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Endo, Akira; Petoussi-Henss, N.*; Zankl, M.*; Bolch, W. E.*; Eckerman, K. F.*; Hertel, N. E.*; Hunt, J. G.*; Pelliccioni, M.*; Schlattl, H.*; Menzel, H.-G.*
Radiation Protection Dosimetry, 161(1-4), p.11 - 16, 2014/10
Times Cited Count：3 Percentile：23.66(Environmental Sciences)In 2007, the International Commission on Radiological Protection (ICRP) revised its fundamental recommendations on radiation protection in ICRP Publication 103 (ICRP103). The recommendations updated the radiation and tissue weighting factors in the radiological protection quantities, equivalent and effective doses, and adopted reference computational phantoms for the calculation of organ doses. These revisions required calculations of conversion coefficients for the protection quantities. The sets of conversion coefficients for external exposures were compiled by the Task Group DOCAL of ICRP, and published in ICRP116. The presentation reviews the conversion coefficients for external radiations calculated using the reference computational phantoms. The conversion coefficients are compared with the existing values given in ICRP74. Contributing factors for any differences between these sets of conversion coefficients as well as the impact for radiation monitoring practice are discussed.
Tanimura, Yoshihiko; Tsutsumi, Masahiro; Yoshizawa, Michio
Radiation Protection Dosimetry, 161(1-4), p.144 - 148, 2014/10
Times Cited Count：10 Percentile：60.52(Environmental Sciences)A Long Counter (LC) is the most appropriate detector to measure neutron fluence due to flat response over a wide neutron energy range. Therefore, it is usually employed as a neutron fluence monitor. The weight of the LC used at FRS is 50 kg. It is too heavy to transfer it from one room to another room. Then we developed a new portable long counter whose weight is 15 kg. The portable LC consists of a 
He or BF
counter and a cylindrical moderator. It was designed to have an almost flat response from a few eV to a few MeV. While typical LCs have air gaps in the front surface, which allow lower-energy neutrons to penetrate deeper into the moderator, the portable LC has little space to make such air gaps due to the small size. Then we employed a polystyrene (PS) moderator instead of a polyethylene (PE) one as a front part of the moderator. As the hydrogen density of PS is nearly half that of PE, lower-energy neutrons can penetrate the PS moderator deeper than the PE moderator.
Am-Be-encapsulation sourceKowatari, Munehiko; Tanimura, Yoshihiko; Yoshizawa, Michio
Radiation Protection Dosimetry, 161(1-4), p.166 - 170, 2014/10
Times Cited Count：2 Percentile：16.31(Environmental Sciences)An attempt to decrease the anisotropic emissions of neutrons from a cylindrical Am-Be encapsulated X3 source was conducted out by Monte Carlo calculations and experiments. Influence of metal materials and shapes of the external casing to the anisotropy factor were focused on. Results obtained by calculations using MCNP4C implied that a light and spherical-shaped casing decreases the anisotropic emission of neutrons. Experimental results using the spherical-shaped aluminum protection case also revealed that the anisotropy factor was close to 1.0 with wide zenith angle ranges.
Sato, Tatsuhiko; Kataoka, Ryuho*; Yasuda, Hiroshi*; Yashiro, Seiji*; Kuwabara, Takao*; Shiota, Daiko*; Kubo, Yuki*
Radiation Protection Dosimetry, 161(1-4), p.274 - 278, 2014/10
Times Cited Count：22 Percentile：84.95(Environmental Sciences)We applied our simulation technique to the analysis of air shower induced by mono-energetic protons and alpha particles, which are the dominant component of SEP. The results of the simulations were summarized in a database containing particle fluxes for each condition as a function of the atmospheric depth. This database was then incorporated into our developing Warning System of AVIation Exposure to SEP called WASAVIES. In this system, the aircrew doses due to SEP exposure are estimated within 6 hours after the flare onset, using the established database multiplied with the SEP fluxes incident to the earth. The MHD Cube model is employed in the determination of the incident SEP fluxes. The procedures for the air shower simulation together with some initial results of the aircrew dose calculations for past ground-level enhancement (GLE) events will be presented at the meeting.
Yashima, Hiroshi*; Sekimoto, Shun*; Ninomiya, Kazuhiko*; Kasamatsu, Yoshitaka*; Shima, Tatsushi*; Takahashi, Naruto*; Shinohara, Atsushi*; Matsumura, Hiroshi*; Satoh, Daiki; Iwamoto, Yosuke; et al.
Radiation Protection Dosimetry, 161(1-4), p.139 - 143, 2014/10
Times Cited Count：2 Percentile：16.31(Environmental Sciences)The neutron activation cross sections up to GeV are important for the neutron dosimetry of the radiation field in high-energy and high-intensity accelerator facilities for a project of intense spallation neutron source. But the evaluation of neutron activation cross section data is not enough above 20 MeV because experimental data are still scarce. This study aimed to measure the neutron activation cross sections of Bi and Co by using a quasi-monoenergetic neutron field. In this symposium, we will present obtained experimental cross section data with the other experimental data (neutron-induced and proton-induced), the calculated data by PHITS code and the evaluated nuclear data.
Li(p,n)Be reactionTanimura, Yoshihiko; Tsutsumi, Masahiro; Yoshizawa, Michio
Radiation Protection Dosimetry, 161(1-4), p.149 - 152, 2014/10
Times Cited Count：2 Percentile：16.31(Environmental Sciences)Mono-energetic neutron calibration fields have been established in the energy range from 8 keV to 19 MeV using an accelerator at FRS. In the 144, 250 and 565 keV fields, mono-energetic neutrons are produced by bombarding a LiF target with accelerated protons in order to cause Li(p,n)Be reactions. Photons mixed in these neutron fields, which are produced by other nuclear reactions, can affect the calibration results. These mixed photon dose should be evaluated. In this paper the photons produced by the nuclear reactions between neutrons and target, its supporting materials and the constructional materials of the irradiation room such as the walls, floor and ceiling. were calculated using the MCNP-ANT code. Then the ambient dose equivalent H*(10) of the photons were evaluated and compared with that of the mono-energetic neutrons.
Mares, V.*; Pioch, C.*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Hatanaka, Kichiji*; Iwase, Hiroshi*; Masuda, Akihiko*; Matsumoto, Tetsuro*; R
hm, W.*; Shima, Tatsushi*; et al.
no journal, ,
Calibration measurements for a Bonner sphere spectrometer (BSS) with 
He proportional counter were performed in quasi-mono-energetic neutron fields at the Research Center for Nuclear Physics (RCNP) at the University of Osaka, Japan. Neutrons with nominal peak energies of 134 MeV and 197 MeV were generated in lithium target. The neutron spectra were determined by BSS measurements in the range from peak energy down to thermal energies using the MSANDB unfolding code. Three different sets of response functions calculated by Monte Carlo codes GEANT4 and MCNP/LAHET were used. For calibration of the BSS, the remaining count rates resulting from neutrons E 
10 MeV were compared to calculated count rates using the independently measured TOF spectra and the response functions of the Bonner spheres. Within the uncertainties involved in the experiment a remarkable overall agreement of the measurements and response calculations was observed.
Sato, Tatsuhiko; Niita, Koji*; Matsuda, Norihiro; Hashimoto, Shintaro; Iwamoto, Yosuke; Iwase, Hiroshi*; Noda, Shusaku; Ogawa, Tatsuhiko; Nakashima, Hiroshi; Fukahori, Tokio; et al.
no journal, ,
Recently, we released PHITS version 2.5, which has the following new features: (1) Incorporation of the latest intra-nuclear cascade model such as INCL 4.6, (2) Implementation of the statistical multi-fragmentation model and high-energy photo-nuclear reaction model, (3) Re-evaluation of the Kerma factors contained in the neutron nuclear data library based on JENDL-4.0, (4) Access to shared-memory parallelism using the OpenMP architecture, (5) Implementation of the uncertainty-estimation function on the basis of history and batch variances, (6) Improvement of the user support tools such as the installers for Windows and MacDetails of these new features will be presented at the meeting.
Li(p,n) quasi-monoenergetic neutron source at RCNP using a proton recoil telescopeHagiwara, Masayuki*; Iwamoto, Yosuke; Iwase, Hiroshi*; Yashima, Hiroshi*; Satoh, Daiki; Matsumoto, Tetsuro*; Masuda, Akihiko*; Nakane, Yoshihiro; Tamii, Atsushi*; Hatanaka, Kichiji*; et al.
no journal, ,
We have measured the energy spectra of the Li(p,n) quasi-monoenergetic neutron source with a time-of-flight (TOF) method employing an organic liquid scintillation detector (NE213) in the previous study. The accuracy of the measured data was limited by that of the detection efficiency determination (15%). In this study, we have used a proton recoils telescope (PRT) for absolute measurements of the neutron spectra, because the detection efficiency of PRT can be determined accurately by the calculation based on the well-known differential n-p scattering cross section and the geometry between the proton radiator and the proton detector. From the measurements, we obtained data on the intensity of the peak neutrons at three incident energy points of 137, 200 and 300 MeV and compared with that obtained with the TOF method employing NE213. The neutron spectra obtained by PRT and by TOF were consistent generally.
