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Iwamoto, Hiroki; Meigo, Shinichiro
EPJ Web of Conferences, 153, p.01016_1 - 01016_9, 2017/09
Times Cited Count：2 Percentile：78.04(Nuclear Science & Technology)
-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：0.03(Nuclear Science & Technology)To 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：0.03(Nuclear Science & Technology)At 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.
Nagai, Haruyasu; Terada, Hiroaki; Tsuzuki, Katsunori; Katata, Genki; Ota, Masakazu; Furuno, Akiko; Akari, Shusaku
EPJ Web of Conferences, 153, p.08012_1 - 08012_7, 2017/09
Times Cited Count：3 Percentile：86.43(Nuclear Science & Technology)In order to assess the radiological dose to the public resulting from the Fukushima Daiichi Nuclear Power Station (FDNPS) accident in Japan, the spatiotemporal distribution of radioactive materials in the environment are reconstructed by computer simulations. In this study, by refining the source term of radioactive materials and modifying the atmospheric dispersion model (ATDM), the atmospheric dispersion simulation of radioactive materials is improved. Then, a database of spatiotemporal distribution of radioactive materials in the air and on the ground surface is developed from the output of the simulation. This database is used in other studies for the dose assessment by coupling with the behavioral pattern of evacuees from the FDNPS accident. The ATDM simulation was improved to use a new meteorological model and sophisticated deposition scheme. Although the improved ATDM simulations reproduced well the 
Cs deposition pattern in the eastern Japan scale, the reproducibility of deposition pattern was decreased in the vicinity of FDNPS. This result indicated the necessity of further refinement of the source term by optimization to the improved ATDM simulations.
Malins, A.; Machida, Masahiko; Niita, Koji*
EPJ Web of Conferences, 153, p.06001_1 - 06001_9, 2017/09
Times Cited Count：1 Percentile：61.21(Nuclear Science & Technology)Sato, Tatsuhiko; Niita, Koji*; Iwamoto, Yosuke; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuda, Norihiro; Okumura, Keisuke; et al.
EPJ Web of Conferences, 153, p.06008_1 - 06008_6, 2017/09
Times Cited Count：6 Percentile：95.25(Nuclear Science & Technology)Particle and Heavy Ion Transport code System, PHITS, has been developed under the collaboration of several institutes in Japan and Europe. It can deal with the transport of nearly all particles up to 1 TeV (per nucleon for ion) using various nuclear reaction models and data libraries. More than 2,500 researchers and technicians have used the code for a variety of applications such as accelerator design, radiation shielding and protection, medical physics, and space and geosciences. This paper briefly summarizes physics models and functions newly implemented in PHITS between versions 2.52 and 2.82.
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：1 Percentile：61.21(Nuclear Science & Technology)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 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：93.93(Nuclear Science & Technology)To 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.
Matsuda, Norihiro; Izumi, Yuichi*; Yamanaka, Yoshiyuki*; Gando, Toshiyuki*; Yamada, Masaaki*; Oishi, Koji*
EPJ Web of Conferences, 153, p.07001_1 - 07001_6, 2017/09
Times Cited Count：0 Percentile：0.03(Nuclear Science & Technology)Yang, Z.-Y.*; Tsai, P.-E.; Lee, S.-C.*; Liu, Y.-C.*; Chen, C.-C.*; Sato, Tatsuhiko; Sheu, R.-J.*
EPJ Web of Conferences, 153, p.04011_1 - 04011_8, 2017/09
Times Cited Count：13 Percentile：99.27(Nuclear Science & Technology)Four widespread used Monte Carlo simulation and transport codes, including GEANT4, FLUKA, MCNPX, and PHITS, are employed to calculate the integrated depth dose curves inside a water phantom for proton radiotherapy, and the results are compared with the experimental data carried out at the ProCure proton therapy center in New Jersey, USA. This is a collaborative study of JAEA, National Tsing Hua University, and ProCure proton therapy center, and this study aims to provide practical information regarding the accuracy and computing efficiency of each Monte Carlo codes for code users as well as the benchmark for further model improvement in each code.
Konno, Chikara; Matsuda, Norihiro; Kwon, Saerom*; Ota, Masayuki*; Sato, Satoshi*
EPJ Web of Conferences, 153, p.01024_1 - 01024_6, 2017/09
Times Cited Count：3 Percentile：86.43(Nuclear Science & Technology)As a benchmark test of JENDL-4.0/HE released in 2015, we have analyzed concrete and iron shielding experiments with the 40 and 65 MeV neutron sources at TIARA in JAEA by using MCNP5 and ACE files processed from JENDL-4.0/HE with NJOY2012. As a result, it was found out that the calculation results with JENDL-4.0/HE agreed with the measured ones in the concrete experiment well, while they underestimated the measured ones in the iron experiment more for the thicker assemblies. We examined JENDL-4.0/HE in detail and it was considered that the larger non-elastic scattering cross sections of 
Fe caused the underestimation in the calculation with JENDL-4.0/HE for the iron experiment.
Yamamoto, Kazami
EPJ Web of Conferences, 153, p.07022_1 - 07022_6, 2017/09
Times Cited Count：1 Percentile：61.21(Nuclear Science & Technology)The J-PARC 3 GeV Rapid Cycling Synchrotron (RCS) delivers a 1-MW, high-intensity beam to the following facilities. In such high-intensity accelerator, the operational beam intensity is limited to keep the exposure to the workers by the residual dose within acceptable tolerances. Therefore we continue to commission the accelerator system to reduce the beam loss. In order to achieve further high-intensity operation, the J-PARC accelerator system was drastically upgraded (Increment of the injection energy of RCS and peak current of Linac) over the past two years. After the upgrade, the beam loss was decreased by the commissioning. The output power was increased; nevertheless the residual doses were kept same level or decreased. Since we replaced the broken collimator which was higher activated, we kept the exposure to the workers within acceptable level.
Hirayama, Hideo*; Kondo, Kenjiro*; Suzuki, Seishiro*; Tanimura, Yoshihiko; Iwanaga, Kohei*; Nagata, Hiroshi*
EPJ Web of Conferences, 153, p.08010_1 - 08010_3, 2017/09
Times Cited Count：2 Percentile：78.04(Nuclear Science & Technology)Pulse height distributions were measured using a CdZnTe detector inside a lead collimator to investigate main source producing high dose rates above the shield plugs of Unit 3 at Fukushima Daiichi Nuclear Power Station. It was confirmed that low energy photons are dominant. Concentrations of Cs-137 under 60 cm concrete of the shield plug were estimated to be between 8.1
10
and 5.710
Bq/cm
from the measured peak count rate of 0.662 MeV photons. If Cs-137 was distributed on the surfaces of the gaps of the shied plugs with radius 6 m and with the averaged concentration of 5 points, 2.610 Bq/cm, total amount of Cs-137 is estimated to be 30 PBq.
Saito, Kimiaki
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