Staging for Wakefield Acceleration Experiment Hardware Development: Fast Kicker and High Power RF Delay Section

Linear colliders based on two-beam wakefield acceleration have a modular design. A fundamental requirement of two beam wakefield acceleration that has yet to be demonstrated is the staging of sequential accelerating modules. For a successful staging demonstration two key things have to be addressed: drive beam separation and the timing between wakes from different stages and the witness beam. Timing was typically addressed by sending the drive beam through a 180 bend, but this led to problems with coherent synchrotron radiation and subsequent beam quality degradation. We propose to use a fast strip line kicker for drive bunch train management. We estimate that the power requirement and turn-on time are well within a grasp of current technology. Synchronization of the main (witness) beam with wakefields generated by the drive beam can be done by a series of variable microwave power delay lines, which eliminates the need to bend the drive beam. We propose to use an overmoded TE01 mode based cylindrical waveguide as a delay line because of the reduced power loss of such mode. In Phase I of this project, we will design and build two essential pieces of hardware for the two beam acceleration staging experiment at Argonne Wakefield Accelerator, a fast stripline kicker and an RF delay line. Specifically, a TE10-TE01 rectangular to cylindrical mode converter will be built for wakefield transport and a delay and a stripline kicker will be designed and manufactured. These components will be cold tested and ready for installation at the AWA. Commercial Applications and Other Benefits: Staging is a key experiment that has to be demonstrated for the validation of the wakefield collider concept. If the main (witness) beam can be made synchronous with the drive beam wakefield coming from separate stages and preservation of the main beam emittance can be shown, then a collider at a given energy can be designed by just stacking together the required number of wakefield modules.