More information on the NMR can be found here
The NMR system is used to measure the proton polarization in the sample, and operates by observing spin flips of the proton at its Larmor frequency. By embedding the inductor of an LCR circuit in the target material, we can detect energy lost or gained in the circuit as a function of the circuit's frequency. A loss of energy in the circuit near the proton's Larmor frequency would indicate the "absorption" of energy as its spin is flipped to be anti-aligned with the magnetic field. Likewise, a gain of energy in the circuit would come from a proton "giving up" energy as it becomes aligned. This gain or loss is visible as a dip or peak in the NMR signal versus frequency. The area under this dip or peak is a proportional measure of the proton polarization in the material.
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