Slice emittance measurements at the SLAC gun test facility

D. H. Dowell, P. R. Bolton, J. E. Clendenin, P. Emma, S. M. Gierman, W. S. Graves, C. G. Limborg, B. F. Murphy, J. F. Schmerge

Research output: Contribution to journalConference articlepeer-review

18 Scopus citations


A goal of the Gun Test Facility (GTF) at SLAC is to investigate the production of high-brightness electron beams for the Linac Coherent Light Source (LCLS) X-ray FEL. High brightness in the RF photocathode gun occurs when the time-sliced emittance is nearly the same as the cathode thermal emittance and when the slices are all lined up, i.e., their Twiss parameters are nearly identical. In collaboration with the BNL Source Development Lab (SDL), we have begun a systematic study of the slice emittance at GTF. The technique involves giving the bunch a near linear energy chirp using the booster linac and dispersing it with a magnetic spectrometer. Combined with knowledge of the longitudinal phase space, this establishes the energy-time correlation on the spectrometer screen. The slice emittances are determined by varying the strengths of the quadrupoles in front of the spectrometer. Spectrometer images for a range of quadrupole settings are then binned into small energy/time windows and analysed for the slice emittance and Twiss parameters. Results for various gun parameters are presented.

Original languageEnglish (US)
Pages (from-to)327-330
Number of pages4
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number1-2
StatePublished - Jul 11 2003
Externally publishedYes
EventProceedings of the 24th International Free Electron Laser Conference - Argonne, IL, United States
Duration: Sep 9 2002Sep 13 2002


  • Free electron lasers
  • Photoinjectors
  • Slice emittance
  • Transverse emittance

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


Dive into the research topics of 'Slice emittance measurements at the SLAC gun test facility'. Together they form a unique fingerprint.

Cite this