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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

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

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

IRDFF-II; A New neutron metrology library

Trkov, A.*; Griffin, P. J.*; Simakov, S. P.*; Greenwood, L. R.*; Zolotarev, K. I.*; Capote, R.*; Aldama, D. L.*; Chechev, V.*; Destouches, C.*; Kahler, A. C.*; et al.

Nuclear Data Sheets, 163, p.1 - 108, 2020/01

 Times Cited Count:23 Percentile:99.09(Physics, Nuclear)

The version II of the International Reactor Dosimetry and Fusion File (IRDFF-II) has been released as a consistent set of nuclear data for fission and fusion neutron metrology applications up to 60 MeV neutron energy. The library is intended to support: (a) applications in research reactors; (b) safety and regulatory applications in the nuclear power generation in commercial fission reactors; and c) material damage studies in support of the research and development of advanced fusion concepts. The paper describes the contents of the library, documents the thorough verification process used in its preparation, and provides an extensive set of validation data gathered from a wide range of neutron benchmark fields. The new library is expected to become the international reference in neutron metrology for multiple applications.

Journal Articles

Measurement of displacement cross sections of aluminum and copper at 5 K by using 200 MeV protons

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

 Times Cited Count:8 Percentile:81.13(Materials Science, Multidisciplinary)

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 $$mu$$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.

Journal Articles

Radiation damage calculation in PHITS and benchmarking experiment for cryogenic-sample high-energy proton irradiation

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.

Journal Articles

Neutron production in deuteron-induced reactions on Li, Be, and C at an incident energy of 102 MeV

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

 Times Cited Count:0 Percentile:0.08

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 (0$$^{circ}$$$$sim$$25$$^{circ}$$ 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.

Journal Articles

Research and development for accuracy improvement of neutron nuclear data on minor actinides

Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Mizuyama, Kazuhito; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.

EPJ Web of Conferences, 146, p.11001_1 - 11001_6, 2017/09

 Times Cited Count:2 Percentile:85.61

Journal Articles

Analysis of energy resolution in the KURRI-LINAC pulsed neutron facility

Sano, Tadafumi*; Hori, Junichi*; Takahashi, Yoshiyuki*; Yashima, Hiroshi*; Lee, J.*; Harada, Hideo

EPJ Web of Conferences, 146, p.03031_1 - 03031_3, 2017/09

 Times Cited Count:1 Percentile:69.68

Journal Articles

Experimental analysis of neutron and background $$gamma$$-ray energy spectra of 80-400 MeV $$^{7}$$Li(p,n) reactions under the quasi-monoenergetic neutron field at RCNP, Osaka University

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

 Times Cited Count:0 Percentile:0.03

To develop 100-400 MeV quasi-monoenergetic neutron field, we measured neutron and unexpected $$gamma$$-ray energy spectra of the $$^{7}$$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 $$gamma$$ 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 $$gamma$$-ray spectra, high-energetic $$gamma$$-rays at around 70 MeV originated from the decay of $$pi$$$$^{0}$$ were observed over 200 MeV. For the 246-MeV proton incident reaction, the contribution of $$gamma$$-ray dose to neutron dose is negligible because the ratio of $$gamma$$-ray to neutron is 0.014.

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

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

Shielding experiments of concrete and iron for the 244 MeV and 387 MeV quasi-mono energetic neutrons using a Bonner sphere spectrometer (at RCNP, Osaka Univ.)

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:0 Percentile:0.03

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 $$^{7}$$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.

Journal Articles

Neutron spectrometry and dosimetry in 100 and 300 MeV quasi-mono-energetic neutron field at RCNP, Osaka University, Japan

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:3 Percentile:92.06

To validate response of an extended range Bonner Sphere Spectrometer (ERBSS) with $$^{3}$$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 $$^{7}$$Li(p,n)$$^{7}$$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.

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:0 Percentile:0.02(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

Systematic measurement of double-differential neutron production cross sections for deuteron-induced reactions at an incident energy of 102 MeV

Araki, Shohei*; Watanabe, Yukinobu*; Kitajima, Mizuki*; Sadamatsu, Hiroki*; Nakano, Keita*; Kin, Tadahiro*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 842, p.62 - 70, 2017/01

 Times Cited Count:8 Percentile:75.2(Instruments & Instrumentation)

Recently, deuteron incident reaction is expected to be used as a neutron source for study of radiation damage in fusion materials, boron neutron capture therapy, and so on. However, experimental data to validate the model is very few. In this work, double-differential neutron production cross sections (DDXs) for deuteron-induced reactions on $$^{nat}$$Li, $$^{9}$$Be, $$^{nat}$$C, $$^{27}$$Al, $$^{nat}$$Cu, and $$^{93}$$Nb at 102 MeV were measured at forward angles $$leq$$ 25$$^{circ}$$ by means of a time of flight (TOF) method with NE213 liquid organic scintillators at the Research Center of Nuclear Physics (RCNP), Osaka University. The experimental DDXs and energy-integrated cross sections were compared with TENDL-2015 data and PHITS calculation. The PHITS calculation showed better agreement with the experimental results than TENDL-2015 for all target nuclei, although the shape of the broad peak around 50 MeV was not satisfactorily reproduced by the PHITS calculation.

Journal Articles

Evaluation of neutron response of criticality accident alarm system detector to quasi-monoenergetic 24 keV neutrons

Tsujimura, Norio; Yoshida, Tadayoshi; Yashima, Hiroshi*

JPS Conference Proceedings (Internet), 11, p.050005_1 - 050005_6, 2016/11

Journal Articles

Measurement of double differential (d,xn) cross sections for carbon at an incident energy of 100 MeV

Araki, Shohei*; Watanabe, Yukinobu*; Kitajima, Mizuki*; Sadamatsu, Hiroki*; Nakano, Keita*; Kin, Tadahiro*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; et al.

JAEA-Conf 2016-004, p.159 - 164, 2016/09

Neutron production data from materials such as Li, Be and C bombarded by deuteron are required for design such as the facility of radiation damage for fusion materials and boron neutron capture therapy. However, there is little measurement of double differential neutron production cross sections (DDXs). Therefore, we have planned a series of DDXs measurements at incident energies more than 100 MeV in the Research Center for Nuclear Physics, Osaka University. The experiment was carried out with a carbon target at the neutron Time of Flight (TOF) course in RCNP. Emitted neutrons were detected by three different-size NE213 liquid organic scintillators (5.08 cm, 12.7 cm and 25.4 cm in dimeter and thickness) located at a distance of 7 m, 24 m and 74 m respectively. The neutron detection efficiencies of the detectors were calculated by SCINFUL-QMD code. It turned out that the calculation data fr carbon does not reproduce the experimental data satisfactorily well.

Journal Articles

Activation experiments for verification of neutron capture cross section of $$^{237}$$Np using variable neutron field at KURRI-LINAC

Takahashi, Yoshiyuki*; Hori, Junichi*; Sano, Tadafumi*; Yagi, Takahiro*; Yashima, Hiroshi*; Pyeon, C. H.*; Nakamura, Shoji; Harada, Hideo

Proceedings of International Conference on the Physics of Reactors; Unifying Theory and Experiments in the 21st Century (PHYSOR 2016) (USB Flash Drive), p.645 - 652, 2016/05

For the reduction of radioactive toxicities, feasibility study of nuclear transmutation of minor actinides (MAs) and long-lived fission products (LLFPs) by utilizing innovative nuclear reactor system (i.e. fast breeder reactors and accelerator-driven systems) has been actively conducted. To design these nuclear reactor systems, the accurate nuclear data are required. Therefore, to obtain more accurate nuclear data, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides(AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program". In a part of this project, the nuclear data of MAs are verified in the variable neutron spectra field at Kyoto University Research Reactor Institute-LINear ACcelerator (KURRI-LINAC) and Kyoto University Critical Assembly (KUCA). And the differential TOF data is cross-checked with an integral data for the validation of $$^{237}$$Np, $$^{241}$$Am, and $$^{243}$$Am. In this summary, the results of reaction rate of neutron capture cross section of $$^{237}$$Np are reported as an example in the study.

Journal Articles

Characterization of high-energy quasi-monoenergetic neutron energy spectra and ambient dose equivalents of 80-389 MeV $$^{7}$$Li(p,n) reactions using a time-of-flight method

Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Araki, Shohei*; Yashima, Hiroshi*; Sato, Tatsuhiko; Masuda, Akihiko*; Matsumoto, Tetsuro*; Nakao, Noriaki*; Shima, Tatsushi*; et al.

Nuclear Instruments and Methods in Physics Research A, 804, p.50 - 58, 2015/12

 Times Cited Count:20 Percentile:91.46(Instruments & Instrumentation)

We have measured neutron energy spectra for the 80, 100 and 296 MeV proton incident reactions at the RCNP cyclotron facility using time-of-flight method. The neutron energy spectrum consisted of the peak and continuum parts and the peak intensity was 0.9-1.1 $$times$$ 10$$^{10}$$ neutrons/sr/$$mu$$C. The ratio of peak intensity of the spectrum to the total intensity was between 0.38 and 0.48. To consider the correction required to derive a response in the peak region from the measured total response for neutron monitors, we proposed the subtraction method using energy spectra between 0$$^{circ}$$ and 25$$^{circ}$$. The normalizing factor k against the 25$$^{circ}$$ neutron fluence that equalizes the 0$$^{circ}$$ neutron fluence in the continuum region was from 0.74 to 1.02. With our previous results, we have obtained data for characterization of monoenergetic neutron field for the $$^{7}$$Li(p,n) reaction with 80$$sim$$389 MeV protons at the RCNP cyclotron facility.

Journal Articles

Accuracy improvement of neutron nuclear data on minor actinides

Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Mizuyama, Kazuhito; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.

EPJ Web of Conferences, 93, p.06001_1 - 06001_5, 2015/05

 Times Cited Count:4 Percentile:87.32

Improvement of accuracy of neutron nuclear data for minor actinides (MAs) and long-lived fission products (LLFPs) is required for developing innovative nuclear system transmuting these nuclei. In order to meet the requirement, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program" at October 2013. The AIMAC project team is composed of researchers in four different fields: differential nuclear data measurement, integral nuclear data measurement, nuclear chemistry, and nuclear data evaluation. By integrating all of the forefront knowledge and techniques in these fields, the team aims at improving the accuracy of the data. The background, overall plan, and recent progress of the AIMAC project will be reviewed.

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