Radial bunch compression: Path-length compensation in an rf photoinjector with a curved cathode

M.J. de Loos, S.B. van der Geer, Y.M. Saveliev, V.M. Pavlov, A.J.W. Reitsma, S.M. Wiggins, J. Rodier, T. Garvey, D.A. Jaroszynski

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


Electron bunch lengthening due to space-charge forces in state-of-the-art rf photoinjectors limits the minimum bunch length attainable to several hundreds of femtoseconds. Although this can be alleviated by increasing the transverse dimension of the electron bunch, a larger initial radius causes path-length differences in both the rf cavity and in downstream focusing elements. In this paper we show that a curved cathode virtually eliminates these undesired effects. Detailed numerical simulations confirm that significantly shorter bunches are produced by an rf photogun with a curved cathode compared to a flat cathode device. The proposed novel method will be used to provide 100 fs duration electron bunches for injection into a laser-driven plasma wakefield accelerator.
Original languageEnglish
Pages (from-to)084201-1-084201-7
JournalPhysical Review Special Topics: Accelerators and Beams
Issue number8
Publication statusPublished - Aug 2006


  • laser-plasma interactions
  • electron beams
  • lasers
  • rf photoinjectors

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