A low-noise integrated SQUID gradiometer for biomagnetic sensors

Author

Lee, Y.H. ; Kwon, H.C. ; Kim, J.M. ; Park, Y.K. ; Park, J.C.

Author_Institution

Korea Res. Inst. of Stand. & Sci., Taejon, South Korea

Volume

35

Issue

5

fYear

1999

fDate

9/1/1999 12:00:00 AM

Firstpage

4097

Lastpage

4099

Abstract

We developed a low-noise and compact SQUID gradiometer for biomagnetic multichannel applications. The SQUID is based on a double relaxation oscillation SQUID and provides very large flux-to-voltage transfer coefficients, allowing simple flux-locked loop electronics to be used for SQUID operation. The pickup coil is a first-order planar gradiometer integrated on the same wafer as the SQUID and has a baseline of 40 mm. The field gradient noise of the SQUID gradiometer in flux-locked loop mode is around 1 fT/cm√Hz at 100 Hz, measured inside a magnetically shielded room

Keywords

SQUID magnetometers; biomagnetism; biomedical measurement; biosensors; magnetic sensors; readout electronics; superconducting device noise; 100 Hz; biomagnetic multichannel applications; biomagnetic sensors; double relaxation oscillation SQUID; field gradient noise; first-order planar gradiometer; flux-locked loop electronics; flux-to-voltage transfer coefficients; low-noise integrated SQUID gradiometer; magnetically shielded room; pickup coil; Biomagnetics; Biosensors; Coils; Critical current; Frequency; Josephson junctions; Magnetic field measurement; Magnetic sensors; SQUID magnetometers; Voltage;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.800767

Filename

800767