- 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

Combined simulation and experimental characterization of space-charge compensation in a high-intensity proton Low Energy Beam Transport (LEBT)

Pallavi Priyadarshini*, Jose V. Mathew, and Rajesh Kumar

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

Phys. Rev. Accel. Beams 29, 064201 – Published 12 June, 2026

DOI: https://doi.org/10.1103/g3pg-mxr1

Abstract

Beam losses in high-intensity proton accelerators are largely caused by space-charge effects, particularly in the low energy beam transport (LEBT) region, where the beam remains nonrelativistic. While space-charge compensation (SCC) through residual gas ionization is a widely used mitigation technique, detailed time-resolved studies combining both simulations and direct experimental measurements are scarce. This work presents a comprehensive investigation of passive SCC in the Low Energy High Intensity Proton Accelerator LEBT using both Particle-in-cell/Monte Carlo Collision simulations and dedicated diagnostics. Detailed simulations using cst particle studio are carried out to investigate how compensating gas type, gas pressure, external magnetic field, and beam parameters affect the space-charge compensation time and degree, as well as the resulting variations in beam potential, emittance, and transverse size. Experimentally, the SCC dynamics are characterized using a diagnostic suite that features a retarding field analyzer (RFA) and our novel, indigenously developed particle monitor probe (PMP). The PMP is applied here to estimate SCC time from the transient ionization electron current at the beam periphery, while the RFA determines the local SCC degree. These measurements provide detailed information on the variation of SCC parameters with gas type, pressure, and solenoidal magnetic field. The combined simulation and experimental results provide new physical insights into the dynamics of SCC, particularly regarding the nonmonotonic effect of magnetic fields, and validate a diagnostic methodology applicable to other high-intensity proton injectors.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (35)

  1. S. S. Kapoor, Accelerator-driven sub-critical reactor system (ADS) for nuclear energy generation, Pramana 59, 941 (2002).
  2. C. Rubbia, C. Roche et al., Conceptual design of a fast neutron operated high power energy amplifier, Report No. CERN-AT-95-44-ET, CERN, 1995, https://www.oecd-nea.org/trw/docs/rubbia/concept.pdf.
  3. O. E. Krivosheev and N. V. Mokhov, Tolerable beam loss at high-intensity proton machines, in Proceedings of the 7th ICFA Mini-Workshop on High Intensity High Brightness Hadron Beams, Lake Como, WI, edited by N. V. Mokhov and W. Chou (Fermilab, Batavia, IL, 2000), Report No. Fermilab-Conf-00/185, pp. 85–88, https://inspirehep.net/files/64a7151e126cdfa221745d84d0a639c0.
  4. T. P. Wangler, RF Linear Accelerators, 2nd ed. (Wiley-VCH, Weinheim, 2008), pp. 291–292.
  5. U. D. Malshe, Low Energy High Intensity Proton Accelerator (LEHIPA), BARC Newsletter, Founder’s Day Special Issue (Bhabha Atomic Research Centre (BARC), Department of Atomic Energy, Government of India, Trombay, Mumbai, 2023), pp. 48–53, https://www.barc.gov.in/barc_nl/2023/spl2023.pdf.
  6. P. Priyadarshini, J. V. Mathew, D. N. Mathad, and R. Kumar, Phase space reconstruction technique for beam optimization in the Low Energy High Intensity Proton Accelerator (LEHIPA), Phys. Scr. 99, 085312 (2024).
  7. C. S. Park, B. Freemire et al., Mitigation of space charge effects using electron column at IOTA ring, CERN Yellow Rep. Conf. Proc. 9, 112 (2020).
  8. E. Boggasch, A. Tauschwitz, H. Wahl, K.-G. Dietrich, D. H. H. Hoffmann, W. Laux, M. Stetter, and R. Tkotz, Plasma lens fine focusing of heavy-ion beams, Appl. Phys. Lett. 60, 2475 (1992).
  9. C. A. Valerio-Lizarraga, J.-B. Lallement, I. Leon-Monzon, J. Lettry, Ø. Midttun, and R. Scrivens, Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions, Rev. Sci. Instrum. 85, 02A505 (2014).
  10. F. Gérardin, N. Chauvin et al., Space-charge compensation in low energy beam lines, in Proceedings of the 7th International Particle Accelerator Conference, IPAC-2016, Busan, Korea (JACoW, Geneva, Switzerland, 2016), pp. 3055–3057.
  11. P. Priyadarshini, J. V. Mathew, R. Pande, S. V. L. S. Rao, and R. Kumar, Design and beam dynamics studies of low energy beam transport for MEHIPA, J. Phys. Commun. 9, 045001 (2025).
  12. V. N. Aseev, P. N. Ostroumov et al., track: The new beam dynamics code, in Proceedings of the 21st Particle Accelerator Conference, Knoxville, TN, 2005 (IEEE, Piscataway, NJ, 2005), pp. 2053–2055.
  13. D. Noll, M. Droba et al., Numerical space-charge compensated studies and comparison of different models in Proceedings of the 7th International Particle Accelerator Conference, IPAC-2016, Busan, Korea (JACoW, Geneva, Switzerland, 2016), pp. 674–676.
  14. N. Chauvin, O. Delferrière, R. Duperrier, R. Gobin, P. A. P. Nghiem, and D. Uriot, Transport of intense ion beams and space charge compensation issues in low energy beam lines (invited), Rev. Sci. Instrum. 83, 02B320 (2012).
  15. A. L. Zhang, S. X. Peng, H. T. Ren, T. Zhang, J. F. Zhang, Y. Xu, Z. Y. Guo, and J. E. Chen, Study on space charge compensation in negative hydrogen ion beam, Rev. Sci. Instrum. 87, 02B915 (2016).
  16. E. Cosgun, M. S. Hur, S. Moon, D. Kim, and M. Chung, Time-resolved space-charge compensation studies for pulsed and matched proton beam in a low-energy transport line, Phys. Rev. Accel. Beams 28, 090102 (2025).
  17. A. Ben-Ismail, R. Duperrier, D. Uriot, and N. Pichoff, Space charge compensation studies of hydrogen ion beams in a drift section, Phys. Rev. ST Accel. Beams 10, 070101 (2007).
  18. S. Peng, P. Lu, H. Ren, J. Zhao, J. Chen, Y. Xu, Z. Guo, J. Chen, H. Zhao, and L. Sun, Key elements of space charge compensation on a low energy high intensity beam injector, Rev. Sci. Instrum. 84, 033304 (2013).
  19. A. J. T. Holmes, Theoretical and experimental study of space charge in intense ion beams, Phys. Rev. A 19, 389 (1979).
  20. D. Winklehner, D. Leitner, D. Cole, G. Machicoane, and L. Tobos, Space-charge compensation measurements in electron cyclotron resonance ion source low energy beam transport lines with a retarding field analyzer, Rev. Sci. Instrum. 85, 02A739 (2014).
  21. N. Chauvin, T. Akagi et al., Deuteron beam commissioning of the linear IFMIF prototype accelerator ion source and low energy beam transport, Nucl. Fusion 59, 106001 (2019).
  22. D. Morris, R. Abel et al., Microwave driven space-charge compensation with optical diagnostics and feedback, in Proceedings of the 14th International Particle Accelerator Conference, IPAC-2023, Venice, Italy (JACoW, Geneva, Switzerland, 2023), pp. 2767–2769.
  23. C. A. Valerio-Lizarraga, I. Leon-Monzon, and R. Scrivens, Negative ion beam space charge compensation by residual gas, Phys. Rev. ST Accel. Beams 18, 080101 (2015).
  24. L. Weissman, Effect of secondary electrons suppression on emittance measurement of an intense, low-energy beam, Rev. Sci. Instrum. 85, 02A710 (2014).
  25. E. Flannigan, O. Tarvainen et al., A review of space charge compensation diagnostics, in Proceedings of International Beam Instrumentation Conference, IBIC-2025, Liverpool, UK (JACoW, Geneva, Switzerland, 2025).
  26. P. Forck, Lecture Notes on Beam Instrumentation and Diagnostics (Joint University Accelerator School, GSI, Darmstadt, Germany, 2018), pp. 48–54, https://indico.cern.ch/event/683638/contributions/2801669/attachments/1563566/2540684/juas_script.pdf.
  27. G. Castro, D. Mascali, R. Miracoli, L. Celona, and S. Gammino, Diffusion processes in microwave discharge ion source and consequences on the upgrade of existing ion sources, Rev. Sci. Instrum. 90, 023301 (2019).
  28. CST studio suite, Dassault systems, https://www.3ds.com/products/simulia/cst-studio-suite.
  29. M. Reiser, Theory and Design of Charged Particle Beams (John Wiley & Sons, New York, 2008).
  30. M. E. Rudd, R. D. Dubois et al., Cross sections for ionization of gases by 5–4000-keV protons and for electron capture by 5-150-keV protons, Phys. Rev. A 28, 3244 (1983).
  31. C. F. Barnett, J. A. Ray, and J. C. Thompson, Atomic and molecular collision cross sections of interest in controlled thermonuclear research, Reports No. ORNL-TM-3113 (Rev.), No. OSTI ID: 4028813, Oak Ridge National Laboratory, 1964.
  32. P. Priyadarshini, J. V. Mathew, and R. Kumar, Particle monitor probe: A novel tool for fast plasma diagnostics, and space charge compensation investigation in high-intensity proton accelerators, Sci. Rep. 16, 9350 (2026).
  33. B. John, K. Jonathan, O. Tarvainen, E. L. Flannigan, D. Faircloth, and D. R. Emerson, Effect of magnetic field on space charge compensation in negative hydrogen ion beams: A computational study, J. Instrum. 20, C05024 (2025).
  34. A. K. Fazlul Haque, M. M. Haque, S. Sultana, M. A. R. Patoary, M. S. Hossain, M. Maaza, and M. Alfaz Uddin, Proton-induced secondary electron emission from elemental solids over the energy domain 1 keV–1000 MeV, Results Phys. 15, 102519 (2019).
  35. R. A. Baragiola, E. V. Alonso, and A. Oliva Florio, Electron emission from clean metal surfaces induced by low-energy light ions, Phys. Rev. B 19, 121 (1979).

Outline

Information

Phys. Rev. Accel. Beams 29, 064201– Published 12 June, 2026
  • Received 2 January 2026
  • Accepted 14 April 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