Exploring multipacting characteristics of a rectangular waveguide

Multipacting (MP) characteristics of the rectangular waveguide used for the CESR-III superconducting RF (SRF) system were investigated by using a newly developed 3-D computer code. MP bands were identified for different operating modes, such as standing wave (SW) mode, traveling wave (TW) mode and the so called mixed wave mode (TW mixed with SW). A comparison between the simulation results and the experimental observations for the installed CESR-III SRF systems was made. Measures to suppress multipactoring were explored. Our simulation results suggested that an external DC magnetic field of a few Gauss of amplitude in the wave propagation direction would be very effective in disturbing the trajectories. Further work will include disk-type windows in the waveguide couplers.