In 1945, Edward Purcell, Robert Pound and Henry Torrey worked on the development of radar during World War II at MIT Radiation Laboratory. Purcell, who led the group, had been successful in producing and detecting radio frequency power and in absorbing such radio frequency power. Purcell’s work led to the discovery of nuclear magnetic resonance (NMR).
Nuclear magnetic resonance is when nuclei in a magnetic field absorb and re-emit electromagnetic radiation. In order to measure NMR, an apparatus must be set at the resonance frequency, which depends on the strength of the magnetic field and the properties of the isotope of the atoms.
In our experiment, our apparatus (Fig.\ref{fig:TeachSpinApparatus}) studies the free precession of nuclear moments in the Earth’s magnetic field by detecting the collective precession of the nuclear magnetic moments in a particular sample.