Shim coils for a compact MRI gradient system based on multilayer flexible printed circuit boards and arrangement scheme of conductor layers

A combined gradient coil and shim coil assembly for use in magnetic resonance (MR) devices, comprising:

• a cylindric carrier tube,
• a gradient coil system arranged concentrically onto the carrier tube,
• a cooling tube assembly positioned around the gradient coil system,
• an active shim coil system constructed on a flexible printed circuit board and comprising a plurality of layers of said flexible printed circuit board, the layers being wound concentrically around an axis of the cylindric carrier tube, each layer of flexible printed circuit board being separated from an adjacent layer by a spacer element, wherein the spacer element is wound in a helical manner around each layer of the flexible printed circuit board so as to separate shim coils of the shim coil assembly from each other and create a helical gap between the layers, and
• a sealing compound with a fluid reaction resin augmented with a heat conductive filler enclosing the components of the combined gradient coil and shim coil assembly to form a cylindrical tube, the sealing compound spreading and filling the helical gap and filling cavities of the gradient and the shim coil systems and between coils of the gradient and the shim coil systems and the carrier tube.