Sub-picosecond FEL micropulse length and electron bunch measurements

Recently, transform limited optical micropulses with lengths of less than 600 fs FWHM have been produced at the Stanford Picosecond Free Electron Laser (FEL) Center. These sub-picosecond FEL optical pulses are important for many types of experiments, especially those investigating fast kinematic processes. In an effort to understand the details of short optical micropulse production, we have made measurements of the electron beamʹs micropulse structure with sub-picosecond resolution using a newly constructed electron beam diagnostic which uses transition radiation.