微型核磁共振陀螺磁屏蔽桶设计与研制

Design and development of magnetic shielding for micro nuclear magnetic resonance gyroscope

磁屏蔽桶可屏蔽外界时空变化磁场对核磁共振陀螺工作磁场的干扰,是核磁共振陀螺不可或缺的重要组件。为减小孔洞及缝隙等不连续结构对小体积磁屏蔽桶屏蔽效果的影响,研究了适用于多孔洞不连续屏蔽桶屏蔽系数计算的磁路法和有限元法,提出了联合解析法、磁路法和有限元法的小型多孔洞高效能屏蔽桶设计方法,该方法采用解析法确定外形尺寸,基于磁路法确定连接方式,利用有限元法确定缝隙精细尺寸,基于该方法,完成了50 cm 3级磁屏蔽桶设计、研制及屏蔽系数测试,实测屏蔽系数优于104,与设计结果较吻合,验证了所提方法的有效性。

Magnetic shielding can be used to eliminate the influence of the temporal and spatial changing exterior magnetic field on the working field of Nuclear Magnetic Resonance Gyroscope(NMRG).It is essential to develop the magnetic shielding for NMRG.For the design of small volume magnetic shielding,the influence of the holes and discontinuous gaps cannot be ignored.Therefore,this article studied the magnetic circuit method and finite element method for calculating the shielding effectiveness of multi-hole discontinuity magnetic shielding.Combining the analytical method,magnetic circuit method and finite element method,this paper proposed the design method of the high-efficiency multi-hole and small-size magnetic shielding.The analytical method is used to determine the outline size,the connection mode is determined based on the magnetic circuit method,and the fine size of the gap is determined by the finite element method,which can be beneficial to obtain the accurate design accuracy with high efficiency.Based on this method,the 50 cubic centimeter(cc)magnetic shielding was developed and tested.Experiment results show that the shielding effectiveness of the 50cc magnetic shielding is better than 104.The experimental result is consistent with the design method,which verifies the effectiveness of the proposed design method.