Radio-frequency (RF) photoinjector-based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe structural changes at the atomic scale with sub-100 fs temporal resolution in a single shot. We analyze the limitations on the temporal and spatial resolution of this technique considering the operating parameters of a standard 1.6 cell RF gun (which is the RF photoinjector used for the first experimental tests of relativistic UED at Stanford Linear Accelerator Center; University of California, Los Angeles; Brookhaven National Laboratory), and study the possibility of employing novel RF structures to circumvent some of these limits. 2009-07-08T16:23:28-07:00 /home/httpd/docserver/releases/20080613005430/public/paper/file/788/PUB00028.pdf 1 788 2009 Microscopy and Microanalysis 2009-07-08T16:23:28-07:00 15, 290-297 2009