88 results about "Nuclear quadrupole resonance" patented technology

This document describes a general system for noise reduction, as well as a specific system for Magnetic Resonance Imaging (MRI) and Nuclear Quadrupole Resonance (NQR). The general system, which is called Calculated Readout by Spectral Parallelism (CRISP), involves reconstruction and recombination of frequency-limited broadband data using separate narrowband data channels to create images or signal profiles. A multi-channel CRISP system can perform this separation using (1) frequency tuned hardware, (2) a frequency filter-bank (or equivalent), or (3) a combination of implementations (1) and (2). This system significantly reduces what we call cross-frequency noise, thereby increasing signal-to-noise-ratio (SNR). A multi-channel CRISP system applicable to MRI and NQR are described.

An antenna and shield apparatus for detecting phenomenal signals using nuclear and electronic resonance detection technology, comprising: a transmit and receive antenna, an electric field shield 60 and an outer shield 52. The antenna is a multiple parallel loop transmit-receive antenna forming a main coil assembly 11 having a plurality of loop segments 20 optionally interconnected by connectors in the form of conducting bars 10, relays 16, or nothing. The electric field shield 60 comprises an inner sleeve of conducting material 60, 68 disposed on the inside of the coil assembly 11 for shielding the electric field emanating from the coil assembly 11 from the target volume circumscribed by the assembly. The outer shield 52 comprises a central screen portion 55, waveguides 57 at either end thereof and a sloping channel portion for interconnecting the two. The coil assembly 11 and the electric field shield 60 are housed within the outer shield 52.

The use of a circuit to adjust the resonance frequency of a high temperature superconductor self-resonant transmit, receive, or transmit and receive coil results in improved performance. The circuit is useful in a frequency detection system, especially in a nuclear quadrupole resonance detection system.

A method and apparatus for imaging within a sample space an object containing quadrupolar nuclei comprises irradiating the object to excite nuclear quadrupole resonance, applying to the object a magnetic field gradient having a profile Bo(x) such that the square of the profile (Bo(x))2 varies linearly with distance (x), detecting resonance response signals from the nuclei, and deriving an image from the response signals. A method of and apparatus for nuclear quadrupole resonance testing an object, and a method of and apparatus for detecting the presence of a particular substance containing a given species of quadrupolar nucleus, are also disclosed.

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.

The decoupling of an array of two or more closely spaced high temperature superconductor sensors can be accomplished by introducing a capacitive decoupling circuit.

A method and apparatus for screening samples to determine which samples include a target material. Generally, the samples are pre-screened to determine which of the samples have a piezoelectric resonance when irradiated with an electric field, to thereby indicate the presence of the target material. The samples that have the piezoelectric resonance are then further screened by a different process to confirm the presence of the target material. For example, samples that have the piezoelectric resonance are further screened for a specific nuclear quadrupole resonance (NQR), a specific nuclear magnetic resonance (NMR) or a specific visual characteristic, to confirm the presence of the target material in the sample. The apparatus and method can be used, for example, to search luggage at ports of entry for the presence of cocaine hydrochloride or heroin hydrochloride.

A series of open-shape nuclear quadrupole resonance (NQR) sensors having environmental noise resilience and a capability for simultaneous independent multi-frequency operation is disclosed. The sensors are multimodal birdcage or TEM-type structures made from single-turn or multi-turn interconnected windows or magnetically coupled elements having uniform distributions of the amplitudes of the corresponding radiofrequency magnetic fields along their surfaces. The phases of these fields change in a cyclical fashion, such that the interference signals are picked up with opposite phases by different parts of the sensors and are, therefore, cancelled out. The devices may have a planar or a curved shape and may or may not be shielded on one side. Planar unshielded sensors may be used to simultaneously detect signals from objects positioned on both of their sides.

A nuclear quadrupole resonance (NQR) sensor assembly includes an active sensor coil configured to transmit radiofrequency (RF) signals to an object of interest and receive return RF signals from the object of interest to generate sensor signals substantially representative of the return signals. The at least one reference coil is configured to receive environmental RF signals to generate reference signals at least partially representative of the environmental RF signals. The at least one reference coil is co-located with the active sensor coil. The active sensor coil and the at least one reference coil are in communication with a correction unit configured to remove interference components from the sensor signals using the reference signals.

A receiving system (11) for connection to an antenna arrangement (19) for detecting response signals from a substance having quadrupolar nuclei excited so as to produce nuclear quadrupole resonance in certain of the quadrupolar nuclei. A method for receiving a response signal via the antennae arrangement (19) is also described. The receiving system (11) includes an amplifier (17) to amplify the received response signal from the antenna arrangement (19) for subsequent processing, a matching section (15) to match the amplifier (17) to the antenna (19), and an isolating switch (13) to isolate the antenna from the receiving system (11). The matching section (15) noise matches the receiving system (11) to the antenna (19) during a receiving period to reduce the Q factor of the antenna without significantly degrading the signal to noise ratio. The isolating switch (13) isolates the receiving system (11) from the antenna (19) during a transmitting period when an excitation signal is transmitted by the antenna (19) to irradiate the substance. It also electrically connects the receiving system (11) to the antenna during the receiving period immediately after the transmitting period.

An instrument for investigating properties of an earth formation includes a body housing a nuclear quadrupole resonance (NQR) probe, the probe having at least one coil wound around a core material and an electronics coupling, the body being adapted for insertion into a wellbore within the earth formation. A method and computer program product are provided.

The invention discloses a low frequency tuning antenna applicable to explosive detection, which comprises a high Q-value tuning circuit, an impedance matching circuit and a ringing signal suppression circuit. The high Q-value tuning circuit receives radio frequency pulse containing characteristic frequency of a sample to be tested and output from a high-power transmitter. The impedance matching circuit is used for turning complex impedance of the high Q-value tuning circuit into 50 ohm, and a phase is 0. The ringing signal suppression circuit has effects that when the transmitter works, Q value of the circuit is high, and the antenna ringing signal suppression circuit does not work; and when the transmitter stops working, the Q value of the circuit is low, and residual energy stored in an antenna coil is consumed as soon as possible through the antenna ringing signal suppression circuit. Therefore, time from closing the transmitter to opening a receiver is shortened, the Q value of the circuit is high during a nuclear quadrupole resonance (NQR) signal receiving period, and detecting sensitivity on weak NQR signals is improved, namely a process that the Q value of a resonance circuit becomes smaller then bigger in a detection process is required.

An NQR scanner for detecting the presence of a substance containing quadrupole nuclei within an object. A pulse generating means (1) generates pulse sequences that are used to irradiate the object in a pulsed magnetic field at a requisite NQR frequency for the substance to be detected. A high power RF transmit amplifier (2) amplifies the signal to produce sufficient magnetic field strength to irradiate a scan volume within which the object is disposed for detection purposes and cause an NQR transition to a detectable level within the substance if present within the object. A method for detecting the presence of a substance containing quadrupole nuclei within an object is also described

The invention provides a method and system for labeling items, wherein the labels contain digital information and can be read when desired. The coding of the labels is done by choosing specifically engineered nano-particles, micro-particles, or liquid material in the form of “ink.” The particles are designed to contain materials with distinguishable NMR (nuclear magnetic resonance) or NQR (Nuclear quadrupole resonance) frequencies and are combined in sets to encode digital information. The NMR/NQR label particle sets are printed on the item to be labeled, or on a label substrate which is then attached to the item to be labeled. In one embodiment, the printed NMR/NQR label consists of an array of spots, each of which may encode one or more digital characters. These spots can be detected and the digital information in the label can be read using a suitable magnetic resonance detector.

The invention discloses an interference canceller applied to detecting a core quadrupole moment resonance signal. The interference canceller comprises a main channel, an auxiliary channel, a space domain interference canceling treatment module between the main channel and the auxiliary channel, and a time domain interference canceling module in the main channel. A master control computer generates an exciting pulse sequence, and the exciting pulse sequence is loaded to a main antenna coil to excite a sample to be detected through a signal generator and a high-power transmitter; an NQR (nuclear quadrupole resonance) signal obtained by excitation is received in the main channel through the main antenna coil, and meanwhile, the space domain interference is received in the auxiliary channel through an auxiliary antenna coil; signals in the main channel and the auxiliary channel enter a space domain interference canceling treatment process through a preamplifier, an analog receiver, A/D (analog to digital) and signal preprocessing, and finally a processing result is transmitted to the master control computer. A double-channel explosive detection system scheme is benefit to suppressing the interference in a space domain; and moreover, a space-time adaptive processing method is firstly adopted to suppress the interference aiming at a double receiving channel explosive detection system.

The use of two or more sensors tuned to the same nuclear quadrupole resonance frequency and detecting the nuclear quadrupole resonance signal results in improved signal-to-noise ratio and therefore improved nuclear quadrupole resonance detection system performance.

A system and method for probing a specimen to determine one or more components by utilizing a first signal to excite the specimen at a nuclear quadrupole resonant frequency and observing changes in a specimen property. One exemplary property may be dielectric constant. Another exemplary property may be magnetic permeability. In one embodiment, the first signal is unmodulated and a second signal is observed for the presence of modulation at the frequency of the first signal. Alternatively, the first signal may be modulated and the second signal may be observed for the presence of the modulation. A system is disclosed wherein the specimen is excited using the first frequency and a radar at the second frequency is used to observe changes in radar reflectivity of the specimen due to the excitation.