Optical Pumping Magnetometer Frequency Acquisition System Design And Implementation

The earth has magnetic which have long been known by people, from ancient times to modern, a generation of people committed to study the earth's magnetic fields, in the process of researching the geomagnetic phenomena related to the physical phenomenon,magnetic field measurement technology continuously gets development. In the aerospace, national defense construction, geological exploration, precision positioning, daily life and other fields,magnetic field measurement technology plays a key role. The development of the magnetometer experienced from the most simple magnetic flux door magnetometer to spin the protons into magnetometer, superconducting magnetic instrument, such as atomic magnetometer, atomic magnetometer because its can measure gradient tensor, most sensitive, light weight, low power consumption, small in volume, no refrigeration equipment and other advantages, is now more and more people.Therefore, the development of more high precision magnetic field measurement technology and magnetic measuring instrument has a very good market value.Optical pumping magnetometer was first recognized after1950, optical pumping magnetometer is a kind of magnetic field measurement instrument which based on the atoms (commonly used potassium (K39); rubidium (Rb87, Rb85); CS (Cs133); helium (He4, He3)) of the energy structure, and developed through the optical pumping effect and magnetic resonance technology. Due to the proportional relationship of the frequency of electromagnetic wave and the optical pumping magnetic resonance magnetometer point external magnetic field, so the magnetic field strength measurements can be converted into frequency measurement. With the continuous development of EDA technology, optical pumping magnetometer in the precision of measurement, measuring speed has greatly mproved. Based on the high sensitivity of the optical pump magnetometer, the measurement of magnetic field intensity, gradient is not always zero drift, do not have to strictly control the direction advantages, the application prospect of optical pumping magnetometer and earth magnetic field measurement is very good, on the world a lot of countries are committed to the study of optical pump magnetometer, has successfully developed a variety of types which applicate in many fields. This paper first introduces the development history of the magnetometer and its application field, the optical pump magnetometer of physics principles, commonly used measurement method for magnetic field and magnetic resonance detection method, discusses the cesium atomic energy level splitting, circularly polarized light to cesium atomic excitation, optical pumping effect and the optical pump magnetic detection system working principle. Based on existing cesium optical pump weak magnetic field intensity detecting circuit system design scheme, the resonance frequency of the measurement system, combined with CPLD technology and high precision fixed gate frequency measurement method, realizes the high-precision frequency continuous measurement, finally gives the debugging and testing results of system. Has the very good application value.