Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 230

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Benchmarking experiments of displacement cross-sections for high-energy proton irradiation with cryogenic-sample

Iwamoto, Yosuke

NEA/NSC/R(2021)2 (Internet), p.316 - 323, 2021/12

For validation of the radiation damage model in Monte Carlo particle transport codes such as PHITS, presenters are continuing measurements of the defect-induced electrical resistivity increase of cryogenic-samples under high-energy proton irradiation related to the displacement cross section. In this presentation, I will introduce measurements of electrical resistivity of aluminum and copper under 125 and 200 MeV proton irradiation at the FFAG accelerator facility in Kyoto University and the cyclotron facility in the Research Center for Nuclear Physics (RCNP), Osaka University. A comparison of experimental displacement cross sections with calculated results using PHITS indicated that the arc-dpa model with the defect production efficiencies provided a better quantitative description of the displacement cross-section than NRT-dpa, which have been widely used.

Journal Articles

Neutron capture cross sections of curium isotopes measured with ANNRI at J-PARC

Kawase, Shoichiro*; Kimura, Atsushi; Harada, Hideo; Iwamoto, Nobuyuki; Iwamoto, Osamu; Nakamura, Shoji; Segawa, Mariko; Toh, Yosuke

Journal of Nuclear Science and Technology, 58(7), p.764 - 786, 2021/07

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

Journal Articles

Journal Articles

Measurement of displacement cross section for proton in the kinetic energy range from 0.4 GeV to 3 GeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

JPS Conference Proceedings (Internet), 33, p.011050_1 - 011050_6, 2021/03

R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and aluminum and copper was used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimated the experiment by about 3 times.

Journal Articles

Measurements of displacement cross section of tungsten under 389-MeV proton irradiation and thermal damage recovery

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.

Journal Articles

Modernization of the DCHAIN-PHITS activation code with new features and updated data libraries

Ratliff, H.; Matsuda, Norihiro; Abe, Shinichiro; Miura, Takamitsu*; Furuta, Takuya; Iwamoto, Yosuke; Sato, Tatsuhiko

Nuclear Instruments and Methods in Physics Research B, 484, p.29 - 41, 2020/12

 Times Cited Count:0 Percentile:0.02(Instruments & Instrumentation)

Journal Articles

Measurement of displacement cross-sections of copper and iron for proton with kinetic energies in the range 0.4 - 3 GeV

Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

Journal of Nuclear Science and Technology, 57(10), p.1141 - 1151, 2020/10

 Times Cited Count:3 Percentile:76.41(Nuclear Science & Technology)

To estimate the structural damages of materials in accelerator facilities, displacement per atom (dpa) is widely employed as a damage index, calculated based on the displacement cross-section obtained using a calculation model. Although dpa is applied as standard, the experimental data of the displacement cross-section for a proton in the energy region above 20 MeV are scarce. Among the calculation models, difference of about factor 8 exist, so that the experimental data of the cross-section are crucial to validate the model. To obtain the displacement cross-section, we conducted experiments at J-PARC. The displacement cross-section of copper and iron was successfully obtained for a proton projectile with the kinetic energies, 0.4 - 3 GeV. The results were compared with those obtained using the widely utilized Norgertt-Robinson-Torrens (NRT) model and the athermal-recombination-corrected (arc) model based on molecular dynamics. It was found that the NRT model overestimates the present displacement cross-section by 3.5 times. The calculation results obtained using with the arc model based on the Nordlund parameter show remarkable agreement with the experimental data. It can be concluded that the arc model must be employed for the dpa calculation for the damage estimation of copper and iron.

Journal Articles

Study of the Li($$d,xn$$) reaction for the development of accelerator-based neutron sources

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

 Times Cited Count:1 Percentile:89.98

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$$^{circ}$$ to 25$$^{circ}$$). 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.

Journal Articles

Calculation of athermal recombination corrected dpa cross sections for proton, deuteron and heavy-ion irradiations using the PHITS code

Iwamoto, Yosuke; Meigo, Shinichiro

EPJ Web of Conferences, 239, p.20011_1 - 20011_4, 2020/09

 Times Cited Count:0 Percentile:0.19

PHITS including the NRT model can calculate displacement cross sections of materials for various particle irradiations in wide energy range. Recently, Nordlund et al. provided the athermal recombination corrected (arc) displacement per atom (dpa) function providing more physically realistic descriptions of primary defect creation in materials. Therefore, the arc-dpa will be used for efficient predictions of the usable lifetime of materials in various accelerator facilities. In this work, the arc-dpa function related with the defect production efficiency was implemented in the radiation damage model in PHITS. As a result, for the displacement cross sections of Cu and W under proton irradiations with energies above 100 MeV, the arc-dpa cross sections are smaller than the NRT-dpa cross sections by a factor of about 3. In this presentation, we will present the arc-dpa cross sections for proton, deuteron and heavy-ion irradiations in the energy region between 100 MeV/u and 3 GeV/u.

Journal Articles

Measurement of displacement cross section of structural materials utilized in the proton accelerator facilities with the kinematic energy above 400 MeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

EPJ Web of Conferences, 239, p.06006_1 - 06006_4, 2020/09

 Times Cited Count:0 Percentile:0.19

R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and copper was used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimated the experiment by about 3 times.

Journal Articles

Estimation of reliable displacements-per-atom based on athermal-recombination-corrected model in radiation environments at nuclear fission, fusion, and accelerator facilities

Iwamoto, Yosuke; Meigo, Shinichiro; Hashimoto, Shintaro

Journal of Nuclear Materials, 538, p.152261_1 - 152261_9, 2020/09

 Times Cited Count:2 Percentile:62.87(Materials Science, Multidisciplinary)

The displacements-per-atom (dpa) is widely used as an exposure unit to predict the operating lifetime of materials in radiation environments. Because the athermal-recombination-corrected dpa (arc-dpa) model is a more realistic model than the standard Norgertt-Robinson-Torrens (NRT) model, new evaluation of radiation damage will be performed using the arc-dpa model as a standard. In this work, the recent arc-dpa model of various materials are incorporated in PHITS, and the rescaling factors (NRT-dpa/arc-dpa) over a wide energy range are reported. For neutron incidences with the energy spectrum determined in selected nuclear facilities and proton incidences with energies of 600 MeV-50 GeV, the rescaling factor for each material is independent of these irradiation conditions with almost the same value for each material. Our findings will be beneficial for rescaling the NRT-dpa model used for radiation damage applications over a wide energy region.

Journal Articles

Estimation of observables

Ogawa, Tatsuhiko; Iwamoto, Yosuke

Hoshasen Shahei Handobukku; Oyohen, p.68 - 74, 2020/03

Atomic Energy Society of Japan is going to compile a book entitled "The handbook of radiation shielding -Advanced Edition-" as the guideline for researchers and engineers working on radiation shielding in Japan. The authors are responsible for a chapter dedicated to "Evaluation of observables". Conventionally, in radiation shielding calculation, the quantities averaged over a lot of radiation particles are assessed; however, fluctuation around the average matters for detector response calculation, and radiation-induced damage. Therefore, algorithms to recover the details on fluctuations, such as the event generator mode of PHITS, are needed. This publication is intended to explain the significance of fluctuation evaluation in radiation transport, the principle to calculate the fluctuation, and the effect of the fluctuation on observables.

Journal Articles

Measurement of defect-induced electrical resistivity change of tungsten wire at cryogenic temperature using high-energy proton irradiation

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.

Journal Articles

Measurement of displacement cross section of structural materials utilized in the proton accelerator facilities with the kinematic energy above 400 MeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

JPS Conference Proceedings (Internet), 28, p.061004_1 - 061004_6, 2020/02

no abstracts in English

Journal Articles

Primary knock-on atoms for accelerator facilities; Simulations and experimental design

Tsai, P.-E.; Iwamoto, Yosuke; Hagiwara, Masayuki*

Transactions of the American Nuclear Society, 121(1), p.13 - 16, 2019/11

The importance of PKA characteristics to radiation damage assessment for proton accelerators has been demonstrated in the paper by the PHITS simulations. In order to obtain accurate results of displacement cross section calculated by PHITS, it is therefore critical to have the physics models implemented in PHITS be properly validated by experimental data. With the new measurement system, which has been being developed here at JAEA, it is expected to provide experimental PKA data with low measurement thresholds and good mass resolutions. The test result we obtained at CYRIC, Tohoku University, for the $$Delta E$$-$$E$$ gas ionization chamber as a part of the new measurement system was very promising. We were able to successfully distinguish C, B, Be, Li, and He elements with threshold energies lower than 1 MeV/nucleon in the configuration of 70-MeV proton beam and 920-nm thick C target. More experiments and tests shall continue in the future with heavier targets and higher proton beam energies.

Journal Articles

Measurement of neutron-production double-differential cross sections in most-forward direction by proton incidences

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.

Journal Articles

Neutron-induced damage simulations; Beyond defect production cross-section, displacement per atom and iron-based metrics

Sublet, J.-Ch.*; Bondarenko, I. P.*; Bonny, G.*; Conlin, J. L.*; Gilbert, M. R.*; Greenwood, L. R.*; Griffin, P. J.*; Helgesson, P.*; Iwamoto, Yosuke; Khryachkov, V. A.*; et al.

European Physical Journal Plus (Internet), 134(7), p.350_1 - 350_50, 2019/07

 Times Cited Count:8 Percentile:41.21(Physics, Multidisciplinary)

Nuclear reaction with nuclear data is the origin of defects produced by cascade damage in irradiated materials. Therefore, it is important to consider nuclear reaction correctly for calculations of the damage energy of Primary Knock on Atom (PKA) and the number of Displacement Per Atom (DPA). Here, radiation damage metrics considering nuclear reaction enables us to simulate transport of each defect and clustering defects in the irradiated material. This paper reviews the theory of nuclear reaction and damage energy and describes the latest methodologies about uncertainty propagation and quantification in nuclear data and damage calculations based on molecular dynamics.

Journal Articles

Measurement of thermal neutron capture cross section of $$^{71}$$Ga with dual monitor foils and covariance analysis

Panikkath, P.*; Otsuka, Naohiko*; Iwamoto, Yosuke; Mohanakrishnan, P.*

European Physical Journal A, 55(6), p.91_1 - 91_9, 2019/06

 Times Cited Count:3 Percentile:52.47(Physics, Nuclear)

The thermal neutron capture cross section of $$^{71}$$Ga was evaluated to be around 4.7 b in many nuclear data libraries. On the other hand, it was evaluated to be 3.71 b in JENDL-4.0. Since these cross section data were obtained by the activation measurement with a monitor foil to determine the absolute value of cross section, data depend on the monitor foil adopted in the measurement. In this work, we measured the thermal neutron capture cross section of $$^{71}$$Ga with a few monitor foils. In the experiment, neutrons decelerated in concrete shield were irradiated with a sample with $$^{71}$$Ga foil and $$^{197}$$Au and $$^{55}$$Mn monitor foils. A covariance analysis was performed to obtain the off-diagonal weighted mean of the results determined with the two monitor reactions. As a result, the thermal neutron capture cross section of $$^{71}$$Ga was 4.05$$pm$$0.27 b and is close to the value of JENDL-4.0.

Journal Articles

Measurement of neutron-production double-differential cross sections of $$^{rm nat}$$C, $$^{27}$$Al, $$^{rm nat}$$Fe, and $$^{rm nat}$$Pb by 20, 34, 48, 63, and 78 MeV protons in the most-forward direction

Satoh, Daiki; Iwamoto, Yosuke; Ogawa, Tatsuhiko

Nuclear Instruments and Methods in Physics Research A, 920, p.22 - 36, 2019/03

 Times Cited Count:1 Percentile:23.13(Instruments & Instrumentation)

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 $$^{rm nat}$$C, $$^{27}$$Al, $$^{rm nat}$$Fe, and $$^{rm nat}$$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.

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.

230 (Records 1-20 displayed on this page)