Bevatron Guide Field Control

The Bevatron guide field power supply has been under computer control for one year. This facility allows operational parameters to be programmed at operator request in order to provide the desired field profiles commensurate with the current experimental program. With a requirement of one part in fifteen thousand accuracy for resonant extraction, the digital system has been enlarged until a realtime closed-loop control function meet this specification. A one gauss window for entry into flat-zones is now maintained, while a relative flatness tolerance of ±1/ 2 gauss is held during the typical 2-sec. flatzone. This paper includes the structure of a new data-acquisition system with emphasis upon the use of a fast magnetic-core memory to gather blocks of data, as well as to hold the necessary digital threshold values to be arithmetically compared with the results of the data gathering facility. Also covered, is the implementation of the system in the detection and ultimate reduction of incipient fault conditions within the guide field power supply.