Speaker
Description
Local X-ray production, beam losses, and surface discolouration in colloidal graphite coated regions of the cavity indicate that multipacting continues to affect the operation of the 150 MHz flat-top cavity of the HIPA Ring Cyclotron.
Particle-in-cell simulations were performed to confirm the phenomenon driving the issues and identify the specific operational conditions where it is driven. Simulations at the nominal cavity voltage show resonant electron trajectories between the electrodes and cavity wall, producing stable multipacting patterns consistent with observed surface discolouration. Guided by these results, the cavity geometry was modified to flatten the field minimum near the backplane, which demonstrated effective mitigation of multipacting undervarious operational conditions.
| Paper status | Resubmitted proceeding files received and assigned to an editor. Accepted. |
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