Development of a hard X-ray split-and-delay line and performance simulations for two-color pump-probe experiments at the European XFEL

A hard X-raySplit-and-Delay Line (SDL) under construction for the Materials Imaging and Dynamics station at the European X-Ray Free-Electron Laser (XFEL) is presented. This device aims at providing pairs of X-ray pulses with a variable time delay ranging from −10 ps to 800 ps in a photon energyrange from 5 to 10 keV for photon correlation and X-ray pump-probe experiments. A custom designed mechanical motion systemincluding active feedback control ensures that the high demands for stability and accuracy can be met and the design goals achieved. Using special radiation configurations of the European XFEL’s SASE-2 undulator (SASE: Self-Amplified Spontaneous Emission), two-color hard x-raypump-probe schemes with varying photon energyseparations have been proposed. Simulations indicate that more than 109 photons on the sample per pulse-pair and up to about 10% photon energyseparation can be achieved in the hard X-rayregion using the SDL.