Development Of Overhauser Vector Magnetometer

In recent years,benefiting from the rapid development of electronic technology and computer technology,various performance indicators of quantum magnetometers have been greatly improved,especially the Overhauser magnetometer.However,the geomagnetic field is a vector field with both magnitude and direction.The Overhauser magnetometer can only measure the magnitude of the magnetic field,but cannot give the direction information of the magnetic field.Therefore,in order to solve the problem that the Overhauser magnetometer acquires a single geomagnetic element,and can take full advantage of its high sensitivity and low noise,the development of the vector Overhauser magnetometer has also been put on the agenda.The research object of this paper is the prototype of our laboratory’s home-grown JOM-4SF Overhauser magnetometer,and how to measure the direction of the magnetic field by installing a quadrature coil system on the basis of it,that is,the development of the vector Overhauser magnetometer.First,this article introduces in detail the principle of the Overhauser magnetometer measuring the magnitude of the geomagnetic field,the system architecture of the JOM-4SF Overhauser magnetometer prototype,and the sensitivity evaluation method.After the magnetic field data measured by the magnetometer prototype is processed by the synchronous method,the sensitivity can reach 0.014nT@3s,reaching the world’s leading level,which lays a good foundation for the development of the vector Overhauser magnetometer.Secondly,from the point of view that the RF polarized signal can affect the quality of the received Larmor signal,we have developed a simple Overhauser magnetometer with variable RF frequency to study the relationship between RF frequency and the degree of polarization of different solutions.Improve the performance of the Vector Overhauser magnetometer by studying some characteristics of the solution.Finally,how to use the Overhauser magnetometer and the auxiliary magnetic field generating device to measure the magnitude and direction of the magnetic field is explained,that is,the measurement principle and implementation scheme of the Overhauser vector magnetometer.The experimental results show that the developed vector Overhauser magnetometer can already automatically measure and record the three geomagnetic elements of total strength of geomagnetic field(F),magnetic inclination(I)and magnetic declination(D).The sensitivity of magnetic inclination angle and magnetic declination angle can reach 0.2805 ° and 0.1562 ° respectively.