The UCLA IR-FEL

Summary form only given. A high-brightness RF gun operating at 2.856 GHz is being used as the injector for an IR-FEL (free-electron laser) experiment. The RF gun consists of a disk loaded, 1.5 cell cavity and a photocathode in the end wall of the cavity. A strong electric field within the half cell near the photocathode quickly accelerates the electrons, thus preventing emittance blow-up. The photocathode is to be driven by a Nd:YAG laser system producing a 10-ps pulse. The power for the RF gun will be supplied by a 25-MW klystron. The RF power is coupled to the cavity via an S-band waveguide attached to the sidewall of the gun. The TE₁₀ mode excited in the waveguide strongly couples to the π-mode with the RF gun while the zero mode is suppressed