Abstract: A method and apparatus for detecting quadrupole nuclei in motion relative to a search region, during the sensing operation, provides a system for decreasing the throughput time of quadrupole resonance (QR) detection systems. The apparatus uses a single QR probe, or a plurality of QR probes, which may be formed into an array, to remotely and non-invasively generate a QR response from one or more targets containing quadrupole nuclei, as they pass through the probe-sensing region. The method employs an optimized pulse sequence that simultaneously increases the QR signal power while reducing the peak power of the RF pulses. The pulse sequence generates a matrix of signals that are processed to improve detection performance by increasing the signal to noise ratio.

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: A method and apparatus for detecting quadrupole nuclei in motion relative to a search region, during the sensing operation, provides a system for decreasing the throughput time of quadrupole resonance (QR) detection systems. The apparatus uses a single QR probe, or a plurality of QR probes, which may be formed into an array, to remotely and non-invasively generate a QR response from one or more targets containing quadrupole nuclei, as they pass through the probe-sensing region. The method employs an optimized pulse sequence that simultaneously increases the QR signal power while reducing the peak power of the RF pulses. The pulse sequence generates a matrix of signals that are processed to improve detection performance by increasing the signal to noise ratio.

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.