Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Cs concentrations in coastal sediments off FukushimaSuzuki, Shotaro*; Amano, Yosuke*; Enomoto, Masahiro*; Matsumoto, Akira*; Morioka, Yoshiaki*; Sakuma, Kazuyuki; Tsuruta, Tadahiko; Kaeriyama, Hideki*; Miura, Hikaru*; Tsumune, Daisuke*; et al.
Science of the Total Environment, 831, p.154670_1 - 154670_15, 2022/07
Times Cited Count：2 Percentile：29.78(Environmental Sciences)Suzuki, Shintaro*; Takubo, Ko*; Kuga, Kentaro*; Higemoto, Wataru; Ito, Takashi; Tomita, Takahiro*; Shimura, Yasumichi*; Matsumoto, Yosuke*; Bareille, C.*; Wadachi, Hiroki*; et al.
Physical Review Research (Internet), 3(2), p.023140_1 - 023140_12, 2021/05
We report our experimental discovery of the transition temperature reaching 20 K in a Yb-based compound at ambient pressure. The Mn substitution at the Al site in an intermediate valence state of 
-YbAlB
not only induces antiferromagnetic transition at a record high temperature of 20 K but also transforms the heavy-fermion liquid state in -YbAlB into a highly resistive metallic state proximate to a Kondo insulator.
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).
Ebihara, Kenichi; Sugiyama, Yuri*; Matsumoto, Ryosuke*; Takai, Kenichi*; Suzudo, Tomoaki
Metallurgical and Materials Transactions A, 52(1), p.257 - 269, 2021/01
Times Cited Count：8 Percentile：53.96(Materials Science, Multidisciplinary)We simulated the thermal desorption spectra of a small-size iron specimen to which was applied during charging with hydrogen atoms using a model incorporating the behavior of vacancies and vacancy clusters. The model considered up to vacancy clusters 
, which is composed of nine vacancies and employed the parameters based on atomistic calculations, including the H trapping energy of vacancies and vacancy clusters that we estimated using the molecular static calculation. As a result, we revealed that the model could, on the whole, reproduced the experimental spectra except two characteristic differences, and also the dependence of the spectra on the aging temperature. By examining the cause of the differences, the possibilities that the diffusion of clusters of 
and 
is slower than the model and that vacancy clusters are generated by applying strain and H charging concurrently were indicated.
-ray energy spectra of 80-400 MeV 
Li(p,n) reactions under the quasi-monoenergetic neutron field at RCNP, Osaka UniversityIwamoto, Yosuke; Sato, Tatsuhiko; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; Masuda, Akihiko*; Matsumoto, Tetsuro*; Iwase, Hiroshi*; Shima, Tatsushi*; Nakamura, Takashi*
EPJ Web of Conferences, 153, p.08019_1 - 08019_3, 2017/09
Times Cited Count：0 Percentile：0.03To develop 100-400 MeV quasi-monoenergetic neutron field, we measured neutron and unexpected -ray energy spectra of the Li(p,n) reaction with 80-389 MeV protons in the 100-m time-of-flight (TOF) tunnel at the Research Center for Nuclear Physics (RCNP). Neutron energy spectra with energies above 3 MeV were measured by the TOF method and energy spectra with energies above 0.1 MeV were measured by the automatic unfolding function of the radiation dose monitor DARWIN. For neutron spectra, the contribution of peak intensity to the total intensity integrated with energies above 3 MeV varied between 0.38 and 0.48. For -ray spectra, high-energetic -rays at around 70 MeV originated from the decay of 
were observed over 200 MeV. For the 246-MeV proton incident reaction, the contribution of -ray dose to neutron dose is negligible because the ratio of -ray to neutron is 0.014.
Theis, C.*; Carbonez, P.*; Feldbaumer, E.*; Forkel-Wirth, D.*; Jaegerhofer, L.*; Pangallo, M.*; Perrin, D.*; Urscheler, C.*; Roesler, S.*; Vincke, H.*; et al.
EPJ Web of Conferences, 153, p.08018_1 - 08018_5, 2017/09
Times Cited Count：0 Percentile：0.03At CERN, gas-filled ionization chambers PTW-34031 (PMI) are commonly used in radiation fields including neutrons, protons and -rays. A response function for each particle is calculated by the radiation transport code FLUKA. To validate a response function to high energy neutrons, benchmark experiments with quasi mono-energetic neutrons have been carried out at RCNP, Osaka University. For neutron irradiation with energies below 200 MeV, very good agreement was found comparing the FLUKA simulations and the measurements. In addition it was found that at proton energies of 250 and 392 MeV, results calculated with neutron sources underestimate the experimental data due to a non-negligible gamma component originating from the target Li(p,n)Be reaction.
Matsumoto, Tetsuro*; Masuda, Akihiko*; Nishiyama, Jun*; Iwase, Hiroshi*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; Yashima, Hiroshi*; Shima, Tatsushi*; et al.
EPJ Web of Conferences, 153, p.08016_1 - 08016_3, 2017/09
Times Cited Count：0 Percentile：0.03Neutron energy spectra behind concrete and iron shields were measured for quasi-monoenergetic neutrons above 200 MeV using a Bonner sphere spectrometer (BSS). Quasi-monoenergetic neutrons were produced by the Li(p,xn) reaction with 246-MeV and 389-MeV protons. The response function of BSS was also measured at neutron energies from 100 MeV to 387 MeV. In data analysis, the measured response function was used and the multiple neutron scattering effect between the BSS and the shielding material was considered. The neutron energy spectra behind the concrete and iron shields were obtained by the unfolding method using the MAXED code. Ambient dose equivalents were obtained as a function of a shield thickness successfully. For the case of the 244 MeV neutron incidence, the multiple neutron scattering effect on the effective dose is large under 50 cm thickness of the concrete shield.
Mares, V.*; Trinkl, S.*; Iwamoto, Yosuke; Masuda, Akihiko*; Matsumoto, Tetsuro*; Hagiwara, Masayuki*; Satoh, Daiki; Yashima, Hiroshi*; Shima, Tatsushi*; Nakamura, Takashi*
EPJ Web of Conferences, 153, p.08020_1 - 08020_3, 2017/09
Times Cited Count：5 Percentile：94.66To validate response of an extended range Bonner Sphere Spectrometer (ERBSS) with 
He proportional counter, neutron energy spectra were measured using an ERBSS in the quasi-mono-energetic neutron field at the Research Center for Nuclear Physics (RCNP). Using 100 MeV and 296 MeV proton beams, neutron fields with nominal peak energies of 96 MeV and 293 MeV were generated via Li(p,n)Be reactions. The energy spectra were measured at a distance of 35 m from the target. To deduce the corresponding neutron spectra from thermal to the nominal maximum energy, the ERBSS data were unfolded using the MSANDB unfolding code. At high energies, the neutron spectra were also measured by means of the TOF method using NE213 organic liquid scintillators. The agreement between ERBSS and TOF neutron spectra above 5 MeV is very good. Comparison in terms of ambient dose equivalent, H
(10) between ERBSS and TOF values for both proton energies shows very good agreement.
Masuda, Akihiko*; Matsumoto, Tetsuro*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Sato, Tatsuhiko; Iwase, Hiroshi*; Yashima, Hiroshi*; Nakane, Yoshihiro; Nishiyama, Jun*; et al.
Nuclear Instruments and Methods in Physics Research A, 849, p.94 - 101, 2017/03
Times Cited Count：0 Percentile：0.02(Instruments & Instrumentation)Quasi-monoenergetic high-energy neutron fields induced by Li(p,n) reactions are used for the response evaluation of neutron-sensitive devices. The quasi-monoenergetic high-energy field consists of high-energy monoenergetic peak neutrons and unwanted continuum neutrons down to the low-energy region. A two-angle differential method has been developed to compensate for the effect of the continuum neutrons in the response measurements. In this study, the two-angle differential method was demonstrated for Bonner sphere detectors, which are typical examples of moderator-based neutron-sensitive detectors, to investigate the method's applicability and its dependence on detector characteristics. Through this study, the adequacy of the two-angle differential method was experimentally verified, and practical suggestions were made pertaining to this method.
Li(p,n) reactions using a time-of-flight methodIwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Araki, Shohei*; Yashima, Hiroshi*; Sato, Tatsuhiko; Masuda, Akihiko*; Matsumoto, Tetsuro*; Nakao, Noriaki*; Shima, Tatsushi*; et al.
Nuclear Instruments and Methods in Physics Research A, 804, p.50 - 58, 2015/12
Times Cited Count：22 Percentile：88.52(Instruments & Instrumentation)We have measured neutron energy spectra for the 80, 100 and 296 MeV proton incident reactions at the RCNP cyclotron facility using time-of-flight method. The neutron energy spectrum consisted of the peak and continuum parts and the peak intensity was 0.9-1.1 
10
neutrons/sr/
C. The ratio of peak intensity of the spectrum to the total intensity was between 0.38 and 0.48. To consider the correction required to derive a response in the peak region from the measured total response for neutron monitors, we proposed the subtraction method using energy spectra between 0
and 25. The normalizing factor k against the 25 neutron fluence that equalizes the 0 neutron fluence in the continuum region was from 0.74 to 1.02. With our previous results, we have obtained data for characterization of monoenergetic neutron field for the Li(p,n) reaction with 80
389 MeV protons at the RCNP cyclotron facility.
-YbAlB at high magnetic fieldsTerashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.
Journal of the Physical Society of Japan, 84(11), p.114715_1 - 114715_4, 2015/11
Times Cited Count：4 Percentile：35.8(Physics, Multidisciplinary)
Si revealed by comparison with nonmagnetic references ThRuSi and LaRuSiEmi, Naoya*; Hamabata, Ryosuke*; Nakayama, Daisuke*; Miki, Toshihiro*; Koyama, Takehide*; Ueda, Koichi*; Mito, Takeshi*; Kohori, Yo*; Matsumoto, Yuji*; Haga, Yoshinori; et al.
Journal of the Physical Society of Japan, 84(6), p.063702_1 - 063702_4, 2015/06
Times Cited Count：10 Percentile：59.66(Physics, Multidisciplinary)-YbAl
Fe
B (
) at low temperatures and high magnetic fieldsTerashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.
Journal of Physics; Conference Series, 592(1), p.012020_1 - 012020_6, 2015/03
Times Cited Count：1 Percentile：43.85Valence fluctuation phenomena in rare-earth intermetallic compounds have attracted attention because the quantum criticality of the valence transition has been proposed theoretically. Recently, it was found that 
-YbAlB shows quantum criticality without tuning and has a strong mixed-valence state. In this study, we measured the magnetization curve and X-ray magnetoabsorption in -YbAlFeB (), which is a locally isostructural polymorph of -YbAlB. The magnetization and X-ray experiments were performed in fields up to 55 and 40 T, respectively. A small increase in the Yb valence was observed at fields where the magnetization curve exhibited a change in slope.
Li(p,n) reactionsIwamoto, Yosuke; Hagiwara, Masayuki*; Iwase, Hiroshi*; Yashima, Hiroshi*; Satoh, Daiki; Matsumoto, Tetsuro*; Masuda, Akihiko*; Pioch, C.*; Mares, V.*; Shima, Tatsushi*; et al.
Progress in Nuclear Science and Technology (Internet), 4, p.657 - 660, 2014/04
The authors measured the neutron energy spectra of the proton incident reaction on the lithium target with 137, 200, 246 and 389 MeV protons at several angles (0, 2.5, 5, 10, 15, 20, 25 and 30), using a time-of-flight (TOF) method employing organic scintillators NE213 at the Research Center for Nuclear Physics (RCNP) of Osaka University. For the neutron energy spectrum at 0, the ratio of the peak neutron intensity to the total one varied between 0.4 and 0.5 depending on the incident energy. In order to consider the correction required to derive the response in the peak region from the measured total response for high-energy neutron detectors, the authors showed the subtractions of H*(10) obtained at larger angles from the 0 data in the continuum part. It was found that subtracting the dose equivalent at about 22 from the 0 data reduces the continuum component most efficiency.
Matsumoto, Tetsuro*; Masuda, Akihiko*; Nishiyama, Jun*; Harano, Hideki*; Iwase, Hiroshi*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Yashima, Hiroshi*; Nakane, Yoshihiro; et al.
Progress in Nuclear Science and Technology (Internet), 4, p.332 - 336, 2014/04
Recently, many high-energy accelerators are used for various fields. Shielding data for high-energy neutrons are therefore very important from the point of view of radiation protection in high energy accelerator facilities. However, the shielding experimental data for high energy neutrons above 100 MeV are very poor both in quality and in quantity. In this study, neutron penetration spectral fluence and ambient dose through iron and concrete shields were measured with a Bonner sphere spectrometer (BSS). Quasi-monoenergetic neutrons were produced by the Li(p,xn) reaction by bombarding a 1-cm thick Li target with 246-MeV and 389-MeV protons in the Research Center for Nuclear Physics (RCNP) of the Osaka University. Shielding materials are iron blocks with a thickness from 10 cm to 100 cm and concrete blocks with a thickness from 25 cm to 300 cm.
Hagiwara, Masayuki*; Iwase, Hiroshi*; Iwamoto, Yosuke; Satoh, Daiki; Matsumoto, Tetsuro*; Masuda, Akihiko*; Yashima, Hiroshi*; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; et al.
Progress in Nuclear Science and Technology (Internet), 4, p.327 - 331, 2014/04
We have developed several hundreds of MeV p-Li quasi-monoenergetic neutron fields in the Research Center for Nuclear Physics (RCNP), Osaka University, Japan. In this study, we extended the measurements to higher energy with a p-Li quasi-monoenergetic neutron source, which was produced from a 1.0-cm-thick lithium target bombarded with 246 and 389 MeV protons, using a larger NE213 scintillator of 25.4-cm in diameter and 25.4-cm in thickness. The large NE213 have good energy resolution for high energy neutrons, because it can stop recoil protons up to 180 MeV. The measured data are compared with the Monte-Carlo codes (PHITS with JENDL-HE data library) in the energy spectra, time spectra and the attenuation length of the peak neutrons. This comparison shows good agreement between experiments and calculations. The attenuation length estimated from the well-fitted curves with single exponential form will be useful for the practical shielding design of high energy accelerator facilities.
Nakane, Yoshihiro; Hagiwara, Masayuki*; Iwamoto, Yosuke; Iwase, Hiroshi*; Satoh, Daiki; Sato, Tatsuhiko; Yashima, Hiroshi*; Matsumoto, Tetsuro*; Masuda, Akihiko*; Nunomiya, Tomoya*; et al.
Progress in Nuclear Science and Technology (Internet), 4, p.704 - 708, 2014/04
no abstracts in English
CoGeO
Soda, Minoru*; Matsumoto, Masashige*; M
nsson, M.*; Kawamura, Seiko; Nakajima, Kenji; Shiina, Ryosuke*; Masuda, Takatsugu*
Physical Review Letters, 112(12), p.127205_1 - 127205_5, 2014/03
Times Cited Count：34 Percentile：83.82(Physics, Multidisciplinary)We demonstrate the existence of the spin-nematic interactions in an easy-plane type antiferromagnet BaCoGeO by exploring the magnetic anisotropy and spin dynamics. The combination of neutron scattering and magnetic susceptibility measurements reveals that the origin of the in-plane anisotropy is an antiferro-type interaction of the spin-nematic operator. The relation between the nematic operator and the electric polarization in the ligand symmetry of this compound is presented. The introduction of the spinnematic interaction is useful to understand the physics of spin and electric dipole in multiferroic compounds.
Iwamoto, Yosuke; Hagiwara, Masayuki*; Matsumoto, Tetsuro*; Masuda, Akihiko*; Iwase, Hiroshi*; Yashima, Hiroshi*; Shima, Tatsushi*; Tamii, Atsushi*; Nakamura, Takashi*
Nuclear Instruments and Methods in Physics Research A, 690, p.10 - 16, 2012/10
Times Cited Count：4 Percentile：32.82(Instruments & Instrumentation)Secondary neutron-production double-differential cross sections (DDXs) have been measured from interactions of 137 MeV and 200 MeV protons in a natural carbon target. The data were measured between 0 and 25 in the laboratory. Benchmark calculations were carried out with the PHITS code using the evaluated nuclear data files of JENDL/HE-2007 and ENDF/B-VII, and the theoretical models of Bertini-GEM and ISOBAR-GEM. For the 137 MeV proton incidence, calculations using JENDL/HE-2007 generally reproduced the shape and the amount of experimental spectra well including the ground state of the 
N state produced by the C(p,n)N reaction. ISOBAR predicts the nucleon emission to the forward angles qualitatively better than the Bertini model and JENDL/HE-2007. These experimental data will be useful to evaluate the carbon data and as benchmark data for investigating the validity of the Monte Carlo simulation for the shielding design of accelerator facilities.
Masuda, Akihiko*; Matsumoto, Tetsuro*; Harano, Hideki*; Nishiyama, Jun*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Nakamura, Takashi*; et al.
IEEE Transactions on Nuclear Science, 59(1), p.161 - 166, 2012/02
Times Cited Count：11 Percentile：64.69(Engineering, Electrical & Electronic)In this study, responses of Bonner sphere spectrometer (BSS) for 245 and 388 MeV neutrons was measured at RCNP, Osaka University. The neutrons are generated in the Li(p,n) reaction and its spectra consist of a high-energy peak and a continuum down to the low energy. Therefore, the observed counts of BSS caused by the continuum need to be subtracted. Adjusting a Li target angle and a collimator position, 0 deg and 30 deg component of generated neutron are available. While the 0 deg component contains both the peak and the continuum, the 30 deg component is considered to contain only the continuum. Therefore, the response of the peak is obtained. The spectra were measured using the time-of-flight (TOF) method with a NE213 scintillator.
