Operational experience with the new LEIR digital low-level RF System

The LEIR Low-Level (LLRF) system is the first all-digital low LLRF system that has been put into operation in a CERN circular machine. It is a very compact system, composed of one VME64x crate and of few NIM modules. System capabilities include typical beam control tasks, such as frequency program, beam phase, radial and extraction synchronization feedback loops, as well as cavity voltage/phase feedback loops. The system is also capable of coping with the large variation of the revolution frequency during an acceleration cycle as well as with the high dynamic range required by the LEIR cavities operation. Extensive diagnostics and observation capabilities are built-in and the system’s control parameters are fully configurable remotely and in-between cycles. Over the various LEIR runs, the LLRF system has proven to be reliable and reproducible as well as extremely flexible and powerful. These characteristics are essential for a LLRF system and LEIR is already profiting from them. Moreover, high beam availability is a fundamental requirement for LHC operation. The LEIR LLRF system is also important in its role as the pilot project for the LLRF renovation of the PS Complex machines. The design of the new LLRF for the four rings of the PS Booster machine has already started and is based upon the technology validated in LEIR. This note provides an overview of the operational results obtained by the LEIR LLRF during the first year s of operation and up to the 2009 ion run. These include the many different types of beams commissioned as well as essential features such as the synchronisation process at extraction, the cavity voltage/phase loop and the double-harmonic operation. This note aims not only at documenting the system capabilities, but also at spreading the knowledge on the system so that colleagues from the RF, OP and ABP groups become proficient with the system’s functioning and operation.