Performance Analysis of a Novel Cylindrical Nanocrystalline Shield for Enhancing Measurement Precision of Weak Magnetic Fields and Rotational Dynamics

With the rapid development of quantum technology, the application of high-precision atomic sensors is becoming increasingly widespread, such as in the detection and navigation of human cardiac, magnetic, and brain magnetic fields.The magnetic shielding system is the foundation for ensuring its high-precision measurement. The study employed the finite element method to quantitatively analyze the variations in magnetic shielding effectiveness for different hole sizes. The effect of nanocrystalline magnetic noise in weak magnetic and rotational measurements is also analyzed, and the use of a transfer function combined with Allan variance is proposed to quantitatively assess the effect of nanocrystalline magnetic noise on the long-term stability of rotational measurements. Furthermore, experimental measurements of the nanocrystalline shielding were conducted under static direct-current (DC). Finally, the K-Rb-4He magnetometer and K-Rb-21Ne were built to perform in-situ magnetic noise testing on the inner layer nanocrystalline magnetic shielding. The shielding effect, magnetic noise level, and long-term stability of inertial measurement were compared between nanocrystallines and ferrites as the innermost layer of magnetic shielding. The final results show that the nanocrystalline alloy as the innermost magnetic shield reduces the magnetic noise by 32.3% and the magnetic noise equivalent long-term rotational error by 45.9% at a smaller volume compared to ferrite.