Simulation optimization of single-shot continuously time-resolved MeV ultra-fast electron diffraction

In a so-called single-shot continuously time-resolved mega-electron-volt ultra-fast electron diffraction (CTR MeV UED) system, a radio-frequency streaking cavity maps the temporally distributed diffraction features into a transverse pattern, from which structural changes within the duration of the electron pulse can be resolved continuously. Due to the high charge density of the MeV beam, such a pattern can be achieved with a single electron pulse. In this paper, we present the proposed configuration and the simulation optimization of such a system. A thin slit is used as the key element to minimize overlaps of the diffraction features when they are streaked. Using polycrystalline aluminum as the sample, we obtain a streaked pattern in which features of different lattice planes are clearly resolved. It is demonstrated that such a system can take an ‘atomic movie’ with a duration of a few picoseconds, and continuously distributed ∼100-femtosecond frames, by using a single electron pulse.