Comparison of experimental tests and theory for a rectangular two-channel dielectric wakefield accelerator structure

Experimental results are reported for test beam acceleration and deflection in a two-channel, cm-scale, rectangular dielectric-lined wakefield accelerator structure energized by a 14-MeV drive beam. The dominant waveguide mode of the structure is at $\ensuremath{\sim}30\text{ }\text{ }\mathrm{GHz}$, and the structure is configured to exhibit a high transformer ratio ($\ensuremath{\sim}12\ensuremath{\mathbin:}1$). Accelerated bunches in the narrow secondary channel of the structure are continuously energized via Cherenkov radiation that is emitted by a drive bunch moving in the wider primary channel. Observed energy gains and losses, transverse deflections, and changes in the test bunch charge distribution compare favorably with predictions of theory.