Auto-tuning and Q-value monitoring of RF cavities at the J-PARC linac

Fang, Z.*; Anami, Shozo*; Michizono, Shinichiro*; Yamaguchi, Seiya*; Kobayashi, Tetsuya; Suzuki, Hiroyuki

In the J-PARC proton linac, each klystron drives two RF cavities. The RF amplitude and phase of the cavities are controlled by an FPGA-based digital feedback control system. The tuning of each cavity is also controlled by a DSP of this control system. In this paper, three methods of f setting of RF cavity will be discussed. The tuning method of RF cavity with flat cavity-phase decay is adopted in the actual operation of the J-PARC linac. In our RF system, the tuning information including detuned frequency and phase, and Q-value of each cavity are measured in real-time and displayed in the PLC Touch Panel of the control system.