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Satoh, Daiki; Maeda, Yoshikazu*; Tameshige, Yuji*; Nakashima, Hiroshi; Shibata, Tokushi*; Endo, Akira; Tsuda, Shuichi; Sasaki, Makoto*; Maekawa, Motokazu*; Shimizu, Yasuhiro*; et al.
Journal of Nuclear Science and Technology, 49(11), p.1097 - 1109, 2012/11
Times Cited Count：14 Percentile：71.22(Nuclear Science & Technology)At the Fukui Prefectural Hospital Proton Therapy Center, neutron doses behind concrete shields and at maze have been measured by using radiation monitors, DARWIN, Wendi-2, a rem meter, and solid state nuclear track detectors. The measured data were compared with the estimations by analytical models and Monte Carlo code PHITS. The analytical model with the parameters employed in shielding design of the facility gave considerably larger estimates than the measured data. This means that the facility was designed with an enough safety margin. The calculation results of PHITS were less than those of the analytical model, and were about 3 times larger than the measured data. From the view point of a safety policy with conservative estimation for shielding design, Monte Carlo simulation is a better tool for estimating radiation safety at accelerator-based proton treatment facilities.
Maeda, Yoshihito; Narumi, Kazumasa; Sakai, Seiji; Terai, Yoshikazu*; Hamaya, Kohei*; Sado, Taizo*; Miyao, Masanobu*
Thin Solid Films, 519(24), p.8461 - 8467, 2011/10
Times Cited Count：8 Percentile：36.17(Materials Science, Multidisciplinary)Yamamoto, Masahiro*; Honda, Yosuke*; Miyajima, Tsukasa*; Uchiyama, Takashi*; Kobayashi, Masanori*; Muto, Toshiya*; Matsuba, Shunya*; Sakanaka, Shogo*; Sato, Kotaro*; Saito, Yoshio*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.860 - 862, 2009/08
A newly 500 kV electron gun (2nd - 500 kV gun) for an ERL light source is designed at KEK. A new concept and state of-the-art technologies of vacuum system, ceramic insulators, high voltage power supply, photocathode and preparation system will be employed. The details are described in this report.
Tokura, Akio*; Maeda, Fumihiko*; Teraoka, Yuden; Yoshigoe, Akitaka; Takagi, Daisuke*; Homma, Yoshikazu*; Watanabe, Yoshio*; Kobayashi, Yoshihiro*
Carbon, 46(14), p.1903 - 1908, 2008/11
Times Cited Count：18 Percentile：50.1(Chemistry, Physical)We have investigated the adsorption of atomic hydrogen on vertically aligned carbon nanotube using 
synchrotron-radiation-based core-level photoelectron spectroscopy and Raman spectroscopy. From C1s spectra, we identified a peak component due to CH bonds of carbon atoms in single-walled carbon nanotubes. We also found the suppression of 
-plasmon excitation, indicating that the hydrogen adsorption deforms the bonding structure. Raman spectra of the single-walled carbon nanotubes indicated that the radial-breathing-mode intensities decreased due to the adsorption-induced bonding-structure deformation. Moreover, the decrease for single-walled carbon nanotubes with small-diameter was more severe than that for large-diameter. Our results strongly suggest that the hydrogen adsorption, which induces the structure deformation from sp
to sp
bonding, depends on the diameter of SWCNTs.
Tokura, Akio*; Maeda, Fumihiko*; Takagi, Daisuke*; Homma, Yoshikazu*; Yoshigoe, Akitaka; Teraoka, Yuden; Watanabe, Yoshio*; Kobayashi, Yoshihiro*
no journal, ,
no abstracts in English
Tokura, Akio*; Maeda, Fumihiko*; Teraoka, Yuden; Yoshigoe, Akitaka; Takagi, Daisuke*; Homma, Yoshikazu*; Watanabe, Yoshio*; Kobayashi, Yoshihiro*
no journal, ,
We have investigated the adsorption of atomic hydrogen on vertically aligned SWNT film. The effects of hydrogen adsorption were investigated by photoelectron spectroscopy and Raman spectroscopy. By fitting C 1s core level spectrum, we found the component attributed to hydrogenation of carbon. The suppression of plasmons was also found. These results indicate that hydrogen adsorption induced bonding structure deformation. Raman spectra demonstrate that the radial-breathing-mode intensity of small-diameter SWNTs is more severely decreased than that of large-diameter SWNTs. The G-band/D-band ratio also decreased after the irradiation. These results indicate the disordering of graphene on small-diameter SWNTs is induced more easily. Our results indicate that the adsorption coefficient of hydrogen atoms for SWNTs with small diameter is higher than that for SWNTs with large diameter.
Matsukura, Bui*; Nakajima, Takahito*; Maeda, Yoshihito; Narumi, Kazumasa; Terai, Yoshikazu*; Sado, Taizo*; Hamaya, Kohei*; Miyao, Masanobu*
no journal, ,
no abstracts in English
Satoh, Daiki; Nakashima, Hiroshi; Shibata, Tokushi; Endo, Akira; Tsuda, Shuichi; Tameshige, Yuji*; Maeda, Yoshikazu*; Sasaki, Makoto*; Maekawa, Motokazu*; Shimizu, Yasuhiro*; et al.
no journal, ,
In order to investigate the optimal design of a proton radiotherapy facility, neutron doses behind shielding walls were measured at the proton therapy center in Fukui prefectural hospital. The radiation monitors, DARWIN, WENDI-2, and REM, were used to assess the neutron doses. The doses obtained by DARWIN and WENDI-2 agreed well. It was found that the REM monitor underestimate the doses due to the lack of sensitivity to neutrons whose energy is above several tens of MeV.
Tameshige, Yuji*; Maeda, Yoshikazu*; Sasaki, Makoto*; Maekawa, Motokazu*; Shimizu, Yasuhiro*; Satoh, Daiki; Nakashima, Hiroshi; Endo, Akira; Shibata, Tokushi; Tsuda, Shuichi; et al.
no journal, ,
no abstracts in English
Yamaguchi, Yukako; Sekio, Yoshihiro; Maeda, Koji; Koma, Yoshikazu; Fujiya, Akihiko*
no journal, ,
no abstracts in English
-emitting nuclides analysis of the stagnant water including sediments in Fukushima Daiichi NPS, 3; Chemical state analysis of -emitting nuclide particles obtained from unit #3 stagnant water sludgeUsui, Akane; Yamaguchi, Yukako; Sekio, Yoshihiro; Maeda, Koji; Koma, Yoshikazu; Konno, Katsuhiro*
no journal, ,
no abstracts in English
-emitting nuclides analysis of the stagnant water including sediments in Fukushima Daiichi NPS, 6; Chemical state analysis of -emitting nuclide particles obtained from unit #3 stagnant water sludge (Part 2)Nitta, Asahi; Usui, Akane; Yamaguchi, Yukako; Sekio, Yoshihiro; Maeda, Koji; Koma, Yoshikazu; Konno, Katsuhiro*
no journal, ,
no abstracts in English
-emitting nuclides analysis of the stagnant water including sediments in Fukushima Daiichi NPS, 10; Chemical state analysis of -emitting nuclide particles obtained from stagnant water sludge sampled from Unit #1 and centralized radioactive waste treatment facilityToyota, Chihiro; Nitta, Asahi; Usui, Akane; Sekio, Yoshihiro; Maeda, Koji; Koma, Yoshikazu; Konno, Katsuhiro*
no journal, ,
no abstracts in English
