PRECISION LLRF CONTROLS FOR THE S-BAND ACCELERATOR REGAE

The linear accelerator REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY delivers electron bunches with a few femtosecond duration for time-resolved experiments of material structure in pump-probe configuration. To achieve the desired 10 fs resolution, the Low Level RF controls for the normal conducting S-band cavities must provide field stability of 0.01% in amplitude and of 0.01 deg in phase. To achieve these demanding stability a recently developed LLRF controller based on the MicroTelecommunications Computing Architecture (MTCA.4) have been installed and commission. In this paper, we report on measurement performance of the LLRF system, the achieved stability and current limitations. THE REGAE FACILITY