Patent ID: 7282913

Claim:
A nuclear quadrupole resonance apparatus for detecting a target substance containing quadrupole nuclei, comprising: a pulse sequence generator to generate a combination of multi-pulse sequences with pulse intervals longer than the time constant of free induction decay T 2 *, but shorter than the time of spin-spin relaxation T 2 , and to generate a preparatory pulse or group of preparatory pulses for creating echo signals between the pulses of the multi-pulse sequences; a detector to detect nuclear quadrupole resonance signals generated from the target substance under conditions of unknown temperature of the target substance in response to the combination of multi-pulse sequences; and a combiner to combine the detected nuclear quadrupole resonance signals generated under conditions of unknown temperature of the target substance into a resulting signal such that the resulting signal contains a prevailing echo component produced by the preparatory pulse or group of preparatory pulses, thereby mitigating the effect of intensity variations.