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Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Aoi, Nori*; Azaiez, F.*; Furutaka, Kazuyoshi; Hatsukawa, Yuichi; Kimura, Atsushi; Kisamori, Keiichi*; Kobayashi, Motoki*; et al.
Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03
Times Cited Count:4 Percentile:58.42(Physics, Nuclear)Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Kobayashi, Motoki*; Kisamori, Keiichi*; Takaki, Motonobu*; Miya, Hiroyuki*; Ota, Shinsuke*; Michimasa, Shinichiro*; Shimoura, Susumu*; et al.
JPS Conference Proceedings (Internet), 6, p.030005_1 - 030005_4, 2015/06
Yamamoto, Keiichi; Takeuchi, Tomoaki; Sano, Tadafumi*; Homma, Ryohei*; Kimura, Nobuaki; Otsuka, Noriaki; Kosuge, Fumiaki*; Nakajima, Ken*; Tsuchiya, Kunihiko
JAEA-Technology 2014-028, 56 Pages, 2015/01
Development of the reactor measurement system was started to obtain real-time in-core nuclear and thermal information, where the quantity measurement of brightness of Cherenkov light was applied. The system would be applied as monitoring system in severe accidents and for advanced operation management technology in existing LWRs. In this report, the calculation and the observation results were summarized about the quantity of the Cherenkov light caused by the and ray emitted from the fuels in the core of Kyoto University Research Reactor.
Otsuka, Noriaki; Takeuchi, Tomoaki; Yamamoto, Keiichi; Shibata, Akira; Kimura, Nobuaki; Takemoto, Noriyuki; Tanimoto, Masataka; Tsuchiya, Kunihiko; Sano, Tadafumi*; Unesaki, Hironobu*; et al.
KURRI Progress Report 2013, P. 215, 2014/10
Investigation of a relation between reactor power and brightness of Cherenkov light at Kyoto University Research reactor (KUR) by a CCD camera was performed due to a development of a real-time in-core measurement technique using Cherenkov light. Analyzing the brightness value of individual RGB color component at each pixel, some of the G and B brightness values reached the maximum value of 8-bit binary number, i.e. 255, above about 2-3 MW. Therefore, we corrected the G and B brightness values by the R signals whose brightness value did not saturate even at 5 MW, the maximum reactor power of KUR. Then, the total brightness value was in proportion to the reactor power after the correction. These results indicate the reactor power can be estimated by the observation of Cherenkov light.
Yoshida, Takashi*; Suzuki, Toshio*; Chiba, Satoshi; Kajino, Toshitaka*; Yokomakura, Hidekazu*; Kimura, Keiichi*; Takamura, Akira*; Hartmann, D.*
Astrophysical Journal, 686(1), p.448 - 466, 2008/10
The neutrino-nucleus reaction cross sections of He and C are evaluated using new shell model Hamiltonians. Branching ratios of various decay channels are calculated to evaluate the yields of Li, Be, and B produced through the -process in supernova explosions. The new cross sections enhance the yields of Li and B produced during the supernova explosion of a 16.2 M star model compared to our previous study by factors of 1.3 and 1.2, respectively. On the other hand, the yield of B decreases by a factor of three. The yields of Li, Be, and the radioactive nucleus Be are found at a level of 10 to 11 M. The temperature of - and -neutrinos inferred from the supernova contribution of B in Galactic chemical evolution models is constrained to be in the range 4.5 MeV to 6.4 MeV. The increase in the Li and B yields due to neutrino oscillations is demonstrated with the new cross sections.
Yoshida, Takashi*; Suzuki, Toshio*; Chiba, Satoshi; Kajino, Toshitaka*; Yokomakura, Hidekazu*; Kimura, Keiichi*; Takamura, Akira*; Hartmann, D. H.*
Astrophysical Journal, 686(1), p.448 - 466, 2008/10
Times Cited Count:89 Percentile:89.5(Astronomy & Astrophysics)The neutrino-nucleus reaction cross sections of He and C are evaluated using new shell model Hamiltonians. The new cross sections enhance the yields of Li and B produced during the supernova explosion of a 16.2 star model compared to the case using the conventional cross sections by about 10%. On the other hand, the yield of B decreases by a factor of two. The yields of Li, Be, and the radioactive nucleus Be are found at a level of . The temperature of - and -neutrinos inferred from the supernova contribution of B in Galactic chemical evolution models is constrained to be in the range 4.3 MeV to 6.5 MeV. The increase in the Li and B yields due to neutrino oscillations is demonstrated with the new cross sections.
Kimura, Hiroyuki*; Kobayashi, Satoru*; Wakimoto, Shuichi; Noda, Yukio*; Kon, Keiichiro*
Ferroelectrics, 354, p.77 - 85, 2007/01
Times Cited Count:22 Percentile:67.36(Materials Science, Multidisciplinary)A review is given on the studies of magnetic properties and dielectric properties as functions of temperature and magnetic field for various multiferroic MnO ( = rare-earth) compounds. We have observed successive dielectric and magnetic phase transitions which concomitantly take place and a so-called multiferroics is realized. In this system, the ferroelectricity is magnetically induced and the commensurate magnetism is indispensable to produce a spontaneous electric polarization. The microscopic origin of the magnetically induced ferroelectricity and the role of the rare-earth magnetic moment for a colossal magnetoelectric effect in MnO will be discussed in the viewpoint of the magnetic structure.
Tanaka, Hirohisa*; Taniguchi, Masashi*; Uenishi, Mari*; Kajita, Nobuhiko*; Tan, Isao*; Nishihata, Yasuo; Mizuki, Junichiro; Narita, Keiichi*; Kimura, Mareo*; Kaneko, Kimiyoshi*
Angewandte Chemie; International Edition, 45(36), p.5998 - 6002, 2006/09
Times Cited Count:172 Percentile:94.89(Chemistry, Multidisciplinary)no abstracts in English
Tanaka, Hirohisa*; Uenishi, Mari*; Taniguchi, Masashi*; Tan, Isao*; Narita, Keiichi*; Kimura, Mareo*; Kaneko, Kimiyoshi*; Nishihata, Yasuo; Mizuki, Junichiro
Catalysis Today, 117(1-3), p.321 - 328, 2006/09
Times Cited Count:195 Percentile:98(Chemistry, Applied)no abstracts in English
Naito, Kazuya*; Tanaka, Hirohisa*; Taniguchi, Masashi*; Uenishi, Mari*; Tan, Isao*; Kajita, Nobuhiko*; Takahashi, Ichiro*; Suzuki, Hiromasa*; Narita, Keiichi*; Hirai, Akimasa*; et al.
SAE 2006 World Congress & Exhibition Technical Papers, 8 Pages, 2006/00
no abstracts in English
Kimura, Hiroyuki*; Wakimoto, Shuichi; Kamada, Yoichi*; Noda, Yukio*; Kakurai, Kazuhisa; Kaneko, Koji; Metoki, Naoto; Kon, Keiichiro*
no journal, ,
MnO( rare earth, Bi, Y) systen achieves a multi-ferroic state where magnetic and ferroelectric orders coexist. We have performed neutron diffraction under magnetic field to study the correlation between field-induced magnetism and ferroelectricity. T-H phase diagram of the magnetic and electric states for two samples, HoMnO and ErMnO, shows perfect agreement between the commensurate-incommensurate magnetic phase boundary and the ferroelectric transition, evincing that the commensurate magnetic state is essential for the ferroelectric state in this system.
Kimura, Hiroyuki*; Wakimoto, Shuichi; Nishihata, Keisuke*; Noda, Yukio*; Kakurai, Kazuhisa; Kon, Keiichiro*
no journal, ,
Multiferroic materials are known to show gigantic magnetoelectric effects. One of the microscopic models for polarization in such systems is based on spin chirality. We have perfoermed polarized neutron scattering experiments using HoMnO single crystal to study correlation between the spin chirality and ferroelectric polarization. We found that the spin chirality is absent in the high temperature paraelectric HT-ICM phase whereas it appears in the ferroelectric LT-ICM phase. This fact demonstrates a strong coupling between the spin chirality and the ferroelctric polarization.
Kakurai, Kazuhisa; Wakimoto, Shuichi; Matsuda, Masaaki*; Ishiwata, Shintaro*; Okuyama, Daisuke*; Taguchi, Yasujiro*; Tokura, Yoshiki*; Nishi, Masakazu*; Nakajima, Taro*; Mitsuda, Setsuo*; et al.
no journal, ,
Otsuka, Noriaki; Yamamoto, Keiichi; Takeuchi, Tomoaki; Kimura, Nobuaki; Matsui, Yoshinori; Tsuchiya, Kunihiko; Sano, Tadafumi*; Nakajima, Ken*; Homma, Ryohei*
no journal, ,
no abstracts in English
Dohi, Terumi; Di Palma, A.*; Fujiwara, Kenso; Adamo, P.*; Kusano, keiichi*; Kimura, Shigeru*; Kanno, Futoshi*; Iijima, Kazuki
no journal, ,
In the surrounding area of the FDNPS, dust samplers have been used as a means of monitoring the radionuclides concentration in the air. However, the installation of dust samplers requires a power supply, which limits the number and location of the samplers. We aim to establish a method to evaluate the radiocaesium concentration and behavior in the air using moss bags, which have been used in air pollution research. Since the moss bags can be easily installed at any place and time, the establishment of the evaluation method using the moss bags will be effective in creating a sense of security among the local governments and their residents around the FDNPS. In this study, we investigated the applicability of moss bags to the evaluation of the concentration and behavior of radiocaesium in the air.
Dohi, Terumi; Kusano, keiichi*; Kimura, Shigeru*; Kanno, Futoshi*; Mochida, Masaharu*
no journal, ,
no abstracts in English