- 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

Quadrupole mode-based multipactor suppression in SSR cavities and its impact on beam dynamics

Alok Kumar Ghosh1,3,*, Gaurav Singh2, Shweta Roy1, Raghwendra Kumar2,3, Vyaghri LS Rao Sista1,3, and Rajesh Kumar1,3

  • *Contact author: alokg@barc.gov.in
PDF

Phys. Rev. Accel. Beams 29, 073201 – Published 29 July, 2026

DOI: https://doi.org/10.1103/djxf-zcrc

Abstract

Multipactor (MP) discharge is a critical limitation in superconducting radio-frequency (SRF) cavities, impacting the quality factor and cryogenic stability. In this article, we present a novel mitigation strategy to mitigate MP discharge by utilizing specific higher order quadrupole modes in single spoke resonator (SSR) cavities, designed for the MEHIPA-II linac. We demonstrate that the presence of a specific quadrupole mode leads to the effective suppression of MP in that SSR cavity and show that the quadrupole modes have minimal influence on the proton beam across the 40–200 MeV energy range. Analytical proofs based on field symmetry, supported by numerical simulations, confirm that the excitation of the quadrupole field results in zero net transverse kick and negligible emittance growth of the proton beam. This approach provides a flexible and alternative solution against persistent electron activity, overcoming a long-standing limitation to stable, high-gradient SRF operation.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (34)

  1. J. R. M. Vaughan, Multipactor, IEEE Trans. Electron Devices 35, 1172 (1988).
  2. R. A. Kishek, Y. Y. Lau, L. K. Ang, A. Valfells, and R. M. Gilgenbach, Multipactor discharge on metals and dielectrics: Historical review and recent theories, Phys. Plasmas 5, 2120 (1998).
  3. A. Iqbal, D.-Q. Wen, J. Verboncoeur, and P. Zhang, Recent advances in multipactor physics and mitigation, High Voltage 8, 1095 (2023).
  4. J. R. M. Vaughan, A new formula for secondary emission yield, IEEE Trans. Electron Devices 36, 1963 (1989).
  5. M. A. Furman and M. T. F. Pivi, Probabilistic model for the simulation of secondary electron emission, Phys. Rev. ST Accel. Beams 5, 124404 (2002).
  6. E. T. Tulu, U. van Rienen, and A. Arnold, Systematic study of multipactor suppression techniques for a superconducting rf gun, Phys. Rev. Accel. Beams 21, 113402 (2018).
  7. L. Wang, T. O. Raubenheimer, and G. Stupakov, Suppression of secondary emission in a magnetic field using triangular and rectangular surfaces, Nucl. Instrum. Methods Phys. Res., Sect. A 571, 588 (2007).
  8. M. Pivi, F. K. King, R. E. Kirby, T. O. Raubenheimer, G. Stupakov, and F. Le Pimpec, Sharp reduction of the secondary electron emission yield from grooved surfaces, J. Appl. Phys. 104, 104904 (2008).
  9. G. Romanov, P. Berrutti, and T. Khabiboulline, Simulation of multipacting in SC low beta cavities at FNAL, Fermi National Accelerator Lab. (FNAL), Technical Report No. FERMILAB-CONF-15-152-TD, 2015.
  10. P. Berrutti, I. Gonin, T. N. Khabiboulline, M. Parise, D. Passarelli, G. Romanov, F. Ruiu, A. Sukhanov, and V. Yakovlev, New design of SSR2 spoke cavity for PIP II SRF linac, Fermi National Accelerator Lab. (FNAL), Technical Report No. FERMILAB-CONF-19-281-TD, 2019.
  11. R. Prakash, A. R. Jana, and V. Kumar, Multipacting studies in elliptic SRF cavities, Nucl. Instrum. Methods Phys. Res., Sect. A 867, 128 (2017).
  12. R. L. Geng, H. Padamsee, S. Belomestnykh, P. Goudket, D. M. Dykes, and R. G. Carter, Suppression of multipacting in rectangular coupler waveguides, Nucl. Instrum. Methods Phys. Res., Sect. A 508, 227 (2003).
  13. D. González-Iglesias, A. M. Pérez, S. Anza, J. V. Cardona, B. Gimeno, V. E. Boria, D. Raboso, C. Vicente, J. Gil, and F. Caspers, Multipactor mitigation in coaxial lines by means of permanent magnets, IEEE Trans. Electron Devices 61, 4224 (2014).
  14. C. Chang, G. Z. Liu, C. X. Tang, C. H. Chen, H. Shao, and W. H. Huang, Suppression of high-power microwave dielectric multipactor by resonant magnetic field, Appl. Phys. Lett. 96, 111502 (2010).
  15. Y. Kalboussi, S. Dadouch, B. Delatte, F. Miserque, D. Dragoe, F. Eozenou, M. Baudrier, S. Tusseau-Nenez, Y. Zheng, and L. Maurice, Multipacting mitigation by atomic layer deposition: The case study of titanium nitride, J. Appl. Phys. 136, 085301 (2024).
  16. A. K. Ghosh and V. L. S. R. Sista, Suppression of multipacting growth in a superconducting spoke resonator by the use of higher order modes, J. Instrum. 19, P03005 (2024).
  17. A. Pathak, S. Roy, S. V. L. S. Rao, and S. Krishnagopal, Design study for medium energy high intensity proton accelerator, Phys. Rev. Accel. Beams 23, 090101 (2020).
  18. T. P. Wangler, RF Linear Accelerators (John Wiley & Sons, New York, 2008).
  19. CST Particle Studio module, CST Studio Suite, Dassault Systèmes Deutschland GmbH, Darmstadt, Germany, https://www.3ds.com/products/simulia/cst-studio-suite.
  20. H. Wang, D. Liu, L. Liu, M. Xie, and L. Meng, Effects of rf magnetic field on upstream dielectric multipactor, Plasma Sources Sci. Technol. 27, 125006 (2018).
  21. D. Uriot and N. Pichoff, TraceWin code, CEA/DSM/IRFU/SACM, Saclay, France (2014), https://www.cea.fr.
  22. G. Singh, Modeling space charge affected electron emission from the curved surface using particle-in-cell technique, Ph.D. thesis, Homi Bhabha National Institute, Mumbai, India, 2023.
  23. G. Singh, R. Kumar, and D. Biswas, Enhanced space charge limited current for curved electron emitters, Phys. Plasmas 27, 103107 (2020).
  24. CST Microwave Studio module, CST Studio Suite, Dassault Systèmes Deutschland GmbH, Darmstadt, Germany, https://www.3ds.com/products/simulia/cst-studio-suite.
  25. S.-H. Kim, R. Afanador, D. L. Barnhart, M. Crofford, B. D. Degraff, M. Doleans, J. Galambos, S. W. Gold, M. P. Howell, and J. Mammosser, Overview of ten-year operation of the superconducting linear accelerator at the spallation neutron source, Nucl. Instrum. Methods Phys. Res., Sect. A 852, 20 (2017).
  26. A. Cravatta, T. Arkan, D. Bafia, J. Kaluzny, S. Posen, J. Vennekate, M. Drury, S. Aderhold, M. Checchin, and D. Gonnella, Multipacting processing in cryomodules for LCLS-II and LCLS-II-HE, arXiv:2306.17274.
  27. S. Posen et al., High gradient performance and quench behavior of a verification cryomodule for a high energy continuous wave linear accelerator, Phys. Rev. Accel. Beams 25, 042001 (2022).
  28. E. Donoghue, G. Wu, J. Mammosser, R. Rimmer, M. Stirbet, L. Phillips, and H. Wang, Studies of electron activities in SNS-Type superconducting RF cavities, in Proceedings of the 12th International Workshop on RF Superconductivity, SRF’05, Cornell University, Ithaca, NY (JACoW, Geneva, Switzerland, 2005), pp. 402–405.
  29. D. B. Caballero, W. Wuensch, K. Szypula, N. Lasheras, B. Gimeno, and A. Golfe, Combined field emission and multipactor simulation in high gradient rf accelerating structures, in Proceedings of the 10th International Particle Accelerator Conference (IPAC’19) (2019), p. 2940.
  30. J. Brown, A. Sukhanov, D. Passarelli, G. Romanov, and T. Xu, Simulations of field emitters and multipacting in PIP-II single spoke resonator type-2, Fermi National Accelerator Laboratory (FNAL), Technical Report No. FERMILAB-CONF-24-0965-TD, 2024.
  31. M. Ball, A. Burov, B. Chase, A. Chakravarty, A. Chen, S. Dixon, J. Edelen, A. Grassellino, D. Johnson, and S. Holmes, The PIP-II conceptual design report, Fermi National Accelerator Lab. (FNAL), Technical Report no. FERMILAB-DESIGN-2017-01 and FERMILAB-TM-2649-AD-APC, 2017.
  32. A. K. Ghosh, M. Jose, V. L. S. R. Sista, and R. Kumar, Design of a higher order mode (HOM) coupler for suppression of multipactor in a 325 MHz SSR cavity, J. Instrum. 20, P07041 (2025).
  33. R. Bailey et al., CAS—CERN accelerator school: Rf for accelerators, Technical Report No. CERN-2011-007, CERN, Ebeltoft, Denmark, 2010, p. 125.
  34. K. Benson, GaN breaks barriers—RF power amplifiers go wide and high, Analog Dialogue 51 (2017), https://www.analog.com/en/resources/analog-dialogue/articles/rf-power-amplifiers-go-wide-and-high.html.

Outline

Information

Phys. Rev. Accel. Beams 29, 073201– Published 29 July, 2026
  • Received 25 February 2026
  • Accepted 27 May 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