[1] Powers T. They practice of cavity RF test system[C]Proceedings of the 12th International Wkshop on RF Superconductivity. 2005: 4070.
[2] Delayen J R. Phase amplitude stabilization of superconducting resonats[D]. Califnia: Califnia Institute of Technology, 1978: 116.
[3] Allison T, Delayen J R, Hovater C, et al. A digital self excited loop f accelerating cavity field control[C]Proceedings of PAC07. 2007: 24812483.
[5] Nicer H. Electroacoustic stability of a superconducting spoke cavity[D]. Sweden: Uppsala University, 2015: 3137.