A Ferroelectric Fast Reactive Tuner (FE-FRT) to Combat Microphonics

A prototype Fast Reactive Tuner (FRT) for superconducting cavities has been developed, which allows the frequency to be controlled by application of a potential difference across a newly developed ultra-low loss ferro-electric material residing within the tuner. The tuner operates at room temperature, outside of the cryostat and coupled to the cavity via an antenna and co-axial cable. This technique allows for active compensation of microphonics, eliminating the need to design over-coupled fundamental power couplers and thus significantly reducing RF power particularly for low beam current applications. Modelling; simulation; and stability analysis, of the tuner; cavity; measurement system; and feedback loop, have been performed in the frequency and time domain, and are compared to the latest experimental results. The potential benefits of applying this techniques to ERLs, which are seen as one of the major use cases, are detailed both in general and with regards to specific projects. Ideas and designs for an improved next generation FRT are also discussed.