Transient Beam Loading Compensation in the Fermilab Main Ring

A requirement for bunch coalescing and bunch rotation for antiproton production in the Fermilab Main Ring is that the net rf voltages be reduced below ~1 kV. At high beam intensities, the fields generated by the beam in a single pass through the rf cavities will exceed this limit. The new compensation systemmonitors the component of the beam current at the fundamental rf frequency as a function of time. This information is then delayed by a single turn and fed back into the high level rf system to cancel the beam-induced fields. The system has compensated the beam-induced voltage generated by a single booster batch to 5% of its initial value.