Performance of the main ring magnet power supply of the KEK 12 GeV proton synchrotron

The main ring magnet power supply of the KEK 12-GeV proton synchrotron consists of several twelve-pulse thyristor rectifiers with DC filters, two reactive power compensators with tuned AC harmonic filters, and an analog and digital hybrid control system. To obtain well-defined parameters such as absolute precision of beam energy, stable beam position, tracking between focusing and bending fields to fix the betatron tune, stable acquisition of extracted beam spill etc., it is necessary to operate this large pulsed power supply with high current reproducibility and low residual current ripple. Several stabilization techniques are described to meet these requirements.<
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