Efficient Compton FELs Based on Sectioned RF Undulator Systems

A high-efficiency regime of multi-stage trapping has been proposed for short-wavelength FELs recently. This scheme use strongly tapered RF undulator sections to be fed by phase-independent short-pulse high-power RF pulsed sources. In this work, we describe simulations of the realization of this multi-stage regime in short-wavelength SASE FELs, as well as profiled microwave systems designed for the realization of tapered rf undulators.