Metamaterial Structures for High-Gradient Wakefield Acceleration

This talk will present the recent advances in novel metamaterial (MTM) structures for structure-based wakefield acceleration (SWFA). SWFA is a promising approach to make compact high-energy particle colliders by achieving high accelerating gradient. The MTM structure designed for SWFA is a “wagon wheel” periodic structure with a negative group velocity, and it can interact strongly with relativistic electron bunches by reversed-Cherenkov radiation. The period of the structure is much smaller than the wavelength. In this way, the MTM structure performs almost as a continuous medium. Two “wagon wheel” MTM structures have been tested at the Argonne Wakefield Accelerator (AWA). The reversed-Cherenkov radiation was verified experimentally. The highest power generated was 380 MW in a 10 ns long pulse at 11.7 GHz from a train of eight electron bunches with an energy of 65 MeV and a total charge of 224 nC. These results demonstrate the unique features of MTM structures that are attractive for future wakefield accelerators. Advantages include the high shunt impedance, the simple and rugged structure, and a large parameter space for optimization.\\ \\ In Collaboration With: Julian Picard, Michael Shapiro, Ivan Mastovsky, Richard Temkin; Massachusetts Institute of Technology. Manoel Conde, John Power, Jiahang Shao, Eric Wisniewsk, Maomao Peng, Gwanghui Ha, Jimin Seok, Scott Doran; Argonne National Laboratory. Chunguang Jing, Euclid Techlabs LLC