Fast automatic adjustment of on-axis shims for high-resolution NMR.
A one-dimensional approach for fast, robust, automatic adjustment of on-axis shims on high-resolution NMR spectrometers based on polynomial fitting of field inhomogeneity is described. Spherical harmonic and nonspherical harmonic terms of the field distribution of shim coils are precalibrated as polynomial coefficients by successively changing shim settings. This method greatly simplifies the shim precalibration and optimization procedures and is readily to be extended to three-dimensions to include off-axis shims.
Shen
J
J
Magnetic Resonance Center, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Rothman
D L
DL
D000465:Algorithms; D005583:Fourier Analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012815:Signal Processing, Computer-Assisted