AN ANALYSIS OF THE OPERATIONAL PERFORMANCE OF THE AUTOMATIC GLOBAL HORIZONTAL BEAM POSITION CONTROL SYSTEM ON THE SRS AT DARESBURY

摘要

The system of automatic global horizontal position control, used routinely at the Daresbury SRS since November 1994, has achieved a dramatic reduction in variations in the measured beam position (the orbit "ripple") at 16 beam position monitors around the ring. The comparatively small drifts in the residual "offset", or average orbit, which is determined by the RF synchronous condition, are not treated by the present approach. The dominant factor in offset drift is believed to be movement of storage ring elements caused by thermal fluctuations over the fill cycle. A programme of investigations aimed at gaining a better understanding of these effects, and of possible correction techniques, is now under way.