The permanent magnet phase shifter for the European X-ray free electron laser

In segmented undulator systems with adjustable gaps, phase shifters are needed to exactly control the phase retardation between electrons and the radiation field over the entire length. A phase shifter based on permanent magnet technology for the use in the European X-ray free electron laser (XFEL) has been developed and tested. Its magnetic design is explained in detail. Requirements and specifications are discussed with special considerations of the boundary conditions set by the XFEL. Magnetic test results are presented and are thoroughly discussed. Special attention is given to the future operation in the XFEL.