New SWIC Scanner/Controller System

W. Kissel, B Lublinsky, A. Frank, J. Smolucha
Fermilab

Since the early 70's Segmented Wire Ion Chambers (SWIC's) have been used in the Fermilab Switchyard beam transport lines to measure beam profiles and intensities. The Switchyard SWIC's as originally engineered have been geographically multiplexed. There are 26 physical SWIC's and only 7 scanners/controllers and therefor all profile data cannot be collected in one beam cycle. In the Main Ring era short cycle times (~10 seconds.) lessened the impact of this limitation. Tevatron era operation of Switchyard uses both SWIC's and BPM's. SWIC's will show profile information and have a much lower beam intensity threshold as compared to BPM's. This is an advantage during tune-up at low intensity especially when dealing with cryogenic transport lines. Long Tevatron cycle times (~60 seconds.) coupled with the need to sequence various SWIC's and their gains on a given controller, have proved to increase startup/tuning time.

The new SWIC controller/scanner system has been designed to ease these limitations. New cabling combined with a new scanner/processor system will allow simultaneous data collection of all SWIC's. Each will have their own specific data collection criteria (gain, sample duration, spill type, to name a few). Existing "Automated Tuning" programs will be able to use either BPM or SWIC position and intensity information.

Hardware as to the new SWIC system is implemented as a distributed system with 68060 based FE, connected via ARCNET to 80186 embedded processors - one per SWIC. 186s are responsible for the actual data collection controller manipulation. Collected data is then shipped to the FE, which is doing data massaging and communications with the consoles. FE software is VxWorks based system, running communications, finite state machines, defining measurements, circular buffers of collected data and special calculations.