Development of high stability resonant kicker for Swiss Free Electron laser

A high stability resonant beam deflector system is being developed as part of the beam switching^[1] of the X-ray Free Electron Laser (SwissFEL) at Paul Scherrer Institute^[2]. To increase facility efficiency the main linac will operate with two electron bunches in one RF pulse. Three identical resonant kickers followed by a DC septum should separate the two bunches, that are 28 ns apart, and send them to two separate undulator lines. Shot-to-shot amplitude stability of each kicker should be better than +/- 80 ppm peak-to-peak, assuming the stability budget is equally split between phase and amplitude jitter^[1]. Development of the resonant kicker prototype and the precision measurement system is described. Preliminary measurements are presented.