Fast Ferroelectric L-Band Tuner for Superconducting Cavities

The effective use of superconducting cavities in a future high-energy accelerator will require rapid adjustments of coupling between the cavities and the external RF power sources. This coupling is needed to compensate for uncontrolled sources of cavity detuning, such as from mechanical vibrations and/or fluctuations in beam loading. However, the time-response of available RF couplers and tuners is not rapid enough to serve this need. This project will continue the development of a tuner with the potential for rapid variations in cavity coupling to an external RF source. The tuner utilizes ferroelectric elements whose dielectric constant can be varied by application of an external voltage. Phase I will involve the study of design variations for optimizing the performance of this tuner. In Phase II the tuner will be implemented at Brookhaven National Laboratory on 700 MHz cavities that are under development for the energy recovery linac. Commercial Applications and other Benefits as described by the awardee Development of efficient tuners that can rapidly alter the coupling between superconducting cavities and external RF sources could have a strong impact on the design and cost of future systems. Fast tuners also could find application in commercial accelerators for medical therapy and industrial processing, thus lowering their costs.