Abstract: A system and method for a magnetic resonance (MR) imaging system includes a coil form, at least one magnet positioned about the coil form and configured to generate a magnetic field, at least one gradient coil for manipulating the magnetic field generated by the at least one magnet by way of a gradient field, and a heat pipe thermally connected to the coil form and having a cryogen therein. The MR imaging system also includes a cryocooler connected to the heat pipe to cool the heat pipe and the cryogen, wherein the coil form is comprised of a thermally conductive material in which eddy currents are substantially reduced during operation of the at least one gradient coil. The present invention has been described in terms of the preferred embodiment, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.

Abstract: A apparatus for low AC loss thermal shielding includes a plurality of thermally conducting fibers positioned along a desired direction of heat conduction. The fibers are electrically insulated from each other. The fibers are bonded together with a matrix, and a thermal link connects the bonded fibers to a cryogenic cold head.

Abstract: A system and method for a magnetic resonance (MR) imaging system includes a coil form, at least one magnet positioned about the coil form and configured to generate a magnetic field, at least one gradient coil for manipulating the magnetic field generated by the at least one magnet by way of a gradient field, and a heat pipe thermally connected to the coil form and having a cryogen therein. The MR imaging system also includes a cryocooler connected to the heat pipe to cool the heat pipe and the cryogen, wherein the coil form is comprised of a thermally conductive material in which eddy currents are substantially reduced during operation of the at least one gradient coil. The present invention has been described in terms of the preferred embodiment, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.

Abstract: The present invention provides an apparatus and method for automatically disconnecting a cryocooler from a cold mass reservoir of a MR system. A cryocooler thermal link includes a first end plate configured to be thermally connected to a cryocooler and a second end plate configured to be thermally connected to a cold mass. A wall encloses a space between the first and the second end plates, the wall having a first end attached to the first end plate and a second end attached to the second end plate. A working fluid is positioned in the space.

Abstract: A apparatus for low AC loss thermal shielding includes a plurality of thermally conducting fibers positioned along a desired direction of heat conduction. The fibers are electrically insulated from each other. The fibers are bonded together with a matrix, and a thermal link connects the bonded fibers to a cryogenic cold head.

Abstract: A system and method for a magnetic resonance (MR) imaging system includes a coil form, at least one magnet positioned about the coil form and configured to generate a magnetic field, at least one gradient coil for manipulating the magnetic field generated by the at least one magnet by way of a gradient field, and a heat pipe thermally connected to the coil form and having a cryogen therein. The MR imaging system also includes a cryocooler connected to the heat pipe to cool the heat pipe and the cryogen, wherein the coil form is comprised of a thermally conductive material in which eddy currents are substantially reduced during operation of the at least one gradient coil. The present invention has been described in terms of the preferred embodiment, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.

Abstract: A method is presented for manufacturing laminate tile metal pole pieces for an MRI. Each laminate tile has a trapezoidal or annular sector shape. The trapezoidal shape allows the tiles to be attached side by side to form a multiple concentric annular array pole piece without using oddly shaped edge filler tiles needed to fill a circular pole piece with square tiles. The pole piece is made by placing a plurality of tiles into a mold and filling the mold with an adhesive substance to bind the plurality of tiles into a unitary tile body. The unitary tile body is then removed from the mold and attached to a pole piece base to form the pole piece. The mold cavity surface preferably has a non-uniform contour. The bottom surface of the unitary tile body forms a substantially inverse contour of the mold cavity surface contour.

Abstract: A laminate tile pole piece for an MRI, a method and a mold for manufacturing laminate tile metal pole pieces for an MRI. Each laminate tile has a trapezoidal or annular sector shape. The trapezoidal shape allows the tiles to be attached side by side to form a multiple concentric annular array pole piece without using oddly shaped edge filler tiles needed to fill a circular pole piece with square tiles. The pole piece is made by placing a plurality of tiles into a mold and filling the mold with an adhesive substance to bind the plurality of tiles into a unitary tile body. The unitary tile body is then removed from the mold and attached to a pole piece base to form the pole piece. The mold cavity surface preferably has a non-uniform contour. The bottom surface of the unitary tile body forms a substantially inverse contour of the mold cavity surface contour.

Abstract: A laminate tile pole piece for an MRI, a method and a mold for manufacturing laminate tile metal pole pieces for an MRI. Each laminate tile has a trapezoidal or annular sector shape. The trapezoidal shape allows the tiles to be attached side by side to form a multiple concentric annular array pole piece without using oddly shaped edge filler tiles needed to fill a circular pole piece with square tiles. The pole piece is made by placing a plurality of tiles into a mold and filling the mold with an adhesive substance to bind the plurality of tiles into a unitary tile body. The unitary tile body is then removed from the mold and attached to a pole piece base to form the pole piece. The mold cavity surface preferably has a non-uniform contour. The bottom surface of the unitary tile body forms a substantially inverse contour of the mold cavity surface contour.

Abstract: A laminate tile pole piece for an MRI. Each laminate tile has a trapezoidal or annular sector shape. The trapezoidal shape allows the tiles to be attached side by side to form a multiple concentric annular array pole piece without using oddly shaped edge filler tiles needed to fill a circular pole piece with square tiles. The pole piece is made by placing a plurality of tiles into a mold and filling the mold with an adhesive substance to bind the plurality of tiles into a unitary tile body. The unitary tile body is then removed from the mold and attached to a pole piece base to form the pole piece. The mold cavity surface preferably has a non-uniform contour. The bottom surface of the unitary tile body forms a substantially inverse contour of the mold cavity surface contour.

Abstract: A laminate tile pole piece for an MRI, a method and a mold for manufacturing laminate tile metal pole pieces for an MRI. Each laminate tile has a trapezoidal or annular sector shape. The trapezoidal shape allows the tiles to be attached side by side to form a multiple concentric annular array pole piece without using oddly shaped edge filler tiles needed to fill a circular pole piece with square tiles. The pole piece is made by placing a plurality of tiles into a mold and filling the mold with an adhesive substance to bind the plurality of tiles into a unitary tile body. The unitary tile body is then removed from the mold and attached to a pole piece base to form the pole piece. The mold cavity surface preferably has a non-uniform contour. The bottom surface of the unitary tile body forms a substantially inverse contour of the mold cavity surface contour.

Abstract: A laminate tile pole piece for an MRI, a method and an apparatus for manufacturing laminate tile metal pole pieces for an MRI. Each laminate tile has a trapezoidal or annular sector shape. The trapezoidal shape allows the tiles to be attached side by side to form a multiple concentric ring pole piece without using oddly shaped edge filler tiles needed to fill a circular pole piece with square tiles. The laminate tiles are formed by unwinding a metal ribbon, guiding the ribbon through an adhesive bath, winding the ribbon on a polygonal bobbin, such as a rectangular bobbin, to form a coil with at least one flat side, removing the coil from the bobbin, cutting the coil into laminate bars and shaping the laminate bars into trapezoidal or annular sector shaped laminate tiles. The apparatus contains an adhesive bath, a polygonal shaped bobbin, bobbin side plates for guiding the ribbon onto the bobbin and pressure plates for controlling the thickness of the coil.

Abstract: A method for operating a superconductive magnet having a superconductor. The magnet is ramped to generally the design current. After that, the magnet is brought to an annealing temperature which is above the operating temperature and below the critical temperature. After that, the magnet is shimmed at a shimming temperature which is at least as cold as the annealing temperature. After that, the magnet is used, at the operating temperature, for a predetermined purpose, such as MRI imaging for medical diagnosis. Preferably, the superconductor has less than twenty-five superconductive filaments.

Abstract: A closed magnetic resonance imaging (MRI) magnet has a single superconductive coil assembly including a toroidal-shaped coil housing containing a pair of superconductive main coils and at least one additional superconductive main coil. A pair of generally-non-permanently-magnetized ferromagnetic rings is spaced radially inward and apart from the superconductive main coils. The ferromagnetic rings allow the design of a shorter MRI magnet because the ferromagnetic rings overcome the gross magnetic field distortions in the imaging volume of the magnet (created by removing some of the additional longitudinally-outermost superconductive main coils, otherwise used in the magnet, to make the magnet shorter) to produce a magnetic field of high uniformity within the imaging volume.

Abstract: An open magnetic resonance imaging (MRI) magnet having first and second spaced-apart superconductive coil assemblies each including a toroidal-shaped coil housing containing a superconductive main coil. A generally annular-shaped permanent magnet array is associated with each coil assembly, being generally coaxially aligned with the associated coil assembly and being spaced radially inward and radially apart from the associated coil assembly's superconductive main coil. The permanent magnet arrays overcome the gross magnetic field distortions in the imaging volume of the superconductive main coils (created by the open space between the magnet's superconductive coil assemblies) to produce a magnetic field of high uniformity within the imaging volume.

Abstract: A superconductive lead assembly for a superconductive device (e.g., magnet) cooled by a cryocooler coldhead having first and second stages. A first ceramic superconductive lead has a first end flexibly, dielectrically, and thermally connected to the first stage and a second end flexibly, dielectrically, and thermally connected to the second stage. A jacket of open cell material (e.g., polystyrene foam) is in general surrounding compressive contact with the first ceramic superconductive lead, and a rigid support tube generally surrounds the jacket. This protects the first ceramic superconductive lead against shock and vibration while in the device. The rigid support tube has a first end and a second end, with the second end thermally connectable to the second stage.

Abstract: A superconductive lead assembly for a superconductive device (e.g., magnet) cooled by a cryocooler coldhead having first and second stages. A first ceramic superconductive lead has a first end flexibly, dielectrically, and thermally connected to the first stage and a second end flexibly, dielectrically, and thermally connected to the second stage. A jacket of open cell material (e.g., polystyrene foam) is in general surrounding compressive contact with the first ceramic superconductive lead, and a rigid support tube generally surrounds the jacket. This protects the first ceramic superconductive lead against shock and vibration while in the device. The rigid support tube has a first end and a second end, with the second end thermally connectable to the second stage.

Abstract: A closed magnetic resonance imaging (MRI) magnet has a single superconductive coil assembly including a toroidal-shaped coil housing containing a pair of superconductive main coils. A pair of generally annular-shaped bucking coils, carrying electric current in a direction opposite to that of the superconductive main coils, is spaced radially inward and apart from the superconductive main coils. The bucking coils allow the design of a shorter MRI magnet because the bucking coils overcome the gross magnetic field distortions in the imaging volume of the magnet (created by removing some of the additional longitudinally-outermost superconductive main coils, otherwise used in the magnet, to make the magnet shorter) to produce a magnetic field of high uniformity within the imaging volume.

Abstract: A closed magnetic resonance imaging (MRI) magnet has a single superconductive coil assembly including a toroidal-shaped coil housing containing a pair of superconductive main coils and at least one additional superconductive main coil. A pair of generally annular-shaped permanent magnet arrays is spaced radially inward and apart from the superconductive main coils. The permanent magnet arrays allow the design of a shorter MRI magnet because the permanent magnet arrays overcome the gross magnetic field distortions in the imaging volume of the magnet (created by removing some of the additional longitudinally-outermost superconductive main coils, otherwise used in the magnet, to make the magnet shorter) to produce a magnetic field of high uniformity within the imaging volume.

Abstract: An open magnetic resonance imaging (MRI) magnet having first and second spaced-apart superconductive coil assemblies each including a toroidal-shaped coil housing containing a superconductive main coil in thermal contact with a cryogenic fluid contained in a dewar. Preferably, each main coil is located outside of and in solid-conduction thermal contact with its corresponding dewar (instead of inside the dewar). Preferably, a surrounding single (not double) thermal shield is cooled by liquid cryogen boil-off or by a cryocooler coldhead. All this allows the main coil to be located closer to the magnet's open space which reduces magnet cost by reducing the amount of coil needed for the same-strength magnetic field.