Beam dynamics studies in a high-brightness photo-injector

A high-brightness photo-injector has been developed at Fermilab in collaboration with the TTF project at DESY. Two systems have been commissioned, one at DESY and one at Fermilab. The injector [1] consists of a 1.625-cell cavity RF gun, a superconducting niobium cavity (both 1.3 GHz), and a magnetic chicane. The gun is designed for an electric field of up to 50 MV/m on the cathode. Emittance compensation solenoids surround the gun to correct the linear space charge emittance growth. A high quantum efficiency Cs2Te photocathode located in the first half-cell produces electrons when illuminated by 263 nm wavelength light (fourth harmonic of the Nd:YLF laser). The laser [2] was designed to produce a train of up to 800 equal amplitude, 10 microJ UV pulses spaced by 1 micros at 1 Hz repetition rate. The laser pulse length is adjustable between 1 and 20 ps FWHM. The superconducting cavity is a 9-cell Nb structure fabricated by industry for TTF. It was tested with RF at DESY before being sent to Fermilab. At present, the cavity is operated at ∼11 MeV/m. Beam measurements with the injector at Fermilab are in progress. Preliminary results for emittance and bunch length will be discussed in this paper. Future plans for the machine will also be described