UCLA

Advanced accelerators have great promise in reducing the size and cost of high energy colliders as well as bringing high brightness x-ray sources to the laboratory tabletop scale. The inverse free electron laser (IFEL) is a high gradient advanced accelerator scheme that is one of the most ecient ways of transferring energy from a laser to an electron beam. By copropagating a laser and a relativistic

electron beam through an undulator in vacuum and taking advantage of resonant ponderomotive motion of the electron beam, IFEL avoids the breakdown associated with other schemes that use a material to couple the laser fields to the electron beams.

This dissertation provides an overview of IFEL, the photoinjector electron beams to be used in IFEL interactions, and two IFEL applications: compression and synchronization of a photoinjector electron beam to a laser application using THz driven IFEL and high gradient acceleration using IFEL.

The numerically investigated THz IFEL application shows that with a 10 J THz 8 pulse train, an electron beam bunch length of 100 fs RMS can be compressed to 14 fs RMS and have the beam's time of arrival jitter relative to an external laser reduced by an order of magnitude.

High gradient acceleration by IFEL was examined experimentally at Lawrence Livermore National Laboratory (LLNL). This experiment marks the first attempt to use sub-picosecond time pulse, TW peak power scale titanium:sapphire laser pulses to perform IFEL acceleration. The demonstrated energy gain from 77 to 120 MeV combined with particle tracking simulations shows an accelerating

gradient of over 200 MeV/m. Because the laser pulse length is the same order as the slippage experienced by the electron beam with respect to the laser and the time of arrival jitter has been measured to be greater than 2 ps, the overlap is investigated through relative single shot time of arrival measurements using electro-optic sampling based spatial encoding techniques. The temporal overlap

measurement was found to be consistent with a cross-correlation model taking into account the independently measured laser and electron beam lengths.