Improved NMR Spectrometer

An improved Pound-Knight-Watkins nuclear magnetic resonance spectrometer is described. The improved spectrometer has an arrangement which reduces frequency fluctuations by a factor of 5–10 at 30 Mc. The spectrometer is capable of stable operation, with sensitive metering, down to an rf level of 0.01 v across the sample coil, an improvement of almost an order of magnitude. The instrument also allows direct measurement of the derivative of χ′, the real part of the susceptibility of the sample.