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.
|Number of pages||8|
|Journal||Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment|
|Publication status||Published - 2015 Jun 29|
- Deflecting structure
- Longitudinal profile
ASJC Scopus subject areas
- Nuclear and High Energy Physics