Abstract:
The use of a superconducting resonator with continuous-wave (CW) excitation allows low-noise quadrupole resonance (QR) detection without the need for a lock-in amplifier. This allows detection times to be greatly reduced. Hence, for the first time, a CW QR spectrometer using a superconducting resonator can be used in a portable device, such as a hand-held wand for detecting explosives.
Abstract:
This invention relates to a method for improving the performance of a nuclear quadrupole resonance detection system by reducing the coupling between the excitation coil(s) that provide the radio frequency magnetic field that excites the quadrupole nuclei and the high temperature superconductor receive coil(s) that detect the resulting nuclear quadrupole resonance signal. The coupling is reduced by shifting the resonance frequency of the excitation coil(s) during signal reception.
Abstract:
Apparatus and methods for locating a nuclear quadrupole resonance are described. In an example method, a search frequency is adjusted using a blind search until a resonance absorption of an analyte is detected, and then an extremum seeking search to be used to locate an extremum frequency.
Abstract:
Narrowband quadrupole resonance (QR) probes were developed from thin-film high- temperature superconducting (HTS) resonators. The QR probes are useful in analyte-detection systems, in particular for the detection of nitrogen-containing compounds. Embodiments of the invention provide greater than an order of magnitude improvement in sensitivity and the ability to reject RF interference sources located outside the pass-band of a superconducting QR probe. Methods and apparatus are described for analyte detection and resonance frequency adjustment.
Abstract:
Narrowband quadrupole resonance (QR) probes were developed from thin-film high- temperature superconducting (HTS) resonators. The QR probes are useful in analyte-detection systems, in particular for the detection of nitrogen-containing compounds. Embodiments of the invention provide greater than an order of magnitude improvement in sensitivity and the ability to reject RF interference sources located outside the pass-band of a superconducting QR probe. Methods and apparatus are described for analyte detection and resonance frequency adjustment.
Abstract:
The use of a superconducting resonator with continuous-wave (CW) excitation allows low-noise quadrupole resonance (QR) detection without the need for a lock-in amplifier. This allows detection times to be greatly reduced. Hence, for the first time, a CW QR spectrometer using a superconducting resonator can be used in a portable device, such as a hand-held wand for detecting explosives.