RF control system for the SC cavity of the TESLA Test Facility injector

The superconducting cavity of the TTF injector, which operates in pulsed mode, must accelerate the non relativistic electron beam to an energy of 10 to 15 MeV. Lorentz forces and microphonics detunings are the major sources of cavity field fluctuation. In order to achieve amplitude and phase stabilities much smaller than 10/sup -3/ and 1 degree, an analog feedback system, mainly based on a self excited loop and I/Q modulators, has been developed. After a description of the RF control module, various measurements without and with beam are reported.