- Physical Review Journals
All JournalsPhysics Magazine

Physical Review Accelerators and Beams

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access

Design and optimization of rf structures for the CLIC main beam injector linacs

A. Kurtulus1,2, S. Doebert1, A. Grudiev1, A. Latina1, J. Leuthold2, J. Smajic2, and Y. Zhao1

  • 1CERN, Geneva, Switzerland
  • 2Institute of Electromagnetic Fields (IEF), ETH Zurich, Zurich, Switzerland

PDF

Phys. Rev. Accel. Beams 29, 051603 – Published 29 May, 2026

DOI: https://doi.org/10.1103/86pr-nhf7

Abstract

The design of the Compact Linear Collider (CLIC) main beam injector complex linacs necessitates high-gradient, traveling-wave accelerating structures engineered to withstand substantial beam-loading effects due to the elevated beam current and demanding acceleration requirements of CLIC operations. In this work, we present a comprehensive design and optimization study of 2 GHz traveling-wave structures tailored to these stringent requirements. The electron and positron linacs accelerate the beams up to 2.8 GeV with a nominal bunch charge of 1 nC, followed by the booster linac, which increases the energy to 9 GeV with a nominal bunch charge of 0.83 nC. Each bunch train consists of 352 bunches, requiring careful management of beam dynamics and wakefield effects to ensure stable operation. Through detailed analytical modeling and extensive parameter sweeps, we optimized the iris geometry of the accelerating structures to enhance shunt impedance, reduce surface electric fields, and suppress long-range wakefields via detuning strategies, thereby minimizing undesired beam-cavity interactions. Given the high beam current, we analyzed beam-loading effects and implemented compensation techniques to minimize bunch-to-bunch energy spread, supporting reliable, high-efficiency acceleration essential for CLIC operations. This study advances the development of high-performance accelerating structures that operate with high beam currents, which is crucial for achieving CLIC goals.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (11)

  1. M. Aicheler, P. Burrows, M. Draper, T. Garvey, P. Lebrun, K. Peach, N. Phinney, H. Schmickler, D. Schulte, and N. Toge, A Multi-TeV Linear Collider Based on CLIC Technology: CLIC Conceptual Design Report, CERN Monographs (CERN, Geneva, 2012), 10.5170/CERN-2012-007.
  2. CLIC Collaboration, 2025 CLIC readiness report, https://indico.cern.ch/event/1439855/contributions/6461475/attachments/3045847/5381772/2025_CLIC_Readiness_Report_v2.pdf (2025) [Accessed 26 June, 2025].
  3. Z. Farkas, H. Hogg, G. Loew, and P. B. Wilson, SLED: A method of doubling SLAC’s energy, in Proceedings of the of 9th International Conference on High Energy Accelerators, SLAC, Stanford, CA, USA (1974), p. 576, https://inspirehep.net/files/a694615a0d2dd92523a8c97a8fa5accf.
  4. M. Benedikt et al., Future Circular Collider Feasibility Study Report Volume 2: Accelerators, Technical Infrastructure and Safety (CERN, Geneva, 2025), 10.17181/CERN.EBAY.7W4X.
  5. J.-Y. Raguin and M. Bopp, The Swiss FEL C-band accelerating structure: RF design and thermal analysis, in Proceedings of the Linear Accelerator Conference, LINAC’12, Tel Aviv, Israel (JACoW, Geneva, Switzerland, 2012), pp. 501–503, https://jacow.org/LINAC2012/papers/TUPB012.pdf.
  6. A. Kurtulus, A. Grudiev, A. Latina, S. Bettoni, P. Craievich, and J.-Y. Raguin, Rf design and optimization of the high-energy linac for the FCC-ee injector complex, Phys. Rev. Accel. Beams 28, 101601 (2025).
  7. cst studio suite, Version 2024.02, Dassault Systèmes, Vélizy-Villacoublay, France (2024), https://www.3ds.com/products-services/simulia/products/cst-studio-suite/.
  8. A. Grudiev, S. Calatroni, and W. Wuensch, New local field quantity describing the high gradient limit of accelerating structures, Phys. Rev. ST Accel. Beams 12, 102001 (2009).
  9. A. Lunin, V. Yakovlev, and A. Grudiev, Analytical solutions for transient and steady state beam loading in arbitrary traveling wave accelerating structures, Phys. Rev. ST Accel. Beams 14, 052001 (2011).
  10. K. L. F. Bane and R. L. Gluckstern, Transverse wakefield of a detuned x-band accelerator structure, Technical Report No. SLAC-PUB-5783, SLAC National Accelerator Laboratory, 1992, https://www.slac.stanford.edu/pubs/slacpubs/5750/slac-pub-5783.pdf.
  11. O. Kononenko, R. Corsini et al., Rf pulse shape control in the compact linear collider test facility, Nucl. Instrum. Methods Phys. Res., Sect. A 897, 72 (2018).

Outline

Information

Phys. Rev. Accel. Beams 29, 051603– Published 29 May, 2026
  • Received 2 November 2025
  • Accepted 9 March 2026
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation