Method for making an nmr coil

Abstract

Three-dimensional RF coils suitable for use in NMR spectroscopy or imaging are described, as well as methods for making such coils. The coil is made from a thin-walled, non-magnetic, electrically insulating tube. The tube is then masked and a first conducting layer is applied, e.g., by evaporation. An additional insulating layer is provided on top of the first conducting layer, and then a second conducting layer is applied. An optional additional insulating layer may then be applied over the second conducting layer. The first and second conducting layer, in combination, are electrically connected to form a self-resonant structure at the selected frequency of the NMR apparatus. The coil may be fine-tuned conventionally by means of a series or parallel capacitor, or by changing the position of a conductive ring around the outside of the coil. Alternately, two tubes may be used, with only one conducting layer deposited on each. If two tubes are used, they are dimensioned to allow one tube to fit within the other. The two tubes may be twisted or telescoped to permit varying degrees of alignment of the conductive patterns deposited on the two tubes, which will serve to fine-tune the NMR tube's resonant frequency.