Abstract:
The characteristic high repetition rate and the high brightness of electron beams delivered by ERLs have led to a great number of ERL-based proposals for hard x-ray sources including x-ray FELs. FEL oscillators requiring comparatively low peak currents are often proposed for FEL sources in ERLs. However, single-pass FELs in SASE or seeded mode do not seem out of reach when bunchcompression schemes for higher peak currents are utilized. Using the proposed Cornell ERL as an example, we present and discuss oscillator and single-pass FEL schemes which provide high-brightness ultra-short x-ray pulses for experiments.