| As an important means of researching on magnet and analyzing the morphology and properties for materials, detecting of weak magnetic field has been used in various practical applications, such as bio-magnetic fields detection used in medical domain, landforms surveys, material defect detection, hydrocarbon resources exploration, underwater magnetic target position fixed, and archaeology and so on. At present, the widely used magnetometers with mature technique are flux-gate magnetometer, nuclear-precession magnetometer, optical pumped magnetometer and superconducting quantum interference device (SQUID).In the measurements of magnetic field using magnetometer, we mainly rely on the relationship between the width of resonant hyperfine spectrum and magnetic field. The magnetic field will be affected by space, temperature, humidity and other factors, even in the steady state environment, it still will change over time. So we prefer considering the uniformity of magnetic field to magnetic field itself. The main feature gives using of the atomic magnetometer in many different fields; the important influence to atomic magnetometer between width of resonant hyperfine spectrum and magnetic field; and some factors of width of resonant hyperfine spectrum. Simulate and calculate the magnetic field of different shapes of current-carrying coils, and analyze the uniformity of magnetic field.According to the size of the simulation design and make rectangular coils doing the measurement of magnetic field. At last, analyze and research the relationship between resonant hyperfine spectrum and magnetic field under different magnetic fields. The main topics we researched are as follows.1. Introduce application and significance of magnetic measurement in detail, describes some design schemes of different magnetometers. Analyze the significance of uniformity of magnetic field to the sensitivity, leading to the main topics we researched.2. Illustrate the advantages of selecting Cs atoms as working substance, introduce the basic theory of the width of resonant hyperfine spectrum in detail and their influence to magnetometer. On the basis, discuss the characteristics of magnetic field generated by Helmholtz coils.3. Analyze the magnetic field generated by commonly used circular coils and optimized rectangular coils and their uniformity. Simulate and calculate the magnetic field in the center of coils, getting the conclusion that rectangular coils are better for atomic magnetometer by comparative analysis.4. According to the size of magnetic shielding device, design and simulate the suitable rectangular coils, analyzing the uniformity of magnetic field. Then choose appropriate materials to make the rectangular coils and measure them, in line with expectations of uniformity requirements.5. Describe the cesium atomic magnetometer device system in detail, and analyzing Zeeman Effect of the Cs D1 line Zeeman sub level. Discuss the effect of uniformity of magnetic field to width of resonant hyperfine spectrum in different magnetic fields. Analyze the change and trend of resonant hyperfine spectrum in different magnetic fields.The innovative results of our work are as follows:1. Considering the sensitivity of magnetometer could be affected by both uniformity of magnetic field and width of resonant hyperfine spectrum, research them respectively.2. Try to use the rectangular coils instead of traditional circular coils, according to the results that the uniformity of magnetic field generated by rectangular coils is better,the change of magnetic field is less than 1%.3. For the strong magnetic environment inside the magnetic shielding device,considering the influence of nonlinear Zeeman Effect, further research the relationship between uniformity of magnetic field and width of resonant hyperfine spectrum. |
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