Two-staged tender X-ray free-electron laser based on the fresh-slice method

Abstract

We present the generation of x-ray free electron laser (XFEL) of mJ level and less than 10 fs duration (rms) using the two-staged fresh-slice method in tender x-ray regime 2.47 keV. The fresh-slice technique is performed by transversely kicking electron beams influenced by a wakefield on a corrugated plate. Using a chicane, a seed FEL pulse produced by the tail slices of the electron beam is overlapped with the fresh head slices. The seed FEL is subsequently amplified by the fresh slices, resulting in a mJ level intensity and short duration. The demonstration performed at PAL-XFEL enhanced the peak power by 60 % compared to the SASE FEL in the normal operation.