Mechanical Optimization of the TD-XPES Station of the SXP Instrument at the European XFEL

The TR-XPES (Time Resolved X-Ray Photoelectron Spectroscopy) setup is the first experimental station integrated at the Soft X-ray Port (SXP) instrument of the European XFEL. It has been developed to perform femtosecond time resolved photoelectron spectroscopy experiments on solid state samples in the soft X-ray photon energy range from 0.25 keV to 3 keV, generated by the SASE3 undulator system. A Pump-Probe Laser (PPL) colinearly propagated with the FEL into the experimental chamber is used to excite the samples. The laser pulses have the same time structure as the FEL beam for the two fundamental output wavelengths, 800 nm and 1030 nm, as well as for the second and third harmonics. Other wavelengths up to 15 microns can be generated with an Optical Parametric Amplifier (OPA) at reduced repetition rate. The main chamber is equipped with a momentum microscope photoelectron spectrometer that allows both real and k-resolved measurements. The sample is mounted on a custom-made hexapod that allows sample cooling and heating. The setup is further equipped with a preparation chamber, a Low Energy Electron Diffraction (LEED) chamber: a load lock and a connection flange for vacuum suitcases. The preparation chamber allows sputtering and annealing of substrates and evaporation of thin films. Samples are transferred to the main chamber using a 1m long transfer arm installed in the LEED chamber. In order to align the whole system with respect to the FEL beam, an alignment system is required. The first realization was done using manual adjustments. In this contribution, an optimization of the TR-XPES station is presented. On the one hand, the ancillary chambers (preparation, LEED, load lock, ⋯) have been reorganized in order to ease and speed-up the sample transfer to the main chamber. On the other hand, an automated alignment table is under development to position the station with respect to the FEL beam with micrometre precision. It is built on an air-pad system that also allows positioning the chamber at different positions along the FEL beamline.