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Journal Articles

Coexistence of magnetoelectric and antiferroelectric-like orders in Mn$$_{3}$$Ta$$_{2}$$O$$_{8}$$

Kimura, Kenta*; Yagi, Naoki*; Hasegawa, Shunsuke*; Hagihara, Masato; Miyake, Atsushi*; Tokunaga, Masashi*; Cao, H.*; Masuda, Takatsugu*; Kimura, Tsuyoshi*

Inorganic Chemistry, 60(20), p.15078 - 15084, 2021/10

Journal Articles

Measurement of displacement cross section for proton in the kinetic energy range from 0.4 GeV to 3 GeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

JPS Conference Proceedings (Internet), 33, p.011050_1 - 011050_6, 2021/03

R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and aluminum and copper was used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimated the experiment by about 3 times.

Journal Articles

Quasifree neutron knockout reaction reveals a small $$s$$-Orbital component in the Borromean nucleus $$^{17}$$B

Yang, Z. H.*; Kubota, Yuki*; Corsi, A.*; Yoshida, Kazuki; Sun, X.-X.*; Li, J. G.*; Kimura, Masaaki*; Michel, N.*; Ogata, Kazuyuki*; Yuan, C. X.*; et al.

Physical Review Letters, 126(8), p.082501_1 - 082501_8, 2021/02

 Times Cited Count:10 Percentile:98.7(Physics, Multidisciplinary)

A quasifree ($$p$$,$$pn$$) experiment was performed to study the structure of the Borromean nucleus $$^{17}$$B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for $$1s_{1/2}$$ and $$0d_{5/2}$$ orbitals, and a surprisingly small percentage of 9(2)% was determined for $$1s_{1/2}$$. Our finding of such a small $$1s_{1/2}$$ component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in $$^{17}$$B. The present work gives the smallest $$s$$- or $$p$$-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of $$s$$ or $$p$$ orbitals is not a prerequisite for the occurrence of a neutron halo.

Journal Articles

Measurement of displacement cross-sections of copper and iron for proton with kinetic energies in the range 0.4 - 3 GeV

Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

Journal of Nuclear Science and Technology, 57(10), p.1141 - 1151, 2020/10

 Times Cited Count:3 Percentile:76.41(Nuclear Science & Technology)

To estimate the structural damages of materials in accelerator facilities, displacement per atom (dpa) is widely employed as a damage index, calculated based on the displacement cross-section obtained using a calculation model. Although dpa is applied as standard, the experimental data of the displacement cross-section for a proton in the energy region above 20 MeV are scarce. Among the calculation models, difference of about factor 8 exist, so that the experimental data of the cross-section are crucial to validate the model. To obtain the displacement cross-section, we conducted experiments at J-PARC. The displacement cross-section of copper and iron was successfully obtained for a proton projectile with the kinetic energies, 0.4 - 3 GeV. The results were compared with those obtained using the widely utilized Norgertt-Robinson-Torrens (NRT) model and the athermal-recombination-corrected (arc) model based on molecular dynamics. It was found that the NRT model overestimates the present displacement cross-section by 3.5 times. The calculation results obtained using with the arc model based on the Nordlund parameter show remarkable agreement with the experimental data. It can be concluded that the arc model must be employed for the dpa calculation for the damage estimation of copper and iron.

Journal Articles

Measurement of displacement cross section of structural materials utilized in the proton accelerator facilities with the kinematic energy above 400 MeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

EPJ Web of Conferences, 239, p.06006_1 - 06006_4, 2020/09

 Times Cited Count:0 Percentile:0.19

R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and copper was used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimated the experiment by about 3 times.

Journal Articles

Horizontal line nodes in Sr$$_2$$RuO$$_4$$ proved by spin resonance

Iida, Kazuki*; Kofu, Maiko; Suzuki, Katsuhiro*; Murai, Naoki; Kawamura, Seiko; Kajimoto, Ryoichi; Inamura, Yasuhiro; Ishikado, Motoyuki*; Hasegawa, Shunsuke*; Masuda, Takatsugu*; et al.

Journal of the Physical Society of Japan, 89(5), p.053702_1 - 053702_5, 2020/05

 Times Cited Count:8 Percentile:87.06(Physics, Multidisciplinary)

Journal Articles

Measurement of displacement cross section of structural materials utilized in the proton accelerator facilities with the kinematic energy above 400 MeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

JPS Conference Proceedings (Internet), 28, p.061004_1 - 061004_6, 2020/02

no abstracts in English

Journal Articles

Measurement of displacement cross-section for structural materials in High-Power Proton Accelerator Facility

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Iwamoto, Hiroki; Hasegawa, Shoichi; Maekawa, Fujio; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*

Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.499 - 501, 2018/06

no abstracts in English

Journal Articles

Excitation spectrum of Josephson vortices on surface superconductor

Kawakami, Takuto*; Nagai, Yuki; Yoshizawa, Shunsuke*; Kim, H.*; Hasegawa, Yukio*; Nakayama, Tomonobu*; Uchihashi, Takashi*; Hu, X.*

Journal of Physics; Conference Series, 568(2), p.022022_1 - 022022_5, 2014/12

 Times Cited Count:1 Percentile:55.09

no abstracts in English

Journal Articles

Imaging Josephson vortices on the surface superconductor Si(111)-($$sqrt{7} times sqrt{3}$$)-In using a scanning tunneling microscope

Yoshizawa, Shunsuke*; Kim, H.*; Kawakami, Takuto*; Nagai, Yuki; Nakayama, Tomonobu*; Hu, X.*; Hasegawa, Yukio*; Uchihashi, Takashi*

Physical Review Letters, 113(24), p.247004_1 - 247004_5, 2014/12

 Times Cited Count:53 Percentile:91.52(Physics, Multidisciplinary)

We have studied the superconducting Si(111)-($$sqrt{7}$$$$times$$$$sqrt{3}$$)-In surface using a $$^{3}$$He-based low-temperature scanning tunneling microscope. Zero-bias conductance images taken over a large surface area reveal that vortices are trapped at atomic steps after magnetic fields are applied. The crossover behavior from Pearl to Josephson vortices is clearly identified from their elongated shapes along the steps and significant recovery of superconductivity within the cores. Our numerical calculations combined with experiments clarify that these characteristic features are determined by the relative strength of the interterrace Josephson coupling at the atomic step.

Journal Articles

Matched refractive-index PIV visualization of complex flow structure in a three-dimentionally connected dual elbow

Yuki, Kazuhisa*; Hasegawa, Shunsuke*; Sato, Tsukasa*; Hashizume, Hidetoshi*; Aizawa, Kosuke; Yamano, Hidemasa

Nuclear Engineering and Design, 241(11), p.4544 - 4550, 2011/11

 Times Cited Count:23 Percentile:88.07(Nuclear Science & Technology)

Journal Articles

Unsteady hydraulic characteristics in large-diameter pipings with elbow for JSFR, 3; Flow structure in a 3-dimentionally connected dual elbow simulating cold-leg piping in JSFR

Yuki, Kazuhisa*; Hasegawa, Shunsuke*; Sato, Tsukasa*; Hashizume, Hidetoshi*; Aizawa, Kosuke; Yamano, Hidemasa

Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13) (CD-ROM), 11 Pages, 2009/09

In this study, the flow structures in a 3-dimentionally connected dual elbow, which simulates a part of the cold leg, are visualized by PIV measurement, and it is discussed on the detailed flow transition from the 1st elbow to the 2nd elbow and the generation of unsteady flow such as a separation that influences flow-induced vibration. Experimental apparatus has a 1/15 scale test section of actual design whose inner diameter and curvature radius ratio are 56mm and 1.0, respectively. For visualization without any image distortion, matched refractive-index PIV measurement is carried out using NaI solution as the working fluid. The Reynolds number is 50,000, and the inlet flow condition to the test section is a fully developed turbulent flow. It is confirmed that it generates a separation along the inner wall of the 1st elbow and one large swirling flow in the 2nd elbow. Furthermore, unsteady flow formed in and/or behind the separation region is transported downstream and flows into the center area of the 2nd elbow.

Oral presentation

Renewal of JMTR of facility, 3; Renewal of instrumentation and control systems

Oto, Tsutomu; Nemoto, Hiroyoshi; Kimura, Tadashi; Watahiki, Shunsuke; Hasegawa, Teiji; Ouchi, Takuya; Echigoya, Shinichi; Fukasaku, Akitomi

no journal, , 

no abstracts in English

Oral presentation

Measurement of DPA cross-section of 0.4 - 3 GeV proton at J-PARC

Matsuda, Hiroki; Meigo, Shinichiro; Maekawa, Fujio; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Makimura, Shunsuke*; Nakamoto, Tatsushi*; Ishida, Taku*

no journal, , 

For a damage evaluation of targets and beam window for a high-intensity proton accelerator facility, DPA based on a model calculation of a cross section of displacement per atom (DPA). However, the models are not sufficiently validated since there are almost no data induced by protons above 20 MeV. Thus, we measure DPA cross section for various measurement at J-PARC by using 0.4-3.0 GeV protons. DPA cross section can be obtained by dividing a resistivity increase after proton irradiation by the resistivity per Frenkel pairs. In this measurement, the sample were placed onto a front edge of a two-stage 4K GM cryocooler (Sumitomo Heavy Industries, Ltd.). In this measurement, an copper wire (diameter 0.25 mm) that was annealed by 800$$^{circ}$$C was employed. The experiment is performed with low-intensity beam at 3NBT line where the proton beam is transported from 3 GeV Synchrotron (RCS) to the Material and Life science Facility (MLF). We started vacuum pumping after an installation and we confirmed that the pressure level achieved the one where the beam can be transported. The achieved temperatures were 4 K around the front edge of the cryocooler and 20 K around the sample due to radiation heat. In this talk, we report a current status of experiment and discuss an effect of a beam profile to the DPA cross section.

Oral presentation

Measurement displacement cross-section of copper for 3-GeV protons

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Iwamoto, Hiroki; Hasegawa, Shoichi; Maekawa, Fujio; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*

no journal, , 

At the 3 GeV proton synchrotron accelerator facility in J-PARC Center, a displacement cross-section of copper with 3 GeV protons was measured. As a result, it was the first time in the world that we could obtain the displacement cross-section of 3 GeV protons. Calculations by the NRT model commonly used for Displacement per Atom (DPA) evaluations, the NRT model was found to overestimate the experiment approximately 3 times. A new model, which is recently developed by Nordlund et al, was shown to reproduce the experiment well.

Oral presentation

Measurement displacement cross section of copper and aluminum for protons in the kinematic region between 0.4 and 3 GeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Iwamoto, Hiroki; Hasegawa, Shoichi; Maekawa, Fujio; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*

no journal, , 

R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and copper and aluminum were used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimates the experiment by about 3 times.

Oral presentation

Measurement of Fe displacement cross section for proton energy region between 0.4 and 3 GeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Iwamoto, Hiroki; Hasegawa, Shoichi; Maekawa, Fujio; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*

no journal, , 

R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and an iron was used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimates the experiment by about 3 times.

Oral presentation

Measurement of displacement cross section in J-PARC for proton kinetic energy range from 0.4 GeV to 30 GeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Iwamoto, Hiroki; Hasegawa, Shoichi; Maekawa, Fujio; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*

no journal, , 

R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We have started to measure the displacement cross section for the protons in the energy region between 0.4 to 30 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on the cryo-cooled sample to maintain damage. Experiments were conducted at the J-PARC Center, and Al and Cu were used as samples. As a result of a comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimated the experiment by about 3 times.

Oral presentation

Measurement of displacement cross section on tungsten for 0.4 - 3 GeV proton projectile

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Iwamoto, Hiroki; Hasegawa, Shoichi; Maekawa, Fujio; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*

no journal, , 

R&D of the structural material such as a beam window, which serves as a partition between the accelerator and the target region, is crucial in the ADS. Although the displacement per atom (DPA) is widely used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV for proton projectile. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on the cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and a tungsten wire sample was applied. It was found that the calculation of the NRT model, which is a widely utilized to calculate DPA, predicted the cross section by about 3 times of the present experiment.

Oral presentation

Measurement of displacement cross section for 8-GeV and 30-GeV protons

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Iwamoto, Hiroki; Hasegawa, Shoichi; Maekawa, Fujio; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*

no journal, , 

In high-intensity proton accelerator facilities, the evaluation of the damage of the materials used for the beam window is essential. The damage is widely estimated by the dpa given by the displacement cross-section. Since the experimental data of the cross-section were scarce, we have started the experiment in the energy region less than 3 GeV. In order to confirm the applicability of the calculation model in the higher energy region, the cross-sections for 8 GeV and 30 GeV protons were measured at the J-PARC MR. The calculation by the NRT model showed overestimation about 2 to 4 times, as shown in the energy range below 3 GeV. It was found that the calculation with the athermal recombination correction model showed remarkably good agreement with the experiment in the energy range up to 30 GeV. It was also shown that the cross-section in the energy region above 3 GeV is proportional to the 1.2th power of the mass number of the target element.

Oral presentation

Measurement of $$sigma_ncdothat{k}_gamma$$ angular dependent term of $$^{139}$$La(n,$$gamma$$)$$^{140}$$La reaction for polarized neutrons

Abe, Ryota*; Ishizaki, Kohei*; Ito, Yuki*; Endo, Shunsuke; Oku, Takayuki; Okudaira, Takuya*; Kameda, Kento*; Kitaguchi, Masaaki*; Kimura, Atsushi; Sakai, Kenji; et al.

no journal, , 

no abstracts in English

21 (Records 1-20 displayed on this page)