Operation of the Tevatron Extraction System

The Fermilab Tevatron is currently in the middle of its second running period for fixed target physics. Steady operation has been established at 800 GeV with 1 × 1013 protons being extracted. Beam spill over the 20 - 23 second flattop is regulated by a closed loop feedback and a feed forward learning system controlled by a microprocessor.1 Eight power supplies have their waveforms programmed by the microprocessor in an attempt to reduce the modulation on the beam spill. In addition the microprocessor can insert a pause in the slow spill and cause the extraction of a high intensity (3 × 1012) fast (1-2 milliseconds long) pulse. A description of the extraction system as well as analysis of the spill modulation encountered during commisssioning are presented in this paper. Current status of the spill structure is also discussed.