• J.H. Han, D. Brice, M.P. Cox, H.C. Huang, S.A. Pande
  Diamond, Oxfordshire

Photocathode RF guns are widely used as injectors for accelerators requiring very high quality beams such as free electron lasers and linear colliders and recently used as ultrafast electron diffraction sources. Even with the limited repetition rate, normal conducting photocathode RF guns generate very low emittance and short pulse electron beams thanks to their high accelerating field and the efficient positioning of focusing solenoids. We report our activity of the design and production of an S-band normal conducting photocathode gun. The RF characteristics, thermal heating and vacuum analyses are discussed.

• J.H. Han
  Diamond, Oxfordshire

At many laboratories S-band photoinjectors operate to provide high quality beams; however the repetition rates are limited to about 100 Hz. This limitation mainly occurs due to the guns where a high RF amplitude of about 100 MV/m is required to keep the beam quality from the space charge force. In this paper we design an injector consisting of an S-band gun with improved cooling and S-band acceleration modules for a repetition rate up to 1 kHz. The technical feasibility and beam dynamics optimization are discussed.

• J.H. Han
  Diamond, Oxfordshire

Ultrashort electron beams can be used for investigating ultrafast dynamics of physical, chemical or biological systems. With an S-band photocathode gun, simulations have been done in order to generate ultrashort electron beams. Optimizations to generate ultrashort electron beams with a small beam divergence and to minimize the system sensitivity against RF jitter are reported.