Heat radiation shield, and dewar employing same

• US 6,131,396 A
• Filed: 09/26/1997
• Issued: 10/17/2000
• Est. Priority Date: 09/27/1996
• Status: Expired due to Term

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Vester, Markus, Duerr, Wilhelm
• Primary Examiner(s): CAPOSSELA, RONALD C
• Application Number:
  US08/938,886
• Time in Patent Office: 1,117 Days
• Field of Search: 62/45.1, 62/51.1, 62/DIG. 13
• US Class Current: 62/51.1
• CPC Class Codes: G01R 33/34 Constructional details, e.g. resonators , specially adapted to MR
• CPC Class Codes: G01R 33/34007 Manufacture of RF coils, e.g. using printed circuit board technology; additional hardware for providing mechanical support to the RF coil assembly or to part thereof, e.g. a support for moving the coil assembly relative to the remainder of the MR system
• CPC Class Codes: G01R 33/34023 Superconducting RF coils
• CPC Class Codes: G01R 33/3403 Means for cooling of the RF coils, e.g. a refrigerator or a cooling vessel specially adapted for housing an RF coil
• CPC Class Codes: H01Q 1/002 Protection against seismic waves, thermal radiation or other disturbances, e.g. nuclear explosion; Arrangements for improving the power handling capability of an antenna
• CPC Class Codes: H01Q 1/364 using a particular conducting material, e.g. superconductor
• CPC Class Codes: Y10S 62/13 Insulation

Abstract

A heat radiation shield has an electrically insulating support on which a mosaic of electrically conductive elementary layers is arranged on at least one side.

Claims

1. A heat radiation shield comprising:

a support composed of electrically insulating material; and

a mosaic formed by a plurality of mosaic elements respectively isolated from each other by gaps, each mosaic element comprising an electrically conductive elementary layer disposed on at least one side of said support, and said mosaic elements being disposed next to one another in a two-dimensional grid.

2. A heat radiation shield as claimed in claim 1 wherein said elementary layers in said mosaic are disposed in a regular grid on said support.

3. A heat radiation shield as claimed in claim 1 wherein each of said elementary layers is of an equal size.

4. A heat radiation shield as claimed in claim 1 wherein each of said elementary layers has a thickness which is substantially equal to a skin depth at a maximum of heat radiation to be shielded.

5. A heat radiation shield as claimed in claim 1 wherein each of said elementary layers contains a metal.

6. A heat radiation shield as claimed in claim 1 wherein said metal comprises a metal selected from the group consisting of aluminum and gold.

7. A heat radiation shield as claimed in claim 1 wherein said support comprises a foil.

8. A heat radiation shield as claimed in claim 1 wherein said support comprises a film.

9. A heat radiation shield as claimed in claim 1 wherein said support comprises a plastic foil.

10. A heat radiation shield as claimed in claim 9 wherein said plastic foil is comprised of a polyester film.

11. A Dewar comprising:

a Dewar vessel having an exterior wall;

a high-temperature superconductive nuclear magnetic resonance antenna contained in said Dewar vessel; and

a heat radiation shield contained in said Dewar vessel between said antenna and said wall, said heat radiation shield comprising an electrically insulating support and a mosaic formed by a plurality of mosaic element, respectively isolated from each other by gaps, each mosaic element comprising an electrically conductive elementary layer disposed on at least one side of said support, and said mosaic elements being disposed next to one another in a two-dimensional grid.

12. A Dewar as claimed in claim 11 wherein said heat radiation shield comprises a first radiation shield, and said Dewar comprising a plurality of additional heat radiation shields, each constructed identically to said first heat radiation shield and being disposed between said antenna and said wall, said first heat radiation shield and said plurality of additional heat radiation shields overlapping each other.

13. A Dewar as claimed in claim 11 wherein said heat radiation shield has a periphery with a plurality of point contacts disposed at said periphery, and wherein said heat radiation shield is attached to said wall exclusively at said point contacts.