Update on study of vacuum RF breakdown in strong magnetic fields

• Alexey Kochemirovskiy (AD)

Room: Meeting Room RF breakdown has a negative impact on a RF cavity’s performance, especially with the presence of strong magnetic fields. The MuCool Test Area at Fermilab is the facility that allows us to study the effects of static magnetic field on RF cavity operation. As a part of this research program, we have tested an 805MHz pillbox-like “modular” cavity in strong external magnetic fields. “Modular” structure of the cavity enables easy dismounting of the endplates to perform inspection of inner surfaces after each run as well as swapping endplates to study the effects of various materials on breakdown phenomenon. Surface inspection after high power runs of modular cavity with flat copper end walls in zero and 3T magnetic fields revealed unique damage patterns and allowed to improve on analysis of breakdown arc characterization. Recent results of high power runs in both zero and 3T magnetic field with copper end walls will be discussed. Next set of measurements on cavity configuration with Beryllium end walls will allow studying surface field emission properties with increased precision.