Patent ID: 7990143

Claim:
A nuclear magnetic resonance machine comprising means for creating an intense main magnetic field B 0 in a usable interior space in the form of a tunnel with axis Z; means for radio-frequency excitation and means for processing radio-frequency signals emitted in response by a body or object placed in said usable interior space, and a first set of solenoidal gradient coils configured for superimposing on the intense magnetic field B 0 components of an additional magnetic field, said gradient coils being incorporated into tubes disposed parallel to the axis Z in an annular cylindrical space situated between an exterior cryogenic enclosure containing said means for creating an intense magnetic field B 0 and said usable interior space, the diameter of the gradient coils being inscribed in a thickness of said annular cylindrical space, the solenoidal gradient coils of the first set being configured to produce a first or X field gradient in a first radial direction (x) of the NMR machine perpendicular to the axis Z and a second or Y field gradient in a second radial direction (y) of the machine also perpendicular to the axis Z, the first direction (x) being perpendicular to the second direction (y); and the NMR machine including amplifiers configured for simultaneously energizing said solenoidal coils with algebraic sums of currents corresponding to the two gradients, characterized in that the annular cylindrical space includes on an external wall thereof annular coils configured for producing a magnetic field gradient oriented parallel to the direction of the main magnetic field B 0 whereas the solenoidal coils producing X and Y field gradients in directions perpendicular to the direction z of the main magnetic field B 0 are all disposed within the thickness of the annular cylindrical space; and in that the solenoidal gradient coils incorporated in tubes constitute individual sources of X and Y field gradients in directions perpendicular to the direction of the axis Z, which are sized as forming part of a set of N contiguous individual sources distributed at the perimeter of the annular cylindrical space, where N=4υ+2, υ being an integer greater than or equal to 1, but where two diametrically opposite individual sources corresponding to an axial plane xOz are omitted to retain only 4υ contiguous individual sources distributed in two subsets separated by gaps, each tube being provided with one individual source.