Two-dimensional NQR using ultra-broadband electronics.
We have recently developed an ultra-broadband instrument that can effectively excite and detect NMR and NQR signals over a wide frequency range. Our current system operates between 100 kHz and 3.2 MHz using an un-tuned sample coil. The major benefits of this instrument compared to conventional NQR/NMR systems include increased robustness, ease of use (in particular for multi-frequency experiments), and elimination of the need for tuning adjustments in the hardware. Here we describe its use for performing two-dimensional (2D) scans, which allow improved interpretation of complex NQR spectra by detecting the connected resonances. Our method relies on population transfers between the three energy levels of spin-1 nuclei (such as (14)N) by using multi-frequency excitation and a single RF coil. Experimental results on pure samples and mixtures are also presented.
Schlumberger-Doll Research, Cambridge, MA 02139, USA. Electronic address: SMandal@slb.com.
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Mandal
Schlumberger-Doll Research, Cambridge, MA 02139, USA. Electronic address: ysong@slb.com.
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Song
D000465:Algorithms; D003198:Computer Simulation; D004574:Electromagnetic Fields; D053834:Explosive Agents / Q000032:analysis*; D005998:Glycine / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009566:Nitrates / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000032:analysis*; D017680:Potassium Compounds / Q000737:chemistry; D015203:Reproducibility of Results
D053834:Explosive Agents; D009566:Nitrates; D004364:Pharmaceutical Preparations; D017680:Potassium Compounds; C023844:potassium nitrate; D005998:Glycine
Broadband; Detection of drugs and explosives; NQR; Single-coil; Two-dimensional NQR