University of Sussex

The University of Sussex-Falmer

Robert J Prance

Christopher J Harland

Helen Prance

Sam Thomas Beardsmore-Rust

Terence D Clark

Philip Watson

Terence Clarke

The invention provides a target object detection system, comprising a plurality of sensing nodes () for positioning at respective detection locations with respect to a detection area () that is situated within a field generated by an ambient AC source of excitation. Each sensing node has at least one electric potential sensor () designed to detect perturbations in said field caused by a target object (), said one sensor including an electrode () responsive to the AC excitation field for generating detection signals, an amplifier () connected to the electrode for receiving and amplifying the detection signals to produce AC measurement signals as output, and at least one feedback circuit () from an output of the amplifier to an input thereof for enhancing the input impedance of the amplifier. A signal processing arrangement () is associated with each sensing node and comprising a filter circuit () adapted to filter out frequencies generated by the ambient AC source of excitation that are outside a pre-defined bandwidth, and a level detector () responsive to the AC measurement signals for monitoring signal amplitude and generating amplitude information for use in producing target object data.

Target position, movement and tracking system

The invention provides a charged particle sensor () for detecting and measuring ionic current generated by charged particles resulting from ionization processes, comprising: a housing (), a detection electrode () enclosed within the housing for collecting the charged particles, and an electrometer () having an input connected to the detection electrode for receiving a DC input signal therefrom and an output () for supplying a DC measurement signal as output. The housing comprises an electrostatic screen () for screening the detection electrode from external electric fields, whereby to reduce the sensitivity of the detection electrode to such fields. The electrostatic screen includes an electrically conducting screening sheet () provided as a second electrode facing the detection electrode and formed with interstices to allow the entry of radiation into the housing, and the second electrode and the detection electrode are arranged to be maintained in use at a bias voltage with respect to one another so as to effect charge separation amongst charged particles resulting from ionization processes and thereby produce an ionic current impinging on the detection electrode.

Apparatus for sensing ionic current

An electrodynamic sensor comprises a high input impedance electrometer adapted to measure small electrical potentials originating from an object under test and having a pair of input probes, characterized in that at least one of said pair of input probes has no direct electrical contact with said object, wherein the circuit arrangement of said electrometer comprises an electrode () connected to an amplifier (), which includes a combination of ancillary circuits cumulatively to increase the sensitivity of said electrometer to said small electrical potentials while not perturbing the electrical field associated therewith.

Electrodynamic sensors and applications thereof

The present invention provides a sensor system and a corresponding sensing method employing the sensor system. The sensor system comprises a sensor () having an input () and an output (), a feedback path () from the output to the input, and a filter () in the feedback path. The filter comprises a narrow band filter, which is tuned or tunable to a respective one of signals that are wanted signals and signals that represent interference signals. The sensor and the filter are arranged so as to alter the relative amplitudes of the wanted signals and the interference signals in order to increase the relative amplitude of the wanted signals and reduce the relative amplitude of the interference signals.

Sensor system and method

The invention provides a method and apparatus for the detection of charge density distribution at the surface of a material sample. The apparatus comprises an electric potential sensor for measuring surface charge on a material sample, wherein the electrical potential sensor includes a probe for capacitively coupling the electric potential sensor to the surface of the material sample, an amplifier for generating a measurement output, the probe being connected to an input of the amplifier and the measurement output being supplied at an output of the amplifier, and a feedback arrangement driven from the output of the amplifier for enhancing the input impedance of the amplifier. A positioning system mounts the probe of the electric potential sensor above the material sample and moves the probe at a constant height over a surface of the said sample, and a processing system receives and processes the measurement output of the electric potential sensor for generating a digital record of the charge density distribution at the surface of the material sample.

Apparatus and method for measuring charge density distribution

The present invention provides an electric potential sensor for the measurement of potentials non-invasively. The sensor comprises at least one detection electrode arranged for capacitive coupling with a sample under test and for generating a measurement signal, and a sensor amplifier adapted to receive the measurement signal as input and to supply an amplified detection signal as output. Input impedance enhancing means are included for providing a high input impedance to the sensor amplifier for increasing the sensitivity of the electrode to reduced electric potentials, and a discrete pre-amplifier stage is arranged to co-operate with the sensor amplifier to reduce the input capacitance of the amplifier.

Electric potential sensor

The invention provides an electric potential sensor including, at least one detection electrode arranged for capacitive coupling with a sample under test and for generating a measurement signal, and a sensor amplifier adapted to receive the measurement signal as input and to supply an amplified detection signal as output. An input impedance enhancing element provides a high input impedance to the sensor amplifier for increasing the sensitivity of the electrode to reduced electric potentials, and a feedback element applies a coherent feedback signal to the input of the sensor amplifier for enhancing the signal to noise ratio of the sensor.

The present invention provides nuclear magnetic resonance apparatus comprising means for applying a static magnetic field (H) to a sample under investigation, a radio frequency circuit arranged to be inductively coupled to the sample by means of an oscillating magnetic field disposed generally perpendicular to the static magnetic field for applying an excitation signal to the sample, and an electric potential sensor (E, E) for detecting the excitation of the sample and for generating a detection output. The electric potential sensor comprises an electrode placed generally perpendicular to the axis of the oscillating magnetic field for capacitively coupling the electric potential sensor to the sample.

Electric potential sensor for use in the detection of nuclear magnetic resonance signals

An electrodynamic sensor comprises a high input impedance electrometer adapted to measure small electrical potentials originating from an object under test and having a pair of input probes, characterized in that at least one of said pair of input probes has no direct electrical contact with said object, wherein the circuit arrangement of said electrometer comprises an amplifier which includes a combination of ancillary circuits cumulatively to increase the sensitivity of said electrometer to said small electrical potentials whilst not perturbing the electrical field associated therewith.

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Brighton, United Kingdom

Robert J Prance