Design considerations on a high-power VUV FEL

We explore the feasibility conditions of a high-power EEL operating in the VUV region (below 100 nm) and exploiting a coupled oscillator triplicator configuration. A high quality beam from a linac is passed through a EEL oscillator and produces laser radiation at 240 nm. The same beam is extracted and then injected into a second undulator tuned at the third harmonic of the first. The bunching produced in the oscillator allows the start up of the laser signal in the second section which operates as an amplifier. We discuss the dynamical behavior of the system and the dependence of the output power on the characteristics of the e-beam and of the oscillator. The possibility of enhancing the output power, adding a tapered section to the second undulator, is finally analyzed