Research And Design Of Overhauser Magnetometer Sensor

The proton magnetometer sensor mainly uses the DC pulse signal to polarize the hydrogen proton,and produce the polarized magnetic field perpendicular to the geomagnetic field.The hydrogen proton produces the macroscopic magnetic moment along the magnetic field and the direction and direction of the polarized magnetic field,and removes the pulse signal Hydrogen protons produce La Moore spin into the phenomenon,this sensor there is a high energy consumption,low precision and other shortcomings.On the basis of the proton magnetometer sensor,the Overhauser magnetometer sensor was developed by introducing the RF excitation signal to produce the electron and the nuclear double resonance phenomenon(Overhauser effect)in the nitroxide radical solution to enhance the magnetization of the hydrogen proton in the direction of the geomagnetic field,To solve the proton magnetometer sensor proton hydrogen proton signal is too weak to improve the accuracy of the sensor magnetometer.The JOM-1 type and JOM-2 type Overhauser magnetometer prototype have been developed independently.The sensitivity of these two groups is 0.14 n T and 0.08 n T respectively,which shows that the sensitivity of JOM-2 magnetometer is larger Improve,but there is still room for improvement.This article mainly from the RF power amplifier circuit improvement and sensor research and design of two aspects of the JOM-2-type magnetometer to improve the introduction: First,the JOM-1 magnetometer in the DDS system chip replacement for the AD9859,to achieve low power Consumption and precision frequency output;Second,the JOM-2 magnetometer in a single RF power amplifier circuit into a two-way RF amplifier circuit,constitute a gradient instrument to achieve the same time on the two sensors RF polarization,reducing the two-way Thirdly,the polarized acquisition part and the high frequency excitation part of the sensor are simulated and analyzed,and the advantages and disadvantages of the JOM-1 type and JOM-2 type magnetometer high frequency excitation part are compared.Q value,the return loss(S11),and the signal acquisition of the sensor,and the effects of different production materials,shielding materials,solution,polarization time and power on the sensor quality factor(Q value),return loss(S11)and signal acquisition.The experimental results show that the higher the Q value of the sensor,the smaller the S11,the smaller the power consumption of the sensor and the more sensitive the external magnetic field changes.The different concentrations of the nitrogen free radicals have different excitation frequency and signal acquisition effect.The Finally,the successful integration of the new sensor and field measurement,the measured results show that: improved JOM-2-type magnetometer performance is stable,accurate and reliable magnetic field test results,and the sensitivity increased to 0.057 nT.