Abstract

At the European X-ray Free Electron Laser (XFEL) facility a new instrument, the Soft X-ray Port (SXP), is currently under commissioning [1]. It is primarily designed for time- and spin-resolved X-ray photo-electron spectroscopy (TR-XPES), but investigations of complex chemical and bio-inorganic molecular systems with fluorescence spectroscopy as well as research on highly charged ions are also envisioned [2]. SXP is located downstream of the SASE 3 soft X-ray undulator system providing ultrafast photon pulses with variable polarization in the energy range between 260 eV and 3000 eV, at MHz repetition rates. Up to 10¹² photons per pulse will be focus at the interaction region in a micrometer spot size resulting in an intensity of more than 10¹⁸ W/cm². These outstanding specifications will enable the complete electronic, chemical and atomic characterization of solids, surfaces and interfaces using TR-XPES. For this purpose, two powerful pump-probe lasers operating in a broad spectral range from the mid-infrared to the ultraviolet region will be available. Herriott-type multi pass cells (MPC) will be used to compress their pulses into the few femtosecond range paving the way for ultrafast time-resolved investigations at the SXP instrument combining intense and tunable soft X-rays with versatile optical laser capabilities.

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