New booster synchronization loop

摘要

The AGS Booster must be synchronized to the AGS rf system before bunch-to-bucket transfer of the beam. The Booster delivers four batches at 7.5 Hz and extraction occurs at full acceleration rate, leaving only 5 ms available for synchronization. An improvement has been made to the synchronization feedback loop. A new loop compensator has been designed using a state variable representation. The three state variables are, beam phase and frequency, and the reference input to the beam control phase loop. The design uses linear quadratic optimum control to achieve greater stability and smaller errors. Lock acquisition, without a transient, is accomplished by a circuit that derives the loop reference from the instantaneous state variable feedback value at loop closing. The reference is brought adiabatically to zero at transfer.