Normal Zone Propagation in Superconducting Focusing Solenoids and Related Quench Protection Issues

Superconducting solenoids are increasingly used as focusing lenses in transport channels of linear RF accelerators of ions. If these accelerators employ superconducting RF cavities, each focusing lens is usually comprised of three coils connected in series: a main coil, which provides the needed focusing strength, and two bucking coils, that help to reduce magnetic field outside the lens.