Keyword: focusing
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WEA3I1 Synchronous Phases and Transit Time Factor cavity, linac, accelerating-gradient, acceleration 241
 
  • J.-M. Lagniel
    GANIL, Caen, France
 
  Synchronous phases (¿s) and transit time factors (T) are THE key parameters for linac designs and operations. While the couple (¿s, T) is still our way of thinking the longitudinal beam dynamics, it is important to have in mind that the original ¿Panofsky¿ definition of these parameters is no longer valid in the case of high accelerating gradients leading to high particle velocity changes and in the case of multi-gap cavities. In this case, a new (¿s, T) definition allowing to keep both acceleration and longitudinal focusing properties is proposed. Examples are given in the SPIRAL2 linac case.  
slides icon Slides WEA3I1 [2.369 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA3I1  
About • Received ※ 27 September 2023 — Revised ※ 12 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 17 October 2023
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THA2C2 Comparison of Longitudinal Emittance of Various RFQs rfq, emittance, simulation, linac 368
 
  • M. Comunian, L. Bellan, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
 
  In various projects a large variety of RFQs has been developed, for different application, with different average current, frequency, and energy range. On this article a comparison, in a scaled way, will be done, using the build RFQs of IFMIF, ESS, SPES, ANTHEM, PIAVE. On particular the beam dynamics characteristics will be analyzed, like transmission, output longitudinal emittance and real performance versus simulation.  
slides icon Slides THA2C2 [6.261 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C2  
About • Received ※ 30 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 16 October 2023
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THA2C4 Alternating Phase Focusing Under Influence of Space Charge Defocusing linac, heavy-ion, software, cavity 377
 
  • S. Lauber, W.A. Barth, R. Kalleicher, M. Miski-Oglu
    HIM, Mainz, Germany
  • W.A. Barth, M. Miski-Oglu, S. Yaramyshev
    GSI, Darmstadt, Germany
  • W.A. Barth
    KPH, Mainz, Germany
 
  Alternating phase focusing (APF) recently emerged as a promising beam dynamics concept for accelerating bunched proton or ion beams in drift tube linear accelerators, eliminating the need for additional transverse and longitudinal focusing lenses. The performance of APF systems, similar to radio frequency quadrupoles, heavily relies on the employed focusing lattice, including the particle synchronous phase in each gap, as well as various hyperparameters such as the number of gaps, the focusing gradient, and the required beam acceptance. However, to fully utilize the cost advantages and mechanical simplicity of APF drift tube linacs, specialized software tools are necessary to streamline the accelerator development process. After successful developement of the HELIAC-APF-IH-DTL for low current and continuous wave duty cycle, this paper presents the design concepts for APF cavities tailored for high-current applications, aiming to facilitate the design and implementation of APF-based accelerators.  
slides icon Slides THA2C4 [4.986 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THA2C4  
About • Received ※ 06 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 18 October 2023
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THBP20 Optics for Landau Damping with Minimized Octupolar Resonances in the LHC optics, resonance, octupole, injection 503
 
  • R. Tomás García, F.S. Carlier, L. Deniau, J. Dilly, J. Keintzel, S. Kostoglou, M. Le Garrec, E.H. Maclean, K. Paraschou, T.H.B. Persson, F. Soubelet, A. Wegscheider
    CERN, Meyrin, Switzerland
 
  Operation of the Large Hadron Collider (LHC) requires strong octupolar magnetic fields to suppress coherent beam instabilities. The amplitude detuning that is generated by these octupolar magnetic fields brings the tune of individual particles close to harmful resonances, which are mostly driven by the octupolar fields themselves. In 2023, new optics were deployed in the LHC at injection with optimized betatronic phase advances to minimize the resonances from the octupolar fields without affecting the amplitude detuning. This paper reports on the optics design, commissioning and the lifetime measurements performed to validate the optics.  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP20  
About • Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023
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THBP44 ImpactX Modeling of Benchmark Tests for Space Charge Validation space-charge, emittance, cavity, proton 583
 
  • C.E. Mitchell, M. Garten, A. Huebl, R. Lehé, J. Qiang, R.T. Sandberg, J.-L. Vay
    LBNL, Berkeley, California, USA
 
  The code ImpactX represents the next generation of the particle-in-cell code IMPACT-Z, featuring s-based symplectic tracking with 3D space charge, parallelism with GPU acceleration, adaptive mesh-refinement, and modernized language features. With such a code comes a renewed need for space charge validation using well-defined benchmarks. For this purpose, the code is continuously checked against a test suite of exactly-solvable problems. The suite includes field calculation tests, dynamical tests involving coasting or stationary beams, and beams matched to periodic focusing channels. To study the long-time multi-turn performance of the code in a more complex setting, we investigate problems involving high-intensity storage rings, such as the GSI benchmark problem for space charge induced trapping. Comparisons against existing codes are made where possible.  
poster icon Poster THBP44 [1.020 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP44  
About • Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 26 October 2023
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