Nuclear Magnetic Resonance at Low Temperatures

Abstract

MEASUREMENTS of radio-frequency absorption and dispersion due to nuclear magnetic resonance have been made at liquid hydrogen temperatures using the same experimental arrangement as described in a recent note¹. We have observed very strong resonant effects due to the protons in liquid and solid hydrogen. On account of the increased Boltzmann factor, the signals were considerably greater than those obtained with substances at room temperature, and were several thousand times the noise voltage. There appeared to be no appreciable change in the phenomena on solidification of the hydrogen. In agreement with the conclusions of Lasarew and Schubnikow² from their experiments on the susceptibility of solid hydrogen, we find the relaxation time for nuclear orientation to be less than one second. The absorption line was very sharp, and we estimate the width to be less than 0.5 gauss (2 kc./sec.).