The 0.1-nm SASE FEL at the Pohang Accelerator Laboratory

Abstract

A next-generation synchrotron-radiation source planned at the Pohang Accelerator Laboratory (PAL) is described in this paper. It is a linac-based free electron laser (FEL) to produce an intense X-ray pulse down to a 0.1-nm wavelength with a 100-fs rms pulse length. This will make it possible for pump-probe experiments, such as dynamics studies of chemical reactions and coherent diffractive imaging, with a peak brilliance approximately ten orders of magnitude higher than that from the third-generation light source. The in-vacuum undulator with a 5.3-mm gap is employed in conjunction with an S-band rf linear accelerator to produce a 10.053-GeV electron beam. If an 1-nC electron beam with a 1.1-mm mrad normalized emittance and a 0.015% relative energy spread passes through the undulator, an output radiation power of similar to 6 MV is expected in approximately a 94-m saturation length. The effect, of the wakefields on the lasing performance is also considered and is shown to be acceptable with the chosen undulator gap .