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Yee-Rendon, B.; Kondo, Yasuhiro; Tamura, Jun; Maekawa, Fujio; Meigo, Shinichiro
Proceedings of 21st Annual Meeting of Particle Accelerator Society of Japan (Internet), p.205 - 209, 2024/10
The Japan Atomic Energy Agency (JAEA) designs a 30-MW CW proton linear accelerator (linac) as a key component for the accelerator-driven subcritical system (ADS) project, aimed at nuclear waste management. The low energy beam transport (LEBT) in JAEA-ADS uses charge neutralization to minimize space-charge effects, which are the primary cause of beam loss in high-power accelerators. During commissioning and power ramp-up, precise control of the duty cycle is required for safety and machine protection; thus, a chopper system will be installed to manage the beam power. The chopper is located at the LEBT, to facilitate the disposal of the excess beam power, but its operation will affect the charge neutralization producing beam transients that could lead to beam loss. To shed light on this, we created a beam optics model for the chopper using an analytic approach to determine the required characteristics like voltage and dimensions, which was confirmed through TraceWin simulations. Subsequently, we analyzed the chopper's impact on space-charge compensation to evaluate the beam transients in the LEBT. This study reports the design of the chopper and its effects on beam performance for the JAEA-ADS LEBT.
Yee-Rendon, B.; Kondo, Yasuhiro; Tamura, Jun; Maekawa, Fujio; Meigo, Shinichiro
Proceedings of 32nd Linear Accelerator Conference (LINAC 2024) (Internet), p.488 - 491, 2024/10
The Japan Atomic Energy Agency (JAEA) is designing a 30-MW CW proton linear accelerator (linac) for nuclear waste transmutation. Space-charge is the primary challenge in achieving low losses and high beam quality for high-power accelerators, especially at low energy levels where space-charge forces are greater. To counteract the space-charge effects, the low-energy beam transport (LEBT) uses a magnetostatic design to enable the neutralization of the beam charge, the so-called space charge compensation. The neutralization is an accumulation process that reaches a charge balance between the main beam and the opposite ionized particles. However, this equilibrium is destroyed by the chopper system used during beam ramping. During those transient regimes, the beam optics conditions are not optimal for the beam, producing considerable degradation that can end in serious damage to the accelerator. Thus, analysis of beam behavior at these periods is essential to develop a robust design and an efficient operation of the JAEA-ADS linac. This study presents the beam dynamics of neutralization build-up and chopper operation for the JAEA-ADS LEBT.
Yee-Rendon, B.; Kondo, Yasuhiro; Tamura, Jun; Maekawa, Fujio; Meigo, Shinichiro
Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.545 - 549, 2023/11
The Japan Atomic Energy Agency (JAEA) is proposing a 30-MW proton linear accelerator (linac) for the application of accelerator-driven subcritical system (ADS) technology to achieve nuclear waste transmutation. A major challenge for the JAEA-ADS linac is the efficient transport of a 35 keV proton beam from the ion source to the radio-frequency quadrupole. In order to achieve this goal, we have optimized a magnetostatic low energy beam transport (LEBT) consisting of two solenoids to reduce the transmission of high-charge ions generated by the source and minimize the growth of proton emittance, while taking into account various space-charge compensation scenarios. In this report, we present the optical design and discuss the multiparticle tracking results of the JAEA-ADS LEBT.
Yee-Rendon, B.; Kondo, Yasuhiro; Tamura, Jun; Nakano, Keita; Maekawa, Fujio; Meigo, Shinichiro
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.179 - 183, 2023/01
The Japan Atomic Energy Agency accelerator-driven subcritical system (JAEA-ADS) pursues the reduction of nuclear waste by transmuting minor actinides. JAEA-ADS project drives a 30-MW proton beam to a lead-bismuth eutectic (LBE) spallation target to produce neutrons for a subcritical core reactor. To this end, the JAEA-ADS beam transport (BT) must provide a suitable beam profile and stable beam power to the beam window of the spallation target to avoid high-thermal stress in the components, such as the beam window. The beam transport was optimized by tracking a large number of macroparticles to mitigate the beam loss, performance with high stability in the presence of errors, and fulfill the length requirement on the transport. This work presents beam transport design and beam dynamics research for the JAEA-ADS project.
Yee-Rendon, B.; Meigo, Shinichiro; Kondo, Yasuhiro; Tamura, Jun; Nakano, Keita; Maekawa, Fujio; Iwamoto, Hiroki; Sugawara, Takanori; Nishihara, Kenji
Journal of Instrumentation (Internet), 17(10), p.P10005_1 - P10005_21, 2022/10
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)To reduce the hazard of minor actinides in nuclear waste, JAEA proposed an accelerator-driven subcritical system (JAEA-ADS). The JAEA-ADS drives a subcritical reactor 800-MWth by 30-MW proton linac delivering the beam to the spallation neutron target inside the reactor. The beam transport to the target (BTT) is required for high-beam power stability and low peak density to ensure the integrity of the beam window. Additionally, the design should have compatible with the reactor design for the maintenance and replacement of the fuel and the beam window. A robust-compact BTT design was developed through massive multiparticle simulations. The beam optics was optimized to guarantee beam window feasibility requirements by providing a low peak density of less than 0.3 
A/mm
. Beam stability was evaluated and improved by simultaneously applying the linac's input beam and element errors. The input beam errors to the reactor were based on the beam degradation obtained by implementing fast fault compensation in the linac. Those results show that the BTT fulfills the requirements for JAEA-ADS.
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.
Oi, Motoki; Meigo, Shinichiro; Akutsu, Atsushi*; Kawasaki, Tomoyuki; Nishikawa, Masaaki*; Fukuda, Shimpei
Proceedings of 12th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '15), p.89 - 96, 2016/00
At J-PARC, 3 GeV proton beam with power of 1MW is delivered to the spallation neutron source (JSNS) through beam transport line called 3NBT. At the high power accelerator facilities even a small abnormal event has a possibility to be critical so that the beam control system is crucial. In order to find tiny anomaly, rapid data analysis system is required. We developed control and data analysis system based on the Experimental Physics and Industrial Control System (EPICS) and Control System Studio (CSS). To carry out beam tuning efficiently, the beam control system based on the Strategic Accelerator Design (SAD) code has been developed. With the several shots of beam and by the one click of operational panel of the screen, required magnet field can be calculated and set automatically. Also we developed automated e-mail system to announce the abnormal event to the experts persons. With these systems, we can reduce both beam tuning time and down time.
Sakamoto, Shinichi; Meigo, Shinichiro; Fujimori, Hiroshi*; Harada, Masahide; Konno, Chikara; Kasugai, Yoshimi; Kai, Tetsuya; Miyake, Yasuhiro*; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research A, 562(2), p.638 - 641, 2006/06
Times Cited Count：9 Percentile：49.99(Instruments & Instrumentation)Materials and Life Science Facility of Japan Proton Accelerator Research Complex (J-PARC) is an experimental facility where neutron and muon beams are provided as powerful probes. They are generated with high-intensity proton beam supplied through a 3-GeV proton beam transport (3NBT) line. Its beam optics and components were designed to transport the proton beam of large emittance with extremely low loss rate. The 3NBT accommodates an intermediate target that causes large beam loss. The scheme of the cascade target system was carefully devised to overcome difficulties due to high radiation.
Oi, Motoki; Meigo, Shinichiro
JAERI-Tech 2005-025, 52 Pages, 2005/03
JAERI-Tech-2005-025.pdf:3.28MB
In the J-PARC 3GeV proton beam transport facility (3NBT), proton beam profile monitor, halo monitor, loss monitor and proton current monitors are used as proton beam monitor. The electric signals from these monitors are converted to digital signal with ADC on CAMAC modules and monitoring with EPICS system through CAMAC controller CC/NET. At the 3NBT proton beam monitor system, these are monitored with frequency of 25Hz and all of these data are archived. In this report, we develop the EPICS system for 3NBT proton beam monitors and confirm the performance of the system. As a result, we can monitor and archive these proton beam monitor signals at 25 Hz with CC/NET and EPICS.
Miyawaki, Nobumasa; Kurashima, Satoshi; Okumura, Susumu; Chiba, Atsuya; Agematsu, Takashi; Kamiya, Tomihiro; Kaneko, Hirohisa; Nara, Takayuki; Saito, Yuichi; Ishii, Yasuyuki; et al.
Proceedings of 17th International Conference on Cyclotrons and Their Applications (CYCLOTRONS 2004), p.208 - 210, 2005/00
A project to expand at TIARA (Takasaki Ion Accelerators for Advanced Radiation Application) facilities of JAERI has been proposed to broaden applications in biotechnology and materials science. Heavy ions with energy more than 100 MeV/n are required for remarkable progress in breeding of plant and development of new materials. The magnet of a superconducting AVF cyclotron with a K number of 900 has been designed to cope with acceleration of both 150 MeV/n heavy ions and 300 MeV protons. The lower limit of energies has been investigated to overlap the energy region covered by the JAERI AVF cyclotron, required to increase beam time for present users. We have designed a beam transport system to satisfy requirements of the applications.
Sakamoto, Shinichi; Meigo, Shinichiro; Konno, Chikara; Kai, Tetsuya; Kasugai, Yoshimi; Harada, Masahide; Fujimori, Hiroshi*; Kaneko, Naokatsu*; Muto, Suguru*; Ono, Takehiro*; et al.
JAERI-Tech 2004-020, 332 Pages, 2004/03
JAERI-Tech-2004-020.pdf:17.93MB
One of the experimental facilities in Japan Proton Accelerator Research Complex (J-PARC) is the Materials and Life Science Experimental Facility (MLF), where high-intensity neutron beams and muon beams are used as powerful probes for materials science, life science and related engineering. The neutrons and muons are generated with high-intensity proton beam from 3-GeV rapid cycling synchrotron (RCS). The high-intensity proton beam has to be effectively transported, and a neutron production target and a muon production target have to be also properly irradiated. The principal design of the 3-GeV proton beam transport facility (3NBT) is systematized.
Agematsu, Takashi; Arakawa, Kazuo; Okumura, Susumu; Nakamura, Yoshiteru; Tajima, Satoshi
KEK Proceedings 2003-19, p.27 - 29, 2004/03
Cyclotron start-up operations require dozens of adjustable parameters to be tuned to maximize extracted beam current. Experienced operators perform this process through trial and error using their experience and intuition. However, the process is difficult for inexperienced operators because operator need to adjust parameters using little information such as measured beam data, alarm, status of components, and so on. We have developed a computer-based visual assistance system for JAERI AVF cyclotron. The system provides a CRT display: the cyclotron beam trajectories, feasible setting regions, search traces and the beam envelopes for external beam transport designed to optimize beam parameter adjustment. The evaluation experiment for the system was carried out and the operation time to reach required beam conditions of the injection region of the cyclotron was reduced by approximately 65%. Also the system is very useful to study the problems on the beam transport such as beam trajectory, envelope, beam profile, spot size and so on.
Morimoto, Iwao; Zheng, X. D.*; Maebara, Sunao; Kishiro, Junichi*; Takayama, Ken*; Horioka, Kazuhiko*; Ishizuka, Hiroshi*; Kawasaki, Sunao*; Shiho, Makoto
Nuclear Instruments and Methods in Physics Research A, 475(1-3), p.509 - 513, 2001/12
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)no abstracts in English
Agematsu, Takashi; Kamiya, Tomihiro; Kaneko, Hirohisa; Mizuhashi, Kiyoshi; Saito, Yuichi; Chiba, Atsuya; Fukuda, Mitsuhiro; Arakawa, Kazuo
Proceedings of 13th Symposium on Accelerator Science and Technology, p.467 - 469, 2001/10
A new project aiming a breakthrough in biotechnology and materials science has been proposed at TIARA (Takasaki Ion Accelerators for Advanced Radiation Application) facilities of JAERI. We have started designing a K900 superconducting AVF cyclotron (K900 SCC). The beam transport line for JAERI K900 SCC has been designed preliminary for heavy ion beams with an energy of more than a hundred MeV/n. An achromatic beam transport system has been designed for high transmission efficiency of ion beams and good adjustability of magnet parameters using the computer code “TRANSPORT".
Goto, Shunji*; Ohashi, Haruhiko*; Takeshita, Kunikazu*; Yabashi, Makina*; Yamakata, Masaaki*; Asano, Yoshihiro; Ishikawa, Tetsuya*
Nuclear Instruments and Methods in Physics Research A, 467-468(Part1), p.813 - 815, 2001/07
Times Cited Count：3 Percentile：28.15(Instruments & Instrumentation)no abstracts in English
Niita, Koji*; Meigo, Shinichiro; Takada, Hiroshi; Ikeda, Yujiro
JAERI-Data/Code 2001-007, 128 Pages, 2001/03
JAERI-Data-Code-2001-007.pdf:5.07MB
no abstracts in English
Hirayama, Toshio; Shirai, Hiroshi; Yagi, Masatoshi; Shimizu, Katsuhiro; Koide, Yoshihiko; Kikuchi, Mitsuru; Azumi, Masafumi
Nuclear Fusion, 32(1), p.89 - 106, 1992/00
Times Cited Count：7 Percentile：32.74(Physics, Fluids & Plasmas)no abstracts in English
Hirayama, Toshio; Kikuchi, Mitsuru; Shirai, Hiroshi; Shimizu, Katsuhiro; Yagi, Masatoshi; Koide, Yoshihiko; Ishida, Shinichi; Azumi, Masafumi
JAERI-M 91-026, 28 Pages, 1991/03
no abstracts in English
Arakawa, Kazuo; Nakamura, Yoshiteru; Yokota, Wataru; Fukuda, Mitsuhiro; Kamiya, Tomihiro; Agematsu, Takashi; Nara, Takayuki; ; Ishibori, Ikuo; Tanaka, Ryuichi; et al.
Proc. of the 4th China-Japan Joint Symp. on Accelerators for Nuclear Science and Their Applications, p.173 - 175, 1991/00
no abstracts in English
