Power supply ramp control in the APS booster synchrotron

摘要

The Advanced Photon Source (APS) booster ramp cycle is completed within 250 ms and repeated at 2 Hz, accelerating positrons from 400 MeV to 7 GeV. Phase-controlled power supplies deliver current to each of the dipole, quadrupole, and sextupole magnet families. In order to maintain constant transverse tunes and chromaticity while the beam is accelerated, quadrupole and sextupole magnet currents must closely track the current in the dipole magnets. This is achieved using a conventional regulator in the power supply together with cycle-cycle corrections applied to the reference waveforms. The system and its performance is described and tuning algorithms are discussed.