Design and High Power Testing of 52.809 MHz RF Cavities for Slip Stacking in the Fermilab Recycler.

For NOvA and future experiments requiring high intensity proton beams, Fermilab is in the process of upgrading the existing accelerator complex for increased proton production. One such improvement is to reduce the Main Injector cycle time, by performing slip stacking, previously done in the Main Injector, in the now repurposed Recycler Ring. Recycler slip stacking requires two new RF cavities operating at slightly different frequencies (df = 1260Hz). These are copper, coaxial, quarter wave cavities with R/Q =13 ohms. They operate at a peak gap voltage of 150 kV with 150 kW peak drive power (60% duty factor), and are resonant at 52.809 MHz with a 10 kHz tuning range. Two have been completed and installed. The design, high power test results, and status of the cavities are presented.