The research and application of angular correlation for helim optically-pumped magnetometer

In this paper, the angular correlation of helium optically-pumped magnetometer was studied based on the magnetization vector equation of optical pumping. When the angle θ between optical axis of sensor and external magnetic field vector equals 0°, the resonance signal S_z reaches its maximum. While θ equals 90 °, S_z is zero and the magnetometer is unable to work. The vertically-installed single optical axis sensor is suitable for the aeromagnetic survey in high latitude area, but it´s unable to work in the low latitude area because of the very small geomagnetic inclination. The horizontally-mounted double orthogonal optical axes sensor was designed. The calculation and measurements showed that the double orthogonal axes sensor is also suitable for low latitude area. The double axes sensor has been mounted on the delta-wing aircraft for the aeromagnetic survey in a West African country (Sierra Leone).