Development of a Tunable Dielectric Loaded Accelerating Structure

Dielectric structures driven by wakefields or external radio frequency (RF) are presently being studied intensively as a promising technique for next generation linear colliders. This project will develop dielectric loaded accelerating structures that can be adjusted in frequency using a bias electric field. The method proposed here is inexpensive and easy to implement without affecting beam quality. A Tunable Dielectric Wakefield Accelerating Structure is to be designed, developed and demonstrated. The Phase I project developed thin (400 µm) cylindrical ferroelectric layers for prototype tunable cylindrical DLA structures. The Phase II project will test the tunable DLA structure. A new type of the tunable dielectric based accelerating structure will be fabricated and tested in a high current beam experiment at the Argonne Wakefield Accelerator. Frequency tuning will be demonstrated at frequencies of 10, 15.6 and 33 GHz. The frequency adjustment will be studied both by varying the temperature and applied high voltage. Finally, a new power source ¿ the tunable 26 GHz power extractor based on a dielectric loaded structure ¿ will be designed and demonstrated. Commercial Applications and other Benefits as described by the awardee: This technology can be applied directly to microwave power sources and switches, passive microwave resonators, filters and phase-shifters, thus finding immediate application in the communications industry. This work also represents a step towards use of dielectric structure technology for efficient cost effective future electron accelerators.