A physics based approach for ramping magnet control in a compact booster
At Duke University, a booster synchrotron was recently commissioned as part of the high intensity gamma-ray source (HIGS) upgrade. For the ramping magnet power supply controls, a scheme was developed to present the high level operator interface in terms of the physics quantities of the accelerator, i.e. the effective focusing strength of the magnets. This scheme allows for the nonlinearities of the magnets - a result of the extremely compact footprint of this booster - to be incorporated into the low level software. This facilitates machine studies and simplifies the use of physics modeling. In addition, it simplifies operation, allowing the booster to ramp to any energy from the 0.24 GeV of the injector linac to the 1.2 GeV maximum of the Duke storage ring. The high level of flexibility of this system is further advanced by incorporating the level of tunability typically found in a storage ring control system. Tuning changes made during steady-state operation are automatically propagated to the waveforms which make up the booster ramp. This approach provides a good match to the wide operation modes of the Duke storage ring and its associated free electron laser (FEL), and may be useful for other compact booster synchrotrons.