Mapping of electrical circuits using chemical-shift imaging

NMR imaging has been found to be extremely useful for biological and medical
applications. There is, however, intensive research for other applications including industrial ones. In this communication one such application, namely the imaging of current densities such as those in electrical circuits, is discussed. The principle of this application is the mapping of the magnetic fields which are induced by currents flowing through conductors. The 3D spatial distribution of the induced magnetic field can be measured by a four-dimensional chemical-shift imaging experiment (I), performed on a sample containing a substance having a single NMR resonance line, such as water, which surrounds the conductor. However, such a measurement provides the spatial distribution of one component of the magnetic field only. In order to measure the spatial distribution of all three components of the magnetic field, three such experiments must be performed. In each one, another axis of the system (x, y, or z) is parallel to the external magnetic field &.