SUPPRESSION OF RADIATION DAMPING IN NMR IN LIQUIDS BY ACTIVE ELECTRONIC FEEDBACK

Radiation damping in high-resolution NMR can be strongly suppressed by RF feedback on the tuned sample circuit, without appreciable degradation of the signal-to-noise ratio for the detection of small signals. The issue of stability of the high-gain RF feedback loop is discussed, and details are given about a practical realization of the necessary very-narrow-band filter. Experimental results confirm the expected performance of the new scheme. (C) 1995 Academic Press, Inc.