Abstract: An electrical coil, particularly a shim coil for use in magnetic resonance imaging spectroscopy, is wound so that there are a plurality of layers with each layer having a plurality of turns. Insulating material is disposed between the turns of each layer. This reduces the capacitance between the turns and has the effect of increasing the self-resonant frequency of the coil. In another embodiment, the coil turn connections are effected so as to divide the overall coil into electrically separated portions and this also increases the self-resonant frequency of the coil.

Abstract: A shim coil for use in magnetic resonance imaging spectroscopy (MRIS) is formed cutting or punching in a sheet of electrically conductive material the required coil pattern. The pattern can be punched using a CNC punch or stamping machine.

Abstract: Magnetic field generating apparatus comprises a pair of axially spaced coils which are so arranged that when energized, they produce a magnetic field which has a zero axial field or substantially zero axial field at an axial position midway between the coils. The annular space between the coils is filled with a material such as steel or steel with a layer of material magnetized in the radial direction, which enhances the radial field strength generated by the coils. The apparatus as application in the growth of single crystals of semiconductor material.