Transverse C-band deflecting structure for longitudinal electron-bunch-diagnosis in XFEL "sACLA"

H. Ego, H. Maesaka, T. Sakurai, Y. Otake, T. Hashirano, S. Miura

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


In the 8 GeV compact X-ray FEL "SACLA," a single bunch of electrons is compressed to a duration of approximately 30 fs to yield a peak current of 3 kA, which creates brilliant self-amplified spontaneous emission. To measure the longitudinal profile of an ultrashort electron bunch and verify the compression, we developed a high-gradient C-band RF deflecting structure 1.8 m long and periodically loaded with racetrack-shaped irises. The irises generated a high deflection gradient for the vertically deflecting HEM11-5π/6 dipole mode and suppressed rotation of the deflection plane. The two structures were fabricated and generated a stable total deflecting voltage exceeding 60 MV and revealed the longitudinal electron-bunch profile with an effective time resolution of approximately 10 fs.

Original languageEnglish
Pages (from-to)381-388
Number of pages8
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Publication statusPublished - 2015 Jun 29
Externally publishedYes


  • C-band
  • Deflecting structure
  • FEL
  • Femtosecond
  • HEM11
  • Longitudinal profile

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


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