Ultimately, accurate time of arrival determination of laser pump and electron beam probe will determine the temporal resolution of the SLAC MeV-Ultrafast Electron Diffraction* (MeV-UED) instrument, and therefore methods to achieve this at femto-second scales is an ultrafast science enabler. Interferometry of THz based e-beam and pump laser THz signals is a natural path towards this goal. As a first step, a detection scheme will be developed in a lab using laser pulses. The second step involves extracting the electron beam signal from a 100 GHz accelerating structure. Subsequently, both pump and electron beam signals are combined, filtered, amplified, and a temporal analysis can be performed. This proposal is for experimental detection and characterization of such signals, which arises from electron beam wakefield excitation of electromagnetic fields in a 100/200 GHz accelerating structure combined with a pump derived signal.

Ultrafast electron diffraction using MeV energy beams (MeV-UED) has enabled unprecedented scientific opportunities in the study of ultrafast structural dynamics in a variety of gas, liquid and solid-state systems. The SLAC MeV-UED program began in 2014 and became an LCLS user facility in 2019. This work will review recent R&D efforts for enhancing the resolution, flux and electron detection of the MeV-UED instrument. Additionally, the integration of Al/ML techniques is being explored to optimize facility operations and accelerate scientific discovery. In all, these will open new avenues for explorations in key areas of ultrafast science.