A method for determining a rotational orientation change using an NMR gyroscope includes making use of a measure of determining, in a vapor cell, which is filled at least with a gaseous first element and a gaseous second element having non-vanishing nuclear spin, a nuclear spin component of the second element in the second direction and a nuclear spin component of the second element in a third direction. The second direction and the third direction are perpendicular to a first direction, which corresponds to the direction of the static magnetic field and to the polarization direction of the nuclear spin of the second element. Moreover, the second direction corresponds to the direction of an applied alternating magnetic field, the frequency of which corresponds to the Larmor frequency of the Larmor precession of the nuclear spin of the second element about the static magnetic field.

A calibration system for magnetometers includes magnetometers configured to measure a magnetic field to be measured; a magnetometer holder fixedly mounted on the magnetometer holder; at least one magnetic field generating device having its position fixed relative to the magnetometers, and used to generate a calibration magnetic field distribution in a space to be measured; and a calculation device configured to calculate the magnitudes of magnetic field vectors at the positions of the magnetometers according to the calibration magnetic field distribution generated by the at least one magnetic field generating device in the space to be measured, receive measured magnitudes of the magnetic field vectors from the magnetometers, and calculate detection gain values of the magnetometers on the basis of the calculated magnitudes of the magnetic field vectors and the measured magnitudes of the magnetic field vector.

A calibration system for magnetometers includes magnetometers configured to measure a magnetic field to be measured; a magnetometer holder fixedly mounted on the magnetometer holder; at least one magnetic field generating device having its position fixed relative to the magnetometers, and used to generate a calibration magnetic field distribution in a space to be measured; and a calculation device configured to calculate the magnitudes of magnetic field vectors at the positions of the magnetometers according to the calibration magnetic field distribution generated by the at least one magnetic field generating device in the space to be measured, receive measured magnitudes of the magnetic field vectors from the magnetometers, and calculate detection gain values of the magnetometers on the basis of the calculated magnitudes of the magnetic field vectors and the measured magnitudes of the magnetic field vector.

A magnetic field generator includes: an upper layer coil composed of a first conductive material and forming a loop circuit having a coil portion; a lower layer coil composed of a second conductive material and forming a loop circuit having a coil portion arranged opposite to the coil portion of the upper layer coil at a predetermined distance; and a substrate supporting the upper layer coil and the lower layer coil and having a dielectric material between the upper layer coil and the lower layer coil. High-frequency currents of opposite phases are passed through the upper layer coil and the lower layer coil, respectively, and a length per loop of the coil portion in the upper layer coil and the coil portion in the lower layer coil is matched to one wavelength of the high-frequency current.

An exemplary wearable sensor unit includes 1) a magnetometer comprising a vapor cell comprising an input window and containing an alkali metal, and a light source configured to output light that passes through the input window and into the vapor cell along a transit path, and 2) a temperature control circuit external to the vapor cell and configured to create a temperature gradient within the vapor cell, the temperature gradient configured to concentrate the alkali metal within the vapor cell away from the transit path of the light.

An exemplary wearable sensor unit includes 1) a magnetometer comprising a vapor cell comprising an input window and containing an alkali metal, and a light source configured to output light that passes through the input window and into the vapor cell along a transit path, and 2) a temperature control circuit external to the vapor cell and configured to create a temperature gradient within the vapor cell, the temperature gradient configured to concentrate the alkali metal within the vapor cell away from the transit path of the light.

A method is provided for sensing a magnetic field in a magnetic gradiometer of the kind in which pump light and light constituting an optical carrier traverse first and second atomic vapor cells that contain host atoms and that are separated from each other by a known distance. According to such method, the host atoms are prepared in a coherent superposition of two quantum states that differ in energy by an amount that is sensitive to an ambient magnetic field. Modulation of the optical carrier in the respective cells gives rise to sidebands that interfere to generate a beat frequency indicative of the magnetic field gradient. The host atoms are prepared at least in a mode that allows measurement of ambient magnetic field components perpendicular to the axis of the pump light. In such mode, the host atoms are spin-polarized by pump light while subjected to a controlled magnetic field directed parallel to the pump beam, and then the controlled magnetic field is adiabatically extinguished.

A method is provided for sensing a magnetic field in a magnetic gradiometer of the kind in which pump light and light constituting an optical carrier traverse first and second atomic vapor cells that contain host atoms and that are separated from each other by a known distance. According to such method, the host atoms are prepared in a coherent superposition of two quantum states that differ in energy by an amount that is sensitive to an ambient magnetic field. Modulation of the optical carrier in the respective cells gives rise to sidebands that interfere to generate a beat frequency indicative of the magnetic field gradient. The host atoms are prepared at least in a mode that allows measurement of ambient magnetic field components perpendicular to the axis of the pump light. In such mode, the host atoms are spin-polarized by pump light while subjected to a controlled magnetic field directed parallel to the pump beam, and then the controlled magnetic field is adiabatically extinguished.

Apparatuses and method are provided for collecting information for imaging. The apparatus has an array of two or more electropermanent magnets, and one or more limited magnetic sensors. The array and limited magnetic sensor are configured to be positioned in a vicinity of a region of interest,

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.