FERMI @ ELETTRA – A SEEDED HARMONIC CASCADE FEL FOR EUV AND SOFT X-RAYS

We describe the machine layout and major performance parameters for the FERMI FEL project funded for construction at Sincrotrone Trieste, Italy, within the next five years. The project will be the first user facility based on seeded harmonic cascade FEL’s, providing controlled, high peak-power pulses. With a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac, the facility will provide tunable output over a range from ~100 nm to ~10 nm, with pulse duration from 40 fs to ~ 1ps, peak power ~GW, and with fully variable output polarization. Initially, two FEL cascades are planned; a single-stage harmonic generation to operate> 40 nm, and a two-stage cascade operating from ~40 nm to ~10 nm or shorter wavelength