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Journal Articles

Quantitative estimation of exposure inhomogeneity in terms of eye lens and extremity monitoring for radiation workers in the nuclear industry

Yoshitomi, Hiroshi; Kowatari, Munehiko; Hagiwara, Masayuki*; Nagaguro, Seiji*; Nakamura, Hajime*

Radiation Protection Dosimetry, 184(2), p.179 - 188, 2019/08

Journal Articles

Establishment of a novel detection system for measuring primary knock-on atoms

Tsai, P.-E.; Iwamoto, Yosuke; Hagiwara, Masayuki*; Sato, Tatsuhiko; Ogawa, Tatsuhiko; Satoh, Daiki; Abe, Shinichiro; Ito, Masatoshi*; Watabe, Hiroshi*

Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 3 Pages, 2018/11

The energy spectra of primary knock-on atoms (PKAs) are essential for radiation damage assessment in design of accelerator facilities. However up to date the experimental data are still limited, due to the poor mass resolution and the high measurement threshold energies in the conventional setup of nuclear physics experiments using solid state detectors, which are typically above a few MeV/nucleon. In this study, a novel detection system consisting of two time detectors and one dE-E energy detector is proposed and being constructed to measure the PKA spectra. The system and detector design was based on Monte Carlo simulations by using the PHITS code. The PHITS simulations show that the system is able to distinguish the PKA isotopes above $$sim$$0.2-0.3 MeV/nucleon for A=20$$sim$$30 amu; the PKA mass identification thresholds decrease to $$<$$0.1 MeV/nucleon for PKAs lighter than 20 amu. The detection system will be tested in the summer of 2017, and the test results will be presented at the conference.

Journal Articles

Investigation of the electronic structure and lattice dynamics of the thermoelectric material Na-doped SnSe

Wu, P.*; Zhang, B.*; Peng, K. L.*; Hagiwara, Masayuki*; Ishikawa, Yoshihisa*; Kofu, Maiko; Lee, S. H.*; Kumigashira, Hiroshi*; Hu, C. S.*; Qi, Z. M.*; et al.

Physical Review B, 98(9), p.094305_1 - 094305_7, 2018/09

 Percentile:100(Materials Science, Multidisciplinary)

Using angle-resolved photoemission spectroscopy and inelastic neutron scattering, we have studied how electronic structures and lattice dynamics evolve with temperature in Na-doped SnSe.

Journal Articles

Effects of magnetic field and pressure on the valence-fluctuating antiferromagnetic compound EuPt$$_2$$Si$$_2$$

Takeuchi, Tetsuya*; Yara, Tomoyuki*; Ashitomi, Yosuke*; Iha, Wataru*; Kakihana, Masashi*; Nakashima, Miho*; Amako, Yasushi*; Honda, Fuminori*; Homma, Yoshiya*; Aoki, Dai*; et al.

Journal of the Physical Society of Japan, 87(7), p.074709_1 - 074709_14, 2018/07

 Times Cited Count:2 Percentile:29.91(Physics, Multidisciplinary)

Journal Articles

Electronic states in EuCu$$_2$$(Ge$$_{1-x}$$Si$$_x$$)$$_2$$ based on the doniach phase diagram

Iha, Wataru*; Yara, Tomoyuki*; Ashitomi, Yosuke*; Kakihana, Masashi*; Takeuchi, Tetsuya*; Honda, Fuminori*; Nakamura, Ai*; Aoki, Dai*; Gochi, Jun*; Uwatoko, Yoshiya*; et al.

Journal of the Physical Society of Japan, 87(6), p.064706_1 - 064706_14, 2018/06

 Times Cited Count:2 Percentile:29.91(Physics, Multidisciplinary)

JAEA Reports

Proceedings of the 2016 Symposium on Nuclear Data; November 17-18, 2016, High Energy Accelerator Research Organization, Tsukuba, Ibaraki, Japan

Sanami, Toshiya*; Nishio, Katsuhisa; Hagiwara, Masayuki*; Iwase, Hiroshi*; Kunieda, Satoshi; Nakamura, Shoji

JAEA-Conf 2017-001, 222 Pages, 2018/01

JAEA-Conf-2017-001.pdf:30.89MB

The 2016 Symposium on Nuclear Data was held at Kobayashi Hall of High Energy Accelerator Research Organization, on November 17 and 18, 2016. The symposium was organized by the Nuclear Data Division of the Atomic Energy Society of Japan in cooperation with Radiation Science Center, High Energy Accelerator Research Organization, Nuclear Science and Engineering Center of Japan Atomic Energy Agency and North Kanto Branch of Atomic Energy Society of Japan. In the symposium, there were one tutorial, "Historical Evolution of Accelerators" and four oral sessions, "Overview of the ImPACT Program - Reduction and Resource Recycling of High Level Wastes through Nuclear Transmutation", "Facilities and experiments for nuclear data in Japan", "Nuclear data from measurement to application", and "Progress of neutron nuclear data measurement and research for its basics and application". In addition, recent research progress on experiments, evaluation, benchmark and application was presented in the poster session. Among 65 participants, all presentations and following discussions were very active and fruitful. This report consists of total 31 papers including 10 oral and 21 poster presentations.

Journal Articles

Assessment of equivalent dose of the lens of the eyes and the extremities to workers under nonhomogeneous exposure situation in nuclear and accelerator facilities by means of measurements using a phantom coupled with Monte Carlo simulation

Yoshitomi, Hiroshi; Hagiwara, Masayuki*; Kowatari, Munehiko; Nishino, Sho; Sanami, Toshiya*; Iwase, Hiroshi*

Proceedings of 14th International Congress of the International Radiation Protection Association (IRPA-14), Vol.3 (Internet), p.1188 - 1195, 2017/11

The equivalent doses to the lens of the eye and extremities for radiation workers should be assessed properly to ensure that the dose limits are not exceeded. Recently, the following two issues has pressed demand on more appropriate evaluation of the equivalent doses of the lens of the eye and extremity. One is the new occupational dose limit for the lens of the eye the ICRP recommended. The other is growing demand on handling of highly activated materials in the maintenance works of an accelerator and contaminated materials during the decommissioning works of nuclear facility, which increases the potential exposure risk to the extremities to a wider variety of radio-nuclides. Since the points to be assessed for the exposures to the lens of the eye and the extremities are apart from the trunk, the homogeneity of the radiation fields would be significantly impact on the assessment of these equivalent doses. However, there has been no sufficient and available method to identify the nonhomogeneous situations systematically in terms of the eye lens or extremity monitoring. The goal of this study is to provide the framework to identify the nonhomogeneous exposure situations. In order to fulfil this purpose, newly proposed indices to represent the homogeneity were calculated by Monte Carlo simulation incorporated with mathematical phantom, verifying the benchmark measurements. Important parameters that significantly impact on these indices were also shown from the various trials of calculations of homogeneity indices.

Journal Articles

Neutron production in deuteron-induced reactions on Li, Be, and C at an incident energy of 102 MeV

Araki, Shohei*; Watanabe, Yukinobu*; Kitajima, Mizuki*; Sadamatsu, Hiroki*; Nakano, Keita*; Kin, Tadahiro*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; et al.

EPJ Web of Conferences (Internet), 146, p.11027_1 - 11027_4, 2017/09

 Percentile:100

In recently years, deuteron-induced reaction is considered to produce the neutron source for application fields such as radiation damage fusion materials and boron neutron capture therapy. However, as the experimental data are not sufficient at incident energies above 60 MeV, the theoretical models are not validated. Therefore, we measured the double differential cross sections (DDXs) for Li, Be and C at 100 MeV at the Research Center for Nuclear Physics in Osaka University. The DDXs were measured at 6 angles (0$$^{circ}$$$$sim$$25$$^{circ}$$ and neutron energy was determined by a time of flight method. Three different-size NE213 liquid organic scintillators located at a distance of 7 m, 24 m and 74 m respectively were adopted as neutron detectors. In the measured DDXs, a broad peak due to deuteron breakup process was observed at approximately half of the deuteron incident energy. The DDXs calculated by PHITS did not reproduce the experimental ones due to lack of theoretical model.

Journal Articles

Experimental analysis of neutron and background $$gamma$$-ray energy spectra of 80-400 MeV $$^{7}$$Li(p,n) reactions under the quasi-monoenergetic neutron field at RCNP, Osaka University

Iwamoto, Yosuke; Sato, Tatsuhiko; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; Masuda, Akihiko*; Matsumoto, Tetsuro*; Iwase, Hiroshi*; Shima, Tatsushi*; Nakamura, Takashi*

EPJ Web of Conferences (Internet), 153, p.08019_1 - 08019_3, 2017/09

 Percentile:100

To develop 100-400 MeV quasi-monoenergetic neutron field, we measured neutron and unexpected $$gamma$$-ray energy spectra of the $$^{7}$$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 $$gamma$$ 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 $$gamma$$-ray spectra, high-energetic $$gamma$$-rays at around 70 MeV originated from the decay of $$pi$$$$^{0}$$ were observed over 200 MeV. For the 246-MeV proton incident reaction, the contribution of $$gamma$$-ray dose to neutron dose is negligible because the ratio of $$gamma$$-ray to neutron is 0.014.

Journal Articles

Characterization of the PTW 34031 ionization chamber (PMI) at RCNP with high energy neutrons ranging from 100 - 392 MeV

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 (Internet), 153, p.08018_1 - 08018_5, 2017/09

 Percentile:100

At CERN, gas-filled ionization chambers PTW-34031 (PMI) are commonly used in radiation fields including neutrons, protons and $$gamma$$-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 $$^{7}$$Li(p,n)Be reaction.

Journal Articles

Shielding experiments of concrete and iron for the 244 MeV and 387 MeV quasi-mono energetic neutrons using a Bonner sphere spectrometer (at RCNP, Osaka Univ.)

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 (Internet), 153, p.08016_1 - 08016_3, 2017/09

 Percentile:100

Neutron 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 $$^{7}$$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.

Journal Articles

Neutron spectrometry and dosimetry in 100 and 300 MeV quasi-mono-energetic neutron field at RCNP, Osaka University, Japan

Mares, V.*; Trinkl, S.*; Iwamoto, Yosuke; Masuda, Akihiko*; Matsumoto, Tetsuro*; Hagiwara, Masayuki*; Satoh, Daiki; Yashima, Hiroshi*; Shima, Tatsushi*; Nakamura, Takashi*

EPJ Web of Conferences (Internet), 153, p.08020_1 - 08020_3, 2017/09

 Times Cited Count:1 Percentile:14.04

To validate response of an extended range Bonner Sphere Spectrometer (ERBSS) with $$^{3}$$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 $$^{7}$$Li(p,n)$$^{7}$$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.

Journal Articles

Magnetic structure and dispersion relation of the $$S$$=1/2 quasi-one-dimensional Ising-like antiferromagnet BaCo$$_{2}$$V$$_{2}$$O$$_{8}$$ in a transverse magnetic field

Matsuda, Masaaki*; Onishi, Hiroaki; Okutani, Akira*; Ma, J.*; Agrawal, H.*; Hong, T.*; Pajerowski, D. M.*; Copley, J. R. D.*; Okunishi, Koichi*; Mori, Michiyasu; et al.

Physical Review B, 96(2), p.024439_1 - 024439_8, 2017/07

 Times Cited Count:2 Percentile:66.33(Materials Science, Multidisciplinary)

Journal Articles

Applicability of the two-angle differential method to response measurement of neutron-sensitive devices at the RCNP high-energy neutron facility

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

 Percentile:100(Instruments & Instrumentation)

Quasi-monoenergetic high-energy neutron fields induced by $$^{7}$$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.

Journal Articles

Systematic measurement of double-differential neutron production cross sections for deuteron-induced reactions at an incident energy of 102 MeV

Araki, Shohei*; Watanabe, Yukinobu*; Kitajima, Mizuki*; Sadamatsu, Hiroki*; Nakano, Keita*; Kin, Tadahiro*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 842, p.62 - 70, 2017/01

 Times Cited Count:4 Percentile:18.09(Instruments & Instrumentation)

Recently, deuteron incident reaction is expected to be used as a neutron source for study of radiation damage in fusion materials, boron neutron capture therapy, and so on. However, experimental data to validate the model is very few. In this work, double-differential neutron production cross sections (DDXs) for deuteron-induced reactions on $$^{nat}$$Li, $$^{9}$$Be, $$^{nat}$$C, $$^{27}$$Al, $$^{nat}$$Cu, and $$^{93}$$Nb at 102 MeV were measured at forward angles $$leq$$ 25$$^{circ}$$ by means of a time of flight (TOF) method with NE213 liquid organic scintillators at the Research Center of Nuclear Physics (RCNP), Osaka University. The experimental DDXs and energy-integrated cross sections were compared with TENDL-2015 data and PHITS calculation. The PHITS calculation showed better agreement with the experimental results than TENDL-2015 for all target nuclei, although the shape of the broad peak around 50 MeV was not satisfactorily reproduced by the PHITS calculation.

Journal Articles

Overview of JENDL-4.0/HE and benchmark calculations

Kunieda, Satoshi; Iwamoto, Osamu; Iwamoto, Nobuyuki; Minato, Futoshi; Okamoto, Tsutomu; Sato, Tatsuhiko; Nakashima, Hiroshi; Iwamoto, Yosuke; Iwamoto, Hiroki; Kitatani, Fumito; et al.

JAEA-Conf 2016-004, p.41 - 46, 2016/09

Neutron- and proton-induced cross-section data are required in a wide energy range beyond 20 MeV, for the design of accelerator applications. New evaluations are performed with recent knowledge in the optical and pre-equilibrium model calculations. We also evaluated cross-sections for p+$$^{6,7}$$Li and p+$$^{9}$$Be which have been highly requested from a medical field. The present high-energy nuclear data library, JENDL-4.0/HE, includes evaluated cross-sections for incident neutrons and protons up to 200 MeV (for about 130 nuclei). We overview substantial features of the library, i.e., (1) systematic evaluation with CCONE code, (2) challenges for evaluations of light nuclei and (3) inheritance of JENDL-4.0 and JENDL/HE-2007. In this talk, we also focus on the results of benchmark calculation for neutronics to show performance of the present library.

Journal Articles

Measurement of double differential (d,xn) cross sections for carbon at an incident energy of 100 MeV

Araki, Shohei*; Watanabe, Yukinobu*; Kitajima, Mizuki*; Sadamatsu, Hiroki*; Nakano, Keita*; Kin, Tadahiro*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; et al.

JAEA-Conf 2016-004, p.159 - 164, 2016/09

Neutron production data from materials such as Li, Be and C bombarded by deuteron are required for design such as the facility of radiation damage for fusion materials and boron neutron capture therapy. However, there is little measurement of double differential neutron production cross sections (DDXs). Therefore, we have planned a series of DDXs measurements at incident energies more than 100 MeV in the Research Center for Nuclear Physics, Osaka University. The experiment was carried out with a carbon target at the neutron Time of Flight (TOF) course in RCNP. Emitted neutrons were detected by three different-size NE213 liquid organic scintillators (5.08 cm, 12.7 cm and 25.4 cm in dimeter and thickness) located at a distance of 7 m, 24 m and 74 m respectively. The neutron detection efficiencies of the detectors were calculated by SCINFUL-QMD code. It turned out that the calculation data fr carbon does not reproduce the experimental data satisfactorily well.

Journal Articles

Characterization of high-energy quasi-monoenergetic neutron energy spectra and ambient dose equivalents of 80-389 MeV $$^{7}$$Li(p,n) reactions using a time-of-flight method

Iwamoto, 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:15 Percentile:5.53(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 $$times$$ 10$$^{10}$$ neutrons/sr/$$mu$$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$$^{circ}$$ and 25$$^{circ}$$. The normalizing factor k against the 25$$^{circ}$$ neutron fluence that equalizes the 0$$^{circ}$$ 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 $$^{7}$$Li(p,n) reaction with 80$$sim$$389 MeV protons at the RCNP cyclotron facility.

Journal Articles

Crossover phase diagram and electronic state in the heavy-fermion metamagnets UIr$$_2$$Zn$$_{20}$$ and UCo$$_2$$Zn$$_{20}$$

Hirose, Yusuke*; Takeuchi, Tetsuya*; Honda, Fuminori*; Yoshiuchi, Shingo*; Hagiwara, Masayuki*; Yamamoto, Etsuji; Haga, Yoshinori; Settai, Rikio*; Onuki, Yoshichika

Journal of the Physical Society of Japan, 84(7), p.074704_1 - 074704_10, 2015/07

 Times Cited Count:5 Percentile:43.76(Physics, Multidisciplinary)

Journal Articles

Measurements and parameterization of neutron energy spectra from targets bombarded with 120 GeV protons

Kajimoto, Tsuyoshi*; Shigyo, Nobuhiro*; Sanami, Toshiya*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Lee, H. S.*; Soha, A.*; Ramberg, E.*; Coleman, R.*; Jensen, D.*; et al.

Nuclear Instruments and Methods in Physics Research B, 337, p.68 - 77, 2014/10

 Times Cited Count:3 Percentile:61.51(Instruments & Instrumentation)

The energy spectra of neutrons were measured by a time-of-flight method for 120 GeV protons on thick graphite, aluminum, copper, and tungsten targets with an NE213 scintillator at the Fermilab Test Beam Facility. Neutron energy spectra were obtained between 25 and 3000 MeV at emission angles of 30, 45, 120, and 150$$^{circ}$$. The spectra were parameterized as neutron emissions from three moving sources and then compared with theoretical spectra calculated by PHITS and FLUKA codes. The yields of the theoretical spectra were substantially underestimated compared with the yields of measured spectra. The integrated neutron yields from 25 to 3000 MeV calculated with PHITS code were 16-36% of the experimental yields and those calculated with FLUKA code were 26-57% of the experimental yields for all targets and emission angles.

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