US Patent 7282913 Pulse sequences for exciting nuclear quadrupole resonance

An apparatus and method for producing a multi-pulse sequence for irradiating a substance provided with quadrupole nuclei with either integer or half-integer spins to detect an NQR signal emitted therefrom. The apparatus has pulse sequence generating means adapted to produce multi-pulse sequences with pulse intervals exceeding T2* and containing a preparatory pulse or group of pulses for creating echo signals between the pulses. The pulse sequence is organised so that the resulting signal contains a prevailing echo component produced by the preparatory pulse or group of pulses.