Open superconductive magnet having a cryocooler coldhead

• US 6,201,462 B1
• Filed: 11/09/1999
• Issued: 03/13/2001
• Est. Priority Date: 11/09/1999
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Wang, Yu, Jiang, Longzhi, Laskaris, Evangelos Trifon, Havens, Timothy John
• Primary Examiner(s): DONOVAN, LINCOLN D
• Application Number:
  US09/436,829
• Time in Patent Office: 490 Days
• Field of Search: 335/216, 335/299, 335/296, 335/297, 335/298, 335/300, 335/301
• US Class Current: 335/299
• CPC Class Codes: G01R 33/3806 Open magnet assemblies for improved access to the sample, e.g. C-type or U-type magnets
• CPC Class Codes: G01R 33/3815 with superconducting coils, e.g. power supply therefor
• CPC Class Codes: H01F 6/04 Cooling

Abstract

An open magnet has vertically aligned first and second assemblies each with at least one superconductive main coil. At least one support member is vertically aligned and attached to, the first and second assemblies. At least one cryocooler coldhead is aligned generally horizontally and has a housing which is attached to, and receives weight-bearing support from, one of the first and second assemblies.

Claims

1. An open magnet comprising:

a) a first assembly including;

(1) a longitudinally-extending and generally-vertically-aligned first axis; and

(2) at least one superconductive main coil generally coaxially aligned with said first axis and carrying a first main electric current in a first direction;

b) a second assembly longitudinally spaced apart from and disposed generally vertically below said first assembly and including;

(1) a longitudinally-extending second axis generally coaxially aligned with said first axis; and

(2) at least one superconductive main coil generally coaxially aligned with said second axis and carrying a second main electric current in said first direction;

c) at least one support member which is generally-vertically-aligned, which has a first longitudinal end attached to said first assembly, and which has a second longitudinal end attached to said second assembly providing cantilevered support to said first assembly; and

d) at least one cyrocooler coldhead which is aligned generally horinzontally and which has a housing attached to, and is proximate to said at least one support member supported by one of said first and second assemblies.

2. The magnet of claim 1, wherein said first assembly includes a first magnet pole piece generally-vertically-aligned to be coaxially aligned with said first axis and spaced apart from said at least one superconductive main coil of said first assembly, and wherein said second assembly includes a second magnet pole piece generally-vertically-aligned to be coaxially aligned with said second axis and spaced apart from said at least one superconductive main coil of said second assembly.

3. The magnet of claim 2, wherein said at least one support member is a non-magnetic material, wherein said first longitudinal end of said at least one support member is attached to said first magnet pole piece, and wherein said second longitudinal end of said at least one support member is attached to said second magnet pole piece.

4. The magnet of claim 1, wherein said at least one cryocooler coldhead includes a first cryocooler coldhead having a first housing and a first cold temperature stage, and wherein said first housing is attached to, and supported by, said first assembly.

5. The magnet of claim 4, wherein said first assembly also includes a first thermal shield generally surrounding said at least one superconductive main coil of said first assembly and a first vacuum enclosure surrounding said first thermal shield, wherein said first housing is attached to, and receives weight-bearing support from, said first vacuum enclosure, and wherein said first stage of said first cryocooler coldhead is thermally connected to said first thermal shield.

6. The magnet of claim 1, wherein said at least one cryocooler coldhead includes a second cryocooler coldhead having a second housing and a cryocooler including at least a first cold temperature stage, wherein said second housing is attached to, and supported by, said second assembly.

7. The magnet of claim 6, whereinsaid second assembly also includes a second thermaly shield generally surrounding said at least one superconductive main coil of said second assembly and a second vacuum enclosure surrounding said second thermal shield, wherein said second housing is attached to, and supported by, said second vacuum enclosure, and wherein said second cryocooler includes at least a first cold temperature stage of said second crycooler coldhead which is thermally connected to second thermal shield.

8. The magnet of claim 1, wherein said at least one cryocooler coldhead includes a first cryocooler coldhead having a first central axis and a first housing and includes a second cryocooler coldhead having a second central axis and a second housing, wherein said first housing is attached to, and is supported by said first assembly and said second housing is attached to, and receives weight-bearing support from, said second assembly, and wherein said first central axis and said second central axis are generally-vertically-aligned in a common vertical plane.

9. The magnet of claim 1, wherein said at least one cryocooler coldhead includes a first cryocooler coldhead having a first central axis and a first housing and includes a second cryocooler coldhead having a second central axis and second housing, wherein said first and second housings each are attached to, and supported by, said first assembly, and wherein said second central axis is aligned generally horizontal to coincide with said first central axis.

10. The magnet of claim 9, wherein said at least one support member consists of a first support member having a first longitudinal axis and a second support member having a second longitudinal axis, wherein said first and second longitudinal axes and said first and second central axes all generally vertically aligned.

11. An open magnet comprising:

a) a first assembly including;

(1) a longitudinally-extending and generally-vertically-aligned first axis;

(2) at least one superconductive main coil generally-vertically-aligned to be coaxially aligned with said first axis and carrying a first main electric current in a first direction; and

(3) a first magnet pole piece generally-vertically-aligned to be coaxially aligned with said first axis and spaced apart from said at least one superconductive main coil of said first assembly;

b) a second assembly longitudinally spaced apart from and disposed generally vertically below said first assembly and including;

(1) a longitudinally-extending second axis generally-vertically-aligned to be coaxially aligned with said first axis;

(2) at least one superconductive main coil generally coaxially aligned with said second axis and carrying a second main electric current in said first direction; and

(3) a second magnet pole piece generally-vertically-aligned to be coaxially aligned with said second axis and spaced apart from said at least one superconductive main coil of said second assembly;

c) non-magnetic first and second support members each generally-vertically-aligned, each having a first longitudinal end attached to said first magnet pole piece, and each having a second longitudinal end attached to said second magnet pole piece, wherein said first and second support members are not diametrically aligned, and wherein said first and second support members are the only support members of said open magnet which are attached to both said first and second magnet pole pieces;

d) a first cryocooler coldhead generally horizontally aligned and having a first housing attached to, and supported by one of said first and second assemblies proximate said first support member; and

e) a second cryocooler coldhead generally horizontally aligned and having a second housing attached to, and supported by one of said first and second assemblies proximate said second support member.

12. The magnet of claim 11, wherein said first assembly also includes a first cryogenic vessel surrounding said at least one superconductive main coil of said first assembly, a first thermal shield generally surrounding said first cryogenic vessel, and a first vacuum enclosure surrounding said first thermal shield, and wherein said second assembly also includes a second cryogenic vessel surrounding said at least one superconductive main coil of said second assembly, a second thermal shield generally surrounding said second cryogenic vessel, and a second vacuum enclosure surrounding said second thermal shield.

13. The magnet of claim 12, wherein said first cryogenic vessel contains a first cryogenic fluid, wherein said second cryogenic vessel contains a second cryogenic fluid.

14. The magnet of claim 13, wherein said first housing of said first cryocooler coldhead is attached to, and receives weight-bearing support from, said first vacuum enclosure, wherein said first cryocooler coldhead is a two-stage cryocooler coldhead having a first stage and a second stage which is colder than said first stage, wherein said second stage is disposed within said first cryogenic vessel, and wherein said first stage of said first cryocooler coldhead is thermally connected to with said first thermal shield.

15. The magnet of claim 14, wherein said second housing of said second cryocooler coldhead is attached to, and receives weight-bearing support from, said second vacuum enclosure, wherein said second cryocooler coldhead is a single-stage cryocooler coldhead having a first stage, and wherein said first stage of said second cryocooler coldhead is thermally connected to with said second thermal shield.

16. The magnet of claim 15, wherein said first cryocooler coldhead has a first central axis and said second cryocooler coldhead has a second central axis, and wherein said first central axis and said second central axis are-aligned-generally horizontally in a common vertical plane.

17. The magnet of claim 16, wherein said first support member has a first longitudinal axis and said second support member has a second longitudinal axis, and wherein said first and second longitudinal axes are generally-vertically-aligned in said common vertical plane.

18. The magnet of claim 14, wherein said second housing of said second cryocooler coldhead is attached to, and receives weight-bearing support from, said first vacuum enclosure, wherein said second cryocooler coldhead is a single-stage cryocooler coldhead having a first stage, and wherein said first stage of said second cryocooler coldhead is thermally connected to with said first thermal shield.

19. The magnet of claim 18, wherein said first cryocooler coldhead has a first central axis and said second cryocooler coldhead has a second central axis, and wherein said second central axis is aligned generally horizontally to coincide with said first central axis.

20. The magnet of claim 19, wherein said first support member has a first longitudinal axis and said second support member has a second longitudinal axis, and wherein said first and second longitudinal axes and said first and second central axes all are generally-vertical-aligned in a common vertical plane.