Measuring device having a squid magnetometer with a modulator for measuring magnetic fields of extremely low frequency

Patent 4864237 Issued on September 5, 1989. Estimated Expiration Date:

September 5, 2006. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

3184674

Method and apparatus for balancing the magnetic field detecting loops of a cryogenic gradiometer using trimming coils and superconducting disks
Patent #: 4320341
Issued on: 03/16/1982
Inventor: Lutes

Rotating SQUID magnetometers and gradiometers
Patent #: 4489274
Issued on: 12/18/1984
Inventor: Berlincourt

Integrated miniature DC SQUID susceptometer for measuring properties of very small samples Patent #: 4588947
Issued on: 05/13/1986
Inventor: Ketchen

Inventor

Hoenig, Eckhardt

Application

No. 06/894685 filed on 08/08/1986

US Classes:

324/248, Superconductive magnetometers327/527Superconductive (e.g., cryogenic, etc.) device

Examiners

Primary: Eisenzopf, Reinhard J.
Assistant: Snow, Walter E.

Attorney, Agent or Firm

Kenyon & Kenyon

International Class

G01R 33/035 (20060101)

Foreign Application Priority Data

1985-08-20 DE

Abstract

An apparatus for measuring magnetic fields which change only at an extremely low frequency contains a SQUID magnetometer which comprises a superconducting flux transformer for inductively coupling the measuring signal into a d-c SQUID sensor. With this apparatus, also quasi-static magnetic fields with frequencies far below 1 Hz should be detectable. A device for modulating the measuring signal to be coupled into the SQUID sensor is associated at least with the flux transformer, the modulation frequency of which is in a frequency range characteristic for low-noise operation of the SQUID. The modulation frequencies are generally above 1 Hz and optionally even above 1 kHz.