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Balance of bunch compression and emittance preservation for high-brightness x-ray free electron laser injectors

C. Davut† and O. Apsimon

B. R. Hounsell, B. L. Militsyn, L. S. Cowie, F. Yaman*, A. D. Brynes, and P. H. Williams

  • *Also at Department of Electrical and Electronics Engineering, Izmir Institute of Technology, 35430 Izmir, Turkiye.
  • †Contact author: can.davut@tenmak.gov.tr
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Phys. Rev. Accel. Beams 28, 091602 – Published 11 September, 2025Erratum Phys. Rev. Accel. Beams 28, 109901 (2025)

DOI: https://doi.org/10.1103/rjns-vqzt

Abstract

This paper presents two conceptual low-energy injector configurations optimized for high-brightness, high-repetition-rate XFELs. The designs were evaluated at a nominal bunch charge of 150 pC using multiobjective optimization techniques and further assessed through start-to-end simulations incorporating collective effects to determine their suitability for delivering high-brightness beams under FEL-relevant conditions. One of the injector design configurations employs a hybrid rf and magnetic compression scheme, while the second relies solely on two-stage rf compression. Start-to-end simulations through the main linac, including collective effects, were performed to assess the suitability of each design for meeting XFEL requirements. The results highlight the critical role of longitudinal charge distribution symmetry in maintaining beam quality during acceleration and compression, and demonstrate that appropriately balancing compressibility, emittance preservation, and phase space linearity is essential for meeting the stringent demands of XFEL operation.

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Erratum

Erratum: Balance of bunch compression and emittance preservation for high-brightness x-ray free electron laser injectors [Phys. Rev. Accel. Beams 28, 091602 (2025)]

C. Davut, O. Apsimon, B. R. Hounsell, B. L. Militsyn, L. S. Cowie, F. Yaman, A. D. Brynes, and P. H. Williams
Phys. Rev. Accel. Beams 28, 109901 (2025)

Article Text

References (44)

  1. J. Rossbach, J. R. Schneider, and W. Wurth, 10 years of pioneering x-ray science at the free-electron laser FLASH at DESY, Phys. Rep. 808, 1 (2019).
  2. C. Bostedt, S. Boutet, D. M. Fritz, Z. Huang, H. J. Lee, H. T. Lemke, A. Robert, W. F. Schlotter, J. J. Turner, and G. J. Williams, Linac Coherent Light Source: The first five years, Rev. Mod. Phys. 88, 015007 (2016).
  3. S. Schreiber, First lasing at 32 nm of the VUV-FEL at DESY, in Proceedings of 27th International Conference on Free Electron Lasers (FEL 2005), Stanford, California, USA (2005), pp. 12–18, https://proceedings.jacow.org/f05/PAPERS/MOOB002.PDF.
  4. P. Emma et al., First lasing of the LCLS X-ray FEL at 1.5 Å, in Proceedings of 23rd Particle Accelerator Conference (PAC 09), Vancouver, BC, Canada (2009), pp. 3115–3119, https://proceedings.jacow.org/PAC2009/papers/th3pbi01.pdf.
  5. E. A. Seddon, J. A. Clarke, D. J. Dunning, C. Masciovecchio, C. J. Milne, F. Parmigiani, D. Rugg, J. C. H. Spence, N. R. Thompson, K. Ueda, S. M. Vinko, J. S. Wark, and W. Wurth, Short-wavelength free-electron laser sources and science: A review, Rep. Prog. Phys. 80, 115901 (2017).
  6. S. Di Mitri, Bunch length compressors, CERN Yellow Rep. Sch. Proc. 1, 363 (2018).
  7. J. Marangos et al., UK XFEL science case, Technical Report, Science and Technology Facilities Council (STFC), 2020, https://www.xfel.ac.uk/wp-content/uploads/2023/02/UK-XFEL-Science-Case-05Oct2020-online-version.pdf.
  8. D. Dunning, D. Angal-Kalinin, J. Clarke, J. Henderson, S. Mathisen, B. Militsyn, M. Roper, E. Snedden, N. Thompson, D. Walsh et al., An introduction to the UK XFEL conceptual design and options analysis, in Proceedings of the 67th ICFA Advanced Beam Dynamics Workshop on Future Light Sources (FLS 2023), Lucerne, Switzerland (2023), https://proceedings.jacow.org/ipac2023/doi/jacow-ipac2023-tupl071/.
  9. D. Dunning, P. Aden, D. Angal-Kalinin, J. Clarke, J. Collier, B. Fell, J. Green, J. Marangos, S. Mathisen, B. Militsyn et al., The UK XFEL conceptual design and options analysis: Mid-term update, in Proceedings of the 14th International Particle Accelerator Conference (IPAC’24), Nashville, Tennessee, USA (2024), https://proceedings.jacow.org/ipac2024/doi/jacow-ipac2024-mopg55/.
  10. F. Sannibale, High-brightness electron injectors for high-duty cycle x-ray free electron lasers, Front. Phys. 11, 1 (2023).
  11. A. Brachmann, Commissioning of LCLS-II, in Proceedings of the Linear Accelerator Conference (LINAC2024), Chicago, IL (JACoW, Geneva, Switzerland, 2024), THZA001, 10.18429/JACoW-LINAC2024-THZA001.
  12. B. Aune et al., Superconducting TESLA cavities, Phys. Rev. ST Accel. Beams 3, 092001 (2000).
  13. F. Sannibale et al., Advanced photoinjector experiment photogun commissioning results, Phys. Rev. ST Accel. Beams 15, 103501 (2012).
  14. F. Zhou, C. Adolphsen, D. Dowell, and R. Xiang, Overview of CW electron guns and LCLS-II RF gun performance, Front. Phys. 11, 282 (2023).
  15. F. Ji, C. Adolphsen, C. Mayes, T. Raubenheimer, R. Coy, L. Xiao, and L. Ge, Beam dynamics studies on a low emittance injector for LCLS-II-HE, in Proceedings of the 5th International Particle Accelerator Conference (NA-PAC2022), Albuquerque, NM (JACoW, Geneva, Switzerland, 2022), pp. 619–622.
  16. S. Kim, C. Adolphsen, L. Ge, W. Hartung, F. Ji, M. Kelly, T. Konomi, J. Lewellen, S. Miller, M. Patil et al., Design of a 185.7 MHz superconducting RF photo-injector quarter-wave resonator for the LCLS-II-HE low emittance injector, in Proceedings of 5th International Particle Accelerator Conference (NA-PAC2022), Albuquerque, NM (JACoW, Geneva, Switzerland, 2022), pp. 245–248.
  17. L. Zheng et al., Design, fabrication, and beam commissioning of a 216.667 MHz continuous-wave photocathode very-high-frequency electron gun, Phys. Rev. Accel. Beams 26, 103402 (2023).
  18. D. Bazyl, Y. Chen, M. Dohlus, and T. Limberg, CW operation of the European XFEL: SC-gun injector optimization, S2E calculations and SASE performance, arXiv:2111.01756.
  19. T. Luo et al., RF design of APEX2 two-cell continuous-wave normal conducting photoelectron gun cavity based on multi-objective genetic algorithm, Nucl. Instrum. Methods Phys. Res., Sect. A 940, 12 (2019).
  20. K. Halbach and R. Holsinger, superfish-A computer program for evaluation of RF cavities with cylindrical symmetry, Part. Accel. 7, 213 (1976), https://inspirehep.net/literature/116636.
  21. C. Mayes, pysuperfish, https://github.com/ChristopherMayes/PySuperfish (2024).
  22. K. Deb, A. Pratap, S. Agarwal, and T. Meyarivan, A fast and elitist multiobjective genetic algorithm: NSGA-II, IEEE Trans. Evol. Comput. 6, 182 (2002).
  23. F.-M. D. Rainville, F.-A. Fortin, M.-A. Gardner, M. Parizeau, and C. Gagné, deap: A python framework for evolutionary algorithms, in Proceedings of the 14th Annual Conference Companion on Genetic and Evolutionary Computation, GECCO ’12 (Association for Computing Machinery, New York, NY, 2012), pp. 85–92, 10.1145/2330784.2330799.
  24. A. Adelmann et al., opal a versatile tool for charged particle accelerator simulations, arXiv:1905.06654.
  25. K. Flöttmann, Note on the thermal emittance of electrons emitted by cesium telluride photocathodes, Technical Report No. DESY-TESLA-FEL-97-01, DESY, Hamburg, Germany, 1997.
  26. Y. Ineichen. Toward massively parallel multi-objective optimization with application to particle accelerators, Ph.D. thesis, ETH Zurich, 2013.
  27. C. Mayes, lume-astra, https://github.com/ChristopherMayes/lume-astra (2019).
  28. D. Z. Khan and T. O. Raubenheimer, Novel bunch compressor chicane: The five-bend chicane, Phys. Rev. Accel. Beams 25, 090701 (2022).
  29. M. Borland, elegant: A flexible SDDS-compliant code for accelerator simulation, in Proceedings of 6th International Computational Accelerator Physics Conference (ICAP’00), Darmstadt, Germany (2000), pp. 1–11, https://www.aps.anl.gov/files/APS-sync/lsnotes/files/APS_1418218.pdf.
  30. E. L. Saldin, E. A. Schneidmiller, and M. V. Yurkov, Longitudinal space charge-driven microbunching instability in the TESLA test facility linac, Nucl. Instrum. Methods Phys. Res., Sect. A 528, 355 (2004).
  31. Z. Huang and K.-J. Kim, Formulas for coherent synchrotron radiation microbunching in a bunch compressor chicane, Phys. Rev. ST Accel. Beams 5, 074401 (2002).
  32. A. D. Brynes et al., Characterisation of microbunching instability with 2D Fourier analysis, Sci. Rep. 10, 5059 (2020).
  33. A. D. Brynes et al., Microbunching instability characterization via temporally modulated laser pulses, Phys. Rev. Accel. Beams 23, 104401 (2020).
  34. Z. Huang, M. Borland, P. Emma, J. Wu, C. Limborg, G. Stupakov, and J. Welch, Suppression of microbunching instability in the Linac Coherent Light Source, Phys. Rev. ST Accel. Beams 7, 074401 (2004).
  35. A. D. Brynes et al., Mitigation of the microbunching instability through transverse Landau damping, Phys. Rev. Accel. Beams 27, 074402 (2024).
  36. S. Di Mitri and M. Cornacchia, Electron beam brightness in linac drivers for free-electron-lasers, Phys. Rep. 539, 1 (2014)..
  37. F. Zhou, D. Dowell, P. Emma, J. Schmerge, C. Mitchell, and F. Sannibale, LCLS-II injector physics design and beam tuning, in Proceedings of the International Particle Accelerator Conference (IPAC2017), Copenhagen, Denmark (2017), https://proceedings.jacow.org/ipac2017/papers/tupab138.pdf.
  38. Dassault Systems, cst studio suite, https://www.3ds.com/products/simulia/cst-studio-suite.
  39. T. Takahashi et al., Development of a 1.3-GHz buncher cavity for the compact ERL, in Proceedings of the 5th International Particle Accelerator Conference (2014), THPRI045, 10.18429/JACoW-IPAC2014-THPRI045.
  40. D. Giove et al., A high brightness beam test facility for ERL applications, in Proceedings of the International Particle Accelerator Conference (IPAC2023) (JACoW, Geneva, Switzerland2023), TUPL164, 10.18429/JACoW-IPAC2023-TUPL164.
  41. P. C. Mahalanobis, On the generalized distance in statistics, Sankhyā A 80, S1 (2018).
  42. M. De Loos, S. Van Der Geer et al., General particle tracer: A new 3D code for accelerator and beamline design, in Proceedings of the 5th European Particle Accelerator Conference (1996), Vol. 1241, https://proceedings.jacow.org/e96/PAPERS/THPG/THP001G.PDF.
  43. L. Serafini and J. B. Rosenzweig, Envelope analysis of intense relativistic quasilaminar beams in rf photoinjectors: mA theory of emittance compensation, Phys. Rev. E 55, 7565 (1997).
  44. M. Ferrario, M. Migliorati, and L. Palumbo, Space charge effects, in Proceedings of the CERN Accelerator School: Synchrotron Radiation and Free-Electron Lasers (2013), pp. 331–356; CERN Yellow Report No. CERN-2014-009, https://cds.cern.ch/record/1982426/files/331-356%20Ferrario.pdf.

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Phys. Rev. Accel. Beams 28, 091602– Published 11 September, 2025
  • Received 15 May 2025
  • Accepted 7 August 2025
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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.

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