Process for manufacturing magnetic field generating devices in nuclear magnetic resonance imaging apparatuses and image generating device according to said process

A process for manufacturing a magnetic field generating device in a Nuclear Magnetic Resonance imaging apparatus, wherein a magnetic field is generated in a cavity or gap delimited by two magnetic pole pieces of the magnetic field generating device and wherein at least one of the magnetic pole pieces has an innermost layer of solid ferromagnetic material, and a layer composed of a plurality of adjacent or overlapping sheets of ferromagnetic material, wherein each of the plurality of sheets includes a plurality of areas, the plurality of areas on each sheet being at least partially separated from each other by a plurality of recesses, slots, or notches formed in the plurality of sheets so as to provide an electric resistance between adjacent ones of the areas so as to limit currents induced in the plurality of sheets from passing between adjacent ones of the areas, wherein each of the areas on each of the plurality of sheets are held together by a portion of the ferromagnetic material, the process comprising:

• arranging the plurality of sheets on the innermost layer of solid ferromagnetic material;
• mechanically pressing the plurality of sheets against each other;
• and
• securing the plurality of sheets to the innermost layer of solid ferromagnetic material.