NMR Instrumentation


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In order to understand how the nuclear magnetic resonance experiment is carried out, it is import to take a look at the instrumentation which carries out the experiment.

Adapted from http://hyperphysics.phy-astr.gsu.edu/Hbase/nuclear/nmrvar.html

As we had seen in theĀ Principle of Nuclear Magnetic ResonanceĀ for the NMR experiment we require one strong magnetic field to create the energy difference between the nuclei and another smaller excitation field. In the above diagram we see the insides of an NMR instrument. In the center of the instrument lies the sample in a suitable solvent. This sample is surrounded by the receiver coils which will detect any changes in magnetic field within the sample. Moving outwards is the Rf emitter coil which is used to excite the nuclei from ground state to higher energy level which would then cause a signal to be generated in the receiver coil. The orientation of this Rf coil is perpendicular to the receiver coil. Moving further outwards is the strong magnetic field H0 which is applied perpendicular to both the receiver coil as well as the Rf coil. Thus since all the magnetic parts are perpendicular to each other, the magnetic fields of each should not interfere with each other.

The vector diagram for the above setup is as shown below.

Vector Diagram for NMR Instrumentation
As can be seen the instrument setup is such that the three magnetic vectors are perpendicular to each other and therefore do not directly interfere with each other.