Accelerator Science

Successful proof of principle test of novel balloon resonator

Superconducting radiofrequency (SRF) technology is the enabling advances in a new generation of proton linacs for discovery science or industrial application. Strong electromagnetic fields created in specially designed resonators are used to accelerate the protons. A class of resonators, termed spoke cavities, is efficient in acceleration but suffers from a phenomenon called ‘multipacting’ wherein a cascade of electrons is released from the surface by the high fields, which can limit the cavity performance. The TRIUMF SRF team has invented a new type of spoke resonator called the `balloon cavity’ with a special shape that virtually eliminates multipacting as an issue for single spoke resonators. A prototype cavity was fabricated and tested at TRIUMF and recent tests confirm the unique capabilities of the new variant.