Patent ID: 8907667

Claim:
An apparatus comprising a magnetic field generator for generating a magnetic field that is homogenous within a sphere centered on a central point, said generator comprising at least one first coil, one second coil and one third coil wound respectively about first, second and third winding axes, said first, second, and third winding axes being mutually orthogonal and secant at a common point corresponding to said central point, a coil or coils wound around a common winding axis being laid out along said winding axis so that a plateau of intensity of a magnetic field generated by said coil or coils occurs at said central point when said coil or coils are crossed by a same current, at least four coils wound around each of said winding axes, said four coils forming two pairs of coils, wherein first and second coils of a pair are symmetric relative to a plane of symmetry perpendicular to said winding axis and passing through said central point, said four coils being spaced from one another to cancel at least a first derivative up to a seventh derivative of a magnetic field generated by said coils, in parallel to the winding axis, at said central point when said coils are powered by the same current, and wherein said coil defines a circle having a diameter that is equal, within 2%, to a diameter of a circle defined by an intersection between a sphere centered on said central point and a plane, perpendicular to a winding axis of said coil, passing through said coil, said sphere being the same for all coils wound around the same winding axis.