A Database Driven Fast Feedback-System For The Stanford Linear Collider

A new feedback system has been developed that stabilizes the SLC beams at many locations. The feedback loops are designed to sample and correct at the repetition rate of the accelerator. Each loop can be distributed across several INTEL 80386 microprocessors that control the SLC hardware. A new communications system, KISNET, has been developed to pass data between the microprocessors at this rate. The software is written using the State SpaCe formalism of digital control theory and is database driven. This allows a new feedback loop to be implemented by setting Lip the on-line database and perhaps installing a communications link. Eighteen such loops have now been implemented and this has measurably improved the performance of the accelerator.