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Kutsukake, Kenichi; Matsuda, Makoto; Nakamura, Masahiko; Ishizaki, Nobuhiro; Kabumoto, Hiroshi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Nakagawa, Sohei; Abe, Shinichi
Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1080 - 1084, 2023/11
no abstracts in English
Maeda, Makoto; Segawa, Mariko; Toh, Yosuke; Endo, Shunsuke; Nakamura, Shoji; Kimura, Atsushi
Journal of Radioanalytical and Nuclear Chemistry, 332(8), p.2995 - 2999, 2023/08
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)Goux, P.*; Glessgen, F.*; Gazzola, E.*; Singh Reen, M.*; Focillon, W.*; Gonin, M.*; Tanaka, Tomoyuki*; Hagiwara, Kaito*; Ali, A.*; Sudo, Takashi*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2023(6), p.063H01_1 - 063H01_15, 2023/06
Times Cited Count：0 Percentile：0.01(Physics, Multidisciplinary)
-ray analysisKinoshita, Norikazu*; Noto, Takuma*; Nakajima, Hitoshi*; Kosako, Kazuaki*; Kato, Takahiro*; Kuroiwa, Yoichi*; Kurabe, Misako*; Sasaki, Yuki*; Torii, Kazuyuki*; Maeda, Makoto; et al.
Journal of Radioanalytical and Nuclear Chemistry, 332(2), p.479 - 486, 2023/02
Kabumoto, Hiroshi; Matsuda, Makoto; Nakamura, Masahiko; Ishizaki, Nobuhiro; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Nakagawa, Sohei; Abe, Shinichi
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1109 - 1113, 2023/01
no abstracts in English
TaEndo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Rovira Leveroni, G.; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto
Nuclear Science and Engineering, 18 Pages, 2023/00
Times Cited Count：1 Percentile：72.91(Nuclear Science & Technology)-ray analysisMaeda, Makoto; Segawa, Mariko; Toh, Yosuke; Endo, Shunsuke; Nakamura, Shoji; Kimura, Atsushi
Scientific Reports (Internet), 12(1), p.6287_1 - 6287_8, 2022/06
Times Cited Count：2 Percentile：31.9(Multidisciplinary Sciences)Endo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Rovira Leveroni, G.; Terada, Kazushi*; Meigo, Shinichiro; Toh, Yosuke; Segawa, Mariko; et al.
Journal of Nuclear Science and Technology, 59(3), p.318 - 333, 2022/03
Times Cited Count：5 Percentile：65.59(Nuclear Science & Technology)Teshigawara, Makoto; Nakamura, Mitsutaka; Kinsho, Michikazu; Soyama, Kazuhiko
JAEA-Technology 2021-022, 208 Pages, 2022/02
JAEA-Technology-2021-022.pdf:14.28MB
The Materials and Life science experimental Facility (MLF) is an accelerator driven pulsed spallation neutron and muon source with a 1 MW proton beam. The construction began in 2004, and we started beam operation in 2008. Although problems such as exudation of cooling water from the target container have occurred, as of April 2021, the proton beam power has reached up to 700 kW gradually, and stable operation is being performed. In recent years, the operation experience of the rated 1 MW has been steadily accumulated. Several issues such as the durability of the target container have been revealed according to the increase in the operation time. Aiming at making a further improvement of MLF, we summarized the current status of achievements for the design values, such as accelerator technology (LINAC and RCS), neutron and muon source technology, beam transportation of these particles, detection technology, and neutron and muon instruments. Based on the analysis of the current status, we tried to extract improvement points for upgrade of MLF. Through these works, we will raise new proposals that promote the upgrade of MLF, attracting young people. We would like to lead to the further success of researchers and engineers who will lead the next generation.
Matsuda, Makoto; Tayama, Hidekazu; Ishizaki, Nobuhiro; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Abe, Shinichi
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.394 - 398, 2021/10
no abstracts in English
Pd and 
TcToh, Yosuke; Segawa, Mariko; Maeda, Makoto; Tsuneyama, Masayuki*; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Ebihara, Mitsuru*
Analytical Chemistry, 93(28), p.9771 - 9777, 2021/07
Times Cited Count：4 Percentile：24.69(Chemistry, Analytical)Tsuchikawa, Yusuke; Abe, Yuta; Oishi, Yuji*; Kai, Tetsuya; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Kimura, Atsushi; Nakamura, Shoji; Harada, Masahide; et al.
JPS Conference Proceedings (Internet), 33, p.011074_1 - 011074_6, 2021/03
In the decommissioning of the Fukushima-Daiichi (1F) Nuclear Power Plant, it is essential to understand characteristics of the melted core materials. The estimation of boride in the real debris is of great importance to develop safe debris removal plans. Hence, it is required to investigate the amount of boron in the melted core materials with nondestructive methods. Prompt gamma-ray activation analysis (PGAA) is one of the useful techniques to determine the amount of borides by means of the 478 keV prompt gamma-ray from neutron absorption reaction of boron. Moreover, it is well known that the width of the 478 keV gamma-ray peak is typically broadened due to the Doppler effect. The degree of the broadening is affected by coexisting materials, and can be recognized by the width of the prompt gamma-ray peak. As a feasibility study, the prompt gamma-ray from boride samples were measured using the ANNRI, NOBORU, and RADEN beamlines at the Materials and Life Science Experimental Facility (MLF) of Japan Proton Accelerator Complex (J-PARC).
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Shimizu, Yusei*; Miyake, Atsushi*; Maurya, A.*; Honda, Fuminori*; Nakamura, Ai*; Sato, Yoshiki*; Li, D.*; Homma, Yoshiya*; Yokoyama, Makoto*; Tokunaga, Yo; et al.
Physical Review B, 102(13), p.134411_1 - 134411_11, 2020/10
Times Cited Count：5 Percentile：26.53(Materials Science, Multidisciplinary)Matsuda, Makoto; Ishizaki, Nobuhiro; Tayama, Hidekazu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Abe, Shinichi; et al.
Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.948 - 952, 2020/09
no abstracts in English
Nakamura, Masahiko; Kutsukake, Kenichi; Matsuda, Makoto
JAEA-Technology 2019-022, 20 Pages, 2020/03
JAEA-Technology-2019-022.pdf:1.73MB
The JAEA Tokai tandem accelerator (an electrostatic accelerator) has the advantage that it can accelerate an ion beam with proportional energy to its acceleration voltage. Therefore the control of an ion beam energy can be automated when the control of the acceleration voltage can be automated by using the scaling operation system: an electromagnetics proportion of optical device parameters, and the ganged control system: a synchronized controlling related devices in the JAEA Tokai Tandem accelerator control system. We should improve several devices to achieve the automatic control of the accelerator voltage. Especially, the positioning system of the corona probe which adjusts the acceleration voltage had to be automated. However the original corona probe was difficult to be applied to the automation by its poor control system and low positioning precision. We have developed the new corona probe which improved defects of the original one. The new corona probe has an automatic and high precision positioning system and enhanced maintainability by new control system, new driven system and new position detection system. We describe about the development of the new corona probe in detail.
NpRovira, G.*; Katabuchi, Tatsuya*; Tosaka, Kenichi*; Matsuura, Shota*; Terada, Kazushi*; Iwamoto, Osamu; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Nobuyuki; Segawa, Mariko; et al.
Journal of Nuclear Science and Technology, 57(1), p.24 - 39, 2020/01
Times Cited Count：10 Percentile：79.13(Nuclear Science & Technology)
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)Matsuda, Makoto; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; et al.
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1270 - 1273, 2019/07
The JAEA-Tokai tandem accelerator was operated over a total of 138 days, and delivered 16 different ions to the experiments in the research fields of nuclear physics, nuclear chemistry, atomic physics, solid state physics and radiation effects in material in FY2018. Maximum acceleration voltage was 16.6 MV. A new beam attenuator was installed at the entrance beam line of the tandem accelerator to facilitate control of the beam current and minimize stripper foil consumption. The main maintenance items included replacing the pellet chain used for about 68,000 hours and the drive motor for the high voltage terminal generator used for about 9 years. A fault has occurred in the building's oxygen deficiency monitor. This paper describes the operational status of the accelerators and the major technical developments of our facility.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.
Science, 364(6437), p.272 - 275, 2019/04
Times Cited Count：259 Percentile：99.73(Multidisciplinary Sciences)The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
