Abstract: The invention provides a charged particle sensor (10) for detecting and measuring ionic current generated by charged particles resulting from ionization processes, comprising: a housing (16), a detection electrode (14) enclosed within the housing for collecting the charged particles, and an electrometer (12) having an input connected to the detection electrode for receiving a DC input signal therefrom and an output (18) for supplying a DC measurement signal as output. The housing comprises an electrostatic screen (16) for screening the detection electrode from external electric fields, whereby to reduce the sensitivity of the detection electrode to such fields.

Abstract: The invention provides a charged particle sensor (10) for detecting and measuring ionic current generated by charged particles resulting from ionisation processes, comprising: a housing (16), a detection electrode (14) enclosed within the housing for collecting the charged particles, and an electrometer (12) having an input connected to the detection electrode for receiving a DC input signal therefrom and an output (18) for supplying a DC measurement signal as output. The housing comprises an electrostatic screen (16) for screening the detection electrode from external electric fields, whereby to reduce the sensitivity of the detection electrode to such fields.

Abstract: The present invention provides a sensor system and a corresponding sensing method employing the sensor system. The sensor system comprises a sensor (12) having an input (20) and an output (22), a feedback path (16) from the output to the input, and a filter (14; 92) 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.

Abstract: 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.

Abstract: 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.

Abstract: The present invention provides nuclear magnetic resonance apparatus comprising means for applying a static magnetic field (H0) 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 (E1, E2) 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.

Abstract: The present invention provides a sensor system and a corresponding sensing method employing the sensor system. The sensor system comprises a sensor (12) having an input (20) and an output (22), a feedback path (16) from the output to the input, and a filter (14; 92) 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.

Abstract: 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.

Abstract: The invention provides an electric potential sensor, comprising 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 provide a high input impedance to the sensor amplifier for increasing the sensitivity of the electrode to reduced electric potentials, and feedback means apply a coherent feedback signal to the input of the sensor amplifier for enhancing the signal to noise ratio of the sensor.

Abstract: The present invention provides nuclear magnetic resonance apparatus comprising means for applying a static magnetic field (H0) 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 (E1, E2) 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.

Abstract: 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, characterised 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.