The magnetron-type varactor for fast control in accelerator RF systems

The rf test of the magnetron-type varactors have shown [1] the proof of principle of this device. The comparison with the other power rf tunable devices, such as ferrite tuners, shows that the varactor has a response time a few orders of magnitude shorter. In the experiments this time was estimated to be in the order of 10-6 sec for operating frequency ∼ 66 MHz. This feature of the varactor opens new applications of the varactor for a fast modulation (in order of few tens of the working rf period) of the amplitude and the phase of the accelerating voltage in the rf cavities. Based on results of numerical simulation and experiments, different applications of the device for fast control and improvements in the design to reduce response time, are considered. (author). 5 refs., 1 fig