Related Experiment Video
Updated: Aug 15, 2026

Frequency Mixing Magnetic Detection Scanner for Imaging Magnetic Particles in Planar Samples
Published on: June 9, 2016
Magnetic field shimming by Fourier analysis
L Brateman1, T T Bowman, S Dønstrup
1Radiology Department, College of Medicine, University of Florida, Gainesville 32610.
Abstract:
The homogeneity of the magnetic field of an Oxford 85/310HR magnet was optimized with the use of passive shims (i.e., pieces of steel) and room-temperature electronic shims. Both the characteristics of the passive shims and the current settings for the room-temperature electronic shims were calculated with the goal of minimizing field inhomogeneities as assessed by Fourier analysis of data from circular field plots. The measurement techniques, the methods of data analysis, and the techniques employed in correcting the magnetic field are presented. Difficulties and constructive approaches are suggested in these descriptions. The final results show a field of excellent homogeneity over a 10-cm-diameter spherical volume, with a peak-to-peak variation of 3.2 ppm, which is better than the manufacturer's expected specification of 5 ppm. A water-filled sphere of 10 cm diameter gave a half-height linewidth of 0.14 ppm after a small amount of additional touch-up shimming. The field homogeneity as corrected is much improved over its original state, allowing the acquisition of improved spectra from samples of a size several centimeters in each linear dimension. Thus the field homogeneity is more useful for in vivo spectroscopy, the purpose for which the magnet was intended.
More Related Videos
09:38Fabrication Procedures and Birefringence Measurements for Designing Magnetically Responsive Lanthanide Ion Chelating Phospholipid Assemblies
Published on: January 3, 2018
07:42Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains
Published on: July 20, 2022
Related Concept Videos
NMR Spectrometers: Resolution and Error Correction
π Electron Effects on Chemical Shift: Overview
Magnetic Fields
A magnetic field is defined by the force that a charged particle experiences...
Plane Electromagnetic Waves II
Magnetic Field due to Moving Charges
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Symmetry in Maxwell's Equations