A Sensitive method for Sr-90 analysis by accelerator mass spectrometry

Sasa, Kimikazu*; Honda, Maki; Hosoya, Seiji*; Takahashi, Tsutomu*; Takano, Kenta*; Ochiai, Yuta*; Sakaguchi, Aya*; Kurita, Saori*; Satou, Yukihiko; Sueki, Keisuke*

Journal of Nuclear Science and Technology, 58(1), p.72 - 79, 2021/01

https://doi.org/10.1080/00223131.2020.1801530

Na-montmorillonite dissolution rate determined by varying the Gibbs free energy of reaction in a dispersed system and its application to a coagulated system in 0.3M NaOH solution at 70C

Oda, Chie; Walker, C.; Chino, Daisuke*; Ichige, Satoru; Honda, Akira; Sato, Tsutomu*; Yoneda, Tetsuro*

Applied Clay Science, 93-94, p.62 - 71, 2014/05

https://doi.org/10.1016/j.clay.2014.02.021

Na-montmorillonite dissolution in a 0.3M NaOH solution has been investigated at pH12 and 70C. The flow-through dissolution experiments were conducted in a dispersed system with varying concentrations of Si and Al to derive a Na-montmorillonite dissolution rate, as a non-linear function of the Gibbs free energy of reaction, dGr. This rate equation was used to simulate the batch-type Na-montmorillonite reaction experiments conducted in a coagulated system. The model simulation of the batch-type experiment adopting the empirical rate equations of Na-montmorillonite dissolution and secondary mineral analcime precipitation were able to reproduce the measured changes in the amount of dissolved Na-montmorillonite and concentrations of Si and Al in solution. The results showed that the empirical rate equation of Na-montmorillonite dissolution determined in the dispersed system was applicable to the coagulated system over a higher dGr range and that the concentrations of Si and Al in the batch experiment were controlled by the precipitation of analcime.

Reactive-transport model analyses of bentonite alteration behavior at alkaline condition generated by cement-water interaction in a TRU wastes repository

Oda, Chie; Honda, Akira; Takase, Hiroyasu*; Ozone, Kenji*; Sasaki, Ryoichi*; Yamaguchi, Kohei*; Sato, Tsutomu*

Nendo Kagaku, 51(2), p.34 - 49, 2013/02

http://ci.nii.ac.jp/naid/110009594110

Proposed TRU repository designs for geological disposal envisage the use of a bentonite buffer to limit the migration of radionuclides by impeding groundwater flow. Under highly alkaline conditions due to cementitious materials could cause a complex series of coupled changes in the porewater chemistry, mineralogy and, ultimately, the mass transport properties of the bentonite buffer. To elucidate the consequences of these coupled changes, reactive-transport model analyses have been conducted for eight bentonite alteration test cases using different combinations of secondary minerals that could form in the bentonite buffer. It was found that after 100,000 years the amount of dissolved bentonite was at a maximum when metastable secondary minerals precipitated. It was also found that the diffusion and hydraulic coefficients after 100,000 years in all test cases were on the same order of magnitude as the initial values.

Development of a 500-kV photocathode DC gun

Nishimori, Nobuyuki; Nagai, Ryoji; Hajima, Ryoichi; Yamamoto, Masahiro*; Miyajima, Tsukasa*; Honda, Yosuke*; Iijima, Hokuto*; Kuriki, Masao*; Kuwahara, Makoto*; Okumi, Shoji*; et al.

Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.20 - 23, 2011/08

http://www.pasj.jp/web_publish/pasj8/proceedings/oral/MOPL05.pdf

no abstracts in English

Development of a 500-kV photo-cathode DC gun for ERL light sources

Nishimori, Nobuyuki; Nagai, Ryoji; Hajima, Ryoichi; Yamamoto, Masahiro*; Honda, Yosuke*; Miyajima, Tsukasa*; Muto, Toshiya*; Iijima, Hokuto*; Kuriki, Masao*; Kuwahara, Makoto*; et al.

Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.995 - 997, 2010/09

http://accelconf.web.cern.ch/AccelConf/LINAC2010/papers/thp111.pdf

Basic vacuum test of 500-kV photocathode DC gun components at KEK

Yamamoto, Masahiro*; Uchiyama, Takashi*; Miyajima, Tsukasa*; Honda, Yosuke*; Sato, Kotaro*; Matsuba, Shunya*; Saito, Yoshio*; Kobayashi, Masanori*; Kurisu, Hiriki*; Hajima, Ryoichi; et al.

Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.717 - 720, 2010/08

http://www.pasj.jp/web_publish/pasj7/proceedings/P_4PM/P_EH_4PM/WEPS124.pdf

A 500-kV photocathode DC electron gun which can supply the beam of a low emittance and a high average current has been developed in collaboration with KEK, JAEA, Hiroshima Univ., Nagoya Univ. and Yamaguchi Univ. The vacuum of the gun chamber has to be lower Extreme High Vacuum for maintain cathode-life time. A titanium chamber and new material of ceramic were employed to reduce outgassing rate. The result of outgassing rate of the gun chamber is described in this report.

Development of a photocathode DC electron-gun for next-generation light-sources

Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki; Muto, Toshiya*; Yamamoto, Masahiro*; Honda, Yosuke*; Miyajima, Tsukasa*; Kuriki, Masao*; Iijima, Hokuto*; Kuwahara, Makoto*; et al.

Kasokuki, 7(2), p.88 - 94, 2010/07

http://ci.nii.ac.jp/naid/40017253048

A 500-kV, 10-mA photocathode DC gun which is designed for next-generation light-sources based on energy-recovery linac has been developed in a collaboration effort of JAEA, KEK, Hiroshima University and Nagoya University. We have utilized a segmented cylindrical ceramic insulator and guard-ring electrodes to prevent any damage to the insulator from electrons emitted by the support-rod electrode. The 500-kV gun was successfully conditioned up to a voltage of 550 kV and a long-time holding test for 8 h was demonstrated at an acceleration voltage of 500 kV. The 500-kV gun consists of a Cockcroft-Walton generator, a segmented cylindrical ceramic insulator, guard-ring electrodes, a support-rod electrode, a vacuum chamber, and a pressurized insulating gas tank. The cathode electrode, anode electrode, and beam line apparatuses are now under fabrication and beam tests of the gun will be started soon.

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

http://accelconf.web.cern.ch/AccelConf/IPAC10/papers/tupe091.pdf

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Development of a photocathode preparation system and a high voltage chamber for a 500 kV DC gun for ERL light sources

Nishimori, Nobuyuki; Nagai, Ryoji; Iijima, Hokuto; Hajima, Ryoichi; Yamamoto, Masahiro*; Muto, Toshiya*; Miyajima, Tsukasa*; Honda, Yosuke*; Kuriki, Masao*; Kuwahara, Makoto*; et al.

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.872 - 874, 2010/03

http://www.pasj.jp/web_publish/pasj6/papers/fppsa10.pdf

no abstracts in English

Development of an electron gun for an ERL based light source in Japan

Nishimori, Nobuyuki; Nagai, Ryoji; Iijima, Hokuto; Honda, Yosuke*; Muto, Toshiya*; Kuriki, Masao*; Yamamoto, Masahiro*; Okumi, Shoji*; Nakanishi, Tsutomu*; Hajima, Ryoichi

AIP Conference Proceedings 1149, p.1094 - 1098, 2009/08

https://doi.org/10.1063/1.3215600

We have constructed a prototype DC photoemission electron gun for a future energy recovery linac (ERL) based light source in Japan. The prototype gun is operated at up to 250 kV. A diagnostic beam line for emittance and bunch length measurements will be constructed soon. A 83.3 MHz Ti:sapphire laser with 500 mW average power and 2 ps pulse length is used to illuminate a GaAs photocathode. The prototype gun is designed to deliver up to 50 mA beam current. We have also designed a new 500 kV DC gun which is capable of producing up to 10 mA electron current with emittance lower than 1 mm-mrad. The high voltage terminal will be isolated by ten ceramics stacked in series. The new gun will satisfy performance required as an injector for the compact ERL, which will be constructed at KEK as a prototype of the future ERL light source. In this talk, our current status of the gun development has been presented.