Optimized Electron Bunch Current Distribution from a Radiofrequency Photo-Emission Source

In beam-driven acceleration, drive bunches with ramped current profiles support enhanced transformer ratios which enable longer interaction lengths thereby increasing the energy gain associated with the witness bunch. The production of such tailored electron bunches can be accomplished via different beam shaping methods. One technique of particular interest, owing to its simplicity, consists in shaping the temporal profile of the laser pulse in photoemission sources. In this contribution we investigate, via a shape-optimization technique, the generation of a ramped bunch distribution using such a laser-shaping technique. Our study takes the example of the Argonne Wakefield Accelerator where a proof-of-principle experiment is being planned. We also discuss limitations associated with the laser shaping and possible improvements.