Rare earth regenerator material particle, rare earth regenerator material particle group, and cold head, superconducting magnet, examination apparatus, and cryopump using the same

Patent metadata

Field	Value
Publication number	US-10513646-B2
Application number	US-201816032713-A
Country	US
Kind code	B2
Filing date	Jul 11, 2018
Priority date	Oct 9, 2012
Publication date	Dec 24, 2019
Grant date	Dec 24, 2019

Abstract

A rare earth regenerator material particle and a regenerator material particle group having a high long-term reliability, and a superconducting magnet, an examination apparatus, a cryopump and the like using the same are provided. A rare earth regenerator material particle contains a rare earth element as a constituent component, and in the particle, a peak indicating a carbon component is detected in a surface region by an X-ray photoelectron spectroscopy analysis.

First claim

What is claimed is:

1. A method for manufacturing a cold head, comprising:
preparing at least one regenerator container; and
filling a plurality of regenerator material particle groups which are different types in the regenerator container,
wherein a generator material particle constituting at least one of the plurality of the regenerator material particle groups is a rare earth generator material particle comprising a rare earth element as a constituent component,
a peak indicating a carbon component and a peak indicating a compound containing the rare earth element and oxygen are detected in a surface region of the rare earth generator material particle by an X-ray photoelectron spectroscopy analysis,
an entire content of carbon in the rare earth generator material particle including the carbon component is 5 mass ppm or more and 100 mass ppm or less, and
the carbon component detected in the surface region of the rare earth generator material particle has at least one selected from the group consisting of a C—C bond, a C—H bond, a C—O bond, a C—O bond, and an O—C═O bond.

2. The method according to claim 1 , wherein the plurality of the regenerator material particle groups are filled in the regenerator container via a metal mesh material.

3. The method according to claim 2 , wherein the metal mesh material is pressed to the regenerator material particle group filled in the regenerator container.

4. The method according to claim 1 , wherein a metal mesh material is filled in a stage of the regenerator container.

5. The method according to claim 4 , wherein a copper mesh material as the metal mesh material is filled in the regenerator container.

6. The method according to claim 1 , wherein a plurality of the regenerator containers are prepared.

7. The method according to claim 6 , wherein a copper mesh material is filled in at least one regenerator container out of the plurality of the regenerator containers.

8. The method according to claim 1 , wherein the rare earth generator material particle comprises an intermetallic compound represented by a composition formula of RMa, wherein R is at least one element selected from the group consisting of rare earth elements, M is at least one element selected from the group consisting of Cu, Ni, and Co, and a is a number of an atomic ratio satisfying 0.1≤a≤4.0.

9. The method according to claim 8 , wherein a peak indicating a compound of the rare earth element and oxygen and a peak indicating a compound of the M element and oxygen are detected in the surface region by the X-ray, photoelectron spectroscopy analysis.

10. The method according to claim 8 , wherein a ratio A/B of an atomicity A of the rare earth element in a compound of the rare earth element and oxygen to an atomicity B of the M element in a compound of the NI element and oxygen exceeds the value of the a.

11. The method according to claim 8 , wherein the intermetallic compound comprises at least one selected from the group consisting of HoCu 2 , HoCu, Er 3 Ni, ErNi, and Er 3 Co.

12. The method according to claim 1 , wherein a lead regenerator material particle group as one group of the plurality of the regenerator material particle groups is filled in the regenerator container.

13. The method according to claim 1 , wherein a gadolinium oxysulfide regenerator material particle group as one group of the plurality of the regenerator material particle groups is filled in the regenerator container.

14. The method according to claim 1 , wherein the plurality of the regenerator material particle groups are filled in the regenerator container sequentially from the particle group with higher specific heat peak temperature.

15. The method according to claim 1 , wherein an operating medium gas is passed through the regenerator container in which the regenerator material particle groups are filled in order to realize a temperature of 10 K or less.

16. The method according to claim 1 , wherein the entire content of carbon in the rare earth generator material particle is 5 mass ppm or more and 50 mass ppm or less.

17. The method according to claim 1 , wherein the regenerator material particle group is filled in the regenerator container while applying a vibration.

18. The method according to claim 1 , wherein the cold head is mounted in a superconducting magnet, an examination apparatus, or a cryopump.

Assignees

• Toshiba Kk
• Toshiba Materials Co Ltd

Inventors

• Yamada Katsuhiko
• Fuse Keiichi

Classifications

• B22F9/08

  by casting, e.g. through sieves or in water, by atomising or spraying (using electric discharge B22F9/14) · CPC title

• C09K5/08

  Materials not undergoing a change of physical state when used (C09K5/16, C09K5/20 take precedence) · CPC title

• F17C5/00

  Methods or apparatus for filling containers with liquefied, solidified, or compressed gases under pressures (adding propellants to aerosol containers B65B31/00) · CPC title

• C09K5/14 Primary

  Solid materials, e.g. powdery or granular · CPC title

• C09K5/00 Primary

  Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion · CPC title