RF Control of High QL Superconducting Cavities

In the last 20 years the requirements for RF Control have increased as the target use has broadened from electron/ion accelerators for Nuclear and Particle Physics to light sources such as Free Electron Lasers. The increasing requirement of cavity field control to meet the spectral and jitter performance specifications for light sources has led system designers to a more rigorous approach in designing the RF controls. Design attention must be applied not only to the hardware and control algorithms but also to the overall accelerating system to meet performance and cost requirements. As an example, cavity QL in Energy Recovery Linacs (ERL) must be optimized such that the RF controls can accommodate the lowest possible RF power given the background cavity microphonics. This paper presents the status and future directions of high QL superconducting RF control systems.