|MICROPHONICS ANALYSIS AND COMPENSATION WITH A FEEDBACK LOOP AT LOW CAVITY GRADIENT|
|Michel Luong, Guillaume Devanz, Eric Jacques, Jorge Novo, Axel Neumann, Oliver Kugeler|
For FEL projects based on a superconducting linac operating in CW mode, the RF power optimization finally comes up against the microphonics disturbances, which result in an unpredictable detuning of the cavities. A new piezoelectric tuner was developed and mounted on a TTF 9-cells cavity with an appropriate instrumentation. This system enables a full characterization of the disturbances and the tuner behavior. Modeling, simulations and experimental validations were carried out to demonstrate the feasibility of a feedback compensation for a multi-cell cavity. The results also bring to some recommendations that may overcome the limitations pointed out in the present experimentation.