Low impedance design with example of kickers (including cables) and potential of metamaterials

Unmatched terminations of single elements were recently identified to be responsible for beam instabilities in the CERN PSB and LEIR machines. Impedance models are needed to estimate the impedance of similar devices and to assess potential intensity limitations. A circuital model that includes the effect of coupling to cables on the beam coupling impedance will be discussed. Moreover, examples of low impedance design with special emphasis on the mitigation of the impedance of ferrite kickers (e.g. longitudinal serigraphy) will be presented and guidelines for optimized impedance design will be provided. Finally, the potential of metamaterials for impedance mitigation will be discussed.