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

TL;DR

This paper details the design, high power testing, and implementation status of 52.809 MHz RF cavities used for slip stacking in Fermilab's Recycler Ring, enhancing proton beam intensity for future experiments.

Contribution

It introduces a novel RF cavity design for slip stacking, including high power testing results and implementation in Fermilab's accelerator complex.

Findings

Cavities operate at 52.809 MHz with a 10 kHz tuning range.

Each cavity achieves 150 kV peak gap voltage and 150 kW peak power.

Two cavities have been successfully installed and tested.

Abstract

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.