Direct-drive and Eddy-current Septum Magnets

Two types of thin septum magnets, direct drive and eddy current, were c mainly in 2-D magnetic aspects. For the direct-drive type, the leakage field depend finite permeability of the magnet core and not on the thickness of the septum conduct suggested that the leakage field be controlled by reducing the current in the septum c or by using a correction coil. There were no significant differences between the t regarding thermal problems caused by high current densities in the thin septa. Th fields with 2-mm septum thicknesses were calculated using OPERA-2d to compare types. For the eddy-current type, the leakage fields calculated using OPERA compared with the calculations from Halbach’s model. The leakage fields for the edd type decayed with long time constants.