EMC issues in RF stations for particle accelerators

RF systems are used in particle accelerators to add energy, to accelerate the beam and to focus the beam in the direction of motion (longitudinal direction). RF stations include a power stage, based on a tunable resonant cavity, and a feedback system, named Low-Level RF (LLRF), that sets the operating points, regulate the cavity fields, keep the structure on resonance and reject both external disturbances from the beam (beam loading) and spurious signals injected to the RF power system. Based on the current and future specifications for the regulation of the accelerating field of the cavities, EMC based design of the LLRF is becoming important to assess the performance requirements. In this paper, an overview of the RF station and the LLRF system is presented, focusing and analyzing the critical areas where an EMC based design is required.