Optimization design of two-dimensional magneto optical trap field coils for cold atom interferometer

High flux of cold atoms is one of the key technologies to realize high-precision cold atom interferometer. The approach of concatenation of two-dimensional Magnetic Optical Trap (2D-MOT) and three-dimensional Magnetic Optical Trap (3D-MOT) is generally used to obtain high flux of cold atoms. The magnetic field distribution of 2D-MOT is the key influencing factor in this appliance. In this paper, three different (rectangular, race-track and saddle) mathematical models of Anti-Helmholtz coils in 2D-MOT were established to analyze the magnetic field distribution. Then, the magnetic field zero drift and the change of magnetic field gradient caused by the error of eccentricity, coils asymmetry, parallelism and inside diameter asymmetry were analyzed, which were produced in the manufacture and installation process using finite element analysis. Results show that the magnetic field gradient provided by saddle coils is more conducive to produce high flux of cold atoms when eccentricity error is less than 1.14 mm, coils asymmetry error is less than 0.016 A and parallelism error is less than 1.02. This work may provide theoretical guidance for the design and fabrication of magnetic system of 2D-MOT of cold atom interferometer.