Cryogenic magnetic probe having new substrate

• US 4,613,816 A
• Filed: 04/03/1984
• Issued: 09/23/1986
• Est. Priority Date: 04/03/1984
• Status: Expired due to Fees

• Current Assignee: Geo-Sensors Corporation
• Original Assignee: Geo-Sensors Corporation
• Inventors: Zeamer, Geoffrey H.
• Primary Examiner(s): Strecker, Gerard R.
• Assistant Examiner(s): Edmonds, Warren S.
• Application Number:
  US06/596,436
• Time in Patent Office: 903 Days
• Field of Search: 324/244, 324/247, 324/248, 324/256, 324/260-262, 324/330, 324/331, 324/346, 324/301, 324/303, 324/319, 336/199, 336/200, 336/205, 336/208, 33/367
• US Class Current: 324/248
• CPC Class Codes: G01R 33/022 Measuring gradient
• CPC Class Codes: G01R 33/0358 coupling the flux to the SQUID gradiometer coils G01R33/022; coils with superconductive winding H01F6/06
• CPC Class Codes: Y10S 505/846 using superconductive quantum interference device, i.e. squid

Abstract

A magnetic probe for detecting the location of a magnetic anomaly. The probe includes an outer dewar jacket that defines a chamber maintained at cryogenic temperatures by a helium reservoir. Mounted on the reservoir in the chamber is a substrate which supports a plurality of pairs of gradiometer coils and a magnetometer. A plurality of SQUIDs detect the magnetic fields sensed by the magnetometer and the pairs of gradiometer coils to determine the magnetic field intensities, directions and gradients from which can be determined location, speed and direction of the anomaly. A valving network connecting the reservoir to a vent allows the probe to be operated in any orientation around its horizontal axis.

Claims

1. A magnetic probe for detecting the range and direction of magnetic anomalies comprising:

(a) a housing defining a chamber;

(b) cryogenic means mounted inside said chamber for maintaining the interior of said chamber at cryogenic temperatures;

(c) magnetic sensing means including;

(i) substrate means situated in said chamber for supporting magnetometer means and a plurality of gradiometer coil means for sensing magnetic field components along selected axes, said substrate means comprising plate means having depending from opposing edges thereof pairs of skirt means, said plate means further supporting a magnetometer support means, each of said pairs of skirt means including means for supporting said gradiometer coil means and said plate means including means adjacent each said skirt means for supporting a said gradiometer coil means, said substrate means being thermally connected to said cryogenic means to maintain said substrate, said magnetometer means and said gradiometer coil means at cryogenic temperatures; and

(ii) detection means situated in said chamber and in thermal contact with said cryogenic means to maintain said detection means at cryogenic temperatures, said detection means being electrically connected to said magnetomer means and to said gradiometer coil means for detecting the direction, strength and gradient of the ambient magnetic field, thereby to provide information as to the direction and range of the magnetic anomalies with respect to the probe.

2. A magnetic probe as defined in claim 1 wherein said substrate means further comprises orthogonal support member means depending from said plate means adjacent to each said skirt means and transverse thereto, each said orthogonal support member means supporting a said gradiometer coil means.

3. A magnetic probe as defined in claim 2 wherein said magnetometer means includes a plurality of magnetometer coil means each lying a plane, with the planes transverse with respect to each other.

4. A magnetic probe as defined in claim 3 wherein said detection means comprises a plurality of detection members, selected ones of which being connected to a magnetometer coil means and others being connected to pairs of gradiometer coil means, said detection means connected to said magnetometer coil means detecting the magnitude of the interference of the magnetic fields generated thereby and said detection means connected to said pairs of gradiometer coil means detecting the gradient of the interference of the magnetic field components along the respective directions.

5. A magnetic probe as defined in claim 1 wherein said housing comprises a dewar means having an interior surface being covered with insulation means, the interior of said insulation means defining said chamber.

6. A magnetic probe as defined in claim 5 wherein said insulation means comprises a selected number of shield means concentric with the interior surface of said dewar means, the spaces defined by said dewar means and said shield means being filled with layers of sheets of a plastic sheeting material having a light-reflective surface.

7. A magnetic probe as defined in claim 6 wherein said dewar means includes means defining an opening for receiving a dewar cap means, each said shield means being concentric with said dewar means and having a tab means in thermal contact with plate means interiorly of said dewar cap means, said respective shield means and plate means being of a thermally conductive material to maintain them at respective uniform temperatures.

8. A magnetic probe as defined in claim 7 further comprising interior housing means disposed interiorly of said sheeting material to retain said sheeting material against the interior wall of said dewar means, said opening being dimensioned to enable the cryogenic means and said magnetic sensing means to be inserted or withdrawn therethrough.

9. A magnetic probe as defined in claim 1 wherein said cryogenic means comprises reservoir means disposed in said chamber for receiving fluid at cryogenic temperatures and thereby maintain said chamber at cryogenic temperatures.

10. A magnetic probe as defined in claim 9 wherein said housing further comprises fill means and vent means in communication with the interior of said reservoir means through fill tube means and vent tube means, respectively.

11. A magnetic probe as defined in claim 10 wherein said vent tube means communicates with the interior of said reservoir means through a valving network comprising:

a. a plurality of vent connection means disposed equi-angularly around said reservoir means; and

b. a like plurality of valving arm means each comprising a plurality of valve means connecting a respective vent connection means to said vent tube means, each said valve means being responsive to the orientation of said probe such that all of the valve means in the valving arm means connected to the vent connection means having the highest elevation are open and at least one of the valve means in the valving arm means connected to the other vent connection means are closed.

12. A magnetic probe as defined in claim 9 wherein said reservoir means includes an interior bulkhead means to inhibit excessive motion of cryogenic fluid in said reservoir means, said interior bulkhead means being perforated to permit the limited flow of cryogenic fluid therethrough.

13. A magnetic probe as defined in claim 9 wherein said cryogenic means further includes litzwire in thermal contact with said reservoir means and extending to and in thermal contact with said magnetic sensing module to enable the cryogenic means to cool said magnetic sensing module to cryogenic temperatures.

14. A substrate member for supporting a plurality of coil means and magnetometer means in a cryogenic magnetic probe, said coil means providing information as to the location of magnetic anomalies, said substrate member comprising plate means having depending from opposing edges thereof a pair of skirt means, said plate means further having depending therefrom a magnetometer support means, each of said skirt means including means for supporting a said coil means, and said plate means further including means adjacent each said skirt means for supporting a said coil means.

15. A magnetic probe as defined in claim 14 wherein said substrate means further comprises orthogonal support member means depending from said plate means adjacent to each said skirt means and transverse thereto, each said orthogonal support member means supporting a said coil means.

16. A magnetic probe as defined in claim 15 wherein said magnetometer means includes a plurality of coil means each lying a plane, with the planes transverse with respect to each other.