Transmission-electron diffraction by MeV electron pulses

We have developed a compact ultrafast electron diffractometer, consisting of a laser-driven rf photocathode that generates 3.0 MeV probe electron pulses, three-stage lens optics, and a custom-built detector for relativistic electrons. High-quality single-shot transmission electron diffraction has been detected from 180-nm-thick Si single crystals, with an excellent special resolution for diffracted beams; the spot width of 0.02 A−1 is obtained. The pulse width is estimated to be 100 fs in duration. Characteristics of the electron beam and other diffractometer features are discussed.