We present a nano-scale photoelectron source, optimized for ultrashort pulse durations and
well-suited for time-resolved diffraction and advanced laser acceleration experiments. A
tungsten tip of several-ten-nanometers diameter mounted in a suppressor-extractor
electrode configuration allows the generation of 30 keV electron pulses with an estimated
pulse duration of 9 fs (standard deviation; 21 fs full width at half maximum) at the gun exit.
We infer the pulse duration from particle tracking simulations, which are in excellent …