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Pb and 
Bi in proton-induced reactions near 100 MeVIwamoto, Hiroki; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Ishi, Yoshihiro*; Uesugi, Tomonori*; Yashima, Hiroshi*; Nishio, Katsuhisa; Sugihara, Kenta*; 
elik, Y.*; et al.
Nuclear Instruments and Methods in Physics Research B, 544, p.165107_1 - 165107_15, 2023/11
Times Cited Count：0 Percentile：0.02(Instruments & Instrumentation)The lack of double-differential cross-section (DDX) data for neutron production below the incident proton energy of 200 MeV hinders the validation of spallation models in technical applications, such as research and development of accelerator-driven systems (ADSs). The present study aims to obtain experimental DDX data for ADS spallation target materials in this energy region and identify issues related to the spallation models by comparing them with the analytical predictions. The DDXs for the (
) reactions of Pb and Bi in the 100-MeV region were measured over an angular range of 30
to 150 using the time-of-flight method. The measurements were conducted at Kyoto University utilizing the FFAG accelerator. The DDXs obtained were compared with calculation results from Monte Carlo-based spallation models and the evaluated nuclear data library, JENDL-5. Comparison between the measured DDX and analytical values based on the spallation models and evaluated nuclear data library indicated that, in general, the CEM03.03 model demonstrated the closest match to the experimental values. Additionally, the comparison highlighted several issues that need to be addressed in order to improve the reproducibility of the proton-induced neutron-production DDX in the 100 MeV region by these spallation models and evaluated nuclear data library.
Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta*; Nishio, Katsuhisa; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; et al.
EPJ Web of Conferences, 284, p.01023_1 - 01023_4, 2023/05
Times Cited Count：0 Percentile：0.21(Nuclear Science & Technology)For accurate prediction of neutronic characteristics for accelerator-driven systems (ADS) and a source term of spallation neutrons for reactor physics experiments for the ADS at Kyoto University Critical Assembly (KUCA), we have launched an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University. As part of this program, the proton-induced double-differential thick-target neutron-yields (TTNYs) and cross-sections (DDXs) for iron, lead, and bismuth have been measured with the time-of-flight (TOF) method. For each measurement, the target was installed in a vacuum chamber on the beamline and bombarded with 107-MeV proton beams accelerated from the FFAG accelerator. Neutrons produced from the targets were detected with stacked, small-sized neutron detectors for several angles from the incident beam direction. The TOF spectra were obtained from the detected signals and the FFAG kicker magnet's logic signals, where gamma-ray events were eliminated by pulse shape discrimination. Finally, the TTNYs and DDXs were obtained from the TOF spectra by relativistic kinematics. The measured TTNYs and DDXs were compared with calculations by the Monte Carlo transport code PHITS with its default physics model of INCL version 4.6 combined with GEM and those with the JENDL-4.0/HE nuclear data library.
Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta; Nishio, Katsuhisa; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; et al.
Journal of Nuclear Science and Technology, 60(4), p.435 - 449, 2023/04
Times Cited Count：3 Percentile：68.71(Nuclear Science & Technology)Double-differential thick target neutron yields (TTNYs) for Fe, Pb, and Bi targets induced by 107-MeV protons were measured using the fixed-field alternating gradient accelerator at Kyoto University for research and development of accelerator-driven systems (ADSs) and fundamental ADS reactor physics research at the Kyoto University Critical Assembly (KUCA). Note that TTNYs were obtained with the time-of-flight method using a neutron detector system comprising eight neutron detectors; each detector has a small NE213 liquid organic scintillator and photomultiplier tube. The TTNYs obtained were compared with calculation results using Monte Carlo-based spallation models (i.e., INCL4.6/GEM, Bertini/GEM, JQMD/GEM, and JQMD/SMM/GEM) and the evaluated high-energy nuclear data library, i.e., JENDL-4.0/HE, implemented in the particle and heavy iontransport code system (PHITS). All models, including JENDL-4.0/HE, failed to predict high-energy peaks at a detector angle of 5. Comparing the energy- and angle-integrated spallation neutron yields at energies of 
20 MeV estimated using the measured TTNYs and the PHITS indicated that INCL4.6/GEM would be suitable for the Monte Carlo transport simulation of ADS reactor physics experiments at the KUCA.
Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Yashima, Hiroshi*; Nishio, Katsuhisa; et al.
JAEA-Conf 2022-001, p.129 - 133, 2022/11
For accurate prediction of neutronic characteristics for accelerator-driven systems (ADS) and a source term of spallation neutrons for reactor physics experiments for the ADS at Kyoto University Critical Assembly (KUCA), we have launched an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University. As part of this program, the proton-induced double-differential thick-target neutron-yields (TTNYs) and cross-sections (DDXs) for iron have been measured with the time-of-flight (TOF) method. For each measurement, the target was installed in a vacuum chamber on the beamline and bombarded with 107-MeV proton beams accelerated from the FFAG accelerator. Neutrons produced from the targets were detected with stacked, small-sized neutron detectors composed of the NE213 liquid organic scintillators and photomultiplier tubes, which were connected to a multi-channel digitizer mounted with a field-programmable gate array (FPGA), for several angles from the incident beam direction. The TOF spectra were obtained from the detected signals and the FFAG kicker magnet's logic signals, where gamma-ray events were eliminated by pulse shape discrimination applying the gate integration method to the FPGA. Finally, the TTNYs and DDXs were obtained from the TOF spectra by relativistic kinematics.
Np and 
Am by accelerator-driven system at Kyoto University Critical AssemblyPyeon, C. H.*; Yamanaka, Masao*; Oizumi, Akito; Fukushima, Masahiro; Chiba, Go*; Watanabe, Kenichi*; Endo, Tomohiro*; Van Rooijen, W. G.*; Hashimoto, Kengo*; Sakon, Atsushi*; et al.
Journal of Nuclear Science and Technology, 56(8), p.684 - 689, 2019/08
Times Cited Count：12 Percentile：80.27(Nuclear Science & Technology)This study demonstrates, for the first time, the principle of nuclear transmutation of minor actinide (MA) by the accelerator-driven system (ADS) through the injection of high-energy neutrons into the subcritical core at the Kyoto University Critical Assembly. The main objective of the experiments is to confirm fission reactions of neptunium-237 (Np) and americium-241 (Am), and capture reactions of Np. Subcritical irradiation of Np and Am foils is conducted in a hard spectrum core with the use of the back-to-back fission chamber that obtains simultaneously two signals from specially installed test (Np or Am) and reference (uranium-235) foils. The first nuclear transmutation of Np and Am by ADS soundly implemented by combining the subcritical core and the 100 MeV proton accelerator, and the use of a lead-bismuth target, is conclusively demonstrated through the experimental results of fission and capture reaction events.
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.
Iwamoto, Yosuke; Yoshiie, Toshimasa*; Yoshida, Makoto*; Nakamoto, Tatsushi*; Sakamoto, Masaaki*; Kuriyama, Yasutoshi*; Uesugi, Tomonori*; Ishi, Yoshihiro*; Xu, Q.*; Yashima, Hiroshi*; et al.
Journal of Nuclear Materials, 458, p.369 - 375, 2015/03
Times Cited Count：13 Percentile：73.22(Materials Science, Multidisciplinary)To validate Monte Carlo codes for the prediction of radiation damage in metals irradiated by 100 MeV protons, defect-induced electrical resistivity changes of copper related to the displacement cross-section were measured with 125 MeV proton irradiation at 12 K. The cryogenic irradiation system was developed with a Gifford-McMahon cryocooler to cool the sample via an oxygen-free high-conductivity copper plate by conduction cooling. The sample was a copper wire with a 250
m diameter and 99.999% purity sandwiched between two aluminum nitride ceramic sheets. The resistivity increase did not change during annealing after irradiation below 15 K. The experimental displacement cross-section for 125 MeV irradiation shows similar results to the experimental data for 1.1 and 1.94 GeV. Comparison with the calculated results indicated that the defect production efficiency in Monte Carlo codes gives a good quantitative description of the displacement cross-section in the energy region 100 MeV.
Kinsho, Michikazu; Noda, Fumiaki*; Ishi, Yoshihiro*; *
JAERI-Research 99-037, 75 Pages, 1999/05
JAERI-Research-99-037.pdf:2.69MB
no abstracts in English
Iwamoto, Yosuke; Yoshida, Makoto*; Nakamoto, Tatsushi*; Ogitsu, Toru*; Yoshiie, Toshimasa*; Sakamoto, Masaaki*; Kuriyama, Yasutoshi*; Uesugi, Tomonori*; Ishi, Yoshihiro*; Mori, Yoshiharu*
no journal, ,
We measured the electrical resistivity under irradiation of 125 MeV proton in copper sample (0.2 um thickness) at cryogenic temperature at the FFAG accelerator facility in Kyoto university. Resistivity was measured by the four-terminal method. As a result, we measured the resistivity of copper at 7.3 K within 20 micro-ohm and temperature of sample. We measured the electrical resistivity under irradiation of 125 MeV proton in copper sample (0.2 um thickness) at cryogenic temperature at the FFAG accelerator facility in Kyoto university. Resistivity was measured by the four-terminal method. As a result, we measured the resistivity of copper at 7.3 K within 20 micro-ohm and temperature of sample.
Iwamoto, Yosuke; Yoshiie, Toshimasa*; Yoshida, Makoto*; Nakamoto, Tatsushi*; Sakamoto, Masaaki*; Kuriyama, Yasutoshi*; Uesugi, Tomonori*; Ishi, Yoshihiro*; Xu, Q.*; Yashima, Hiroshi*; et al.
no journal, ,
To validate the radiation damage calculation in the PHITS code for proton irradiation over 100 MeV, we have developed the device for electrical resistance measurement under cryogenic condition. A copper wire with 99.999% purity in a diameter of 250-m was set with a serpentine-shaped line on the AlN sheet which has high thermal conductivity and electric insulation. The sample was annealed for 1 h at 1,000C before irradiation. After annealing, the sample was cooled with an oxygen-free high-conductivity copper plate by conduction cooling. The electrical resistivity changes in the sample were measured using the four-probe technique. As a result, the residual resistivity ratio of the sample was about 1,800 between room temperature and 11 K. After 125 MeV proton irradiation with 1.45
10
(proton/cm
) at 11 K, the total resistance increase was 1.53 
, while the resistivity of copper before irradiation was 29.41 .
Iwamoto, Yosuke; Yoshiie, Toshimasa*; Yoshida, Makoto*; Nakamoto, Tatsushi*; Sakamoto, Masaaki*; Kuriyama, Yasutoshi*; Uesugi, Tomonori*; Ishi, Yoshihiro*; Xu, Q.*; Yashima, Hiroshi*; et al.
no journal, ,
To validate Monte Carlo code PHITS for the prediction of radiation damage in metals, the damage rate (defect-induced electrical resistivity changes / particle fluence) related to the displacement cross-section of copper were measured with 125 MeV proton irradiation under 12 K at the FFAG facility in the Kyoto University Research Reactor Institute. The sample was a copper wire with a 250-m diameter and 99.999% purity and was cooled by conduction cooling. After 125 MeV proton irradiation with 1.4510
protons/m at 12 K, the total resistivity increase was 4.9410
m (resistance increase: 1.53), while the resistivity of copper before irradiation was 9.49 10
m (resistance: 29.41). Comparison with other experimental results indicated that the damage rate by 125 MeV protons is almost same with those by 1.1 GeV protons and is higher than the damage rate by 14 MeV neutrons by a factor of 1.4. For the comparison with the PHITS results, the experimental data is smaller than the calculated result without the defect production efficiency by a factor of about 2.5 and that with the defect production efficiency by a factor of about 1.4, respectively. It indicates that the defect production efficiency in PHITS gives a good quantitative description of the displacement cross-section.
Okabe, Kota; Yoshimoto, Masahiro; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Kinsho, Michikazu; Taniguchi, Akihiro*; Sato, Akira*; Miyake, Yasuhiro*; Mori, Yoshiharu*
no journal, ,
no abstracts in English
Iwamoto, Hiroki; Meigo, Shinichiro; Nishio, Katsuhisa; Ishi, Yoshihiro*; Hirose, Kentaro; Iwamoto, Yosuke; Kuriyama, Yasutoshi*; Maekawa, Fujio; Makii, Hiroyuki; Nakano, Keita; et al.
no journal, ,
no abstracts in English
Nakano, Keita; Iwamoto, Hiroki; Meigo, Shinichiro; Nishio, Katsuhisa; Ishi, Yoshihiro*; Hirose, Kentaro; Iwamoto, Yosuke; Kuriyama, Yasutoshi*; Maekawa, Fujio; Makii, Hiroyuki; et al.
no journal, ,
For accurate prediction of neutronic characteristics for accelerator-driven system (ADS), an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University has been launched. As a part of this program, energy spectra of spallation neutron from 100-MeV proton-induced reactions on Fe, Pb, and Bi are plan to be measured. In this report, the results of the measurement on Fe target will be presented.
Nakano, Keita; Iwamoto, Hiroki; Meigo, Shinichiro; Nishio, Katsuhisa; Ishi, Yoshihiro*; Hirose, Kentaro; Iwamoto, Yosuke; Kuriyama, Yasutoshi*; Maekawa, Fujio; Makii, Hiroyuki; et al.
no journal, ,
Toward the realization of Accelerator-Driven System (ADS), we have been measuring the nuclear data for ADS using Kyoto University FFAG accelerator. In this presentation, we report the outline and the results of the energy spectrum measurement of neutrons produced by 107 MeV proton-induced reactions on lead and bismuth, which are the most important nuclides in ADS.
Iwamoto, Hiroki; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta; Nakano, Keita; Nishio, Katsuhisa; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; et al.
no journal, ,
For the purpose of research and development of accelerator-driven nuclear transmutation systems, neutron yields of 107-MeV proton incident on iron, lead and bismuth targets were measured by the flight time method using the FFAG accelerator at Kyoto University. The energy spectra of the neutron yield obtained by the measurements were compared with results of particle transport analysis with the nuclear reaction models (INCL4.6/GEM, Bertini/GEM, JQMD/GEM and JQMD/SMM/GEM) incorporated in the Monte Carlo particle transport calculation code PHITS and the nuclear data library JENDL-4.0/HE. As a result, it was found that the INCL4.6/GEM, which was the reference model of PHITS, best reproduced the experimental values.
Np fission chamberIwamoto, Hiroki; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta*; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Yashima, Hiroshi*; Nishio, Katsuhisa; et al.
no journal, ,
no abstracts in English
Iwamoto, Hiroki; Meigo, Shinichiro; Nishio, Katsuhisa; Ishi, Yoshihiro*; Hirose, Kentaro; Iwamoto, Yosuke; Kuriyama, Yasutoshi*; Makii, Hiroyuki; Maekawa, Fujio; Mori, Yoshiharu*; et al.
no journal, ,
An experimental program for the research and development of Accelerator-Driven System (ADS) was carried out from FY2019 to FY2022. In this program, nuclear data on 100 MeV proton-induced spallation reactions on ADS target materials were experimentally obtained using the FFAG accelerator at Institute for Integrated Radiation and Nuclear Science, Kyoto University. Specifically, the proton-induced double-differential thick target neutron yield (TTNY) for Fe, Pb, and 
Bi, neutron-production double-differential cross sections (DDX) for Pb and Bi, fission rate of Np by spallation neutrons, 
Pb(p,f) reaction and Bi(p,f) reactions, the mass number distribution of fission fragments produced in the Pb(p,f) and Bi(p,f) reactions, and the fission neutrons. As a result of comparing the measured data with the analytical values obtained by various nuclear reaction models, issues to be addressed toward the advancement of nuclear reaction models for proton-induced spallation reactions in the 100 MeV region were clarified.
