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Journal Articles

Atmospheric ionizations by solar X-rays, solar protons, and radiation belt electrons in September 2017 space weather event

Murase, Kiyoka*; Kataoka, Ryuho*; Nishiyama, Takanori*; Sato, Kaoru*; Tsutsumi, Masaki*; Tanaka, Yoshimasa*; Ogawa, Yasunobu*; Sato, Tatsuhiko

Space Weather, 21(12), p.e2023SW003651_1 - e2023SW003651_11, 2023/12

 Times Cited Count:0 Percentile:0.01(Astronomy & Astrophysics)

Comprehensive understandings of their global impact on the atmosphere require whole pictures of spatio-temporal distributions of the ionization due to them. We estimate the altitude profiles of the ionization rate during the space weather event occurred in September 2017 by using the Particle and Heavy Ion Transport code System (PHITS) with input of the particle fluxes obtained by satellites. The estimates are then compared with measurements of the ionization altitude, ionization intensity, and electron density by the radars in the polar region such as the PANSY radar at Syowa Station and the EISCAT in Tromso, Norway. We conclude that the PHITS simulation results reproduce those ionizations measured by ground-based instruments with inputs of observed ionization sources by satellites within a factor of 2.

Journal Articles

Development of DynamicMC for PHITS Monte Carlo package

Watabe, Hiroshi*; Sato, Tatsuhiko; Yu, K. N.*; Zivkovic, M.*; Krstic, D.*; Nikezic, D.*; Kim, K. M.*; Yamaya, Taiga*; Kawachi, Naoki*; Tanaka, Hiroki*; et al.

Radiation Protection Dosimetry, 13 Pages, 2023/00

 Times Cited Count:0 Percentile:0.01(Environmental Sciences)

Previously, we have developed DynamicMC for modelling relative movement of ORNL phantom in a radiation field for MCNP. Using this software, 3-dimensional dose distributions in a phantom irradiated by a certain mono-energetic source can be deduced through its graphical user interface (GUI). In this study, we extended DynamicMC to be used in combination with the PHITS by providing it with a higher flexibility for dynamic movement for a less sophisticated anthropomorphic phantom. We anticipate that the present work and the developed open-source tools will be in the interest of nuclear radiation physics community for research and teaching purposes.

Journal Articles

Mesospheric ionization during substorm growth phase

Murase, Kiyoka*; Kataoka, Ryuho*; Nishiyama, Takanori*; Nishimura, Koji*; Hashimoto, Taishi*; Tanaka, Yoshimasa*; Kadokura, Akira*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Ogawa, Yasunobu*; et al.

Journal of Space Weather and Space Climate (Internet), 12, p.18_1 - 18_16, 2022/06

 Times Cited Count:1 Percentile:22.72(Astronomy & Astrophysics)

We identified two energetic electron precipitation (EEP) events during the growth phase of moderate substorms and estimated the mesospheric ionization rate for an EEP event for which the most comprehensive dataset from ground-based and space-born instruments was available. The mesospheric ionization signature reached below 70 km altitude and continued for ~15 min until the substorm onset, as observed by the PANSY radar and imaging riometer at Syowa Station in the Antarctic region. We also used energetic electron flux observed by the Arase and POES 15 satellites as the input for the air-shower simulation code PHITS to quantitatively estimate the mesospheric ionization rate. Combining the cutting-edge observations and simulations, we shed new light on the space weather impact of the EEP events during geomagnetically quiet times, which is important to understand the possible link between the space environment and climate.

Journal Articles

Transient ionization of the mesosphere during auroral breakup; Arase satellite and ground-based conjugate observations at Syowa Station

Kataoka, Ryuho*; Nishiyama, Takanori*; Tanaka, Yoshimasa*; Kadokura, Akira*; Uchida, Herbert Akihito*; Ebihara, Yusuke*; Ejiri, Mitsumu*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Sato, Kaoru*; et al.

Earth, Planets and Space (Internet), 71(1), p.9_1 - 9_10, 2019/12

 Times Cited Count:8 Percentile:40.25(Geosciences, Multidisciplinary)

Transient ionization of the mesosphere was detected at around 65 km altitude during the isolated auroral expansion occurred at 2221-2226 UT on June 30, 2017. A general-purpose Monte Carlo particle transport code PHITS suggested that significant ionization is possible in the middle atmosphere due to auroral X-rays from the auroral electrons of $$<$$10 keV.

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, 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 $$gamma$$-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

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

 Times Cited Count:1 Percentile:10.62(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

Response measurement of various neutron dose equivalent monitors in 134-387 MeV neutron fields

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

Journal Articles

Response measurement of a Bonner sphere spectrometer for high-energy neutrons

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:12 Percentile:66.54(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 $$^{7}$$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.

Journal Articles

Behavior of environmental tritium at NIFS Toki Site of Japan

Sugihara, Shinji*; Tanaka, Masahiro*; Tamari, Toshiya*; Shimada, Jun*; Takahashi, Tomoyuki*; Momoshima, Noriyuki*; Fukutani, Satoshi*; Atarashi-Andoh, Mariko; Sakuma, Yoichi*; Yokoyama, Sumi*; et al.

Fusion Science and Technology, 60(4), p.1300 - 1303, 2011/11

 Times Cited Count:2 Percentile:18.29(Nuclear Science & Technology)

The purpose of this study is to develop the technique to evaluate the environmental tritium behavior of the nuclear facility origin. Tritium concentrations of river water, precipitation and ground water around the NIFS site were determined by low background liquid scintillation measurement system combined with the electrolysis using solid polymer electrolyte. The electric conductivity and flow rate of the river and isotopic ratio of oxygen and hydrogen of water samples were also measured. The tritium concentrations in precipitation showed the seasonal variation and the range were 0.09-0.78 Bq/L. The tritium concentrations of river water and ground water were almost constant, 0.34 and 0.24 Bq/L respectively. The simple dynamic model for the site around the NIFS facilities was developed using measured data, and the behavior of tritium was simulated.

Journal Articles

Characterisation of quadi-monoenergetic neutron energy spectra using $$^{7}$$Li(p,n) reactions at 246-389 MeV

Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Itoga, Toshiro*; Sato, Tatsuhiko; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; et al.

Proceedings of 10th Meeting of the Task Force on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF-10), p.53 - 61, 2011/03

The neutron energy spectra penetrating 10 to 100 cm thick iron and 25 to 200 cm thick concrete shields have been measured using 138, 243 and 387 MeV quasi-monoenergetic neutron sources at the Research Center for Nuclear Physics (RCNP) facility, Osaka University. The source neutrons were produced from a 1 cm thick lithium target bombarded with 140, 245 and 388 MeV protons. Two types of NE213 liquid organic scintillators and Bonner ball neutron spectrometers were used for the neutron energy spectrum measurement. The TOF and unfolding methods were applied to estimate the energy spectra behind the shield in the peak energy region and continuous energy region, respectively. We have also measured the neutron energy spectra and angular distribution of the source neutron above 1 MeV in the angular range from 0$$^{circ}$$ to 30$$^{circ}$$ with the TOF method. All measured data were compared with the PHITS Monte Carlo calculations.

Journal Articles

Quasi-monoenergetic neutron energy spectra for 246 and 389 MeV $$^{7}$$Li(p,n) reactions at angles from 0$$^{circ}$$ to 30$$^{circ}$$

Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Itoga, Toshiro*; Sato, Tatsuhiko; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; et al.

Nuclear Instruments and Methods in Physics Research A, 629(1), p.43 - 49, 2011/02

 Times Cited Count:21 Percentile:82.72(Instruments & Instrumentation)

The authors measured the neutron energy spectra of a quasi-monoenergetic $$^{7}$$Li(p,n) neutron source with 246 and 389 MeV protons set at seven angles (0$$^{circ}$$, 2.5$$^{circ}$$, 5$$^{circ}$$, 10$$^{circ}$$, 15$$^{circ}$$, 20$$^{circ}$$ and 30$$^{circ}$$), using a time-of-flight (TOF) method employing organic scintillators NE213 at the Research Center for Nuclear Physics (RCNP) of Osaka University. The energy spectra of the source neutrons were precisely deduced down to 2 MeV at 0$$^{circ}$$ and 10 MeV at other angles. The cross sections of the peak neutron production reaction at 0$$^{circ}$$ were on the 35-40 mb line of other experimental data, and the peak neutron angular distribution agreed well with the Taddeucci formula. Neutron energy spectra below 100 MeV at all angles were comparable, but the shapes of the continuum above 150 MeV changed considerably with the angle.

Journal Articles

Experimental method for neutron elastic scattering cross-section measurement in intermediate energy region at RCNP

Satoh, Daiki; Iwamoto, Yosuke; Hagiwara, Masayuki*; Iwase, Hiroshi*; Yashima, Hiroshi*; Sanami, Toshiya*; Sato, Tatsuhiko; Endo, Akira; Sakamoto, Yukio; Nakane, Yoshihiro; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.20 - 23, 2011/02

An experimental method and data processing procedure have been developed for the measurement of neutron elastic scattering cross sections in intermediate energy region above 100 MeV. The data were obtained at Research Center for Nuclear Physics (RCNP) in Osaka University by utilizing a $$^{7}$$Li(p,n) quasi-monoenergetic neutron source and Time-of-Flight (TOF) technique.

Journal Articles

Microdosimetric evaluation of the neutron field for BNCT at Kyoto University Reactor by using the PHITS code

Baba, Hiromi*; Onizuka, Yoshihiko*; Nakao, Minoru*; Fukahori, Mai*; Sato, Tatsuhiko; Sakurai, Yoshinori*; Tanaka, Hiroki*; Endo, Satoru*

Radiation Protection Dosimetry, 143(2-4), p.528 - 532, 2011/02

 Times Cited Count:8 Percentile:53.37(Environmental Sciences)

The PHITS simulation were performed to reproduce the geometrical setup of an experiment that measured the microdosimetric energy distributions at the Kyoto University Reactor (KUR) where two types of tissue equivalent proportional counters (TEPC) were used, one with A-150 wall alone and another with a 50 ppm boron loaded A-150 wall. It was found that the PHITS code is a useful tool for the simulation of the energy deposited in tissue in BNCT based on the comparisons with experimental results.

Journal Articles

Determination of trace amounts of plutonium in low-active liquid wastes from spent nuclear-fuel reprocessing plants by flow injection-based solid-phase extraction/electrochemical detection system

Taguchi, Shigeo; Yamamoto, Masahiko; Surugaya, Naoki; Kurosawa, Akira; Hiyama, Toshiaki; Tanaka, Tatsuhiko*

Journal of Radioanalytical and Nuclear Chemistry, 288(2), p.435 - 441, 2011/01

 Times Cited Count:6 Percentile:44.28(Chemistry, Analytical)

Journal Articles

Measurement of neutron elastic scattering cross sections for carbon at 134 MeV

Satoh, Daiki; Iwamoto, Yosuke; Hagiwara, Masayuki*; Iwase, Hiroshi*; Yashima, Hiroshi*; Sato, Tatsuhiko; Endo, Akira; Sakamoto, Yukio; Nakane, Yoshihiro; Nakashima, Hiroshi; et al.

Radiation Measurements, 45(10), p.1159 - 1162, 2010/12

 Times Cited Count:1 Percentile:9.99(Nuclear Science & Technology)

Elastic neutron-scattering cross sections for carbon nucleus have been measured by using 134-MeV monoenergetic neutron beam in Research Center for Nuclear Physics (RCNP), Osaka University. The measured angles were set at 6$$^{circ}$$, 8$$^{circ}$$, and 15$$^{circ}$$ in laboratory system. The liquid organic scintillators, whose size is 12.7 cm in diameter and 12.7 cm in thickness, were mounted at each angle as neutron detector. In the off-line analysis, the events of elastic-neutron scattering were extracted on basis of the Time-of-Flight (TOF) information. The results were compared with the data measured by the groupe of U.C. Davis with a recoil proton spectrometer and the evaluations of the nuclear data libraries, JENDL/HE-2007 and ENDF/B-VII.0. Our results show a good agreement with the data of U.C. Davis. This indicates that our experimental method based on the TOF teqnique is appropriate to the measurement of elastic neutron-scattering cross section in this energy region. In addition, we exhibit that the data of ENDF/B-VII.0 represent the experimental data, but JENDL/HE-2007 underestimates about 30$${%}$$ in the forward angle region.

Journal Articles

Determination of trace amounts of uranium by stripping voltammetry using a boron-doped diamond electrode

Taguchi, Shigeo; Surugaya, Naoki; Kurosawa, Akira; Hiyama, Toshiaki; Tanaka, Tatsuhiko*

Bunseki Kagaku, 59(11), p.1035 - 1041, 2010/11

 Times Cited Count:1 Percentile:3.7(Chemistry, Analytical)

no abstracts in English

Journal Articles

Rapid determination of trace uranium in liquid wastes from spent nuclear-fuel reprocessing plants using on-line solid-phase extraction / electrochemical detection

Taguchi, Shigeo; Surugaya, Naoki; Kurosawa, Akira; Hiyama, Toshiaki; Tanaka, Tatsuhiko*

Bunseki Kagaku, 58(10), p.901 - 907, 2009/10

 Times Cited Count:0 Percentile:0.01(Chemistry, Analytical)

An on-line analysis system using a solid-phase extraction column coupled to electrochemical detection has been developed for rapid determination of small amounts of uranium in liquid wastes of spent nuclear-fuel reprocessing plants. A sample solution with a concentration of 3 M HNO$$_{3}$$ was loaded onto the column: packed with U/TEVA$$^{textregistered}$$ resin. The interference elements were rinsed by passing 3 M HNO$$_{3}$$ through the column. The adsorbed uranium was eluted with 0.1 M HNO$$_{3}$$. The eluate was directly introduced into a flow-electrolysis cell. The result of five repeated analyses for a standard solution containing 2.5 $$mu$$g (0.1 mL at 25 $$mu$$g mL$$^{-1}$$) of uranium was found to be 2.5 $$pm$$ 0.025 $$mu$$g (mean $$pm$$ 1 $$sigma$$). The detection limit calculated from 3 times the standard deviation of background current was 56 ng. The analysis time required for one sample was within 5 min. The recoveries of uranium in actual nuclear waste reprocessing solutions were 92% $$sim$$ 112%.

Journal Articles

Microdosimetric study for secondary neutrons in phantom produced by a 290 MeV/nucleon carbon beam

Endo, Satoru*; Tanaka, Kenichi*; Takada, Masashi*; Onizuka, Yoshihiko*; Miyahara, Nobuyuki*; Sato, Tatsuhiko; Ishikawa, Masayoshi*; Maeda, Naoko*; Hayabuchi, Naofumi*; Shizuma, Kiyoshi*; et al.

Medical Physics, 34(9), p.3571 - 3578, 2007/09

 Times Cited Count:7 Percentile:25.96(Radiology, Nuclear Medicine & Medical Imaging)

Absorbed doses from main charged particle beams and charged-particle fragments have been measured with high accuracy for particle therapy but there are few reports for doses from neutron components produced as fragments. This study describes measurements on neutron dose produced by carbon beam, microdosimetric distributions of secondary neutrons produced by 290 MeV/nucleon carbon beams have been measured by using a tissue equivalent proportional counter (TEPC) at the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). The ratios of neutrons to charged particle fragments dominated to be 11 to 89 % in the absorbed doses at the side and below the faces of the acrylic phantom (300 mm height $$times$$ 300 mm width $$times$$ 253 mm thickness).

Journal Articles

Development of neutron-monitor detectors applicable to energies from thermal to 100MeV

Endo, Akira; Kim, E.; Yamaguchi, Yasuhiro; Sato, Tatsuhiko; Yoshizawa, Michio; Tanaka, Susumu; Nakamura, Takashi; Rasolonjatovo, A. H. D.*

Journal of Nuclear Science and Technology, 41(Suppl.4), p.510 - 513, 2004/03

no abstracts in English

Oral presentation

Measurement of neutron production cross sections at 180-degrees in the intermediate energy region

Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Iwase, Hiroshi*; Yashima, Hiroshi*; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; Sato, Tatsuhiko; Tamii, Atsushi*; et al.

no journal, , 

Neutron energy spectra at 180 degrees produced from thin lithium target bombarded with 140 MeV protons were measured at the irradiation room of neutron TOF course in RCNP of Osaka University. The neutron energy spectra were obtained by using the time-of-flight technique in the energy range from 10 MeV to incident proton energy. To compare the experimental results, Monte Carlo calculations by the PHITS and MCNPX codes were performed using the Bertini/GEM, Bertini/Dresner models for neutron energy spectra at 180 degrees. It was found that calculated results at 180 degrees with Bertini/Dresner agreed with experimental one well.

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