Nuclear magnetic resonance apparatus and methods

摘要

The nuclear magnetic resonance spin density distribution in a sample is obtained by subjecting the sample to a static magnetic field and exciting the sample with a selective or non-selective r.f. excitation pulse and a combination of magnetic field gradients which vary in directions along and orthogonal to the direction of the static field. One or more of the gradients are repetitively reversed to allow cyclic regrowth and decay of the free induction decay signal.