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-ray measurements of the 
Th isomerMuramatsu, Haruka*; Hayashi, Tasuku*; Yuasa, Naoki*; Konno, Ryohei*; Yamaguchi, Atsushi*; Mitsuda, Kazuhisa*; Yamasaki, Noriko*; Maehata, Keisuke*; Kikunaga, Hidetoshi*; Takimoto, Misaki; et al.
Journal of Low Temperature Physics, 200(5-6), p.452 - 460, 2020/09
Times Cited Count：1 Percentile：6.04(Physics, Applied)Th nuclear clock isomer determined by absolute -ray energy differenceYamaguchi, Atsushi*; Muramatsu, Haruka*; Hayashi, Tasuku*; Yuasa, Naoki*; Nakamura, Keisuke; Takimoto, Misaki; Haba, Hiromitsu*; Konashi, Kenji*; Watanabe, Makoto*; Kikunaga, Hidetoshi*; et al.
Physical Review Letters, 123(22), p.222501_1 - 222501_6, 2019/11
Times Cited Count：36 Percentile：89.11(Physics, Multidisciplinary)Nakamura, Keisuke; Morishita, Yuki; Takasaki, Koji; Maehata, Keisuke*; Sugimoto, Tetsuya*; Kiguchi, Yu*; Iyomoto, Naoko*; Mitsuda, Kazuhisa*
Journal of Low Temperature Physics, 193(3-4), p.314 - 320, 2018/11
Times Cited Count：0 Percentile：0(Physics, Applied)Takasaki, Koji; Yasumune, Takashi; Onishi, Takashi; Nakamura, Keisuke; Ishimi, Akihiro; Ito, Chikara; Osaka, Masahiko; Ono, Masashi*; Hatakeyama, Shuichi*; Takahashi, Hiroyuki*; et al.
JAEA-Research 2013-043, 33 Pages, 2014/01
JAEA-Research-2013-043.pdf:13.81MB
In the Fukushima Daiichi Nuclear Power Plant, it is assumed that the core fuels melted partially or wholly, and the normal technique of accounting for a fuel assembly is not applicable. Therefore, it is necessary to develop the transparent and rational technique of accounting in the process of collection and storage of fuel debris. In this research, an application of the superconducting phase Transition Edge Sensor microcalorimeter (TES microcalorimeter) is studied for the accounting of nuclear materials in the fuel debris. It is expected that the detailed information of nuclear materials and fission products in fuel debris is obtained by using a high-resolution characteristic of TES microcalorimeter. In this report, the principle of TES microcalorimeter, the measurement experiment using TES in JAEA, and the simulated calculation using the EGS5 code system are summarized.
Nakamura, Keisuke; Maeda, Makoto*; Yasumune, Takashi*; Maehata, Keisuke*; Ishibashi, Kenji*; Tanaka, Keiichi*; Umeno, Takahiro*; Takasaki, Koji; Momose, Takumaro
Radiation Protection Dosimetry, 146(1-3), p.88 - 91, 2011/07
Times Cited Count：1 Percentile：10.73(Environmental Sciences)A Transition Edge Sensor (TES) microcalorimeter has been developed for use as an energy dispersive X-ray spectrometer. A TES microcalorimeter is a thermal detector used to measure the energy of an incident photon with increase in temperature. In this work, a TES microcalorimeter with a 5
m Au absorber was developed for use in measuring LX rays emitted from transuranium elements. Furthermore, as a cooling system a dilution refrigerator utilizing a Gifford-McMahon refrigerator was used, which needs no liquid helium. The performance of the TES microcalorimeter was evaluated by measuring the LX rays emitted by an 
Am source. This system proved effective in the measurement of the LX rays because the full width at half maximum of the L
X ray was about 80 eV.
Maehata, Keisuke*; Nakamura, Keisuke*; Yasumune, Takashi*; Ishibashi, Kenji*; Takasaki, Koji; Tanaka, Keiichi*; Odawara, Akikazu*; Nagata, Atsushi*
Journal of Nuclear Science and Technology, 47(3), p.308 - 313, 2010/03
Times Cited Count：5 Percentile：35.74(Nuclear Science & Technology)A phase transition edge sensor (TES) microcalorimeter was developed for the energy dispersive measurement of LX-ray photons emitted from transuranium elements. The phase transition temperature of the TES was designed to be 200 mK by using bilayer structure of Au of 120 nm thick and Ti of 50 nm thick. The Au layer of 5.0 m thick was deposited on the Au/Ti bilayer for absorption efficiency of 50% and counting rate of 100 counts per second in the detection of LX-ray photons with the energy from 10 to 20 keV. The TES microcalorimeter was operated for the detection of LX-ray photons emitted from Am, 
Pu and 
Pu sources. The decay time constant of 180 s of detection signal pulses allowed the TES microcalorimeter operating with the counting rate higher than 100 counts per second. The energy resolution was obtained to be 50 eV of FWHM value for a peak corresponding to 
Np L
X-ray of 17.75 keV.
; ; ;
Nihon Genshiryoku Gakkai-Shi, 10(12), p.684 - 685, 1968/00
no abstracts in English
Nakamura, Keisuke; Iijima, Nobuo; Yamashita, Tomoyuki; Shiba, Kozo; Momose, Takumaro
no journal, ,
no abstracts in English
Maeda, Makoto*; Maehata, Keisuke*; Iyomoto, Naoko*; Ishibashi, Kenji*; Takasaki, Koji; Nakamura, Keisuke; Aoki, Katsunori; Mitsuda, Kazuhisa*; Tanaka, Keiichi*
no journal, ,
no abstracts in English
Kanazawa, Nobuyuki; Nakamura, Keisuke; Miyauchi, Toru; Chikazawa, Tatsuya*; Kurosawa, Hideaki*; Shiba, Kozo
no journal, ,
no abstracts in English
Nakamura, Keisuke; Maeda, Makoto*; Aoki, Katsunori; Yasumune, Takashi; Takasaki, Koji; Maehata, Keisuke*; Iyomoto, Naoko*; Ishibashi, Kenji*; Mitsuda, Kazuhisa*; Tanaka, Keiichi*
no journal, ,
no abstracts in English
Nakamura, Keisuke; Aoki, Katsunori; Takasaki, Koji; Maeda, Makoto*; Maehata, Keisuke*; Iyomoto, Naoko*; Ishibashi, Kenji*; Mitsuda, Kazuhisa*; Tanaka, Keiichi*
no journal, ,
no abstracts in English
raysYamazaki, Takumi; Takada, Chie; Nakamura, Keisuke; Sagawa, Naoki; Hoshi, Katsuya; Nakagawa, Takahiro; Takimoto, Misaki; Tanimura, Yoshihiko*; Takahashi, Fumiaki; Momose, Takumaro; et al.
no journal, ,
no abstracts in English
Nakamura, Keisuke; Maeda, Makoto; Maehata, Keisuke*; Iyomoto, Naoko*; Ishibashi, Kenji*; Takasaki, Koji; Mitsuda, Kazuhisa*
no journal, ,
A transition-edge-sensor (TES) microcalorimeter has been developed for measurement of X-rays and -rays with ultra-high energy resolution. In this work, we developed a four-pixel TES microcalorimeter to measure L X-rays emitted by transuranium elements. Each TES was composed of bilayer film of a 120-nm-thick Au layer and a 50-nm-thick Ti layer, and the transition temperature was approximately 130 mK. An absorber deposited on each Au-Ti bilayer was a 5-m-thick layer of Au to achieve an absorption efficiency of 35-80% for the energy range of L X-rays (10-30 keV). The developed four pixel TES microcalorimeter was irradiated with L X-rays emitted form Pu-238, Pu-239, and Am-241 sources. As the result, we obtained an L X-ray energy spectrum with high energy resolution of 
40 eV (full width at half maximum) for an L X-ray of 17.75 keV.
Nakamura, Keisuke; Maeda, Makoto; Morishita, Yuki; Takasaki, Koji; Maehata, Keisuke*; Iyomoto, Naoko*; Ishibashi, Kenji*; Mitsuda, Kazuhisa*
no journal, ,
no abstracts in English
Watanabe, Yuki; Nakamura, Keisuke; Akasu, Kohei; Okuyama, Shun; Namiki, Atsushi
no journal, ,
no abstracts in English
Nakamura, Keisuke; Sugimoto, Tetsuya*; Maehata, Keisuke*; Iyomoto, Naoko*; Ishibashi, Kenji*; Morishita, Yuki; Takasaki, Koji; Mitsuda, Kazuhisa*
no journal, ,
no abstracts in English
-rays using a TES microcalorimeter with a Sn absorber; Analysis of energy spectrum with Monte Carlo simulationYasumune, Takashi; Takasaki, Koji; Nakamura, Keisuke; Ono, Masashi*; Irimatsukawa, Tomoya*; Takahashi, Hiroyuki*
no journal, ,
no abstracts in English
Nakamura, Keisuke; Sugimoto, Tetsuya*; Maehata, Keisuke*; Iyomoto, Naoko*; Ishibashi, Kenji*; Morishita, Yuki; Takasaki, Koji; Mitsuda, Kazuhisa*
no journal, ,
no abstracts in English
Imahashi, Atsushi; Nakamura, Keisuke; Watanabe, Yuki; Namiki, Atsushi; Takahashi, Yoshiharu*; Kinugawa, Nobuyuki*
no journal, ,
no abstracts in English
