Method for generating coherent phase profile NMR signals through combined RF impulses with incoherent phase profiles

摘要

In a method for generating nuclear magnetic resonance (NMR) signals from a test volume with sample matter which is exposed to a highly homogeneous steady-state magnetic field B0, by radiating a sequence of at least two radio-frequency (RF) pulses into the test volume, the at least two RF pulses exciting nuclear spins of the sample matter, in resonance, within the test volume in a frequency band which is narrow in relation to their frequency, the phases of the at least two RF pulses are selected as a function of their frequency in such a manner that the phases of the NMR signals generated by each individual one of the at least two RF pulses are randomised in such a manner that the vectorial sum over the signal intensities of the individual signals is zero, whereas the combination of the at least two RF pulses leads to the formation of observable coherent magnetisation of the sample matter. Using these so-called "white" RF pulses, unwanted NMR signals can be suppressed in a simple manner without additional gradient circuits in the case of multi-pulse excitation. IMAGE