Stability evaluation of femtosecond S-band linac with photocathode RF gun

Femtosecond S-band linac with the BNL/GUN IV of Nuclear Engineering Research Laboratory, University of Tokyo, has recorded 240fs(FWHM), 6 pai mm. mrad(rms), 350pC/bunch. Maximum charge per bunch at the exit of the injector and QE were 7nC and 1.5 / 10(-4), respectively. After the cathode damage was found, re-measured emittance was 20 pai mm, mrad. Timing jitter between the femtosecond electron bunch and the drive laser for the injector was 330fs for the minutes and 1.9ps for hours. Detailed of the system are described, including the electron bunch diagnosis system. Further, the plasma gun work to produce 10fs, 20MeV electron single bunch without any timing jitter is also mentioned. Those date and information give important mile stones for development of future SASE-FEL including LCLS.