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Journal Articles

Unified description of the fission probability for highly excited nuclei

Iwamoto, Hiroki; Meigo, Shinichiro

Journal of Nuclear Science and Technology, 56(2), p.160 - 171, 2019/02

 Percentile:100(Nuclear Science & Technology)

We present a new model to describe the fission probability of the high-energy fission model, as deduced from the intranuclear cascade calculation with the Intra-Nuclear Cascade model of Li$`{e}$ge (INCL) version 4.6 and Prokofiev's phenomenological systematics of the proton-induced fission cross sections. This model is implemented in the de-excitation model of the Generalized Evaporation Model (GEM), and applied to Monte Carlo spallation reaction simulation using the Particle and Heavy Ion Transport code System (PHITS). Comparing with experimental data for subactinide nuclei shows that this model can provide a unified prediction of the proton-, neutron-, and deuteron-induced fission cross sections with markedly improved accuracy. The calculated fission fragments tend to shift to higher mass numbers. To account for the isotopic distributions of fission fragments within the framework of a coupled INCL/GEM, modification of INCL is required, especially for description of the highly-excited states of residual nuclei.

Journal Articles

Measurement of activation cross sections of aluminum for protons with energies between 0.4 GeV and 3.0 GeV at J-PARC

Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Hiroki

Progress in Nuclear Science and Technology (Internet), 6, p.171 - 174, 2019/01

Activation cross sections of various materials are strongly required for the improvement of the accuracy of nuclear design and the reduction of the construction costs for spallation neutron sources and transmutation systems. Activation cross sections have been measured in several facilities. However, they have low accuracy and precision. Especially, there are merely experimental data with 3 GeV protons which are used for spallation neutron source (MLF) in J-PARC, the experimental data is required for the improvement of the target materials. Thus, we measured cross sections of tungsten, gold, indium, and beryllium with 0.4 GeV to 3.0 GeV protons. Moreover, ones of aluminium that are set with materials were also measured for a variation of this experiment. It was found that more accurate data than current ones would be measured by using precise beam controls and highly accurate beam monitoring. We compared the experimental data, the evaluated data (JENDL-HE/2007), and the calculations with several intra-nuclear cascade models by PHITS code. Although the experimental data agreed with JENDL-HE/2007, the calculations underestimated about 40%. This could come from the evaporation model (GEM) being included in PHITS code. We found that the calculations agreed with the experimental data by upgrading PHITS code. The cross sections for the other materials have been analysed so far.

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:2 Percentile:16.17(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

Proton-induced activation cross section measurement for aluminum with proton energy range from 0.4 to 3 GeV at J-PARC

Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Hiroki

Journal of Nuclear Science and Technology, 55(8), p.955 - 961, 2018/08

 Times Cited Count:1 Percentile:38.14(Nuclear Science & Technology)

We have started an experimental program to measure activation cross sections systematically in the proton-induced spallation reaction in structural materials commonly used in high-intensity proton accelerator-based facilities, such as Japan Proton Accelerator Research Complex (J-PARC). As the first step of the program, aluminum (Al) was chosen to verify the adequacy of the measurement technique implemented in a J-PARC proton beam environment because data of Al have been relatively well studied both by experimental measurement and simulation. Activation cross sections of $$^{7}$$Be, $$^{22}$$Na, and $$^{24}$$Na in Al were measured at proton energy points from 0.4, 1.3, 2.2 to 3.0 GeV, which could be delivered smoothly from the synchrotron. The validity of experimental data has been verified by introducing an effective proton numbers determination procedure. We compared the measured data with existing experimental data, the evaluated data (JENDL-HE/2007), and the calculations with several intra-nuclear cascade models by the Particle and Heavy Ion Transport code System (PHITS) code. Although the experimental data agreed with JENDL-HE/2007, the calculations underestimated about 40%. This could come from the evaporation model (generalized evaporation model) being implemented in the PHITS code. We found that the calculations agreed with the experimental data by an upgraded PHITS code.

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

Beam instruments for high power spallation neutron source and facility for ADS

Meigo, Shinichiro

Proceedings of 61st ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB 2018) (Internet), p.99 - 103, 2018/07

As the increase of beam power, beam instruments play an essential role in the Hadron accelerator facility. In J-PARC, the pitting erosion on the mercury target vessel for the spallation neutron source is one of a pivotal issue to operate with the high power of the beam operation. Since the erosion is proportional to the 4th power of the beam current density, the minimization of the peak current density is required. To achieve low current density, the beam-flattening system by nonlinear beam optics in J-PARC, by which the peak density was successfully reduced by 30% than the density with the conventional case optics. Since the ADS requires a very powerful accelerator with the beam power such as 30 MW, a robust beam profile monitor is required, especially for the observation of the beam status on the target continuously. A candidate material for the beam monitor was developed by using heavy-ion of Ar beam to give the damage efficiently.

Journal Articles

Measurement of activation cross sections of the target and the proton beam window materials at J-PARC

Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Hiroki

Journal of Physics; Conference Series, 1021(1), p.012016_1 - 012016_4, 2018/06

For the improvement of the accuracy of nuclear design for spallation neutron sources and transmutation systems, nuclear reaction cross sections are required. Considering decommissioning of the accelerator facilities, accurate cross sections are mandatory. The activation cross sections have been measured in several facilities. However, they have low accuracy and precision. Especially, since there is almost no data for 3 GeV protons which are used for spallation neutron source (JSNS) in J-PARC, the experimental data is required for the improvement of the target materials.For the sake of the forthcoming full-time measurement of the activation cross sections for various nuclei, we measured the ones of aluminium with 0.4, 1.3, 2.2, and 3.0 GeV protons as the test purpose. It was found that more accurate data than current ones would be measured by using precise beam controls and highly accurate beam monitoring. We compared the experimental data, the evaluated data (JENDL-HE/2007), and the calculations with several intra-nuclear cascade models by PHITS code. Although the experimental data agreed with JENDL-HE/2007, the calculations underestimated about 40%. This could come from the evaporation model (GEM) being included in PHITS code. We found that the calculations agreed with the experimental data by upgrading PHITS code.

Journal Articles

The Measurements of neutron energy spectrum at 180 degrees with the mercury target at J-PARC

Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Hiroki

Journal of Physics; Conference Series, 1021(1), p.012017_1 - 012017_4, 2018/06

Spallation neutron at 180 degrees is of important for an evaluation of radiation protection for ADS (Accelerator-Driven System) and the nuclear physics. It was, however, quite difficult to measure it. We measured the energy spectrum of spallation neutron at 180 degrees at the proton transport beam line (3NBT) to MLF (Materials and Life Science Experimental Facility) on J-PARC by the NE213 liquid scintillator. The irradiated proton energy was 3 GeV, and the intensity was 1$$times$$10$$^{10}$$ protons above. The neutron energy was determined by Time-Of-Flight method with n-gamma discrimination. We also simulated the energy spectrum by using PHITS code and compared with measured spectrum. In this paper, the overview of the experiment and the results are described.

Journal Articles

Target test facility for ADS and cross-section experiment in J-PARC

Meigo, Shinichiro; Iwamoto, Hiroki; Matsuda, Hiroki; Takei, Hayanori

Journal of Physics; Conference Series, 1021(1), p.012072_1 - 012072_4, 2018/06

no abstracts in English

Journal Articles

Shielding analysis of Transmutation Experimental Facility

Iwamoto, Hiroki; Matsuda, Hiroki; Meigo, Shinichiro

Journal of Physics; Conference Series, 1021(1), p.012049_1 - 012049_4, 2018/06

To promote research, development, and demonstration of elemental technologies for accelerator-driven systems (ADS), the Japan Atomic Energy Agency (JAEA) is planning to construct Transmutation Experimental Facility (TEF) at J-PARC. At ADS Target Test Facility (TEF-T), 250-kW H$$^{-}$$ beams accelerated by the 400-MeVLINAC will be derived to a lead-bismuth eutectic (LBE) target for the material examinations aimed for the ADS. The TEF-T will operate as a spallation neutron source especially for research and development of semiconductor by using high-energy neutrons. For the license of this facility, the shielding design is important because unnecessary shield increase drastically the cost of construction. In this study, shielding analysis was carried out for whole structure of the TEF in detail toward the construction. To reduce the neutron flux and cost efficiently, an iron and an ordinary concrete will be employed as shield. The detailed structure for the shielding was determined by the PHITS code based on the intra-nuclear cascade with statistical decay model. It was found that the backward neutrons from the target are important to reduce the cost of the shielding so that we have plan to measure by using J-PARC accelerator. Shielding including the beam tunnel, hot-cell to maintain the LBE target, beam dumps for beam commissioning, and a neutron beam port for multipurpose utilization were also determined. This paper presents the results of the shielding analysis for these components and the shielding structure of the whole TEF.

Journal Articles

Measurement of displacement cross-section for structural materials in High-Power Proton Accelerator Facility

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

Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.499 - 501, 2018/06

no abstracts in English

Journal Articles

Cross section measurement in J-PARC for neutronics of the ADS

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Hiroki

Proceedings of 13th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '17) (Internet), p.396 - 402, 2018/05

no abstracts in English

Journal Articles

Beam extraction by the laser charge exchange method using the 3-MeV LINAC in J-PARC

Takei, Hayanori; Hirano, Koichiro; Tsutsumi, Kazuyoshi; Meigo, Shinichiro

Plasma and Fusion Research (Internet), 13(Sp.1), p.2406012_1 - 2406012_6, 2018/03

The Japan Proton Accelerator Research Complex (J-PARC) has a plan to build the Transmutation Physics Experimental Facility (TEF-P), in which a 400-MeV negative proton (H$$^{-}$$) beam will be delivered from the J-PARC linac. Since the TEF-P requires a stable proton beam with a power of less than 10 W, a stable and meticulous beam extraction method is required to extract a small amount of the proton beam from the high power beam using 250 kW. To fulfil this requirement, the Laser Charge Exchange (LCE) method has been developed. To demonstrate the charge exchange of the H$$^{-}$$, a preliminary LCE experiment was conducted using a linac with energy of 3 MeV in J-PARC. As a result of the experiment, a charge-exchanged H$$^{+}$$ beam with a power of about 8 W equivalent and an accuracy of about 2% was obtained under the J-PARC linac beam condition.

Journal Articles

Beam extraction by the laser charge exchange method using the 3-MeV linac in J-PARC

Takei, Hayanori; Hirano, Koichiro; Meigo, Shinichiro; Tsutsumi, Kazuyoshi*

Proceedings of 6th International Beam Instrumentation Conference (IBIC 2017) (Internet), p.435 - 439, 2018/03

The Japan Proton Accelerator Research Complex (J-PARC) has a plan to build the Transmutation Physics Experimental Facility (TEF-P), in which a 400-MeV negative proton (H$$^{-}$$) beam will be delivered from the J-PARC linac. Since the TEF-P requires a stable proton beam with a power of less than 10 W, a stable and meticulous beam extraction method is required to extract a small amount of the proton beam from the high power beam using 250 kW. To fulfil this requirement, the Laser Charge Exchange (LCE) method has been developed. To demonstrate the charge exchange of the H$$^{-}$$, a preliminary LCE experiment was conducted using a linac with energy of 3 MeV in J-PARC. As a result of the experiment, a charge-exchanged H$$^{+}$$ beam with a power of about 8 W equivalent and an accuracy of about 2% was obtained under the J-PARC linac beam condition.

Journal Articles

Profile monitor on target for spallation neutron source

Meigo, Shinichiro; Matsuda, Hiroki; Takei, Hayanori

Proceedings of 6th International Beam Instrumentation Conference (IBIC 2017) (Internet), p.373 - 376, 2018/03

no abstracts in English

JAEA Reports

Assessment of lead-bismuth-eutectic leak at ADS Target Test Facility in Transmutation Experimental Facility of J-PARC

Iwamoto, Hiroki; Maekawa, Fujio; Matsuda, Hiroki; Meigo, Shinichiro

JAEA-Technology 2017-029, 39 Pages, 2018/01

JAEA-Technology-2017-029.pdf:2.68MB

Under an assumption that an incident of lead-bismuth eutectic (LBE) leak from an LBE circulation system occurred during a 250-kW beam operation, an estimation of radiation dose at the site boundary for the ADS Target Test Facility (TEF-T) in Transmutation Experimental Facility (TEF) of J-PARC was conducted using various conservative assumptions. As a result, the radiation dose at the site boundary was estimated to be about 660 $$mu$$Sv, which were dominated by mercury, noble gas, and iodine produced as spallation products from the LBE. Even though the incident scenario was made conservatively, it was shown that the estimated total dose was lower than the annual radiation dose due to natural sources, and the TEF-T has sufficient safety margin for the leak of radioactivity.

Journal Articles

Validation of PHITS spallation models from the perspective of the shielding design of transmutation experimental facility

Iwamoto, Hiroki; Meigo, Shinichiro

EPJ Web of Conferences (Internet), 153, p.01016_1 - 01016_9, 2017/09

 Percentile:100

Journal Articles

Measurement of aluminum activation cross section and gas production cross section for 0.4 and 3-GeV protons

Meigo, Shinichiro; Nishikawa, Masaaki; Iwamoto, Hiroki; Matsuda, Hiroki

EPJ Web of Conferences (Internet), 146, p.11039_1 - 11039_4, 2017/09

 Percentile:100

no abstracts in English

Journal Articles

Beam-based compensation of extracted-beam displacement caused by field ringing of pulsed kicker magnets in the 3 GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Harada, Hiroyuki; Saha, P. K.; Tamura, Fumihiko; Meigo, Shinichiro; Hotchi, Hideaki; Hayashi, Naoki; Kinsho, Michikazu; Hasegawa, Kazuo

Progress of Theoretical and Experimental Physics (Internet), 2017(9), p.093G01_1 - 093G01_16, 2017/09

AA2017-0286.pdf:4.64MB

The 3 GeV rapid cycling synchrotron (RCS) of the J-PARC is a high intensity proton accelerator of 1 MW. The accelerated proton beams in the RCS are extracted by eight pulsed kicker magnets and are delivered to a materials and life science experimental facility and main ring synchrotron. However, the fields of the magnets experience ringing that displaces the position of the extracted beam. This is a major issue from the viewpoint of target integrity and large beam loss. The ringing was directly measured as the displacement of the extracted beams by using a shorter pulsed beam and scanning the entire trigger timing of the kickers. We managed to cancel out the ringing by optimizing trigger timing and achieved the beam extraction with high accuracy. We developed automatic correction system of the timing and now have a higher stability. In this paper, we report our procedure and experimental results for ringing compensation.

Journal Articles

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex, 1; Pulsed spallation neutron source

Takada, Hiroshi; Haga, Katsuhiro; Teshigawara, Makoto; Aso, Tomokazu; Meigo, Shinichiro; Kogawa, Hiroyuki; Naoe, Takashi; Wakui, Takashi; Oi, Motoki; Harada, Masahide; et al.

Quantum Beam Science (Internet), 1(2), p.8_1 - 8_26, 2017/09

At the Japan Proton Accelerator Research Complex (J-PARC), a pulsed spallation neutron source provides neutrons with high intensity and narrow pulse width to promote researches on a variety of science in the Materials and life science experimental facility. It was designed to be driven by the proton beam with an energy of 3 GeV, a power of 1 MW at a repetition rate of 25 Hz, that is world's highest power level. A mercury target and three types of liquid para-hydrogen moderators are core components of the spallation neutron source. It is still on the way towards the goal to accomplish the operation with a 1 MW proton beam. In this paper, distinctive features of the target-moderator-reflector system of the pulsed spallation neutron source are reviewed.

164 (Records 1-20 displayed on this page)