METHOD FOR MEASUREMENT OF MAGNETIC FIELDS, METHOD FOR PRODUCTION OF GRADIENT COILS, GRADIENT COIL, AND APPARATUS FOR MAGNETIC RESONANCE IMAGING

摘要

For the purpose of realizing a method for measuring, after stopping application of a gradient magnetic field, the residual magnetic field and a method for manufacturing a gradient coil by causing the characteristics of the residual magnetic fields, revealed by the measurement, to be reflected in it, a magnetically resonant sample is arranged at a measuring point on the surface of an imaginary sphere in a measuring space; a gradient magnetic field is applied to the measuring space; RF excitation is carried out after stopping the application of the gradient magnetic field to measure FID signals generated by the sample; the magnetic field intensity is calculated on the basis of a difference in differentials of the phases of the FID signals; and a magnetic field intensity is fitted into a spheric surface function.