Analysis of single-shot, lasing-induced changes of the longitudinal electron bunch properties has proven invaluable for fs-scale reconstruction of otherwise difficult to measure x-ray FEL pulse profiles. In this talk, we report on measurements following the recent installation of an X-band transverse deflecting mode cavity at the LCLS. Limitations of the FEL pulse profiling technique employed are discussed. An unprecedented 1 to 3 fs RMS time resolution of x-ray and electron bunch profiles is demonstrated. Phenomena impacting x-ray FEL performance are also observed. The new tool is proven as a powerful diagnostic in support of user experiments and machine improvement studies.
A unique X-ray source, of exceptional brightness and with pulse widths as low as 30 fs rms, has been proposed at the Stanford Linear Accelerator Center. Named the Sub-Picosecond Photon Source (SPPS), the facility takes 30 Gev bunches from the linac and compresses them in three stages to achieve peak currents of 30 kA in the Final Focus Test Beam (FFTB) beamline. The existing FFTB can accommodate an undulator of up to 10 m in length which will deliver ~10<SUP>8</SUP> 1.5 A photons per pulse in a 0.1% bandwidth with a peak brightness of ~10<SUP>25</SUP> photons/sec/mm<SUP>2</SUP>/mrad<SUP>2</SUP>/0.1% BW, in a pulse width of ~80 fs FWHM. The short electron bunches are also ideal for plasma and wakefield studies as well as providing abundant R&D possibilities for verifying short bunch behavior in the future Linac Coherent Light Source (LCLS).