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.

Embodiments of the invention provide an arrangement where a small detection coil of an NQR system is mounted on the end of a carrier such as a prodder stick, and is then carried by the carrier into the very near vicinity of, and more particularly for example into contact with, a possible target explosive device. Because the detection coil is brought into contact with or into the very near vicinity of the target, the transmitted NQR signals, and the resultant QR response, can be much lower power, to the extent that such a system can be made fully man-portable, and also be much lower cost to manufacture. As a consequence, NQR explosive detections systems may be deployed in larger numbers than has heretofore been possible, thus increasing the certainty of, and hence safety, of landmine detection, and improving clearance rates.

There is described a method for determining the relative quantities of the expected components in a multi-component mixture of solids. The proposed quantification method makes use of a time domain nuclear magnetic resonance (TD-NMR) spectrometer and requires that, for each of the expected components in the mixture, a T1 saturation recovery curve (SRCi) is measured and recorded. The saturation recovery curve for the mixture sample (SRCmix) is determined from a measurement of the sample with the spectrometer. The relative amounts of the expected components present in the mixture sample are determined by fitting a linear combination of the component SRCs (SRCi) to the SRCmix. The resulting value of each weighting coefficient in the fit provides the relative proportion of the corresponding component in the overall sample.

The present invention is directed to a detector and a method for detecting explosive substances and drugs by nuclear quadrupole resonance designed for screening baggage and people at border crossing points in airports, ports, railway stations and in other locations which require strong measures against terrorism and smuggling of prohibited substances such as explosives and drugs. According to the present invention, the detector comprises a central processing unit (UC) which connects to a storage, data processing, and interface unit (USPI) provided with a user console (IC) 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, and which has a compact build and includes all the hardware modules and software components necessary for operation, being made up of 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 which are, in principle, already known. According to the present invention, the detection method consists of: measuring the ambient temperature with a sensor; digitally converting the temperature value and reading it in the software application which controls the radio processing system (SPR); calculating the NQR frequency by using the coefficient of variation specific to each target substance and transmitting that value (fo) to a programmable RF signal generator (DDS); ordering, by means of the software application, RF pulses with a certain duration (TRF) during which the signal frequency will increase in 10 stages within a predetermined range i around fo, i.e. fof/2; identifying the substance by real-time discrimination of the received signal based on a set of four combined criteria applied to the spectral response obtained by means of the fast Fourier transform FFT.

A system and method for detecting a nucleus of interest in a chemical using a nuclear quadrupole resonance transition. An excitation pulse is used to excite one or more nuclei of interest, if they present in a sample, to an excited state, the energy of which depends on the magnetic field in the sample. The magnetic field in the sample is modulated, after the end of the excitation pulse, while the nuclei of interest decay from the excited state, so that the radiation they emit is frequency modulated. The frequency modulation is detected in the emitted radiation. In some embodiments a DC magnetic field is applied to the sample, during the application of the excitation pulse, to tune the frequency of the transition being excited.

The invention features a method of monitoring a clotting process by measuring a signal characteristic of the NMR relaxation of water in a sample undergoing endotoxi-induced clotting to produce NMR relaxation data and determining from the NMR relaxation data a magnetic resonance parameter of water in the sample characteristic of the level of endotoxin present in the sample.

A whole-body transmission x-ray scanner includes a collimated x-ray source, a linear x-ray camera configured to detect x-rays, a counterweight, and a positioner that aligns the source and ray camera and moves the source and camera synchronously to scan and acquire radiographic images of an object located therebetween. The positioner comprises a cable alignment assembly connecting the counterweight directly to the x-ray source and camera to maintain alignment of the source and camera during a scanning mode in which the source and camera move from one end of the object to another end. The positioner comprises a motor, a bi-directional crossover slide track bearing assembly connected to the source, and a conveyor operatively connected to the motor and to the slide track bearing assembly to move the slide track bearing assembly in a loop that correspondingly translates the source and camera along a single linear axis.

In a first technique one or more tuned circuits (traps) are placed in series in the metal detector coil, tuned to the operating frequency of the other sensor. In another technique a single turn coil of wire, or a small number of turns coil, is used as the metal detector coil, in combination with a step up transformer at the coil feed, to increase the EMF of the coil. In a further technique, the metal detector coil is formed in a plane that has regard to the sensing field of the other sensor. In another technique, the feed for the metal detector coil comprises a twisted pair of wires, which are routed along an axis in order to try to minimize and equalize the effect of the metal detector feed on the operation of the other antenna.

A system and method for system for performing a magnetic resonance imaging (MRI) process using an MRI system is provided. A coil system includes a substrate configured to follow a contour of a portion of a subject to be imaged by the MRI system and at least one coil coupled to the substrate and forming a spiral pattern.

A whole-body transmission x-ray scanner includes an x-ray source, an x-ray camera, a controller, and a positioner aligning the source and camera to point x-rays towards the camera and moving the source and camera synchronously to scan and acquire radiographic images of an object located therebetween. The positioner includes a closed-loop cable alignment assembly fixed to the source and to the camera to maintain alignment of the source and camera during a scanning mode in which the source and camera move from one end of the object to another end. The positioner includes a motor controlled by the controller, a bi-directional crossover slide track bearing assembly connected to the source, and a conveyor connected to the motor and bearing assembly such that, actuation of the motor by the controller moves the slide track bearing assembly in a loop that correspondingly move the source and camera along a single linear axis.