A modular 31-channel SQUID system for biomagnetic measurements

Author

Dossel, O. ; David, B. ; Fuchs, M. ; Kruger, J. ; Ludeke, K.-M. ; Wischmann, H.-A.

Author_Institution

Philips GmbH Forschungslaboratorien, Forschungsabteilung Tech. Syst., Hamburg, Germany

Volume

3

Issue

1

fYear

1993

fDate

3/1/1993 12:00:00 AM

Firstpage

1883

Lastpage

1886

Abstract

A modular multichannel superconducting quantum interference device (SQUID) system, in which every channel can be optimized or replaced individually, was further improved. The number of channels was increased to 31. The noise level is better than 10 fT/ square root Hz. A novel way of RF shielding using conductive paint avoids degradation of the SQUID characteristics due to RF interference without introducing significant extra noise, so that the system works without any Faraday cage. A simplified way of coupling the modulation and feedback signal directly to the SQUID was developed and tested successfully. The SQUID module with superconducting connections to the gradiometer and its superconducting shield was miniaturized to an outer diameter of 5 mm, so that it can be placed near the gradiometer without introducing significant unbalance. Tests have demonstrated that the accuracy of the system with respect to the localization of a single current dipole is better than 2 mm.<>

Keywords

SQUIDs; biomagnetism; biomedical equipment; biomedical measurement; interference suppression; magnetic shielding; magnetometers; modules; patient diagnosis; RF shielding; biomagnetic measurements; clinical diagnostics; conductive paint; gradiometer; modular 31-channel SQUID system; modulation feedback signal coupling; multichannel SQUID; noise level; single current dipole localization; superconducting connections; superconducting shield; Biomagnetics; Degradation; Electromagnetic interference; Feedback; Noise level; Paints; Radio frequency; SQUIDs; Superconducting device noise; Superconducting devices;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.233313

Filename

233313