Generation and Characterization of Electron Bunches with Ramped Current Profiles in a Dual-Frequency Superconducting Linear Accelerator

摘要

We report on the successful experimental generation of electron bunches withramped current profiles. The technique relies on impressing nonlinearcorrelations in the longitudinal phase space using a superconducingradiofrequency linear accelerator operating at two frequencies and acurrent-enhancing dispersive section. The produced $\sim 700$-MeV bunches havepeak currents of the order of a kilo-Amp\`ere. Data taken for variousaccelerator settings demonstrate the versatility of the method and inparticular its ability to produce current profiles that have a quasi-lineardependency on the longitudinal (temporal) coordinate. The measured bunchparameters are shown, via numerical simulations, to produce gigavolt-per-meterpeak accelerating electric fields with transformer ratios larger than 2 indielectric-lined waveguides.