RF system for the Duke 1 GeV storage ring

The RF frequency is 178.5 MHz. An amplifier built by the QEI corporation provides 50 kW power. All the power feeds to a single-cell RF cavity, built by BINP at Novosibirsk, Russia, giving a gap voltage of 720 kV. An ANT circulator is used in the feed line. There are four basic feed-back loops to stabilize the system operation: (1) Cavity frequency tuning loop. (2) Cavity voltage control loop. (3) RF phase stabilization loop. (4) Synchrotron oscillation damping loop. The whole system has been tested and operated since December 1993. It has provided secure and stable operation for the storage ring.