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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.
-doped YAlO
in the temperature range from 4.2 to 175 KYasumune, Takashi; Kurihara, Masakazu*; Maehata, Keisuke*; Ishibashi, Kenji*; Yoshikawa, Akira*
Nuclear Instruments and Methods in Physics Research A, 726, p.37 - 40, 2013/08
Times Cited Count：1 Percentile：11.54(Instruments & Instrumentation)Yb-doped yttrium-aluminum perovskites (YAP:Yb) are expected to be scintillator materials with high light yield and short scintillation decay time because of their charge transfer (CT) luminescence. Since the CT luminescence of Yb is strongly affected by thermal quenching, to use YAP:Yb as a scintillator material, it is necessary to measure the scintillation properties of YAP:Yb at low temperatures. Since it is difficult to detect scintillation light at low temperatures, scintillation properties of YAP:Yb characterized by irradiating with -rays or other radiation below 100 K have not been reported. We conducted measurements of the temperature dependence of emission wavelength spectrum of YAP:Yb by irradiating with 
-rays from a 
Sr/Y source in the temperature range from 4.2 K to 175 K. The emission peak at around 340-350 nm and 500-520 nm were observed in the emission wavelength spectra. The light yield of YAP:Yb was characterized by using an avalanche photodiode in detection of 662 keV -rays from a 
Cs source in the temperature range from 50 K to 175 K. The light yield increased with decreasing temperature and reached 11,000 photons/MeV at a temperature of 4.2 K.
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.
Meigo, Shinichiro; Shigyo, Nobuhiro*; Iga, Kiminori*; Iwamoto, Yosuke*; Kitsuki, Hirohiko*; Ishibashi, Kenji*; Maehata, Keisuke*; Arima, Hidehiko*; Nakamoto, Tatsushi*; Numajiri, Masaharu*
AIP Conference Proceedings 769, p.1513 - 1516, 2005/05
For validation of calculation codes that are employed in the design of accelerator facilities, spectra of neutrons produced from a thick iron target bombarded with 1.5-GeV protons were measured. The calculated results with NMTC/JAM were compared with the present experimental results. It is found the NMTC/JAM generally shows in good agreement with experiment. Furthermore, the calculation gives good agreement with the experiment for the energy region 20 to 80 MeV, whereas the NMTC/JAM gives 50 % of the experimental data for the heavy nuclide target such as lead and tungsten target.
Meigo, Shinichiro; Takada, Hiroshi; Chiba, Satoshi; *; *; *; Maehata, Keisuke*; Shigyo, Nobuhiro*; Watanabe, Yukinobu*; Numajiri, M.*
Nuclear Instruments and Methods in Physics Research A, 431(3), p.521 - 530, 1999/00
Times Cited Count：38 Percentile：91.42(Instruments & Instrumentation)no abstracts in English
Katagiri, Masaki; Kishimoto, Maki; Ukibe, M.*; Nakamura, Tatsuya*; Kurakado, M.*; Maehata, Keisuke*; *; Nakazawa, Masaharu*
Japanese Journal of Applied Physics, 37(SUPPL.37-2), p.13 - 18, 1998/00
Times Cited Count：7 Percentile：36.37(Physics, Applied)no abstracts in English
Maehata, Keisuke*; *; *; *; *; *; Shimizu, Hirohiko*; Katagiri, Masaki; *
Denshi Gijutsu Sogo Kenkyujo Iho, 61(6-7), p.361 - 366, 1997/00
no abstracts in English
Katagiri, Masaki; Kishimoto, Maki; H.Kraus*; Ukibe, M.*; Kurakado, M.*; Nakazawa, Masaharu*; Maehata, Keisuke*; *; Nakamura, Tatsuya*
Proc. of 7th Int. Workshop on Low Temperature Detectors (LTD-7), p.39 - 44, 1997/00
no abstracts in English
Maehata, Keisuke*; *; *; *; *; *; *; *; *; Katagiri, Masaki
Japanese Journal of Applied Physics, 35(2A), p.L178 - L181, 1996/00
Times Cited Count：1 Percentile：8.28(Physics, Applied)no abstracts in English
*; *; *; Shigyo, Nobuhiro*; Maehata, Keisuke*; Meigo, Shinichiro; Takada, Hiroshi; Chiba, Satoshi; Numajiri, M.*; Nakamura, Takashi*; et al.
Journal of Nuclear Science and Technology, 32(9), p.827 - 833, 1995/09
Times Cited Count：30 Percentile：92.13(Nuclear Science & Technology)no abstracts in English
Meigo, Shinichiro; Takada, Hiroshi; Chiba, Satoshi; *; *; *; Maehata, Keisuke*; Shigyo, Nobuhiro*; *; Watanabe, Yukinobu*; et al.
PSI-Proceedings 95-02, Vol. 2, 0, p.442 - 453, 1995/00
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
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
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
