EFFICIENT EXCITATION AND RINGING SUPPRESSIONIN NUCLEAR QUADRUPOLE RESONANCE

摘要

Detection of materials using nuclear quadrupole resonance (NQR)is often hampered by interference from remote radio frequency sources suchas radio stations, and from local sources such as piezoelectric and magneto-acoustic ringing. NQR pulse sequences have been devised that reduce oreliminate the ringing, but these pulse sequences also reduce the NQR signal.We show that the signal reduction is the result of destructive interferencebetween spin echoes created by multiple echo formation pathways. Thedestructive interference can be greatly reduced using composite refocusingpulses in the NQR pulse sequences to force the echoes into selected echoformation pathways.