FEL2026 - 42nd International Free Electron Laser Conference

Space Charge Studies for Enhanced SASE at the Soft X-ray Beamline Athos at SwissFEL

MOZ01

24 Aug 2026, 14:00

25m

Invited Oral Presentation Session 3: FEL theory and Machine Learning FEL Theory and Machine Learning (Invited)

Speaker

Sven Reiche (Paul Scherrer Institute)

Description

We present studies on enhanced SASE at the soft X-ray beamline Athos at SwissFEL. The generation of a series of current spikes with 790 nm spacing is injected into the Athos undulator beamline. Due to strong space charge forces the optimum performance occurs with a strong positive taper of the undulator field. There is a clear modal structure in the observed spectra, indicating the presence of a train of attosecond FEL pulses with no intrinsic phase-locking. The space-charge dynamics causes an elongation of the current spike and a redshift in the bunching spectra, which determines the optimum taper gradient