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Journal Articles

Design and beam dynamic studies of a 30-MW superconducting linac for an accelerator-driven subcritical system

Yee-Rendon, B.; Kondo, Yasuhiro; Maekawa, Fujio; Meigo, Shinichiro; Tamura, Jun

Physical Review Accelerators and Beams (Internet), 24(12), p.120101_1 - 120101_17, 2021/12

The Japan Atomic Energy Agency (JAEA) is working on the research and development of a 30-MW continuous wave (CW) proton linear accelerator (linac) for the JAEA accelerator-driven subcritical system (ADS) proposal. The linac will accelerate a 20 mA proton beam to 1.5 GeV, using mainly superconducting cavities. The main challenge for an ADS accelerator is the high reliability required to prevent thermal stress in the subcritical reactor; thus, we pursue a robust lattice to achieve stable operation. To this end, the beam optics design reduces the emittance growth and the beam halo through the superconducting part of the linac. First, we simulated an ideal machine without any errors to establish the operation conditions of the beam. Second, we applied element errors and input beam errors to estimate the tolerance of the linac design. Finally, we implemented a correction scheme to increase the lattice tolerance by reducing the beam centroid offset on the transverse plane. Massive multiparticle simulations and a cumulative statistic of 1$$times$$10$$^{8}$$ macroparticles have shown that the JAEA-ADS linac can operate with less than 1 W/m beam losses in error scenarios.

Journal Articles

Design of the MEBT for the JAEA-ADS Project

Yee-Rendon, B.; Kondo, Yasuhiro; Maekawa, Fujio; Meigo, Shinichiro; Tamura, Jun

Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.790 - 792, 2021/08

The Medium Energy Beam Transport (MEBT) will transport a CW proton beam with a current of 20 mA and energy of 2.5 MeV from the exit of the normal conducting Radiofrequency Quadrupole (RFQ) to the superconducting Half-Wave resonator (HWR) section. The MEBT must provide a good matching between the RFQ and HWR, effective control of the emittance growth and the halo formation, enough space for all the beam diagnostics devices, among others. This work reports the first lattice design and the beam dynamics studies for the MEBT of the JAEA-ADS.

Journal Articles

Measurement of thick target neutron yield at 180$$^{circ}$$ for a mercury target induced by 3-GeV protons

Matsuda, Hiroki; Iwamoto, Hiroki; Meigo, Shinichiro; Takeshita, Hayato*; Maekawa, Fujio

Nuclear Instruments and Methods in Physics Research B, 483, p.33 - 40, 2020/11

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

A thick target neutron yield for a mercury target at an angle of 180$$^{circ}$$ from the incident beam direction is measured with the time-of-flight method using a 3-GeV proton beam at the Japan Proton Accelerator Research Complex (J-PARC). Comparing the experimental result with a Monte Carlo particle transport simulation by the Particle and Heavy Ion Transport code System (PHITS) shows that there are apparent discrepancies. We find that this trend is consistent with an experimental result of neutron-induced re- action rates obtained using indium and niobium activation foils. Comparing proton-induced neutron-production double-differential cross-sections for a lead target at backward directions between the PHITS calculation and experimental data suggests that the dis- crepancies for our experiments would be linked to the neutron production calculation around 3 GeV by the PHITS spallation model and/or the calculation of nonelastic cross-sections around 3 GeV in the particle transport simulation.

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

Cavity and optics design of the accelerator for the JAEA-ADS project

Yee-Rendon, B.; Tamura, Jun; Kondo, Yasuhiro; Hasegawa, Kazuo; Maekawa, Fujio; Meigo, Shinichiro; Oguri, Hidetomo

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.107 - 111, 2019/07

JAEA Reports

Assessment report on research and development activities in FY 2018; Activity "Research and development on J-PARC" (Interim report)

J-PARC Center

JAEA-Evaluation 2019-003, 52 Pages, 2019/06


Evaluation Committee of Research Activities for J-PARC for interim assessment of Japan Proton Accelerator Research Complex evaluated the management and research activities of J-PARC center on the explanatory documents and oral presentations during the period from April 2015 to December 2018. This report summarizes the results of the assessment by the Committee with the Committee report attached.

Journal Articles

Pulse-by-pulse switching of operational parameters in J-PARC 3-GeV RCS

Hotchi, Hideaki; Watanabe, Yasuhiro; Harada, Hiroyuki; Okabe, Kota; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yoshimoto, Masahiro

Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.1041 - 1044, 2018/06

Journal Articles

Performance and status of the J-PARC accelerators

Hasegawa, Kazuo; Hayashi, Naoki; Oguri, Hidetomo; Yamamoto, Kazami; Kinsho, Michikazu; Yamazaki, Yoshio; Naito, Fujio*; Koseki, Tadashi*; Yamamoto, Noboru*; Hori, Yoichiro*

Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.2290 - 2293, 2017/06

The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a 30 GeV Main Ring Synchrotron (MR). We have taken many hardware upgrades such as front end replacement and energy upgrade at the linac, vacuum improvement, collimator upgrade, etc. The beam powers for the neutrino experiment and hadron experiment from the MR have been steadily increased by tuning and reducing beam losses. The designed 1 MW equivalent beam was demonstrated and user program was performed at 500 kW from the RCS to the neutron and muon experiments. We have experienced many failures and troubles, however, to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented.

Journal Articles

New injection scheme of J-PARC rapid cycling synchrotron

Yamamoto, Kazami; Kamiya, Junichiro; Saha, P. K.; Takayanagi, Tomohiro; Yoshimoto, Masahiro; Hotchi, Hideaki; Harada, Hiroyuki; Takeda, Osamu*; Miki, Nobuharu*

Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.579 - 581, 2017/05

The 3-GeV Rapid Cycling Synchrotron of Japan Proton Accelerator Research Complex aims to deliver 1-MW proton beam to the neutron target and Main Ring synchrotron. Present beam power of the Rapid Cycling Synchrotron is up to 500-kW and the higher radiation doses were concentrated in the injection area. These activations were caused by the interaction between the foil and the beam. To reduce the worker dose near the injection point, we have studied a new design of the injection scheme to secure enough space for radiation shielding and bellows. In the new system, two of four injection pulse bump magnets are replaced and we are able to ensure the additional space around the injection foil chamber. So far, new injection system seems not impossible. However, preliminary study result indicated that temperature of the duct and shielding metals would be slightly higher. The eddy current due to the shift bump magnet field generates heat. Thus we have to study details of above effect.

Journal Articles

Impact of PHITS spallation models on the neutronics design of an accelerator-driven system

Iwamoto, Hiroki; Nishihara, Kenji; Iwamoto, Yosuke; Hashimoto, Shintaro; Matsuda, Norihiro; Sato, Tatsuhiko; Harada, Masahide; Maekawa, Fujio

Journal of Nuclear Science and Technology, 53(10), p.1585 - 1594, 2016/10

 Times Cited Count:11 Percentile:81.57(Nuclear Science & Technology)

Journal Articles

Nuclear technology and potential ripple effect of superconducting magnets for fusion power plant

Nishimura, Arata*; Muroga, Takeo*; Takeuchi, Takao*; Nishitani, Takeo; Morioka, Atsuhiko

Fusion Engineering and Design, 81(8-14), p.1675 - 1681, 2006/02

 Times Cited Count:3 Percentile:25.6(Nuclear Science & Technology)

In a fusion reactor plant, a neutral beam injector (NBI) will be operated for a long time, and it will allow neutron streaming from NBI ports to outside of the plasma vacuum vessel. It requires the superconducting magnet to develop nuclear technology to produce stable magnetic field and to reduce activation of the magnet components. In this report, the back ground of the necessity and the contents of the nuclear technology of the superconducting magnets for fusion application are discussed and some typical investigation results are presented, which are the neutron irradiation effect on Nb$$_{3}$$Sn wire, the development of low activation superconducting wire, and the design concept to reduce nuclear heating and nuclear transformation by streaming. In addition, recent activities in high energy particle physics are introduced and potential ripple effect of the technology of the superconducting magnets is described briefly.

Journal Articles

Derivation of simple evaluation method for thermal shock damage on accelerator materials caused by out-of-control beam pulses and its application to J-PARC

Takei, Hayanori; Kobayashi, Hitoshi*

Journal of Nuclear Science and Technology, 42(12), p.1032 - 1039, 2005/12

 Times Cited Count:3 Percentile:25.79(Nuclear Science & Technology)

In high-intensity proton accelerator facilities, a failure of an electromagnet that steers beam pulses may result in thermal shock damage on the accelerator component by injecting an out-of-control pulse. It is important that a Machine Protection System (MPS) is appropriately designed to prevent this damage in the facilities such as Japan Proton Accelerator Research Complex (J-PARC). In this study, the simple evaluation method for the allowable injection time before the operation of the MPS was derived from the relation between the thermal stress and the yield stress of materials.The derived evaluation method was then applied to J-PARC. The allowable injection time for each component ranged from 0.1 to 70 $$mu$$s.

Journal Articles

Characterization of radionuclides formed by high-energy neutron irradiation

Yokoyama, Sumi; Sato, Kaoru; Noguchi, Hiroshi; Tanaka, Susumu; Iida, Takao*; Furuichi, Shinya*; Kanda, Yukio*; Oki, Yuichi*; Kaneto, Taihei*

Radiation Protection Dosimetry, 116(1-4), p.401 - 405, 2005/12

 Times Cited Count:1 Percentile:11.17(Environmental Sciences)

The physicochemical property of radionuclides suspended in the air is an important parameter to evaluate internal doses due to the inhalation of the airborne radionuclides and to develop the air monitoring system in high-energy proton accelerator facilities. This study focuses on the property of radioactive airborne chlorine ($$^{38}$$Cl and $$^{39}$$Cl) and sulfur ($$^{38}$$S) formed from Ar gas by irradiation with high-energy neutrons. As a result of the irradiation to a mixture of Ar gas and dry air, $$^{38}$$Cl and $$^{39}$$Cl existed as non-acidic gas and $$^{38}$$S was present as acidic gas. Further, it was found that in the high-energy neutron irradiation to aerosol containing-Ar gas, the higher the amount of radioactive aerosols becomes, the lower that of radioactive acidic gas becomes.

Journal Articles

Radiation safety design for the J-PARC project

Nakashima, Hiroshi; Nakane, Yoshihiro; Masukawa, Fumihiro; Matsuda, Norihiro; Oguri, Tomomi*; Nakano, Hideo*; Sasamoto, Nobuo*; Shibata, Tokushi*; Suzuki, Takenori*; Miura, Taichi*; et al.

Radiation Protection Dosimetry, 115(1-4), p.564 - 568, 2005/12

 Times Cited Count:7 Percentile:47.08(Environmental Sciences)

The High Intensity Proton Accelerator Project, named as J-PARC, is in progress, aiming at studies on the latest basic science and the advancing nuclear technology. In the project, the high-energy proton accelerator complex of the world highest intensity is under construction. In order to establish a reasonable shielding design, both simplified and detailed design methods were used in the shielding design of J-PARC. This paper reviews the present status of the radiation safety design study for J-PARC.

Journal Articles

Concept of transmutation experimental facility

Oigawa, Hiroyuki; Sasa, Toshinobu; Kikuchi, Kenji; Nishihara, Kenji; Kurata, Yuji; Umeno, Makoto*; Tsujimoto, Kazufumi; Saito, Shigeru; Futakawa, Masatoshi; Mizumoto, Motoharu; et al.

Proceedings of 4th International Workshop on the Utilisation and Reliability of High Power Proton Accelerators, p.507 - 517, 2005/11

Under the framework of J-PARC, the Japan Atomic Energy Research Institute (JAERI) plans to construct the Transmutation Experimental Facility (TEF). The TEF consists of two facilities: the Transmutation Physics Experimental Facility (TEF-P) and the ADS Target Test Facility (TEF-T). The TEF-P is a critical facility which can accept a 600 MeV - 10 W proton beam. The TEF-T is a material irradiation facility using a 600 MeV - 200 kW proton beam, where a Pb-Bi target is installed, but neutron multiplication by nuclear fuel will not be attempted. This report describes the purposes of the facility, the present status of the conceptual design, and the expected experiments to be performed.

Journal Articles

Design study around beam window of ADS

Oigawa, Hiroyuki; Tsujimoto, Kazufumi; Kikuchi, Kenji; Kurata, Yuji; Sasa, Toshinobu; Umeno, Makoto*; Nishihara, Kenji; Saito, Shigeru; Mizumoto, Motoharu; Takano, Hideki*; et al.

Proceedings of 4th International Workshop on the Utilisation and Reliability of High Power Proton Accelerators, p.325 - 334, 2005/11

The Japan Atomic Energy Research Institute (JAERI) is conducting the research and development (R&D) on the Accelerator-Driven Subcritical System (ADS) for the effective transmutation of minor actinides (MAs). The ADS proposed by JAERI is the 800 MWth, Pb-Bi cooled, tank-type subcritical reactor loaded with (MA+Pu) nitride fuel. The Pb-Bi is also used as the spallation target. In this study, the feasibility of the ADS was discussed with putting the focus on the design around the beam window. The partition wall was placed between the target region and the ductless-type fuel assemblies to keep the good cooling performance for the hot-spot fuel pin. The flow control nozzle was installed to cool the beam window effectively. The thermal-hydraulic analysis showed that the maximum temperature at the outer surface of the beam window could be repressed below 500 $$^{circ}$$C even in the case of the maximum beam power of 30 MW. The stress caused by the external pressure and the temperature distribution of the beam window was also below the allowable limit.

Journal Articles

Research and development program on accelerator driven subcritical system in JAERI

Tsujimoto, Kazufumi; Oigawa, Hiroyuki; Ouchi, Nobuo; Kikuchi, Kenji; Kurata, Yuji; Mizumoto, Motoharu; Sasa, Toshinobu; Nishihara, Kenji; Saito, Shigeru; Umeno, Makoto*; et al.

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10

The Japan Atomic Energy Research Institute (JAERI) has been proceeding with the research and development (R&D) on accelerator-driven subcritical system (ADS). The ADS proposed by JAERI is a lead-bismuth (Pb-Bi) eutectic cooled fast subcritical core with 800 MWth. To realize such an ADS, some technical issues should be studied, developed and demonstrated. JAERI has started a comprehensive R&D program since the fiscal year of 2002 to acquire knowledge and elemental technology that are necessary for the validation of engineering feasibility of the ADS. The first stage of the program had been continued for three years. The program is conducted by JAERI, and many institutes, universities and private companies were involved. Items of R&D are concentrated on three technical areas peculiar to the ADS: (1) superconducting linear accelerator (SC-LINAC), (2) Pb-Bi eutectic as spallation target and core coolant, and (3) subcritical core design and technology. In the present work, the outline and the results in the first stage of the program are reported.

Journal Articles

Neutron facility at high intensity proton accelerator project

Oyama, Yukio; Ikeda, Yujiro

Hoshasen To Sangyo, (107), p.45 - 51, 2005/09

JAERI and KEK are jointly conducting high intensity proton accelerator project (J-PARC). The outline of the J-PARC project and a design concept of the neutron source facility at J-PARC are described in detail.

Journal Articles

Current status of 1 MW pulse spallation neutron source (JSNS) of J-PARC

Ikeda, Yujiro

Journal of Nuclear Materials, 343(1-3), p.7 - 13, 2005/08

 Times Cited Count:23 Percentile:83.1(Materials Science, Multidisciplinary)

This paper reports the current status of The Materials and Life Experimental Facility construction under the high intensity proton accelerator projet(J-PARC), which has been conducted by JAERI and KEK collaboratively.Alng with designs and schedule of the neutron source, critical technical issues, e.g., mercury target material and moderator materials, which are still remained to be settled, and activities for development are shown.

JAEA Reports

Standard of radiation monitor based on LAN and PLC technology for J-PARC

Miyamoto, Yukihiro; Sakamaki, Tsuyoshi*; Maekawa, Osamu*; Nakashima, Hiroshi

JAERI-Tech 2004-054, 72 Pages, 2004/08


A standard is provided for the radiation monitor based on LAN (Local Area Network) and PLC (Programmable Logic Controller) technology at the introduction to the Japan Proton Accelerator Research Complex (J-PARC). The monitor consists of radiation measurement equipments and the central monitoring panel. The formers are installed in the radiation field, and the latter is installed in the control room and composed of PLC, which are connected with LAN. Extension of the existing standard and the conformity to the international standard were thought as important in providing the standard. The standard is expected to improve the compatibility, maintenancability and productivity of the components.

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