We report on the successful experimental generation of electron bunches with ramped current profiles. The technique relies on impressing nonlinear correlations in the longitudinal phase space using a superconducing radiofrequency linear accelerator operating at two frequencies and a current-enhancing dispersive section. The produced ∼700-MeV bunches have peak currents of the order of a kilo-Amp\`ere. Data taken for various accelerator settings demonstrate the versatility of the method and in particular its ability to produce current profiles that have a quasi-linear dependency on the longitudinal (temporal) coordinate. The measured bunch parameters are shown, via numerical simulations, to produce gigavolt-per-meter peak accelerating electric fields with transformer ratios larger than 2 in dielectric-lined waveguides.
@article{arxiv.1109.1413,
title = {Generation and Characterization of Electron Bunches with Ramped Current Profiles in a Dual-Frequency Superconducting Linear Accelerator},
author = {P. Piot and C. Behrens and C. Gerth and M. Dohlus and F. Lemery and D. Mihalcea and P. Stoltz and M. Vogt},
journal= {arXiv preprint arXiv:1109.1413},
year = {2012}
}