| 摘要 |
In an example embodiment, a nuclear magnetic resonance (NMR) logging tool comprises an arrangement of one or more magnets that generates a static magnetic field (B0) in a material body. A pair of first and second antenna coils is attached to the tool around an antenna core, wherein the turns of the first and second antenna coils are unaligned with either a longitudinal axis of the tool, or an orthogonal axis substantially transverse thereto. Circuitry drives the pair of first and second antenna coils in concert to produce a radio frequency field (B1) in the material body. In one embodiment, the turns in the first antenna coil are separated from corresponding turns in the second oppositely wound antenna coil by an angle (α). In an example embodiment, the angle (α) is selected to minimize a power draw of the tool, or maximize one or more of SNR/echo, (I), SNR/ time, or (II) of the tool, for a predetermined configuration of the magnet arrangement and antenna core of the tool. |
