Abstract: The present description concerns a support helmet (130) for a medical imaging or treatment device, comprising a head cap (131) provided with a plurality of through openings (133), each opening being adapted to receiving an elementary imaging or treatment module (110) assembled in the opening so as to slide along an axis substantially orthogonal to the head cap.

Abstract: The invention relates to a method for determining a coupling between magnetometers of an array of N magnetometers, for example with optical pumping, where each magnetometer comprises a field cancellation system capable of being activated to operate the magnetometer in zero field. This method comprises a first phase (P1) during which the N magnetometers are separated into N?1 magnetometers whose field cancellation system is deactivated and a measuring magnetometer whose field cancellation system is activated. This first phase comprises: the generation (GENj), by the magnetometers, of a plurality of reference magnetic fields of known amplitudes and distinct directions, the measurement (MESi), by the measuring magnetometer, of the ambient magnetic field on a plurality of measurement axes determination (CALCij) of coupling coefficients between the measuring magnetometer and each of the N magnetometers from said measurement and said known amplitudes.

Abstract: The present description concerns a support helmet (130) for a medical imaging or treatment device, comprising a head cap (131) provided with a plurality of through openings (133), each opening being adapted to receiving an elementary imaging or treatment module (110) assembled in the opening so as to slide along an axis substantially orthogonal to the head cap.

Abstract: A magnetometer is provided which measures an ambient magnetic field having a frequency range of interest. An optical pumping source emits in the direction of a cell filled with an atomic gas a light beam linearly polarised in a polarisation direction. A parametric resonance excitation circuit induces in the cell a radiofrequency magnetic field having two components orthogonal to the polarisation direction and each oscillating at its own oscillation frequency. A parametric resonance detection circuit performs synchronous detection at an inter-harmonic of oscillation frequencies of an electrical signal outputted by a photodetector arranged to receive the light beam having passed through the cell. A zero-field servo-control circuit generates from the synchronous detection a compensation magnetic field opposite to a component of the ambient magnetic field oriented in the polarisation direction.

Abstract: A magnetometer is provided which measures an ambient magnetic field having a frequency range of interest. An optical pumping source emits in the direction of a cell filled with an atomic gas a light beam linearly polarised in a polarisation direction. A parametric resonance excitation circuit induces in the cell a radiofrequency magnetic field having two components orthogonal to the polarisation direction and each oscillating at its own oscillation frequency. A parametric resonance detection circuit performs synchronous detection at an inter-harmonic of oscillation frequencies of an electrical signal outputted by a photodetector arranged to receive the light beam having passed through the cell. A zero-field servo-control circuit generates from the synchronous detection a compensation magnetic field opposite to a component of the ambient magnetic field oriented in the polarisation direction.

Abstract: An optical pumping and isotropic measurement magnetometer. The magnetometer is all-optical in the sense that resonance between Zeeman sub-levels is induced by modulating the intensity or the frequency of the pump beam. Resonance is detected either using the pump beam itself or an unmodulated probe beam. The pump beam is linearly polarised and its polarisation direction is kept constant relative to the direction of the magnetic field to be measured, so that a measurement independent of the orientation of the field can be made.

Abstract: A magnetometer including a detector configured to measure the amplitude of an output signal at an oscillation frequency to deduce a component of a magnetic field to be measured starting from the value of a resonance gradient, including a main excitation source outputting a measurement signal oscillating at a main oscillation frequency and a secondary excitation source outputting a reference signal with known amplitude oscillating at a secondary oscillation frequency, the detector being configured to measure the output signal amplitude at a harmonic of the secondary oscillation frequency and to deduce said resonance gradient. The invention also applies to a network of magnetometers and a method of measuring a magnetic field without slaving and compensation of fluctuations of the resonance gradient.

Abstract: A device for measuring an electric field in a conducting medium, including: two electrodes separated by a volume of an insulating material; a current measurement device; a voltage measurement device; and a switch enabling to alternately connect the current measurement device and the voltage measurement device between the electrodes.

Abstract: The invention relates to a method of localisation of vector magnetometers arranged in a network, comprising the following steps: generation (EMi), by a magnetic field source (S), of m reference magnetic fields with known amplitudes and known and distinct directions; measurement (MESj) of the m reference magnetic fields along n axes of magnetometers in the network, m and n being such that m*n?6; determination (LOCj) of the position and orientation of magnetometers of the network from said measurements, relative to the magnetic field source. The invention also includes a magnetic field measurement instrument that includes a network of vector magnetometers and is capable of implementing the localisation method. Application to the imagery of biomagnetic fields, for example in magnetocardiography or in magnetoencephalography.

Abstract: A device for measuring an electric field in a conducting medium, including: an insulating enclosure; first, second, and third pairs of electrodes, the electrodes of a same pair being arranged on opposite external walls of the enclosure, and the electrodes of the first, second, and third pairs being centered on first, second, and third orthogonal axes; a first conductive coil; a first pair of switches enabling to alternately connect the first coil between the electrodes of the first, of the second, and of the third pair of electrodes; and a single magnetometer.

Abstract: A device for measuring an electric field in a conducting medium comprises: two electrodes separated by a volume of an insulating medium; a device for measuring current coupled to said electrodes; and adjustment elements making it possible to vary a quantity on which the electrical conductivity of the field measuring device depends.

Abstract: The invention relates to a magnetic field measurement device, including a detector (4) configured to measure the amplitude of an output signal at a harmonic of an oscillation frequency of an excitation source, said amplitude being proportional to the magnetic field (B) to be measured, characterised in that it comprises an excitation circuit configured to associate with a principal excitation source (B1cos?t) oscillating at a principal oscillation frequency at least one secondary excitation source (B2cos(?/3t+?2)) oscillating at a secondary oscillation frequency that is a fraction of the principal oscillation frequency, said fraction being odd if said harmonic is odd, and even if said harmonic is even.

Abstract: A magnetic resonance optical pumping isotropic magnetometer including a laser, a gas filled cell, a HF discharge circuit, RF magnetic field generating coils surrounding the cell, a first frequency regulating mechanism of an RF generator, a second polarization regulating mechanism of the laser beam, and a third regulating mechanism of the direction of the RF magnetic field. The direction of polarization of the laser beam at an inlet of the cell is orthogonally aligned with the magnetic field to be measured by virtue of a liquid crystal polarization rotator. The magnetometer is well-adapted to an integrated arrangement.

Abstract: An optical pumping and isotropic measurement magnetometer. The magnetometer is all-optical in the sense that resonance between Zeeman sub-levels is induced by modulating the intensity or the frequency of the pump beam. Resonance is detected either using the pump beam itself or an unmodulated probe beam. The pump beam is linearly polarised and its polarisation direction is kept constant relative to the direction of the magnetic field to be measured, so that a measurement independent of the orientation of the field can be made.

Abstract: A device for measuring an electric field in a conducting medium comprises: two electrodes separated by a volume of an insulating medium; a device for measuring current coupled to said electrodes; and adjustment elements making it possible to vary a quantity on which the electrical conductivity of the field measuring device depends.

Abstract: A device for measuring an electric field in a conducting medium, including: two electrodes separated by a volume of an insulating material; a current measurement device; a voltage measurement device; and a switch enabling to alternately connect the current measurement device and the voltage measurement device between the electrodes.

Abstract: A device for measuring an electric field in a conducting medium, including: an insulating enclosure; first, second, and third pairs of electrodes, the electrodes of a same pair being arranged on opposite external walls of the enclosure, and the electrodes of the first, second, and third pairs being centered on first, second, and third orthogonal axes; a first conductive coil; a first pair of switches enabling to alternately connect the first coil between the electrodes of the first, of the second, and of the third pair of electrodes; and a single magnetometer.

Abstract: A magnetic shielding including at least one side wall defining a cavity to contain an object to be magnetically isolated. The side wall includes between three and five layers of ferromagnetic metallic material and between three and five layers of polymer material including a ferromagnetic powder. Two adjacent metallic layers are separated by a polymer material layer.

Abstract: A magnetometer including a detector configured to measure the amplitude of an output signal at an oscillation frequency to deduce a component of a magnetic field to be measured starting from the value of a resonance gradient, including a main excitation source outputting a measurement signal oscillating at a main oscillation frequency and a secondary excitation source outputting a reference signal with known amplitude oscillating at a secondary oscillation frequency, the detector being configured to measure the output signal amplitude at a harmonic of the secondary oscillation frequency and to deduce said resonance gradient. The invention also applies to a network of magnetometers and a method of measuring a magnetic field without slaving and compensation of fluctuations of the resonance gradient.

Abstract: The invention relates to a magnetic field measurement device, including a detector (4) configured to measure the amplitude of an output signal at a harmonic of an oscillation frequency of an excitation source, said amplitude being proportional to the magnetic field (B) to be measured, characterised in that it comprises an excitation circuit configured to associate with a principal excitation source (B1cos?t) oscillating at a principal oscillation frequency at least one secondary excitation source (B2cos(?/3t+?2)) oscillating at a secondary oscillation frequency that is a fraction of the principal oscillation frequency, said fraction being odd if said harmonic is odd, and even if said harmonic is even.