Biomagnetic measurements with HTS SQUID magnetometers in moderate shielded environments

• Published in: IEEE transactions on applied superconductivity 2003-06, Vol.13 (2), p.381-384
• Main Authors: Herng-Er Horng, Shou-Yen Hung, Jen-Tzong Jeng, Shu-Hsien Liao, Hsu, S.-C., Ji-Chuu Hwang, Hong-Chang Yang
• Format: Article
• Language: English
• Subjects: Applied sciences; Biomagnetics; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Magnetic components, instruments and techniques; Magnetic noise; Magnetic shielding; Magnetometers for magnetic field measurements; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Noise level; Noise measurement; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Signal to noise ratio; SQUID magnetometers; Superconducting device noise; Superconducting devices; Working environment noise
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2003.813859

An HTS SQUID magnetometer for biomagnetic measurements was implemented in a moderate noise shielded environment. The intrinsic noises of the SQUID magnetometer shielded with a tri-layer magnetic shielding cylinder were 50 fT/Hz/sup 1/2/ above 10 Hz and 100 fT/Hz/sup 1/2/ at 0.1 Hz. The moderate shielded environments are constructed of mu-metal layers. With the moderate shielding the magnitude of the QRS complex of a rat specimen was found to be around 10 pT and the signal-to-noise ratio was larger than 10. The requirements for improving biomagnetic measurements in the moderate magnetic shielding are discussed.