Nakayama, Hiromasa; Satoh, Daiki; Nagai, Haruyasu; Terada, Hiroaki
Journal of Nuclear Science and Technology, 58(9), p.949 - 969, 2021/09
We introduced a detailed dose calculation method considering building shielding effects into LOcal-scale High-resolution atmospheric DIspersion Model using LES (LOHDIM-LES). To estimate quickly and accurately dose distributions considering shielding effects of buildings, we employed the calculation method using dose-response matrices which were evaluated by photon transport simulations with Particle and Heavy-Ion Transport code System (PHITS). Compared to the air dose rate data obtained from monitoring posts in an actual nuclear facility, it was shown that the calculated dose rate is reasonably simulated well. It is concluded that LOHDIM-LES equipped with the calculation method using dose-response matrices can reasonably estimate the air dose rates considering shielding effects of individual buildings and structures.
Iwamoto, Yosuke; Yoshida, Makoto*; Matsuda, Hiroki; Meigo, Shinichiro; Satoh, Daiki; Yashima, Hiroshi*; Yabuuchi, Atsushi*; Shima, Tatsushi*
Materials Science Forum, 1024, p.95 - 101, 2021/03
To predict the lifetime of target materials in high-energy radiation environments at spallation neutron sources, radiation transport codes such as PHITS are used to calculate the displacements per atom (DPA) value. In this work, to validate calculated DPA values of tungsten, we implemented 0.25-mm-diameter wire sample of tungsten in a proton irradiation device with a Gifford-McMahon cryocooler and measured the defect-induced electrical resistivity changes related to the displacement cross section using 389-MeV protons at 10 K. As well as our previous results for aluminum and copper, calculated results with defect production efficiencies provided good agreements with experimental data. Based on measurements of recovery of the defects through annealing, about 85% of the damage remained at 60 K, and the same tendency is observed in other experimental result for reactor neutron irradiation.
Petoussi-Henss, N.*; Satoh, Daiki; Schlattl, H.*; Zankl, M.*; Spielman, V.*
Radiation and Environmental Biophysics, 60(1), p.93 - 113, 2021/03
In this study, the nuclide-specific organ dose coefficients of pregnant female and its fetus for environmental external exposures have been evaluated. The radiation sources were uniformly put in the soil at the depth of 0.5 g cm or in the atmosphere. The environmental radiation fields for the soil contamination were analyzed by using the radiation transport code PHITS, and the fields for the air submersion were taken from the existing data analyzed by the YURI code. The numerical models of the pregnant female and its fetus were put in the environmental radiation fields, and the radiation transport simulations were performed using the EGS code to obtain the organ absorbed doses. From the simulation results, it was found that the radionuclide-specific uterus doses of the pregnant female agreed with the total body doses of the fetus within 6%, except for some radionuclides which emit the low-energy photons below 50 keV. Using the organ dose coefficients evaluated in the present study, the doses of the pregnant female and its fetus can be estimated easily from the data of activity concentration of the radionuclides distributed in the environment.
Satoh, Daiki; Nakayama, Hiromasa; Furuta, Takuya; Yoshihiro, Tamotsu*; Sakamoto, Kensaku
PLOS ONE (Internet), 16(1), p.e0245932_1 - e0245932_26, 2021/01
In this study, we developed a simulation code named SIBYL, which estimates external gamma-ray doses at ground level from radionuclides distributed nonuniformly in atmosphere and on ground. SIBYL can combine with the local-scale atmospheric dispersion model LOHDIM-LES, and calculate the dose distributions according to the map of the activity concentrations simulated by LOHDIM-LES. To apply the SIBYL code to emergency responses of nuclear accidents, the time-consuming three-dimensional radiation transport simulations were performed in advance using the general-purpose Monte Carlo code PHITS, and then the results were compiled to the database for the SIBYL's dose calculations. Moreover, SIBYL can consider the dose attenuation by obstacles and the changes of terrain elevations. To examine the accuracy of SIBYL, typical five cases including Kr emission from a ventilation shaft and Cs dispersion inside urban area were investigated. The results of SIBYL agreed within 10% with those of PHITS at the most of target locations. Furthermore, the calculation speed was approximately 100 times faster than that of PHITS.
Watanabe, Yukinobu*; Sadamatsu, Hiroki*; Araki, Shohei*; Nakano, Keita*; Kawase, Shoichiro*; Kin, Tadahiro*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; et al.
EPJ Web of Conferences, 239, p.20012_1 - 20012_4, 2020/09
Accelerator-based neutron sources induced by deuteron beams are attractive for study of nuclear transmutation of radioactive waste as well as radiation damage for fusion reactor materials. In the present work, we have carried out a Double Differential cross section (DDX) measurement for Li at 200 MeV in the Research Center for Nuclear Physics (RCNP), Osaka University. A deuteron beam accelerated to 200 MeV was transported to the neutron experimental hall and focused on a thin Li target. Emitted neutrons from the target were detected by two different-size EJ301 liquid organic scintillators located at two distances of 7 m and 20 m, respectively. The neutron DDXs were measured at six angles from 0 to 25). The neutron detection efficiencies of the detectors were calculated by SCINFUL-QMD code. We will present the results of the present DDX measurement and compare them with theoretical model calculations with DEURACS and PHITS.
Iwamoto, Yosuke; Yoshida, Makoto*; Matsuda, Hiroki; Meigo, Shinichiro; Satoh, Daiki; Yashima, Hiroshi*; Yabuuchi, Atsushi*; Kinomura, Atsushi*; Shima, Tatsushi*
JPS Conference Proceedings (Internet), 28, p.061003_1 - 061003_5, 2020/02
To predict the lifetime of target materials in high-energy radiation environments at spallation neutron sources, radiation transport codes such as PHITS are used to calculate the displacements per atom (DPA) value. In this work, to validate calculated DPA values of tungsten, we implemented 0.25-mm-diameter wire sample of tungsten in a proton irradiation device with a Gifford-McMahon cryocooler and measured the defect-induced electrical resistivity changes related to the displacement cross section using 389-MeV protons at 10 K. In comparison with experimental data under 1.1 and 1.9 GeV proton irradiation, we found that damage rate of tungsten increases with proton energy due to increase the number of secondary particle s produced by nuclear reactions.
Kofler, C.*; Domal, S.*; Satoh, Daiki; Dewji, S.*; Eckerman, K.*; Bolch, W. E.*
Radiation and Environmental Biophysics, 58(4), p.477 - 492, 2019/11
In the current radiation protection system, the International Commission on Radiological Protection (ICRP) recommends to use the effective dose for dose estimation. The effective dose is derived from the organ doses calculated using the computational human models (phantoms) defined by the ICRP to represent the reference person at each age. Questions arise, however, among the general public regarding the accuracy of organ and effective dose estimates based upon reference phantom methodologies, especially for those individuals with heights and/or weights that differ from the nearest age-matched reference person. In this paper, the detriment-weighted dose was defined for non-reference persons as the same manner to the effective dose for reference person. The doses were calculated for external exposure to radionuclides in a soil using 351-member phantom library based on the data of the U.S. population reported by the U.S. National Center for Health Statistics. The results for 33 nuclides were listed in the paper. Especially, for the environmental relevant radionuclides of Sr, Sr, Cs, and I, the detriment-weighted dose of 1-year-old phantom agreed with the effective dose within 5%, while the range of percent differences in these two quantities increased with increases the body size and age, e.g. +15% to -40% for adults.
Satoh, Daiki; Iwamoto, Yosuke; Ogawa, Tatsuhiko
2017-Nendo Ryoshi Kagaku Gijutsu Kenkyu Kaihatsu Kiko Shisetu Kyoyo Jisshi Hokokusho (Internet), 1 Pages, 2019/08
Many neutrons are produced in forward directions by intermediate-energy proton-induced reactions. While it is known that collective motion in a target nucleus plays important role in this neutron production, validity of theoretical model and nuclear-data library has not been examined well due to a lack of experimental data. Hence, we obtained systematic data of neutron-production double-differential cross section in the most-forward direction. The experiment was performed at TIARA of Takasaki Advanced Radiation Research Institute, QST. 34-MeV proton beams were bombarded upon thin carbon, aluminum, iron, and lead target, and the neutrons produced in the most-forward direction were led to experimental room passing through a collimator. Scintillation detectors were used to the neutron detection. In comparison with the calculation results of PHITS, it was found that the theoretical model INCL always overestimate the cross sections, and the evaluated nuclear-data library JENDL-4.0/HE reproduce the measure spectra better than the INCL does.
Satoh, Daiki; Iwamoto, Yosuke; Ogawa, Tatsuhiko
Nuclear Instruments and Methods in Physics Research A, 920, p.22 - 36, 2019/03
The Particle and Heavy Ion Transport code System (PHITS) is a general purpose particle transport simulation code developed by the Japan Atomic Energy Agency (JAEA). The PHITS is utilized in various areas including a shielding design of accelerator facilities. Unfortunately, it is known that theoretical models and evaluated nuclear data used in the PHITS cannot reproduce the neutron production in most-forward direction for proton incidences. Hence, the present study aimed to obtain the experimental data of neutron-production double-differential cross sections of C, Al, Fe, and Pb by 20, 34, 48, 63, and 78 MeV protons in most-forward direction for improvement of theoretical models and nuclear data. The experiment has been performed at the ion irradiation facility (TIARA) of the National Institutes for Quantum and Radiological Science and Technology. The proton beams provided by the cyclotron were incident to the target sample. The neutrons produced by nuclear reactions were pass through the collimator in the most-forward direction, and measured with an organic scintillator at the experimental room. The kinetic energy of those neutrons was determined by the time-of-flight method. The obtained results were compared with the results of the theoretical model INCL and the nuclear-data library JENDL-4.0/HE used in the PHITS. It was found that the INCL and JENDL-4.0/HE cannot reproduce the peak structures observed for light nuclei, because they do not consider the nuclear transition between discrete states of nucleus. In addition, the JENDL-4.0/HE agreed with the experimental data of energy-integrated cross section within a factor of 2, but the INCL gave approximately 6 times larger values.
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 0.2-0.3 MeV/nucleon for A=2030 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.
Iwamoto, Yosuke; Yoshida, Makoto*; Yoshiie, Toshimasa*; Satoh, Daiki; Yashima, Hiroshi*; Matsuda, Hiroki; Meigo, Shinichiro; Shima, Tatsushi*
Journal of Nuclear Materials, 508, p.195 - 202, 2018/09
To validate the displacement damage model in radiation transport codes used for the estimation of radiation damages at accelerator facilities, we measured electrical resistance increase of aluminum and copper induced by radiation defects under the cryogenic 200 MeV proton irradiation. The irradiation device had the structure to cool two irradiation samples at same time using thermal conductance. The aluminum and copper wire with 250 m diameter was sandwiched between two AlN plates with excellent thermal conductivity and electrical insulation. As a result, temperature of irradiation samples was kept at below 5 K under proton irradiation with beam intensity below 3 nA. The experimental displacement cross section agreed with calculated results with defect production efficiency.
Iwamoto, Yosuke; Matsuda, Hiroki; Meigo, Shinichiro; Satoh, Daiki; Nakamoto, Tatsushi*; Yoshida, Makoto*; Ishi, Yoshihiro*; Kuriyama, Yasutoshi*; Uesugi, Tomonori*; Yashima, Hiroshi*; et al.
Proceedings of 61st ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB 2018) (Internet), p.116 - 121, 2018/07
The radiation damage model in the radiation transport code PHITS has been developed to calculate the basic data of the radiation damage including the energy of the target Primary Knock on Atom (PKA). For the high-energy proton incident reactions, a target PKA created by the secondary particles was more dominant than a target PKA created by the projectile. To validate the radiation damage model in metals irradiated by 100 MeV protons, we developed a proton irradiation device with a Gifford-McMahon cryocooler to cryogenically cool wire samples. By using this device, the defect-induced electrical resistivity changes related to the DPA cross section of copper and aluminum were measured under irradiation with 125 and 200 MeV protons at cryogenic temperature. A comparison of the experimental data with the calculated results indicates that the DPA cross section with defect production efficiencies provide better quantitative descriptions.
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, 146, p.11027_1 - 11027_4, 2017/09
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 (025 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.
Iwamoto, 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
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
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.
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
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
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.
Satoh, Daiki; Furuta, Takuya; Takahashi, Fumiaki; Lee, C.*; Bolch, W. E.*
Journal of Nuclear Science and Technology, 54(9), p.1018 - 1027, 2017/09
The personal dose equivalent was calculated for the public (newborns; 1-, 5-, 10-, and 15-year-old children; and adults) in an environment contaminated with radioactive cesium (Cs and Cs) distributed in a soil at specific depths of 0.0, 0.5, 2.5, 5.0, 10.0, and 50.0 g/cm. Monte Carlo calculations were performed using pediatric and adult computational phantoms incorporated into a particle and heavy ion transport code system (PHITS). Compared with the effective dose and ambient dose equivalent at a height of 100 cm above the ground, the personal dose equivalent was found to provide an acceptable assessment for the effective dose and did not exceed the ambient dose equivalent in the environmental radiation field, while the personal dose equivalent values increased for younger subjects. The weighted-integral method to obtain the personal dose equivalent for a volumetric source was applied to the analysis of exponential radioactive cesium distributions in the soil observed in Fukushima, and the calculation results successfully reproduced the measured data.
Hirouchi, Jun; Okura, Takehisa; Satoh, Daiki
Nihon Genshiryoku Gakkai-Shi ATOMO, 59(3), p.152 - 155, 2017/03
no abstracts in English
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
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.