US 5,494,033 AGranted

Biomagnetometer with sealed vacuum enclosure and solid conduction cooling

AssigneeBiomagnetic Technologies, Inc.

InventorsD. Scott Buchanan, Laurence Warden, Scott W. Riley, Richard T. Johnson, K. Randy Brimhall, Keith A. Esser

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Abstract

A biomagnetometer includes a magnetic field sensor including a magnetic field pickup coil and a detector of small electrical currents flowing within the pickup coil. A vacuum-tight enclosure surrounds the sensor. The enclosure has a concavely upwardly curved first wall, with the magnetic field pickup coil located adjacent to the first wall. A vented reservoir of liquefied gas is located within the enclosure, and a solid thermal conductor extends from the sensor. There is a vacuum-tight thermal feedthrough by which the solid thermal conductor passes between the interior and the exterior of the enclosure. Electronic circuitry for filtering and amplifying the signals of the detector is also provided. Such a biomagnetometer is placed below the body of a reclining subject, and a second portion of the biomagnetometer can be placed above the body. In one form, the enclosures are shaped to form a cavity that receives the head of the subject therein, to achieve full head coverage of the pickup coils in the biomagnetometer.

Claims14

Dependent claims

A biomagnetometer, comprising:

a magnetic field sensor, including
a magnetic field pickup coil, and
an electrical current detector in electrical communication with the pickup coil;
a vented reservoir of liquefied gas;
an uninterrupted solid thermal conductor extending from the magnetic field sensor to the interior of the reservoir;
a vacuum-tight thermal feedthrough by which the solid thermal conductor passes between the exterior and the interior of the reservoir;
a vacuum-tight enclosure surrounding the magnetic field sensor, the reservoir, the solid thermal conductor, and the vacuum-tight thermal feedthrough, the enclosure having a wall including a concavely upwardly curved first wall portion with the magnetic field pickup coil located adjacent to the first wall portion;
an electronic circuit, at least a portion of the electronic circuit being located exterior to the enclosure;
an electrical lead extending from the electrical current detector to the portion of the electronic circuit located exterior to the enclosure;
a vacuum-tight electrical feedthrough by which the electrical lead passes between the interior and the exterior of the enclosure;
a second enclosure having a concavely downwardly curved second wall, the downwardly curved second wall being positioned in facing relation to the upwardly curved first wall portion;
a second magnetic field sensor, including
a second magnetic field pickup coil located within the second enclosure adjacent to the curved second wall, and
a second electrical current detector in electrical communication with the second pickup coil;
and
means for cooling the second magnetic field sensor.

13 more elements

A biomagnetometer, comprising:

means for sensing a magnetic field, the means for sensing including
an array of magnetic field pickup coils, and
an array of detectors of small electrical currents flowing in the respective pickup coils;
a vacuum-tight enclosure surrounding the means for sensing and having a concavely downwardly curve first wall;
a vented reservoir of cryogenic liquid located within the enclosure;
a solid thermal conductor extending from the means for sensing into the reservoir;
and
a vacuum-tight thermal feedthrough for the solid thermal conductor extending through a wall of the reservoir between the exterior of the reservoir and the interior of the reservoir;
second means for sensing a magnetic field, the second means for sensing including
a second array of magnetic field pickup coils, and
a second array of detectors of small electrical currents flowing in the respective pickup coils;
a second enclosure surrounding the second means for sensing, the second enclosure having a concavely downwardly curved second wall positioned in facing relation to the first wall;
and
means for cooling the second means for sensing.

11 more elements

Dependencies are inferred from the claim text.