  Pushing the limits in temporal resolution for transmission electron
microscopy (TEM) requires a revolutionary change in the electron source
technology. In this paper we study the possibility of employing a
radiofrequency photoinjector as the electron source for a time-resolved TEM. By
raising the beam energy to the relativistic regime we minimize the space charge
effects which otherwise limit the spatio-temporal resolution of the instrument.
Analysis and optimization of the system taking into account the achievable beam
brightness, electron flux on the sample, chromatic and spherical aberration of
the electron optic system, and space charge effects in image formation are
presented and supported by detailed numerical modeling. The results demonstrate
the feasibility of 10 nanometer - 10 picosecond spatio-temporal resolution
single-shot MeV TEM.
