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[en] We have completed an ultra-high vacuum system for investigations of cathodes in a triode configuration under high electric fields E (up to ∝100 MV/m) and pulsed tunable laser illumination (3.5 ns, 10 Hz, hν=0.5-5.9 eV, >0.3 mJ) . Measurements of the cathode current by a picoammeter and of the electron energy by a spectrometer for DC as well as laser-pulsed beams are enabled. The cathodes can be 3D-positioned with μm precision and cooled or heated in the range of 77-400 K. System commissioning with DC field emission from a W tip yielded a work function φ of 4.7 eV and a spectrometer resolution of <10 meV. Precise determination of the emitter temperature from the spectra at low currents (down to 60 nA) demonstrated the high sensitivity of the system. The suitability for laser-pulsed beams was shown with photoemission from a n-GaP(100) wafer. Quantum efficiency QE(hν) measurements at low E revealed expected band structure effects and φ values of 3.5-4.6 eV depending on the actual oxide layer. In order to develop novel highly brilliant electron sources, the suitability of various materials for photo-induced field emission by indirect (QE(hν,E)) and direct electron spectroscopy will be performed next.