journal Articles

An Investigation of microbial effect as biofilm formation on radionuclide migration

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$$^{-10}$$ m$$^{2}$$/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.

Journal Articles

Beam loss particle tracking in J-PARC linac

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 $$H^{0}$$ which have been generated by interactions between $$H^{-}$$ and remnant gas. Although beam loss has been measured with proportional counters, we have not succeeded to estimate absolute amplitude of $$H^{0}$$. We have succeeded to reconstruct proton tracks which are generated from $$H^{0}$$ using scintillating fiber hodoscopes which were installed in the ACS section.

Journal Articles

Status of beam loss evaluation at J-PARC linac

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$$_{2}$$ 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 $$gamma$$ 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 $$^{3}$$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$$_{2}$$ 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.

Journal Articles

Local spin ordering in the antiferromagnetic as well as paramagnetic LaMnO$$_3$$ phase revealed by polarized spin-selected 1${it s}$ $$rightarrow$$3${it d}$ absorption spectra

Hayashi, 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:14 Percentile:56.38(Materials Science, Multidisciplinary)

no abstracts in English

Oral presentation

Evaluation of coprecipitation with trace element on carbonate mineral by solid solution model, 2

Yoshida, Yasushi*; Yoshikawa, Hideki; Sato, Tomofumi*

no journal, , 

no abstracts in English

Oral presentation

Co-precipitation reaction for Ba and Ra into calcite

Yoshida, Yasushi*; Yoshikawa, Hideki; Nakazawa, Toshiyuki*; Sato, Tomofumi*

no journal, , 

To evaluate incorporation behavior of Me$$^{2+}$$ larger than Ca in ion radius, co-precipitation experiment were implemented. Partition coefficient is generally used to estimate co-precipitation reaction and this parameter is reported to be affected by precipitation rate of calcite. Therefore, under the condition of variety of R, D for Me$$^{2+}$$ larger than Ca into calcite was measured. For trace elements Ra and Ba were used. As a result of experiment Partition coefficient for Ba (or Ra) are decreasing toward the slow R. This tendency is consistent with the reported data. The values of D of Ba and Ra which are low imply those large radius elements are difficult to incorporated into crystal lattice and inclusion is presumably induced by distortion of lattice structure. In addition there is no notable difference of D for Ra and Ba despite difference of radius length. It indicates an extent of inclusion does not depend on a difference of ion radius between Ra and Ba.

Oral presentation

Characterization of the biofilm

Yoshikawa, Hideki; Miura, Masahiko*; Sato, Tomofumi*; Matsubara, Masaaki*

no journal, , 

A characterization for SRB biofilm and Cs sorption experiment with the film were carried out.

Oral presentation

Beam loss measurements with scintillation fibers at the J-PARC linac

Sako, Hiroyuki; Kikuzawa, Nobuhiro; Miura, Akihiko; Maruta, Tomofumi; Adachi, Satoshi; Imai, Kenichi; Sato, Susumu; Sugimura, Hitoshi

no journal, , 

At Annular Coupled Structure linac (ACS) in J-PARC linac, high residual radiation due to beam loss has been observed. Since the beam loss is approximately proportional to the residual gas pressure, the observed beam loss may be caused by the H$$^{0}$$'s which are generated by the electron stripping by the residual gas. We are going to evaluate beam loss by counting H$$^{+}$$'s emitted outside the beam duct. We have developed hodoscopes with the sensitive area of 64 mm $$times$$ 64 mm, which consists of 16 fibers of 4 mm $$times$$ 4 mm $$times$$ 64 mm. Scintillation photons are measured by the multi-anode photo-multipliers. We report beam loss measurements by the hodoscopes.

Oral presentation

Study of deep subsurface microbial community under changing redox conditions using quantitative method

Sasaki, Yoshito; Asano, Takahiro*; Amano, Yuki; Sato, Tomofumi; Iwatsuki, Teruki; Yoshikawa, Hideki

no journal, , 

no abstracts in English

Oral presentation

Planktonic and attached microbes in deep subsurface

Sasaki, Yoshito; Asano, Takahiro*; Ise, Kotaro; Sato, Tomofumi; Murakami, Hiroaki; Amamiya, Hiroki; Amano, Yuki; Iwatsuki, Teruki; Yoshikawa, Hideki

no journal, , 

no abstracts in English

27 (Records 1-20 displayed on this page)