Patent ID: 7355400

Claim:
A nuclear quadrupole resonance apparatus for detecting a substance containing nuclear quadrupole nuclei, comprising: a pulse sequence generator adapted to generate a combination of two or more steady state free precession pulse sequences, the steady state free precession pulse sequences having phases that alternate in a pattern to excite nuclear quadrupole nuclei in a frequency bandwidth which exceeds the frequency bandwidth covered by each of the steady state free precession pulse sequences individually to thereby minimize intensity variations caused by unknown temperature of the substance, wherein there are at least two different phases alternated in at least one of the pulse sequences; a detector to detect a nuclear quadrupole resonance signal generated from the substance under conditions of unknown temperature of the substance in response to the combination of steady state free precession pulse sequences, the detector being arranged to add the spectral components of the nuclear quadrupole resonance signals obtained from each of the steady state free precession pulse sequences of said combination; and a phase shifter to periodically shift the phases of the pulses of said steady state free precession pulse sequences according to a predetermined order.