| Abstract: | Suppression of systematic noise artifacts which complicate the understanding of broadline NMR spectra remains a difficult problem. Many strategies for canceling noise have evolved; many appear designed for very specific hardware implementations. In this paper we address the problem of artifact suppression in noise-based (stochastic) NMR, where low power pulses applied at high duty cycle are used to probe the spectral frequencies found in an NMR or NQR experiment. While typical peak powers are reduced by four to six orders of magnitude as compared to conventional NMR experiments, this power reduction corresponds only to an approximate halving of the idealized electronic ring-down in a tuned circuit; where other systematic sources of noise contribute, the recovery time advantage of noise spectroscopy may be larger or smaller. We suggest a simple experimental modification which exploits the linear response properties of nuclear spins in the presence of small rotations to demonstrate how ring-down—from whatever source—can be substantially eliminated as a problem in noise spectroscopy. This should provide substantial improvements in quantitation and lineshape measurements in NMR spectra of many solid state systems. |
