Cryostat with magnet arrangement which includes an LTS portion and an HTS portion

Patent metadata

Field	Value
Publication number	US-9766311-B2
Application number	US-201615267667-A
Country	US
Kind code	B2
Filing date	Sep 16, 2016
Priority date	Sep 18, 2015
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A cryostat includes a magnet arrangement for the generation of a magnetic field B0, the magnet arrangement comprising an LTS portion having at least one LTS section made from a conventional low-temperature superconductor and an HTS portion having at least one HTS section made from a high-temperature superconductor. The HTS portion is arranged radially within the LTS portion, and the cryostat is designed to control the temperature of the LTS portion and the HTS portion independently of one another, wherein the HTS portion is electrically isolated from the LTS portion, and is designed to be superconductingly short-circuited. The invention proposes a cryostat with magnet arrangement which enables a high magnetic field strength in a compact space and, at the same time, can be easily constructed.

First claim

The invention claimed is:

1. A cryostat having a magnet arrangement for the generation of a magnetic field B 0 , wherein the magnet arrangement comprises:
a low-temperature superconductor (LTS) portion having at least one LTS section made from a conventional low-temperature superconductor; and
a high-temperature superconductor (HTS) portion having at least one HTS section made from a high-temperature superconductor and being arranged radially within the LTS portion, wherein the cryostat is designed to control the temperature of the LTS portion and the HTS portion independently of each other, and wherein the HTS portion is electrically isolated from the LTS portion and is configured to allow it to be superconductingly short-circuited.

2. The cryostat according to claim 1 , wherein the HTS portion has no current feed lines.

3. The cryostat according to claim 1 , wherein the LTS portion can be short-circuited by means of one or more superconducting switches.

4. The cryostat according claim 1 , wherein the at least one HTS section comprises a closed superconducting cylindrical sleeve or one or more closed superconducting rings in a radial layer.

5. The cryostat according to claim 4 , wherein said radial layer is deposited on a cylindrical support body.

6. The cryostat according to claim 1 , wherein at least one HTS section comprises a coil section which is wound in the form of a solenoid with a tape conductor and is superconductingly short-circuited.

7. The cryostat according to claim 1 , wherein the LTS portion comprises at least two LTS sections, including an LTS main section and an LTS shield section.

8. The cryostat according to claim 7 , wherein the magnet arrangement has a plurality of charging connections with which the at least two LTS sections can be charged with electrical current and discharged independently of one another.

9. The cryostat according to claim 7 , wherein the at least two LTS sections each generate a different magnetic field characteristic.

10. The cryostat according to claim 1 , wherein the cryostat forms a first, outer helium tank for the LTS portion and forms a second, inner helium tank for the HTS portion.

11. The cryostat according to claim 10 , further comprising a radiation shield arranged between the first helium tank and the second helium tank.

12. The cryostat according to claim 1 , wherein the cryostat forms a helium tank for the LTS portion, wherein the HTS portion is arranged in a vacuum chamber which also contains the helium tank, and wherein the HTS portion can be thermally coupled to and decoupled from the helium tank by means of a heat switch.

13. A method for charging the magnet arrangement of a cryostat according to claim 1 , the method comprising:
a) cooling the LTS portion below a transition temperature T c,LTS and holding the HTS portion above a transition temperature T c,HTS ;
b) charging at least a first LTS section to an interim current I IN , wherein the interim current I IN differs from a first operating current I B 1 ;
c) cooling the HTS portion below its transition temperature T c,HTS ; and
d) changing a current I LTS 1 in at least the first LTS section to the first operating current I B 1 , as a result of which the HTS portion is inductively charged.

14. The method according to claim 13 , wherein, during step (b), the LTS portion overall is charged with the same interim current I IN and, during step (d), the LTS portion overall is changed to the same first operating current I B 1 .

15. The method according to claim 13 , wherein the magnet arrangement has at least two LTS sections and a plurality of charging connections with which the at least two LTS sections can be charged with electrical current and discharged independently of one another, and wherein, in step (b), at least one second LTS section is, in turn, charged to a second operating current I B 2 , and wherein, in steps (c) and (d), the current I LTS 2 of the at least one second LTS section is maintained at the second operating current I B 2 .

16. The method according to claim 15 , wherein the operating currents I B 1 and I B 2 are different.

17. The method according to claim 13 , wherein the at least one first LTS section comprises an LTS shield section of the magnet arrangement, and wherein, in step (b), the interim current I IN has an opposite sign to the first operating current I B 1 in step (d).

18. The method according to claim 13 , wherein the magnitude of the interim current I IN is greater than the first operating current I B 1 , and, in step (d), the magnitude of the current I LTS 1 is reduced to the first operating current I B 1 without changing a sign of the current I LTS 1 .

19. The method according to claim 13 , wherein, after step (c), the LTS portion and the HTS portion are held at substantially the same temperature.

20. The method according to claim 13 , wherein the LTS portion is, in turn, superconductingly short-circuited in an additional step (e).

Assignees

• Bruker Biospin Gmbh

Inventors

• Wikus Patrick
• Frantz Wolfgang

Classifications

• H01F6/06 Primary

  Coils, e.g. winding, insulating, terminating or casing arrangements therefor · CPC title

• G01R33/3815

  with superconducting coils, e.g. power supply therefor · CPC title

• G01R33/3804 Primary

  Additional hardware for cooling or heating of the magnet assembly, for housing a cooled or heated part of the magnet assembly or for temperature control of the magnet assembly · CPC title

• H01F6/04

  Cooling · CPC title

• H03K17/92

  by the use, as active elements, of superconductive devices · CPC title