An ultracold electron source for ultrafast electron diffraction experiments

We have developed an electron source that creates ultrashort, ultracold electron bunches by accelerating electrons which are created by pulsed near-threshold photoionization of a cloud of laser-cooled atoms. Because of the very high coherence length of these bunches, we can use the source to perform ultrafast electron diffraction (UED) experiments on crystals of macromolecules.