Design and Application of Robust Rf Pulses for Toroid Cavity NMR SpectroscopyJournal of Magnetic Resonance
AbstractWe present robust radio frequency (rf) pulses that tolerate a factor of six inhomogeneity in the B-1 field, significantly enhancing the potential of toroid cavity resonators for NMR spectroscopic applications. Both point-to-point (PP) and unitary rotation (UR) pulses were optimized for excitation, inversion, and refocusing using the gradient ascent pulse engineering (GRAPE) algorithm based on optimal control theory. In addition, the optimized parameterization (OP) algorithm applied to the adiabatic BIR-4 UR pulse scheme enabled ultra-short (50 mu s) pulses with acceptable performance compared to standard implementations. OP also discovered a new class of non-adiabatic pulse shapes with improved performance within the BIR-4 framework. However, none of the OP-BIR4 pulses are competitive with the more generally optimized UR pulses. The advantages of the new pulses are demonstrated in simulations and experiments. In particular, the DQF COSY result presented here represents the first implementation of 2D NMR spectroscopy using a toroid probe.
Citation InformationThomas E. Skinner, Michael Braun, Klaus Woelk, Naum I. Gershenzon, et al.. "Design and Application of Robust Rf Pulses for Toroid Cavity NMR Spectroscopy" Journal of Magnetic Resonance Vol. 209 Iss. 2 (2011) p. 282 - 290 ISSN: 1090-7807
Available at: http://works.bepress.com/naum_gershenzon/5/