The invention concerns a magnet winding in an air coil configuration with windings built from conducting elements which surround a magnetic field axis and are wound in at least two layers with at least one layer transition.
A magnet winding of this kind is, by way of example, known in the art from the publication "SOLENOID MAGNET DESIGN, The Magnetic and Mechanical Aspects of Resistive and Superconducting Systems" by D. Bruce Montgomery, 1980, Robert E. Krieger Publishing Company, Huntington, N.Y.
For many applications, a highly homogeneous magnetic field, which can be produced with the aid of axially symmetric, in particular, rotationally symmetric coil configurations is necessary. For the production of such fields, loops or rings are necessary which, in practice, must be wound from wires whose diameter can be relatively large compared to the winding radius, in particular, with coils from normally conducting copper wire. Actual coils require a transition from one winding layer to another which results in a considerable winding error. In an angular region about the coil axis in which the transition from one layer to another takes place, the corresponding innermost radial winding has, on the average, only one conducting element per two layers compared to two conducting elements in the other angular region outside of the layer transition, that is to say, one in each layer. In this manner, a local defect in the magnetic field is produced by the coil in the region of the layer transition.