NQR METHOD FOR STRESS AND PRESSURE IMAGING

Pure nuclear quadrupole resonance parameters such as the linewidth, th e line moments, and the resonance frequency are influenced by mechanic al stress or pressure. A surface-coil method is described which permit s the spatially resolved measurement of those quantities near surfaces of solid objects. The rotating-frame nuclear quadrupole resonance ima ging (rho NQRI) technique makes depth resolution feasible with the aid of gradients of the radiofrequency amplitude. Test experiments for th e determination of the spatial distribution of bending stress and pres sure are reported. Diverse probe substances are suggested. It is demon strated that the technique is suitable for contactless pressure or str ess measurements. (C) 1994 Academic Press, Inc.