Development Of JOM-1OVERHAUSER Magnetometer

Overhauser magnetometer is developed on the base of proton precessionmagnetometer. It is a kind of high-precision static magnetic sensor based on theprinciples of dynamic nuclear polarization. Under the RF excitation, electronparamagnetic resonance occurs in the radical-rich solution that full of unpairedelectrons. The solution contains electron spin and nucleus spin at the same time.Through the interaction of the two spin systems, energy of the electron paramagneticresonance is transferred to hydrogen nuclei in the solvent. Then nucleus magneticresonance occurs. Resonance protons are strongly oriented. The oriented protons dolarmor precession along the direction of the external magnetic field through theprocess of relaxation. Since the frequency of larmor procession is proportional to thegeomagnetic field, by precisely measuring the frequency of larmor procession we canaccurately get the geomagnetic field. Compared to the static polarization with aconstant magnetic field, dynamic nuclear polarization has greatly increased thenuclear polarization. Resonance signal strength will be increased obviously, and alsosignificantly improve the precision of magnetic measurement.This paper firstly introduces the research background and status both at homeand abroad, aiming at illustrating the research significance of this topic.In thefollowing pages the working principle of Overhauser magnetometer is expounded andsystem hardware design scheme of the self-developed JOM-1type Overhausermagnetometer is elaborated, including radio frequency signal source design, poweramplification circuit design, the whole machine power layout design and the emc,preamplifier circuit design and instrument noise analysis, signal conditioning circuitdesign, digital part and the working sequence, The human-computer interactioninterface,etc. Finally, the sensitivity index of JOM-1type Overhauser magnetometerand results of some field experiments aiming at improving the sensitivity of the instrument are provided.Tests show that the instrument has realized basic functions such as polarization,sampling, measuring results display, data storage, data review, serial datacommunication, time management, GPS, battery capacity check and so on. Signal tonoise ratio can reach96:1. The instrument has good stability and its sensitivity canreach0.14nT. Both walking measurement model and base station measurementmodel are supported. It also has the advantages of low power consumption and fastcontinuous measurement.Development of JOM-1type Overhauser magnetometer willhelp improve the independent research and development ability of Overhausermagnetometer, to realize industrialization of Overhauser magnetometer in our countryas soon as possible.