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ais, A.*; Bouly, F.*; Yee-Rendon, B.
Proceedings of 14th International Particle Accelerator Conference (IPAC 23) (Internet), p.4097 - 4100, 2023/09
Reliability in high power hadron accelerators is a major issue, particularly for Accelerator Driven Systems (ADS). For example, the Japan Atomic Energy Agency (JAEA) ADS maximum frequency of beam trips longer than 5 min was set to 42 per year. A significant number of breakdowns are caused by the failure of accelerating cavities or by their associated systems. Hence, we studied how these can be effectively reduced. To this end, we developed the numerical tool LightWin that aims to determine the compensation settings for any superconducting (SC) linac automatically and systematically. This tool has been successfully used for the MYRRHA SC linac. In this work, we applied LightWin to compensate for several failure scenarios involving the last section of the JAEA ADS linac and compared the associated retuned settings and beam performance to those found in a previous study with TraceWin.
Yee-Rendon, B.; Kondo, Yasuhiro; Tamura, Jun; Maekawa, Fujio; Meigo, Shinichiro
Proceedings of 14th International Particle Accelerator Conference (IPAC 23) (Internet), p.1591 - 1593, 2023/05
The Japan Atomic Energy Agency (JAEA) is designing a 30 MW continuous wave (cw) superconducting proton linear accelerator (linac) for the Accelerator Driven System (ADS) proposal. The JAEA-ADS linacs ion source must provide a proton beam over 20 mA with an energy of 35 keV and a normalized rms emittance of less than 0.1 
mm mrad. As the extraction system determines the beam properties and quality, systematic optimizations on the geometry and input values of the extraction system design were conducted using the AXCEL-INP 2-D simulation program to satisfy the goal requirements. This work describes the extraction system design and reports the beam dynamics results of the first study for the proton source of the JAEA-ADS linac.
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.
Jameson, R. A.*; Yee-Rendon, B.
Journal of Instrumentation (Internet), 17(12), p.P12011_1 - P12011_11, 2022/12
Times Cited Count：0 Percentile：0(Instruments & Instrumentation)A new application of vane modulation variation in a Radio Frequency Quadrupole (RFQ) cell has been applied that significantly improves beam bunching and longitudinal emittance control to achieve lower longitudinal rms emittance at the RFQ output. This procedure occurs in the individual cells, is independent of the overall design, and therefore is general, affording an extra parameter for beam manipulation. It can be applied besides the usual goals of vane modulation variation, e.g., to achieve higher acceleration efficiency. Examples of the cumulative effects on the overall design are provided to point out further exploration avenues for the designer.
Yee-Rendon, B.
Proceedings of 31st International Linear Accelerator Conference (LINAC 2022) (Internet), p.310 - 313, 2022/10
Accelerator-driven subcritical systems (ADS) offer an advantageous option for the transmutation of nuclear waste. ADS employs high-intensity proton linear accelerators (linacs) to produce spallation neutrons for a subcritical reactor. Besides the challenges of any megawatt proton machine, ADS accelerator must operate with stringent reliability to avoid thermal stress in the reactor structures. Thus, ADS linacs have adopted a reliability-oriented design to satisfy the operation requirements. This work provides a review and the present status of the ADS linacs in the world.
Yee-Rendon, B.; Kondo, Yasuhiro; Maekawa, Fujio; Meigo, Shinichiro; Tamura, Jun; Cicek, E.*
Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.793 - 795, 2021/08
The Five-cell Elliptical Superconducting Radio-Frequency Cavities (SRFC) provide the final acceleration in the JAEA-ADS linac (from 600 MeV to 1.5 GeV); thus, their performance is essential for the success of the JAEA-ADS project. After their optimization of the cavity geometry to achieve a high-acceleration gradient with lower electromagnetic peaks, the next step in the R&D strategy is the accurate estimation of beam-cavity effects which can affect the performance of the cavities. To this end, multipacting studies were developed to investigate its effect in the cavity operation regimen and find countermeasures. The results of this study will help in the development of the SRFC models and in the consolidation of the JAEA-ADS project.
Yee-Rendon, B.; Kondo, Yasuhiro; Maekawa, Fujio; Meigo, Shinichiro; Tamura, Jun
Journal of Physics; Conference Series, 1350(1), p.012197_1 - 012197_7, 2019/12
Times Cited Count：2 Percentile：72.74(Physics, Particles & Fields)Yee-Rendon, B.; Kondo, Yasuhiro; Maekawa, Fujio; Meigo, Shinichiro; Tamura, Jun
Journal of Physics; Conference Series, 1350(1), p.012198_1 - 012198_6, 2019/12
Times Cited Count：2 Percentile：51.97(Physics, Particles & Fields)Futatsukawa, Kenta*; Fang, Z.*; Fukui, Yuji*; Shinozaki, Shinichi; Mizobata, Satoshi; Sato, Yoshikatsu*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.486 - 489, 2017/12
In the J-PARC linac, the LLRF systems consist of twenty-four 324-MHz systems and twenty-five 972-MHz systems for ACS cavities. The 324-MHz LLRF systems, which were installed in the stations of RFQ, DTLs, and SDTLs, have been used since the beginning of the J-PARC and are more than ten years into the development. Realistically speaking, the incensement of the failure frequency for these systems is expected. Additionally, it is difficult to maintain those for some discontinued boards of a digital feedback (DFB) and a digital feedforward (DFF) at cPCI, and the older OS and developing environment of software. Therefore, we are starting to study the new LLRF system of the next generation. In the present, we are exploring several possibilities of a new way and investigating each advantage and disadvantage. The project and the status of the development for the new system in the J-PARC linac LLRF are introduced.
Seya, Michio; Kureta, Masatoshi; Soyama, Kazuhiko; Nakamura, Hironobu; Harada, Hideo; Hajima, Ryoichi
Proceedings of INMM 55th Annual Meeting (Internet), 10 Pages, 2014/07
JAEA has been implementing development programs of basic technologies of the following advanced NDA (non-destructive assay) of nuclear material (NM) for nuclear safeguards and security. (1) Alternative to 
He neutron detection using ZnS/B
O
ceramic scintillator, (2) NRD (neutron resonance densitometry) using NRTA (neutron resonance transmission analysis) and NRCA (neutron resonance capture analysis), (3) NRF (nuclear resonance fluorescence)-NDA using laser Compton scattered (LCS) 
-rays (intense mono-energetic -rays). The development program (1) is for NDA systems that use ZnS/BO ceramic scintillator as alternative neutron detector to He for coming shortage of its supply. The program (2) is for a NDA system of isotopic composition measurement (non-destructive mass spectroscopy) in targets such as particle-like melted fuel debris using NRTA and NRCA. The program (3) is for NDA systems using a specific NRF reaction of certain Pu/U isotope caused by mono-energetic LCS -ray with energy tuned to the specific excited state of the isotope. This paper introduces above three programs.
Minehara, Eisuke; Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Iijima, Hokuto; Nishitani, Tomohiro; Kimura, Hideaki*; Oguri, Daiichiro*; et al.
Proceedings of 13th International Conference on Nuclear Engineering (ICONE-13) (CD-ROM), 10 Pages, 2005/05
The JAERI FEL has recently discovered the new FEL lasing of 255fs ultra fast pulse, 6-9% high-efficiency, one gigawatt high peak power, a few kilowatts average power, and wide tunability of medium and far infrared wavelength regions at the same time. Using the new lasing and energy-recovery linac technology, we could extend a more powerful and more efficient free-electron laser (FEL) than 10kW and 25%, respectively, for nuclear industry, pharmacy, medical, defense, shipbuilding, semiconductor industry, chemical industries, environmental sciences, space-debris, power beaming and so on. In order to realize such a tunable, highly-efficient, high average power, high peak power and ultra-short pulse FEL, we need the efficient and powerful FEL driven by the JAERI compact, stand-alone and zero boil-off super-conducting RF linac with an energy-recovery geometry. Our discussions on the FEL will cover the application of non-thermal peeling, cutting, and drilling to decommission the nuclear power plants, and to prevent stress-corrosion cracking in nuclear industry and roadmap for the industrial FELs, the JAERI compact, stand-alone and zero-boil-off cryostat concept and operational experience, the new, highly-efficient, high-power, and ultra fast pulse lasing mode, and the energy-recovery geometry.
Yamazaki, Yoshishige
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004), p.1351 - 1353, 2004/00
The J-PARC (Japan Proton Accelerator Research Complex) is under construction in JAERI Tokai site. The beam commissioning will start there by the end of 2006. Prior to this, the front end of the linac was beam-commissioned in 2003 at KEK. The negative hydrogen beam with a peak current of 30 mA was accelerated up to 20 MeV by the first tank of the three DTL's following the 3-MeV RFQ linac. The 324-MHz DTL contains the electro quadrupole magnets with water-cooling channels specially fabricated by means of electroforming and wire-cutting technologies. The construction status of the J-PARC accelerator is also presented.
Suganuma, Kazuaki; Anami, Shozo*; Kubota, Chikashi*; Chishiro, Etsuji; Yamaguchi, Seiya*
Proceedings of 28th Linear Accelerator Meeting in Japan, p.78 - 80, 2003/08
This report a design and adjustment of 324MHz Waveguide System of The J-PARC LINAC.
Kondo, Yasuhiro; Ueno, Akira*; Ikegami, Masanori*; Ikegami, Kiyoshi*
Proceedings of 28th Linear Accelerator Meeting in Japan, p.69 - 71, 2003/08
A 3.115m long, 324MHz, 3MeV radio-frequency quadrupole (RFQ) linac is used as the first RF accelerator of the J-PARC linac. We have performed RFQ simulations to provide a particle distribution for an end-to-end (from the RFQ entrance to the injection point of the rapid cycling synchrotron (RCS)) simulation of the J-PARC linac. Two simulation codes, PARMTEQM and TOUTATIS are used for the RFQ simulations. The simulated emittances show good agreements with the ones measured at the exit of the medium energy beam transport (MEBT).
Minehara, Eisuke; Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki
Proceedings of 28th Linear Accelerator Meeting in Japan, p.31 - 32, 2003/08
Current status of the JAERI superconducting RF linac driven free-electron laser has been reported to describe some details of the FEL device and application researches. In the presentation, several progresses and achievements itimized below have been reproted briefly. Firstly a semi-perpetual, non-stop and continous operation of the JAERI cryogenic and refrigeration system is only available in the world for the JAERI superconducting linac-based FEL. Secondly a conceptual design and each vital component of the ERL(energy recovery linac) light souce has recently been developed and progressed quickly as the next-generation light source. Thirdly,large-scaled industrial applications have been briefly reported here.
Minehara, Eisuke
Proceedings of 28th Linear Accelerator Meeting in Japan, p.402 - 403, 2003/08
The JAERI superconducting RF linac-based free-electron laser has successfully generated 6% highly-efficient, a few hundreds of femtosecond, and several kW class high power FEL light several years ago. In the presentation, it will be reprted that the JAERI plans to develop the higher power free-electron lasers and their application to large-scale non-thermal precision manufacturing technology.
Minehara, Eisuke
Hoshasen To Sentan Iryo Gijutsu, p.135 - 142, 2003/06
Medical applications of Free-Electron Lasers(FELs), especially the FEL driven by a superconducting rf linac, look very promising because of the compactness, high efficiency, high power capability, tunability, ultra-short pulse width and so on. Here, the linac-based FEL is explained briefly and discussed all about the remarkable features and the road maps near future. Finally, some possible and usable applications of the FELs will be introduced and discussed in the relationship with the features above.
Minehara, Eisuke
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, 247 Pages, 2003/00
A 400m-long superconducting RF linac cryostat is conceptually designed and discussed to optimize the advanced low-temperature cryostat for an ERL light source. A low temperature cryostat for superconducting RF linacs and other superconducting devices should be designed and made to minimize its heat invasion through the heat bridges between the room and low temperature parts. The cryostat also should be designed and made to minimize total number of the heat cycles for the rest of its life after the initial test. We can expect that the total number of the heat bridges is roughly proportional to the number of the cryostat, and a life interval between two contiguous cryostat malfunctions inversely proportional to the number of the heat cycles. Therefore, if we can design and make a single and long cryostat to realize the operation less than a half cycle for the rest of its life, we can run our cryostat for a very longer interval than tens of years and with minimum electricity.
Yamazaki, Yoshishige
Proceedings of 2003 Particle Accelerator Conference (PAC 2003) (CD-ROM), p.576 - 580, 2003/00
The JAERI-KEK Joint Project for the High Intensity Proton Accelerator, now referred to as the J-PARC Project (Japan Proton Accelerator Research Complex), comprises a 400-MeV linac, a 3-GeV, 25-Hz Rapid-Cycling Synchrotron (RCS), and a 50-GeV Main Synchrotron (MR). In contrast to the SNS or the ESS, the J-PARC makes use of the RCS in order to produce MW-class pulsed spallation neutrons rather than a combination of the full-energy linac and the compressor ring.
Ao, Hiroyuki; Hayashizaki, Noriyosu*; Paramonov, V.*
Proceedings of 2003 Particle Accelerator Conference (PAC 2003) (CD-ROM), p.2826 - 2828, 2003/00
An Annular Coupled Structure (ACS) has been developed for upgrade of a J-PARC (Japan Proton Accelerator Research Complex) linac from 180 MeV to 400 MeV. Although install area is prepared for the ACS cavities at an initial construction, it will be used as a beam-transport line temporarily. Aluminum and copper models were fabricated for RF properties confirmation based on an initial design, and for final optimization. RF measurement procedure of the ACS structure was also studied thorough the R&D process. Many items should be considered for mass production; schedule, handling parts, utilities, and so on. The measurement results of models and some fabrication status are presented.
