J.Y. Li, T. Hu, J. Yang, B.Q. Zeng
HUST, Wuhan, People’s Republic of China
H.G. Xu
SINR, Jiading, Shanghai, People’s Republic of China
Funding:This work was supported by National Natural Science Foundation of China (NSFC) under Project Numbers 11905074. Electron linear accelerators with an energy of ~MeV are widely required in industrial applications. Whereas miniaturized accelerators, especially those working at X-band, attract more and more attention due to their compact structures and high gradients. Since the performance of a traveling wave (TW) accelerator is determined by its structures, considerable efforts must be made for structure optimization involving numerous and complex parameters. In this context, functional key parameters are obtained through deep analysis for structure and particle motion characteristics of the TW accelerator, then a multi-objective genetic algorithm (MOGA) is successfully applied to acquire an optimized phase velocity distribution which can contribute to achieving a high capture ratio and a low energy spread. Finally, a low-energy X-band TW tube used for rubber vulcanization is taken as an example to verify the reliability of the algorithm under a single-particle model. The capture ratio is 91.2%, while the energy spread is 5.19%, and the average energy is 3.1MeV.
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B. Yee-Rendón, Y. Kondo, F. Maekawa, S.I. Meigo, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
The Japan Atomic Energy Agency (JAEA) is working in the research and development of an Accelerator Driven Subcritical System (ADS) for the transmutation of nuclear waste. To this end, JAEA is designing a 30-MW cw proton linear accelerator (linac) with a beam current of 20 mA. The JAEA-ADS linac starts with a Normal Conducting (NC) up to an energy of 2.5 MeV. Then, five Superconducting (SC) sections accelerate the beam up to 1.5 GeV. The biggest challenge for this ADS linac is the stringent reliability required to avoid thermal stress in the subcritical reactor, which is higher than the achieved in present accelerators. For this purpose, the linac pursues a strong-stable design that ensures the operation with low beam loss and fault-tolerance capabilities to continue operating in case of failure. This work presents the beam dynamics results toward achieving high reliability for the JAEA-ADS linac.
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P. Zhu, Y.C. He, D.P. Jin, Y.L. Zhang
IHEP, Beijing, People’s Republic of China
L. Wang, X. Wu, K. Xue
IHEP CSNS, Guangdong Province, People’s Republic of China
The high-quality of fast machine protection system(FPS) is one of the significant conditions for the stable and reliable operation of the Chinese Spallation Neutron Source (CSNS) accelerator. Based on the design concept of high availability, high reliability and high maintainability, we adopt the distributed architecture based on "high-performance Field Programmable Gate Array (FPGA) chip + Gigabit Transceiver with Low Power (GTP)+ VME bus read and write by real-time", which is demonstrated the superior performance to satisfy the requirements of the CSNS accelerator during commissioning and operation. The main design and implementation include: (1) develop diversity signal interface boards achieving a flexible interaction; (2) explore and realize protection strategies improving beam efficiency; (3) self-define and implement the creative and practical functions enhancing the robustness of the system, such as signal heartbeat monitoring, fail-safe mechanism, automatic reset, and so on. The CSNS accelerator fast machine protection system has been put into operation for nearly five years with strong operability and availability, thorough traversal and response time-consuming tests.
V. Kain, N. Madysa, P.K. Skowroński, I. Vojskovic
CERN, Geneva, Switzerland
N. Bruchon
University of Trieste, Trieste, Italy
S. Hirlaender, G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta
The CERN H⁻ linear accelerator, LINAC4, served as a test bed for advanced algorithms during the CERN Long Shutdown 2 in the years 2019/20. One of the main goals was to show that reinforcement learning with all its benefits can be used as a replacement for numerical optimization and as a complement to classical control in the accelerator control context. Many of the algorithms used were prepared beforehand at the electron line of the AWAKE facility to make the best use of the limited time available at LINAC4. An overview of the algorithms and concepts tested at LINAC4 and AWAKE will be given and the results discussed.
A. Gatera, J. Belmans, S. Boussa, F. Davin, W. De Cock, V.R.A. De florio, F. Doucet, L. Parez, F. Pompon, A. Ponton, D. Vandeplassche, E. Verhagen
SCK•CEN, Mol, Belgium
Dr. Ben Abdillah, C. Joly, L. Perrot
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
F. Bouly, E. Froidefond, A. Plaçais
LPSC, Grenoble Cedex, France
H. Podlech
IAP, Frankfurt am Main, Germany
J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
C. Zhang
GSI, Darmstadt, Germany
The MYRRHA project at SCK•CEN, Belgium, aims at coupling a 600 MeV proton accelerator to a subcritical fission core operating at a thermal power of 60 MW. The nominal proton beam for this ADS has an intensity of 4 mA and is delivered in a quasi-CW mode. MYRRHA’s linac is designed to be fault tolerant thanks to redundancy implemented in parallel at low energy and serially in the superconducting linac. Phase 1 of the project, named MINERVA, will realise a 100 MeV, 4 mA superconducting linac with the mission of demonstrating the ADS requirements in terms of reliability and of fault tolerance. As part of the reliability optimisation program the integrated prototyping of the MINERVA injector is ongoing at SCK•CEN in Louvain-la-Neuve, Belgium. The injector test stand aims at testing sequentially all the elements composing the front-end of the injector. This contribution will highlight the beam dynamics choices in MINERVA’s injector and their impact on ongoing commissioning activities. *angelique.gatera@sckcen.be
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P.N. Ostroumov, F. Casagrande, K. Fukushima, M. Ikegami, T. Kanemura, S.H. Kim, S.M. Lidia, G. Machicoane, T. Maruta, D.G. Morris, A.S. Plastun, J.T. Popielarski, J. Wei, T. Xu, T. Zhang, Q. Zhao, S. Zhao
FRIB, East Lansing, Michigan, USA
Funding:Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University. The Facility for Rare Isotope Beams (FRIB), a major nuclear physics facility for research with fast, stopped, and reaccelerated rare isotope beams, is approaching the commencement of user operation in 2022 as planned. The readiness of the linear accelerator for the production of rare isotopes was verified by the acceleration of Xenon-124 and Krypton-86 heavy ion beams to 212 MeV/u using all 46 cryomodules with 324 superconducting cavities. Several key technologies were successfully developed and implemented for the world¿s highest energy continuous wave heavy ion beams, such as full-scale cryogenics and superconducting radiofrequency resonator system, stripping heavy ions with a thin liquid lithium film flowing in an ultrahigh vacuum environment, and simultaneous acceleration of multiple-charge-state-heavy ion beams. These technologies are required to achieve ultimate FRIB beam energies beyond 200 MeV/u and beam power up to 400 kW. High intensity pulsed beams capable in delivering 200 kW beams to the target in CW mode were studied in the first segment of the linac.
