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Time-resolved photoemission with ultrafast pump and probe pulses is anemerging technique with wide application potential. Real-time recording ofnon-equilibrium electronic processes, transient states in chemical reactions orthe interplay of electronic and structural dynamics offers fascinatingopportunities for future research. Combining valence-band and core-levelspectroscopy with photoelectron diffraction for electronic, chemical andstructural analysis requires few 10 fs soft X-ray pulses with some 10 meVspectral resolution, which are currently available at high repetition ratefree-electron lasers. The PG2 beamline at FLASH (DESY, Hamburg) provides a highpulse rate of 5000 pulses/s, 60 fs pulse duration and 40 meV bandwidth in anenergy range of 25-830 eV with a photon beam size down to 50 microns indiameter. We have constructed and optimized a versatile setup commissioned atFLASH/PG2 that combines FEL capabilities together with a multidimensionalrecording scheme for photoemission studies. We use a full-field imagingmomentum microscope with time-of-flight energy recording as the detector formapping of 3D band structures in ($k_x$, $k_y$, $E$) parameter space withunprecedented efficiency. Our instrument can image full surface Brillouin zoneswith up to 7 {\AA} $^{-1}$ diameter in a binding-energy range of several eV,resolving about $2.5\times10^5$ data voxels. As an example, we present resultsfor the ultrafast excited state dynamics in the model van der Waalssemiconductor WSe$_2$.

Time- and momentum-resolved photoemission studies using time-of-flight momentum microscopy at a free-electron laser