Magnetic field gradient coils with closely packed windings and methods of manufacturing same

A magnetic field gradient coil comprising:

• a mold including a keying feature that defines a winding pattern of a coil section of the magnetic field gradient coil;
• an electrically insulating back plate;
• and
• an electrical conductor disposed on the backplate;
• wherein a surface of the electrical conductor opposite from the electrically insulating back plate includes a keying feature extending along the length of the electrical conductor, the keying feature comprising a longitudinal groove, a longitudinal ridge, or a line of discrete protrusions spaced apart along the electrical conductor, the keying feature of the electrical conductor mated with the keying feature of the mold.

A magnetic field gradient coil manufacturing method comprising:

• (i) inserting elements into openings on an outside surface of an electrically insulating carrier;
• (ii) wrapping an electrical conductor turn around the outside surface of the electrically insulating carrier with one side of the wrapped electrical conductor alongside elements inserted into openings on the outside surface of the electrically insulating carrier and the other side of the wrapped electrical conductor not alongside elements inserted into openings on the outside surface of the electrically insulating carrier;
• (iii) removing the elements alongside the one side of the wrapped electrical conductor from the openings;
• and
• (iv) repeating operations (ii) and (iii) to wrap the electrical conductor turns of a magnetic field gradient coil around the outside surface of the electrically insulating carrier.

A magnetic field gradient coil manufacturing method comprising:

• (i) laying electrical conductor onto a mold with a keying feature of the electrical conductor that extends along the length of the electrical conductor engaging a mating keying feature of the mold wherein the keying feature of the mold defines a winding pattern of a coil section of a magnetic field gradient coil and the laid electrical conductor forms the coil section;
• (ii) attaching an electrically insulating back plate to a side of the coil section opposite from the mold;
• and
• (iii) removing the mold from the coil section.