The CLARA Free Electron Laser test facility currently under construction at Daresbury Laboratory requires a high brightness electron photoinjector: an RF photocathode source, capable of operating at a 400 Hz repetition rate with a field in the cavity of 100 MV/m, and with up to 120 MV/m fields in lower repetition rate modes. The photoinjector will produce 20 to 250 pC electron beams at a momentum of 4-6 MeV/c and features a load-lock interchangeable cathode system.
The photocathode source was designed by a multidisciplinary team of accelerator physicists, RF scientists and engineers, magnet system scientists, vacuum scientists and engineers, mechanical engineers and many more others from STFC Accelerator Science and Technology Centre and the Engineering Technology Centre, Cockcroft Institute and Institute for Nuclear Research of Russian Academy of Science. After three years of design, evaluation, optimisation, fabrication and tuning the source cavity has safely arrived at Daresbury Laboratory. Acceptance tests performed at the manufacturer and at Daresbury confirm good agreement of the cavity parameters with the design specification.
Members of the photoinjector development team with the source cavity.