Technical Papers and Presentations

Charged particle accelerators require large dipole fields with stringent homogeneity requirements needed to bend particle beams without defocussing. Commonly superconducting saddle coil magnets are used with an iron core to enhance the bore field. The iron uneven magnetization brings undesired multipole fields that need to be compensated for by pre-conditioning the beam with additional magnets. Bending saddle coils dramatically distort the bore field generating undesired multipole fields costly to compensate for. A bent iron core also significantly contributes to the multipole content of the bore field, its effect strongly depending on its shape and saturation state. AML’s Double-Helix (DH) winding technology allows for the design of magnetic field with arbitrary multipole content through precise positioning of conductors, thus making compensation for any field inhomogeneity practical. The paper presents the analysis of the effect of the iron core on the field homogeneity of a 3.5T bent dipole built at the Advanced Magnet Lab and the optimized winding leading to a pure dipole field.