Optimization and beam dynamics of a superconducting radio-frequency gun

Recent advances in superconducting radio-frequency (RF) technology and a better understanding of RF photoinjector design optimization make it possible to propose a specific design for a superconducting RF gun that can simultaneously produce both ultra-high peak brightness and high average current. Such a device is a critical component of next generation X-ray sources, such as self-amplified spontaneous emission free-electron lasers (SASE FEL) and energy recovery linac-based systems. The design presented in this paper is scaled from the present state-of-the-art normal conducting RF photoinjector that has been studied in the context of the linac coherent light source and SPARC SASE FEL injection schemes. Issues specific to the superconducing RF photoinjector, such as accelerating gradient limit, RF cavity and cryostat design, and compatibility with magnetic focusing and laser excitation of a photocathode are discussed.