Capacitor-based detection of nuclear magnetization: Nuclear quadrupole resonance of surfaces

• Published in: Journal of magnetic resonance (1997) 2011-03, Vol.209 (1), p.79-82
• Main Authors: Gregorovič, Alan, Apih, Tomaž, Kvasić, Ivan, Lužnik, Janko, Pirnat, Janez, Trontelj, Zvonko, Strle, Drago, Muševič, Igor
• Format: Article
• Language: English
• Subjects: Capacitors; Coiling; Conduction; E-field detection; Electric Capacitance; Equipment Design; Equipment Failure Analysis; Magnetic Resonance Spectroscopy - instrumentation; Magnetics - instrumentation; Magnetization; NQR; Nuclear quadrupole resonance; Optimization; Parallel plates; RF sensors; Surface layer; Surfaces; Thin samples; Transducers
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/j.jmr.2010.12.002

A high RF voltage on a parallel plate capacitor creates an associated RF magnetic field inside it. This magnetic field is here used to excite nuclear magnetization in the sample placed between the plates. The precession of this magnetization then induces a small but measurable voltage on the same capacitor, thus giving information about the sample itself. [Display omitted] ► Detection of nuclear magnetization in thin capacitors. ► Low S/N for bulk samples compared to standard coil detection. ► Higher S/N for surface layers on conducting bodies compared to surface coils. We demonstrate excitation and detection of nuclear magnetization in a nuclear quadrupole resonance (NQR) experiment with a parallel plate capacitor, where the sample is located between the two capacitor plates and not in a coil as usually. While the sensitivity of this capacitor-based detection is found lower compared to an optimal coil-based detection of the same amount of sample, it becomes comparable in the case of very thin samples and even advantageous in the proximity of conducting bodies. This capacitor-based setup may find its application in acquisition of NQR signals from the surface layers on conducting bodies or in a portable tightly integrated nuclear magnetic resonance sensor.