Low temperature susceptibility compensation

• US 20050062022A1
• Filed: 09/24/2003
• Published: 03/24/2005
• Est. Priority Date: 09/24/2003
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Varian Incorporated (Agilent Technologies, Inc.)
• Inventors: Barbara, Thomas M., Swiet, Thomas de
• Granted Patent: US 7,476,330 B2
• Time in Patent Office: Days
• US Class Current: 252/500
• CPC Class Codes: G01R 33/387 Compensation of inhomogeneities
• CPC Class Codes: H01F 1/0018 Diamagnetic or paramagnetic materials, i.e. materials with low susceptibility and no hysteresis H01F1/0036 takes precedence
• CPC Class Codes: H01F 1/42 of organic or organo-metallic materials , e.g. grapheneH01F1/44 takes precedence

Abstract

An composition exhibiting a desired value of magnetic susceptibility, which can be used to fabricate components in an NMR device, and method thereof, wherein the composition comprises a metal ion selected from the group consisting of Gd⁺³, Fe⁺³ and Mn⁺² and an amorphous material using a ligand or chelating agent to solubilize the metal ion throughout the marphous material, wherein the magnetic susceptibility of the composition exhibits a desired value at cryogenic temperatures such as nearly zero susceptibility at temperatures at or below 77° K.

Claims

1. An amorphous composition comprising an amorphous matrix, a metal ion selected from the group consisting of Gd³⁺, Fe⁺³ and Mn⁺², and a ligand, said composition having a selected induced magnetization at cryogenic temperatures.

2. The composition of claim 1, wherein said ligand binds said metal ion and effects solubility thereof in said amorphous matrix.

3. The composition of claim 2, wherein said metal ion is Gd³⁺ and is in the form of Gd(Lg)₃ or, in the alternative, in the form of Gd(ACAc)_3′

wherein Ac is acetylacetonate, and Lg is 2,2,6,6-tetramethyl-3,5-heptanedionate.

4. The composition of claim 1, wherein said amorphous matrix comprises epoxy resin.

5. The composition of claim 1, wherein said amorphous matrix comprises a glass.

6. The composition of claim 1, wherein said amorphous matrix comprises a plastic.

7. The composition of claim 1, wherein said composition is characterized by magnetization equal to that of another selected material for exposure of both said materials by an applied magnetic field.

8. The composition of claim 1, wherein said selected magnetic susceptibility is zero.

9. The composition of claim 1, wherein said selected magnetic susceptibility is reached at a selected temperature below substantially 77°

K.

10. The composition of claim 1, wherein said metal ion is Gd⁺³.

15. The method of claim 11, wherein said composition has a magnetization equal to the magnetization of another material in the presence of the same magnetic field.

11. A method of preparing an amorphous composition to exhibit a desired susceptibility at cryogenic temperatures, comprising the steps of:

mixing a metal ion selected from the group consisting of Gd³⁺, Fe⁺³ and Mn⁺², with an amorphous matrix and a ligand so that the resulting composition has a nearly zero magnetic susceptibility at said cryogenic temperatures.

12. The method of claim 11, wherein said ligand binds said metal ion and effects solubility thereof in said composition.

13. The method of claim 11, wherein said metal ion is Gd and is in the form selected from the group consisting of Gd(Lg)₃ and Gd(AcAc)_3′

wherein Ac is acetylacetonate, and Lg is 2,2,6,6-tetramethyl-3,5-heptanedionate.

14. The method of claim 11, wherein said amorphous matrix is epoxy resin.

16. An NMR apparatus comprising a magnet for producing a polarizing field and utilizing a composition subject to said polarizing field, said composition an amorphous comprising a selected amorphous material and a metal ion selected from the group consisting of Gd³⁺, Fe⁺³ and Mn⁺², and a ligand said composition having a selected value of magnetizationat cryogenic temperatures.

17. The NMR apparatus of claim 16, wherein said ligand binds said metal ion and effects solubility thereof in said composition.

18. The NMR apparatus of claim 16, wherein said cryogenic temperatures are at or below 77°

K.

19. The NMR apparatus of claim 16, wherein said composition is surrounded by a material exhibiting a magnetization of zero and said selected value is zero.