Femtosecond Synchronisation for Externally-Injected Laser Wakefield Acceleration at CLARA

LWFA has been hugely successful in demonstrating high gradient and high energy acceleration of electrons, recently up to 8GeV in 20cm. The shot-to-shot energy stability and bandwidth of these sources remains however below that of conventional accelerators; this is due to the intrinsically nonlinear and noisy nature by which particles are 'self-injected' into the laser wakefield. One attractive method to improve the performance of LWFA would be to inject high quality bunches from a conventional accelerator into a LWFA, which would allow energy gain in a linear regime and preserves the injected bunch quality.

This project is aimed towards a practical demonstration of externally-injected laser wakefield acceleration at the CLARA electron accelerator facility (STFC Daresbury Laboratory), by evaluating and measuring laser-electron beam synchronization with femtosecond resolution. A diagnostic capable of resolving the electron-laser synchronization directly with such high resolution is technologically challenging and not immediately available commercially; a key element of this project will be to design, build and evaluate the operation of this diagnostic. The magnitude of the laser-electron beam synchronization will be heavily dependent on sources of noise in the high energy laser. The project will seek to quantify (and where possible, resolve) sources of noise and drift in a high energy Ti:Sapphire master oscillator / power amplifier laser system, available in the laser laboratory adjacent to the CLARA accelerator.