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Fujimori, Shinichi; Kawasaki, Ikuto; Takeda, Yukiharu; Yamagami, Hiroshi; Sasabe, Norimasa*; Sato, Yoshiki*; Shimizu, Yusei*; Nakamura, Ai*; Maruya, A.*; Homma, Yoshiya*; et al.
Electronic Structure (Internet), 5(4), p.045009_1 - 045009_7, 2023/11
Osawa, Takahito; Nagasawa, Shunsaku*; Ninomiya, Kazuhiko*; Takahashi, Tadayuki*; Nakamura, Tomoki*; Wada, Taiga*; Taniguchi, Akihiro*; Umegaki, Izumi*; Kubo, Kenya*; Terada, Kentaro*; et al.
ACS Earth and Space Chemistry (Internet), 7(4), p.699 - 711, 2023/04
The concentrations of carbon and other major elements in asteroid samples provide very important information on the birth of life on the Earth and the solar-system evolution. Elemental analysis using muonic X-rays is one of the best analytical methods to determine the elemental composition of solid materials, and notably, is the only method to determine the concentration of light elements in bulk samples in a non-destructive manner. We developed a new analysis system using muonic X-rays to measure the concentrations of carbon and other major elements in precious and expectedly tiny samples recovered from the asteroid Ryugu by spacecraft Hayabusa2. Here we report the development process of the system in 4 stages and their system configurations, The analysis system is composed of a stainless-steel analysis chamber, an acrylic glove box for manipulating asteroid samples in a clean environment, and Ge semiconductor detectors arranged to surround the analysis chamber. The performance of the analysis system, including the background level, which is crucial for the measurement, was greatly improved from the first stage to the later ones. Our feasibility study showed that the latest model of our muonic X-ray analysis system is capable of determining the carbon concentration in Hayabusa2's sample model with an uncertainty of less than 10 percent in a 6-day measurement.
Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count:3 Percentile:80.29(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Pospil, J.*; Yamamoto, Etsuji; Haga, Yoshinori
Physical Review B, 105(11), p.115128_1 - 115128_6, 2022/03
Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)Kawasaki, Ikuto; Kobata, Masaaki; Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Physical Review B, 104(16), p.165124_1 - 165124_8, 2021/10
Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)Okumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I.-H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.
IEEE Transactions on Applied Superconductivity, 31(5), p.2101704_1 - 2101704_4, 2021/08
Times Cited Count:1 Percentile:11.71(Engineering, Electrical & Electronic)A superconducting transition-edge sensor (TES) microcalorimeter is an ideal X-ray detector for experiments at accelerator facilities because of good energy resolution and high efficiency. To study the performance of the TES detector with a high-intensity pulsed charged-particle beam, we measured X-ray spectra with a pulsed muon beam at the Japan Proton Accelerator Research Complex (J-PARC) in Japan. We found substantial temporal shifts of the X-ray energy correlated with the arrival time of the pulsed muon beam, which was reasonably explained by pulse pileup due to the incidence of energetic particles from the initial pulsed beam.
Okumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I. H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.
Physical Review Letters, 127(5), p.053001_1 - 053001_7, 2021/07
Times Cited Count:9 Percentile:78.48(Physics, Multidisciplinary)We observed electronic X rays emitted from muonic iron atoms using a superconducting transition-edge-type sensor microcalorimeter. The energy resolution of 5.2 eV in FWHM allowed us to observe the asymmetric broad profile of the electronic characteristic and X rays together with the hypersatellite X rays around 6 keV. This signature reflects the time-dependent screening of the nuclear charge by the negative muon and the -shell electrons, accompanied by electron side-feeding. Assisted by a simulation, this data clearly reveals the electronic - and -shell hole production and their temporal evolution during the muon cascade process.
Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Yamamoto, Etsuji; Haga, Yoshinori
Electronic Structure (Internet), 3(2), p.024008_1 - 024008_8, 2021/06
Kobayashi, Masaki*; Anh, L. D.*; Suzuki, Masahiro*; Kaneta-Takada, Shingo*; Takeda, Yukiharu; Fujimori, Shinichi; Shibata, Goro*; Tanaka, Arata*; Tanaka, Masaaki*; Oya, Shinobu*; et al.
Physical Review Applied (Internet), 15(6), p.064019_1 - 064019_10, 2021/06
Times Cited Count:0 Percentile:28.82(Physics, Applied)Fukasawa, Takuro*; Kusaka, Shotaro*; Sumida, Kazuki; Hashizume, Mizuki*; Ichinokura, Satoru*; Takeda, Yukiharu; Ideta, Shinichiro*; Tanaka, Kiyohisa*; Shimizu, Ryota*; Hitosugi, Taro*; et al.
Physical Review B, 103(20), p.205405_1 - 205405_6, 2021/05
Times Cited Count:7 Percentile:67.62(Materials Science, Multidisciplinary)Fujimori, Shinichi; Kawasaki, Ikuto; Takeda, Yukiharu; Yamagami, Hiroshi; Nakamura, Ai*; Homma, Yoshiya*; Aoki, Dai*
Journal of the Physical Society of Japan, 90(1), p.015002_1 - 015002_2, 2021/01
Times Cited Count:12 Percentile:80.33(Physics, Multidisciplinary)Takeda, Takahito*; Sakamoto, Shoya*; Araki, Kosei*; Fujisawa, Yuita*; Anh, L. D.*; Tu, N. T.*; Takeda, Yukiharu; Fujimori, Shinichi; Fujimori, Atsushi*; Tanaka, Masaaki*; et al.
Physical Review B, 102(24), p.245203_1 - 245203_8, 2020/12
Times Cited Count:7 Percentile:45.15(Materials Science, Multidisciplinary)Hirahara, Toru*; Otrokov, M. M.*; Sasaki, Taisuke*; Sumida, Kazuki*; Tomohiro, Yuta*; Kusaka, Shotaro*; Okuyama, Yuma*; Ichinokura, Satoru*; Kobayashi, Masaki*; Takeda, Yukiharu; et al.
Nature Communications (Internet), 11, p.4821_1 - 4821_8, 2020/09
Times Cited Count:35 Percentile:93.42(Multidisciplinary Sciences)Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.
Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05
Times Cited Count:14 Percentile:74.77(Physics, Multidisciplinary)The structure of a neutron-rich F nucleus is investigated by a quasifree () knockout reaction. The sum of spectroscopic factors of orbital is found to be 1.0 0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 35% O, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.
Kawasaki, Ikuto; Kobata, Masaaki; Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Nakamura, Ai*; Iha, Wataru*; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Journal of the Physical Society of Japan, 89(4), p.044704_1 - 044704_6, 2020/04
Times Cited Count:3 Percentile:31.8(Physics, Multidisciplinary)Fujimori, Shinichi; Kawasaki, Ikuto; Takeda, Yukiharu; Yamagami, Hiroshi; Nakamura, Ai*; Homma, Yoshiya*; Aoki, Dai*
Journal of the Physical Society of Japan, 88(10), p.103701_1 - 103701_5, 2019/10
Times Cited Count:24 Percentile:84.85(Physics, Multidisciplinary)Sumida, Kazuki*; Kakoki, Masaaki*; Reimann, J.*; Nurmamat, M.*; Goto, Shinichi*; Takeda, Yukiharu; Saito, Yuji; Kokh, K. A.*; Tereshchenko, O. E.*; Gdde, J.*; et al.
New Journal of Physics (Internet), 21(9), p.093006_1 - 093006_8, 2019/09
Times Cited Count:10 Percentile:65.58(Physics, Multidisciplinary)Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.
Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07
Times Cited Count:7 Percentile:56.64(Physics, Multidisciplinary)Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.
Kawasaki, Ikuto; Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Iha, Wataru*; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Physical Review B, 100(3), p.035111_1 - 035111_8, 2019/07
Times Cited Count:8 Percentile:42.56(Materials Science, Multidisciplinary)Sakamoto, Shoya*; Tu, N. T.*; Takeda, Yukiharu; Fujimori, Shinichi; Hai, P. N.*; Anh, L. D.*; Wakabayashi, Yuki K.*; Shibata, Goro*; Horio, Masafumi*; Ikeda, Keisuke*; et al.
Physical Review B, 100(3), p.035204_1 - 035204_8, 2019/07