Jun 24 – 28, 2019
Crowne Plaza Brussels Le Palace
Europe/Zurich timezone

HOM damping design studies for FCC-ee cavities

Jun 25, 2019, 8:30 AM
Crea/Explo (1st floor)


1st floor

Presentation Superconducting RF & associated technologies SRF


Shahnam Gorgi Zadeh (Rostock University)


The present baseline of FCC-ee considers 400 MHz single-cell cavities for the Z-pole machine, 400 MHz four-cell cavities for the W and H modes of operation, complemented by 800 MHz five-cell cavities for the tt operation. In this presentation different higher order mode (HOM) damping schemes are compared for the four operating scenarios of FCC-ee. The longitudinal and transverse impedance of the HOM-damped cavities are compared with an impedance limit set by synchrotron radiation. Studying one cavity is usually not sufficient to fully characterize the behavior of cavities in a module. In a module composed of several cavities, some modes could arise which are not present in a single cavity. Furthermore, there is a difference between the amount of power absorbed by the HOM couplers in a single cavity and cavities in a module due to the effect of end beam pipes. Therefore, the HOM power for a single-cavity and four-cavity module with different HOM damping schemes is calculated as well and the power handling capabilities required for the respective schemes is determined.

Primary author

Shahnam Gorgi Zadeh (Rostock University)


Presentation materials