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Sato, Shin*; Ono, Hirokazu; Tanai, Kenji; Yamamoto, Shuichi*; Fukaya, Masaaki*; Shimura, Tomoyuki*; Niunoya, Sumio*
Jiban Kogaku Janaru (Internet), 15(3), p.529 - 541, 2020/09
no abstracts in English
Sakai, Hiroshi*; Enami, Kazuhiro*; Furuya, Takaaki*; Kako, Eiji*; Kondo, Yoshinari*; Michizono, Shinichiro*; Miura, Takako*; Qiu, F.*; Sato, Masato*; Shinoe, Kenji*; et al.
Proceedings of 56th ICFA Advanced Beam Dynamics Workshop on Energy Recovery Linacs (ERL 2015) (Internet), p.63 - 66, 2015/12
no abstracts in English
Sato, Shinichiro; Meguro, Tomomi*; Suezaki, Takashi*; Yamamoto, Kenji*; Oshima, Takeshi
Proceedings of 40th IEEE Photovoltaic Specialists Conference (PVSC-40) (CD-ROM), p.1825 - 1829, 2014/06
Performance degradation of super-straight type amorphous silicon germanium alloy (a-SiGe) solar cells due to proton irradiation are investigated using an in-situ current-voltage measurement system. The results show that a-Si solar cells have higher radiation resistance than a-SiGe solar cells. Also, the room temperature annealing effects immediately after irradiation are investigated and it is shown that the recovery of the short-circuit current is especially prominent in all the parameters. Based on the obtained results, we propose a radiation hardened design of amorphous silicon alloy multi-junction solar cells.
Tanai, Kenji; Fujita, Tomoo; Noda, Masaru*; Yamamoto, Shuichi*; Shimura, Tomoyuki*; Sato, Shin*
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.167 - 172, 2013/01
Japan Atomic Energy Agency has been planning in-situ gas migration test in Horonobe URL, Hokkaido. This paper discusses the optimum gas injection procedure for the test to understand gas migration behaviour in surrounded rock. The stepwise constant gas injection was selected, taking into account domestic and overseas gas related research results. Hydro-mechanical-gas coupling analysis which is able to consider the dissolved methane in Horonobe groundwater was applied to evaluate the gas behaviour. The results have indicated no significant mechanical damages to the rock and have supported the sppropriateness of selected gas injection procedure for the test.
Tanai, Kenji; Fujita, Tomoo; Sato, Shin*; Noda, Masaru*; Yamamoto, Shuichi*; Shimura, Tomoyuki*
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.173 - 178, 2013/01
Japan Atomic Energy Agency has been planning 
gas migration test in Horonobe URL, Hokkaido. It is expected that dissolved methane in Horonobe groundwater might have an effect on gas migration behaviour in bedrock. A series of two-phase multi-component analyses by use of GETFLOWS were conducted to understand the influence of dissolved methane. The increase of total gas pressure has been shown due to the existence of dissolved methane. The results also indicated that the injected nitrogen gas volume was influenced by dissolved methane.
Kuchiyama, Takashi*; Hasegawa, Shigehiko*; Yamamoto, Kenji*; Teraoka, Yuden; Asahi, Hajime*
Japanese Journal of Applied Physics, 50(12), p.121101_1 - 121101_4, 2011/12
Times Cited Count：1 Percentile：4.76(Physics, Applied)Umemori, Kensei*; Furuya, Takaaki*; Kako, Eiji*; Noguchi, Shuichi*; Sakai, Hiroshi*; Sato, Masato*; Shishido, Toshio*; Watanabe, Ken*; Yamamoto, Yasuchika*; Shinoe, Kenji*; et al.
Proceedings of 15th International Conference on RF Superconductivity (SRF 2011) (Internet), p.956 - 961, 2011/07
The Compact ERL (cERL) project is advanced in Japan. Its aim is to demonstrate the circulation of 100 mA electron beams with energy of 35-200 MeV. Superconducting cavities are key components for realizing ERL and used for injector part and main linac part. Critical issue for the injector part is the development of input power coupler. Prototype input couplers were fabricated and high power test was performed. Cooling ability of HOM coupler is also important for CW operation of cavity. At main linac part, HOM damped 9-cell cavities are applied to avoid BBU instabilities. Prototypes were fabricated for the cavity, the input coupler and the HOM absorber. Their performance was investigated. For both parts, cryomodules are under construction and will be completed in 2012.
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
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.
Sakai, Hiroshi*; Furuya, Takaaki*; Kako, Eiji*; Noguchi, Shuichi*; Sato, Masato*; Sakanaka, Shogo*; Shishido, Toshio*; Takahashi, Takeshi*; Umemori, Kensei*; Watanabe, Ken*; et al.
Proceedings of 45th Advanced ICFA Beam Dynamics Workshop on Energy Recovery Linacs (ERL '09) (Internet), p.57 - 62, 2010/05
Development of a SC Cavity Injector Cryomodule and Main linac Cryomodule for the compact ERL is being continued at KEK since 2006. Design of an injector cryomodule containing three 2-cell 1.3-GHz cavities for Injector Cryomodule and two 9-cell 1.3-GHz cavities for Main linac Cryomodule are almost completed. Status of R&D and design details are reported.
Umemori, Kensei*; Furuya, Takaaki*; Kako, Eiji*; Noguchi, Shuichi*; Sakai, Hiroshi*; Sato, Masato*; Shishido, Toshio*; Takahashi, Takeshi*; Watanabe, Ken*; Yamamoto, Yasuchika*; et al.
Proceedings of 14th International Conference on RF Superconductivity (SRF 2009) (Internet), p.896 - 901, 2009/09
Construction of the Compact ERL is planned in Japan, in order to test the key technology to realize a future ERL based X-ray light source. The operation of 60-200 MeV beam energy and 100 mA beam current are proposed. The superconducting cavity is one of the key components and applied for the injector part and the main linac part. At the injector part, most challenging issue is an input coupler, which has to handle more than 300 kW input power per cavity. On the other hand, strong HOM damping is required for the main linac, in order to avoid beam instabilities and large heat load at cryomodules. Status of cavity developments, together with cryomodule developments, including input couplers and HOM couplers/absorbers, are described in this paper.
Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06
Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.
Yamamoto, Yasuchika*; Hayano, Hitoshi*; Kako, Eiji*; Noguchi, Shuichi*; Sato, Masato*; Shishido, Toshio*; Umemori, Kensei*; Watanabe, Ken*; Sakai, Hiroshi*; Shinoe, Kenji*; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.888 - 891, 2008/00
In KEK, the new Superconducting RF Test Facility(STF) is being constructed, including the electro-polish system (EP), the high pressure rinsing system (HPR), the clean-room, the refrigerator system, the high power RF source system, and the vertical test system. The cavity is generally measured in the vertical cryostat for the performance test. The new vertical test facility was constructed since the last year, and completed at the beginning of March. The first test was done for the total system check at the beginning of July.
Tanai, Kenji; Yamamoto, Mikihiko*; Seki, Yoshitaka*
JAEA-Research 2007-057, 71 Pages, 2007/07
JAEA-Research-2007-057.pdf:1.77MB
In underground repositories for radioactive waste, significant quantities of gases may be generated as a result of metal corrosion. These gases may migrate through the engineered barrier system and the geological barrier. The potential impact of gas generation, accumulation and migration on the performances of the various barriers such as drainage of contaminated water from the repository and/or damaging of the engineered barriers due to a gas over-pressure should be assessed. The sensitivity analysis was carried out using the modified TOUGH2 model in order to clarify the impact of any input parameters. The following facts became clear as a result of this study. For the cementitious material (waste/cementitious filler), an impact of the absolute permeability and residual pore-water saturation was large. For the buffer material, absolute permeability of gas, capillary exclusion pressure and residual pore-water saturation was large.
Tanai, Kenji; Yamamoto, Mikihiko*
JNC TN8400 2003-051, 107 Pages, 2004/02
JNC-TN8400-2003-051.pdf:1.42MB
Suitable modelling of gas production and migration behaviour is strongly required for performance assessment of radioactive waste disposal in a geological repository. Especially for gas migration in buffer materials, it is very important to examine their ability to reproduce in herent gas migration behaviour which is caused by creation of discrete pathways in clay materials. JNC has examined the limitation of reproducibility of conventional two-phase flow model and anhanced TOUGH2 which has newly developed module implemented expanded Kozeny-Carman relationship and pathway dilation/resealing model. JNC also surveyed the state of the art of model development of gas migration in multi-barriers. In FY 2003, the surverillance of gas migration modelling was continued and handled migration mechanisms, basic mathematical models, strength and weakness of each developed gas migration models were extracted and tabulated. Based on these outcomes, thebasic correspondence of models to barrier materials, which should apply to performance assessment for a near-field system, was examined. In consequence, conventional two-phase flow models of gas migration are generally applicable for cementitious materials and rocks without mudrocks. But if it is required to understand more precisely the distribution of gas release at the surface, then more detailed uderstanding of flow in fractures would be required. For clay and mudrocks, it is necessary that comparison of applicability with three types of models, which include GAMBIT-GWS model, conventional two-phase flow models coupled with effect of stress field and expanded Kozeny-Carman relationship with pathway dilation/resealing model.
Tanai, Kenji; Yamamoto, Mikihiko*
JNC TN8400 2003-024, 23 Pages, 2003/11
The knowledge obtained from previous studies are as follows, i) The gas permeabilities are 10
m
for the 30wt% sand mixtures at a dry density of 1.6 Mg m
and 10
to 10
mfor the bentonite (100%) at a dry density of 1.8 Mg m, ii) The breakthrough pressure seems to be almost the same as the swelling pressure at constant volume condition, iii) Gas pathways created during the first gas injection period are closed due to bentonite swelling during the resaturation period. For the recent experiment, it is obtained two peak of gas flow rate. In particular, maximum flow rate at secondary peak is obtained apploximately 1667cc min
. This peak is probably indicative of generation of cracks in the specimen by particle displacement. Breakthrough pressure (2.5 MPa) is larger than the swelling pressure of the bentonite (swelling pressure is approximately 1.0 MPa at a dry density of 1.6 Mg m). It may be that there is a time lag between the gas pressure change in the clay and expansion of cracks due to large pumping rate (0.05 cc min-1). The gas migration pathways are unstable due to stress condition in bentonite specimen and/or heterogeneity of specimen. The distribution of bulk density in the specimen was measured to demonstrate that X-ray CT was reliable new technique for the non-distructive measurement of gas migration through bentonite specimen. The degree of X-ray attenuation depends on the bulk density of the bentonite specimen. The change in bulk density in this test specimen is not cleared from this test case. These experimental results are probably indicative of migration along preferential pathways rather than uniform flow in the matrix of bentonite specimen.
Noda, Masaru*; Yamamoto, Shuichi*; Shimura, Tomoyuki*; Sato, Shin*; Tanai, Kenji; Fujita, Tomoo
no journal, ,
no abstracts in English
Sato, Shin*; Yamamoto, Shuichi*; Noda, Masaru*; Shimura, Tomoyuki*; Fujita, Tomoo; Tanai, Kenji
no journal, ,
no abstracts in English
Tanai, Kenji; Fujita, Tomoo; Noda, Masaru*; Yamamoto, Shuichi*; Shimura, Tomoyuki*; Sato, Shin*
no journal, ,
no abstracts in English
Fujita, Tomoo; Tanai, Kenji; Shimura, Tomoyuki*; Noda, Masaru*; Yamamoto, Shuichi*; Sato, Shin*
no journal, ,
no abstracts in English
Yamashita, Hayato; Yamashita, Takuya; Onizawa, Takashi; Nagae, Yuji; Yamamoto, Kenji*; Shudo, Shingo*; Kawasaki, Kenji*; Kubo, Koji*
no journal, ,
no abstracts in English
