Embodiments of an SLR antenna having differential signal contacts and a tuning circuit configured to tune the at least one resonance frequency of the SLR antenna to a predetermined operational frequency are disclosed. Embodiments of a tuning circuit include a balun transformer connected between the differential signal contacts of the SLR antenna and a single-ended input/output contact, a first variable capacitance connected between the balun transformer and the single-ended input/output contact, and a variable reactive component connected between the differential signal contacts of the SLR antenna and between differential contacts of the balun transformer.

The technology disclosed in this invention belongs to both the field of Nuclear Quadrupole Resonance (NQR) and nuclear geomagnetic resonance application. Technically, a nuclear quadrupole resonance detection system and its antenna are provided. The antenna includes two coils to make a gradient antenna wherein they simultaneously receive both the signal from the target region and the external radio frequency interference. Structurally, the first coil is positioned as a regular circular coil, while the second coil is annular and evenly distributed around the first coil peripherally. These coils are on the same plane with equal areas but have opposite winding directions. The systems specific to the disclosed antenna are also included. The configuration of the invented antenna can effectively increase the capability of suppressing environmental electromagnetic radio frequency interference, thereby enhancing the detection of the NQR or geomagnetic resonance signals. Consequently, the signal-to-noise ratio of the system is improved.

Systems and methods for pre-tuning a main Nuclear Quadrupole Resonance (NQR) probe using a forward sensing probe include a determination of an amount of resonance detuning of the forward sensing probe caused by a moving object entering a field of view of the forward sensing probe. The amount of resonance detuning is used to pre-tune the main probe such that when the moving object enters a field of view of the main probe, the main probe will move back into tune while delivering optimal power to the object for measurement and identification of a material therein.

Technologies relating to a magnetic resonance spectrometer are disclosed. The magnetic resonance spectrometer may include a doped nanostructured crystal. By nanostructuring the surface of the crystal, the sensor-sample contact area of the crystal can be increased. As a result of the increased sensor-sample contact area, the output fluorescence signal emitted from the crystal is also increased, with corresponding reductions in measurement acquisition time and requisite sample volumes.

System for detecting explosive substances and drugs by nuclear quadrupole resonance having a central processing unit (UC) which connects to a storage, data processing, and interface unit (USPI) provided with a user console (1C) and a with a head (CS1) for scanning explosives/drugs around the legs and a head (CS2) for scanning suspicious objects on the ground or that cannot be moved having a radio processing system (SPR) which includes a programmable RF signal generator (DDS) which transmits RF pulses to a power amplifier (AP) coupled to an interface for gain control and for the acquisition of the reflected signal level (IAP), a series-parallel tuning circuit (CA) consisting of a flat spiral ferrite-core coil (L) and two variable capacitors (CV1, CV2) driven by two stepper motors (M1, M2) which are controlled by an automatic tuning matching module (WIAA) through control interfaces.

Embodiments of an SLR antenna having differential signal contacts and a tuning circuit configured to tune the at least one resonance frequency of the SLR antenna to a predetermined operational frequency are disclosed. Embodiments of a tuning circuit include a balun transformer connected between the differential signal contacts of the SLR antenna and a single-ended input/output contact, a first variable capacitance connected between the balun transformer and the single-ended input/output contact, and a variable reactive component connected between the differential signal contacts of the SLR antenna and between differential contacts of the balun transformer.

A method of authenticating an article, the method comprising: reading a label associated with the article, the label comprising article fingerprint information; retrieving, in dependence on the article fingerprint information, an article fingerprint, the fingerprint describing the resonance response of the article to an excitation signal; applying an excitation signal to the article; receiving the resonance response of the article to the excitation signal; comparing the resonance response to the fingerprint; and determining in dependence on the comparison whether the article is authentic.

The technology disclosed in this invention belongs to both the field of Nuclear Quadrupole Resonance (NQR) and nuclear geomagnetic resonance application. Technically, a nuclear quadrupole resonance detection system and its antenna are provided. The antenna includes two coils to make a gradient antenna wherein they simultaneously receive both the signal from the target region and the external radio frequency interference. Structurally, the first coil is positioned as a regular circular coil, while the second coil is annular and evenly distributed around the first coil peripherally. These coils are on the same plane with equal areas but have opposite winding directions. The systems specific to the disclosed antenna are also included. The configuration of the invented antenna can effectively increase the capability of suppressing environmental electromagnetic radio frequency interference, thereby enhancing the detection of the NQR or geomagnetic resonance signals. Consequently, the signal-to-noise ratio of the system is improved.

An example includes performing near infra-red (NIR) spectrometry to provide NIR measurement data for a sample compound. The method also includes performing magnetic resonance (MR) spectrometry to provide MR measurement data for the sample compound. The method also includes analyzing, by a computing device, the MR measurement data in view of the NIR measurement data to characterize the sample compound.

A magnetic resonance detection (MRD) system for and methods of detecting and classifying multiple chemical substances is disclosed. In one example, the presently disclosed MRD system is a nuclear quadrupole resonance (NQR) detection system that provides multi-frequency operation for substantially full coverage of the explosive NQR spectrum using a broadband transmit/receive (T/R) switch (or duplexer) and a single multi-frequency radio frequency (RF) transducer. More particularly, the MRD system provides a frequency-agile system that can operate over a wide band of frequencies or wavelengths. Further, a method of detecting and classifying various chemical substances is provided that includes pulse sequencing with frequency hopping, phase cycling for reducing or substantially eliminating background noise, and/or a process of mitigating amplitude modulation (AM) radio interference.