Development of an electromagnetic phase shifter using a pair of cut-core coils for a cross undulator

This paper describes the development of a phase shifter that can be used in cross undulators for fast polarization switching. The phase shifter is composed of a pair of cut-core coils and a thin-walled stainless steel duct. Evaluation of the magnetic fields of the phase shifter indicates that the switching frequency of this simple and low-cost device can exceed 30 Hz.