A device for measuring the intensity of minute magnetic fields comprising an optical magnetometer having a source for the emission of radiation, a radiation absorption cell means having the emitted radiation directed therethrough, and detector means for producing an output proportional to the intensity of impinging radiation from the source, wherein the detector means comprises a paraboloidal mirror and a detector element sensitive to the radiation and arranged within the mirror in a plane parallel to and in front of the latus rectum of the mirror, the open end of the mirror facing the cell means and having a diameter sufficient to receive the full beam of radiation passing through the cell whereby the radiation is collected by the mirror and directed toward the detector element.
A system for measuring the earth's magnetic field includes a magnetometer and apparatus for maintaining a predetermined magnetometer tilt in the magnetic meridional plane regardless of changes in vehicle heading. The magnetometer is of the type whose optimum measurement sensitivity is defined by a cone of predetermined angle that is symmetric about its optical axis. It is engaged to a planar platform by gimbal apparatus forming orthogonal axes of rotation that cooperates with a rotatable hemispherical strip to allow the magnetometer to be continuously repointed during changes in the heading of a carrier vehicle so that it is maintained in the magnetic meridional plane at a predetermined tilt angle.
In a magnetic field measuring device, conveyed by a carrier vehicle and released from this vehicle in order to be put into action, the excitation means and the measuring means of a nuclear magnetic resonance helium magnetometer are separated. These measuring means are fixed to a body which includes devices for the transmission and exploitation of the measurements given by the measuring means, and this set is released after the exzcitation is completed while the excitation means remain fixed in the carrier vehicle. This makes it possible to fabricate smaller and lighter magnetic localizing buoys.
