Multipactor threshold sensitivity to total electron emission yield in small gap waveguide structure and TEEY models accuracy

Abstract

Radio-frequency (RF) systems used in vacuum can be damaged by electronic avalanches triggered by the multipactor effect. This undesirable phenomenon can appear for RF components used in space communication payloads as well as in experimental fusion devices, among others. To determine the multipactor breakdown threshold, expensive multipactor experimental tests can be made or multipactor simulations can be performed. This second method uses the Total Electron Emission Yield (TEEY) curve as input and the breakdown threshold predicted by simulation highly depends on this curve. Consequently we decided to make a sensitivity study of multipactor breakdown threshold in relation to the TEEY curve variations. We study the silver conductor material with a RF waveguide transformer. Two critical energy regions are found for a small gap waveguide structure: energies around first cross-over energy and energies between the first cross-over and the yield maximum. Electron emission data have to be accurate on these regions to get a coherent multipactor threshold. Six TEEY models are benchmarked with respect to their capability to accurately model these regions.