NUCLEAR QUADRUPOLE RESONANCE TESTING

Methods of testing a sample in which long composite pulses comprising a sequence of short closely spaced pulse elements are disclosed. The pulses generate a qualitatively different response characteristic, which can be tailored as desired by suitable adjustment of the pulses. Near sinusoidal dependence on pulse length can be attained, and effective, efficient, inversion pulses can be produced. Typically each pulse element generates a small flip angle of a few degrees, and the sequence contains tens or even hundreds of elements. Similar excitation and effects may be produced by amplitude modulating a carrier, rather than switching pulses on and off; there is little discernible difference in the excitation seen by the sample.