Internal Trim Coils for CBA Superconducting Magnets

In order to correct iron saturation effects and shape the beam working line, superconducting trim coils have been constructed, which operate inside the main coils. Detailed studies of mechanical properties, quench behaviour, fields produced and hysteresis have lead to the production of accelerator quality coils generating the required strength harmonics up to cos (7¿). These are routinely installed in CBA main magnets and operate at 80% of short sample with negligible training in an ambient field of more than 5.3T.