Neuromagnetic SQUID measurement in a superconducting magnetic shield

Authors
Ohta, H Aono, M Matsui, T Uchikawa, Y Kobayashi, K Tanabe, K Takeuchi, S Narasaki, K Tsunematsu, S Koyabu, Y Kamekawa, Y Nakayama, K Koike, TS Hoshino, K Kotaka, H Sudoh, E Takahara, H Yoshida, S Shinada, K Takahata, M Yamada, Y Kamijo, K
Citation
H. Ohta et al., Neuromagnetic SQUID measurement in a superconducting magnetic shield, IEEE APPL S, 9(2), 1999, pp. 4073-4076
Citations number
3
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
ISSN journal
10518223 → ACNP
Volume
9
Issue
2
Year of publication
1999
Part
3
Pages
4073 - 4076
Database
ISI
SICI code
1051-8223(199906)9:2<4073:NSMIAS>2.0.ZU;2-X
Abstract
A superconducting magnetic shield of high-Tc superconductor Bi(Pb)-Sr-Ca-Cu -Ox has been constructed whose diameter is 65 cm and length is 160 cm respe ctively. We have successfully observed somatosensory evoked magnetic fields coming out from human brains in the superconducting magnetic shield stimul ating the median nerves of patients by current pulses. We made a 64-channel whole-head SQUID magnetometer of SNS (Superconductor/ Normal metal / Super conductor) junctions. The sensitivities of the dc SQUID of mesoscopic SNS j unctions are around 5 fT / root Hz even in rather unfavorable surroundings. The magnetic shield can reduce a magnetic field to around - 80 dB or 10(-4 ) even at as low a frequency as 0.05 Hz.