Nuclear quadrupole resonance single-pulse echoes.
We report the first detection of a spin echo after excitation of a powder sample by a single pulse at the resonance frequency during nuclear quadrupole resonance (NQR). These echoes can occur in samples that have an inhomogeneously broadened line, in this case due to the distribution of electric field gradients. The echoes are easily detectable when the Rabi frequency approaches the linewidth and the average effective tipping angle is close to 270 degrees. When limited by a weak radio-frequency field, the single-pulse echo can be used to increase the signal to noise ratio over conventional techniques. These effects can be used to optimize the NQR detection of contraband containing quadrupole nuclei and they are demonstrated with glycine hemihydrochloride and hexhydro-1,3,5-trinitro-1,3,5-triazine (RDX).
Department of Physics and Astronomy, George Mason University, 4400 University Drive MS 3F3, Fairfax, VA 22030, USA. dprescot@gmu.edu
David W
DW
Prescott
Joel B
JB
Miller
Chris
C
Tourigny
Karen L
KL
Sauer
D000465:Algorithms; D017352:Echo-Planar Imaging / Q000379:methods*; D053834:Explosive Agents / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012815:Signal Processing, Computer-Assisted; D013113:Spin Labels
D053834:Explosive Agents; D013113:Spin Labels