Critical factors in the design of sensitive high resolution nuclear magnetic resonance spectrometers

Abstract

An analysis is given of the factors which influence the performance of a Fourier transform n.m.r. spectrometer including field homogeneity, probe design, transient circuit behaviour, Johnson noise, non linear analysis, phase sensitive detection in quadrature, and signal processing. The building of a spectrometer based upon the analysis of these factors is described, as is the use of a cyclically ordered phase sequence (CYCLOPS) which renders the use of quadrature Fourier transformation easy. Theoretical deductions are experimentally verified, and the performance of the instrument is demonstrated with spectra obtained from caesium and phosphorus resonances.