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High temperature RF SQUIDs for biomedical applications.

Y Zhang·Y Tavrin·M Mück·A I Braginski·C Heiden·T Elbert·S Hampson
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Abstract

We have been investigating the feasibility of radio-frequency RF, low-noise superconducting quantum interference device (SQUID) magnetometers and gradiometers operating in liquid nitrogen at 77 K. Using flux-focusing structures fabricated from epitaxial YBa2Cu3O7-chi films, we have attained a magnetic field resolution for a magnetometer of better than 200 fT Hz-1/2 at less than 1 Hz, i.e. over the low signal-frequency range important for biomedical diagnostics. At 77 K, this magnetometer recorded diagnostically useful heart signals, voluntary eye-blink signals, and also the first evoked response of a human brain. These and similar results were obtained in a magnetically shielded room. We were also able to record heart signals in the absence of any shielding when using a first-order gradiometer. An improvement in the magnetic field resolution of our magnetometers and gradiometers by, at least, another order of magnitude is possible and probable.

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Y Zhang, Y Tavrin, M Mück, A I Braginski, C Heiden, T Elbert, S Hampson. 1993. High temperature RF SQUIDs for biomedical applications.. https://doi.org/10.1088/0967-3334%2F14%2F2%2F002

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