Compact Multi-Point Quantum Magnetometer With a Molded Foaming 3D MEMS Vapor Cell for Magnetic Localization

• Published in: Journal of microelectromechanical systems Vol. 34; no. 3; pp. 316 - 323
• Main Authors: Zhang, Jianfeng, Shang, Jintang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2025; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Atomic measurements; Atoms; Coils; Compact multipoint quantum magnetometer; Cylinder heads; Ferromagnetism; Field coils; Foaming; Localization; Location awareness; Magnetic field measurement; Magnetic fields; magnetic localization; Magnetic noise; Magnetic shielding; Magnetometers; molded foaming 3D MEMS vapor cell; Radio frequency; Rubidium; Spatial resolution; vector synthesis method
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2025.3553291

Currently, medical magnetic localization necessitates complex and costly gradient coil systems, primarily due to the limited sensitivity of the magnetic sensors in use. This article presents a highly sensitive, compact multipoint quantum magnetometer (CMQM) characterized by a straightforward design and low cost. The core of the sensor is a MEMS 3D Rubidium (Rb) atomic cell with an optical path of 3.0 cm, which is manufactured through a mold foaming process. The size of the compact sensor head is less than 11.5 cm 3 . The CMQM obtains magnetic field magnitude at six points by measuring Larmor frequency of rubidium atoms within corresponding positions. A uniform magnetic field coils is calibrated with the CMQM within a ferromagnetic shield. The vector synthesis method is used to enhance the accuracy by reducing interference from remanent magnetic field. The deviation between the measured magnetic field and those predicted using closed cylinder approximation (CCA) is less than 1.1%. The magnetic noise density at different points varies between 2.289 pT/Hz 1/2 and 6.015 pT/Hz 1/2 . The effective magnetic resolution of the CMQM is ~0.65 nT. Theoretical spatial resolution of the CMQM can reach to <inline-formula> <tex-math notation="LaTeX">17.5~\mu </tex-math></inline-formula>m with a simple circular coil. [2024-0230]