Methods of indicating nuclear spin density distribution

摘要

Spin density distribution in a sample subjected to a static magnetic field along a y-axis is determined by subjecting the sample to an initial magnetic field gradient Gz to the static field together with a 90 DEG selective rf pulse to select a strip. The Gz gradient is then replaced by a filter gradient Gx for a limited period of time during which the free induction signal only partially decays and then immediately replacing the filter gradient by a read gradient Gy and then reading out the free induction decay signal. The sequence may be repeated cyclically with a delay between each cycle. (FIG. 4).