  Traditionally the improvement of static magnetic field homogeneity of the
magnet in Nuclear Magnetic Resonance (NMR) spectroscopy is performed manually,
which has many limitations. However, in recent years a number of automated
shimming techniques based on Fourier Imaging Technique have been proposed.
Existing 3D automated shimming methods require special, Pulsed Field Gradient
(PFG) hardware, which is not available on majority of high-resolution NMR
spectrometers. The modified technique, presented in this thesis uses the normal
NMR hardware provided with the majority of high-resolution NMR spectrometers.
The 3D shimming technique described was optimised for use with Varian UNITY
INOVA spectrometers and successfully tested with both protonated and deuterated
solvents. A method for calibrating linear transverse shim field gradients and
correcting any non-orthogonality and imbalance of strengths is proposed. The
effect of thermal convection on field mapping was observed and is reported here
for the first time.
