US-20260128199-A1 - SUPERCONDUCTING MAGNET AND MAGNETIC RESONANCE IMAGING APPARATUS

US20260128199A1US 20260128199 A1US20260128199 A1US 20260128199A1US-20260128199-A1

Abstract

A superconducting magnet apparatus includes a superconducting coil, a structure, a refrigerant tank, a heat exchanger, a freezer, a solid heat conductor, and a vacuum container. The superconducting coil is formed of a superconducting wire that forms a magnetic field. The structure is formed of a superconductor and is electrically connected to the superconducting coil. The refrigerant tank stores a refrigerant. The heat exchanger is exposed to inside of the refrigerant tank. The freezer cools the refrigerant. The solid heat conductor makes direct or indirect thermal connection between the refrigerant tank and the superconducting coil and the structure. The superconducting coil or the structure is formed using at least two structures having different operation temperatures or superconducting characteristics for superconduction.

Inventors

Takehiro Shibuya
Hiromi Kawamoto
Katsutoshi Mizuno
Sadanori Tomiha
Michiru KAJIWARA

Assignees

CANON MEDICAL SYSTEMS CORPORATION

Dates

Publication Date: 20260507
Application Date: 20251104
Priority Date: 20241106

Claims (12)

1 . A superconducting magnet apparatus comprising: a superconducting coil that is formed of a superconducting wire that forms a magnetic field; a structure that is formed of a superconductor and that is electrically connected to the superconducting coil; a refrigerant tank that stores a refrigerant; a heat exchanger that is exposed to inside of the refrigerant tank; a freezer that cools the refrigerant; a solid heat conductor that makes direct or indirect thermal connection between the refrigerant tank and the superconducting coil and the structure; and a vacuum container that seals in the superconducting coil, the structure, the refrigerant tank, the heat exchanger, the freezer, and the solid heat conductor, wherein the superconducting coil or the structure is formed using at least two structures having different operation temperatures or superconducting characteristics for superconduction.
2 . The superconducting magnet apparatus according to claim 1 , wherein the superconducting characteristic is a critical temperature, a critical magnetic field, or a critical current.
3 . The superconducting magnet apparatus according to claim 1 , wherein the superconducting coil or the structure is formed using at least two of a low-temperature superconducting material, a high-temperature superconducting material, a protective material, a matrix, and a base material having different properties of thermal conductivity or specific heat.
4 . The superconducting magnet apparatus according to claim 1 , wherein the solid heat conductor is formed of metal that is formed into a plate shape, an angular shape, a tape shape, or a sheet shape and that has high heat conductivity or metal that is formed into a form of a cylindrical pipe and in which heat conductivity is set according to a structure that makes thermal contact.
5 . The superconducting magnet apparatus according to claim 1 , further comprising: a pipe that conveys the refrigerant from the refrigerant tank to at least any one of the structure and the superconducting coil; and a heat capacity ensuring member that is attached to the solid heat conductor and that ensures heat capacity of the solid heat conductor.
6 . The superconducting magnet apparatus according to claim 5 , wherein at least one of members that are the solid heat conductor, the pipe, the heat capacity ensuring member, and a heater thermally makes contact with at least one part of a structure having small heat capacity out of the superconducting coil and the structure and at least two of parameters of size, heat conductivity, and heat load of the at least one of the members are set according to the operation temperature and the superconducting characteristics.
7 . The superconducting magnet apparatus according to claim 5 , wherein the solid heat conductor thermally makes contact with at least one part of the pipe.
8 . The superconducting magnet apparatus according to claim 1 , wherein the solid heat conductor thermally makes contact with at least one part of the superconducting coil.
9 . The superconducting magnet apparatus according to claim 5 , wherein the superconducting coil or the structure contains a high-temperature superconducting material or a low-temperature superconducting material, wherein the superconducting coil or the structure is thermally connected to any one of a low-temperature end and a high-temperature end of the freezer via at least one of the refrigerant tank, the pipe, the solid heat conductor, and the refrigerant.
10 . The superconducting magnet apparatus according to claim 5 , wherein the superconducting coil or the structure includes a first superconducting coil or a second structure containing a low-temperature superconducting material, and a second superconducting coil or a second structure containing a high-temperature superconducting material, wherein the first superconducting coil or the first structure is thermally connected to a low-temperature end of the freezer via at least one of the refrigerant tank, the pipe, the solid heat conductor, and the refrigerant, wherein the second superconducting coil or the second structure is thermally connected to a high-temperature end of the freezer via at least one of the refrigerant tank, the pipe, the solid heat conductor, and the refrigerant.
11 . The superconducting magnet apparatus according to claim 9 , wherein the freezer includes one or more freezers in each of which a setting is made such that it is possible to maintain a superconducting state against a heat load caused by a structure to be cooled, wherein the superconducting coil is thermally connected to the one or more freezers.
12 . A magnetic resonance imaging apparatus comprising the superconducting magnet apparatus according to claim 1 as a static magnetic field magnet that generates a static magnetic field in an imaging space in which a subject is placed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2024-194321, filed on Nov. 6, 2024; the entire contents of which are incorporated herein by reference. FIELD Embodiments described herein and the drawings relate generally to a superconducting magnet apparatus and a magnetic resonance imaging apparatus. BACKGROUND A magnetic resonance imaging (MRI) apparatus including a superconducting magnet apparatus as a static magnetic field magnet that generates a static magnetic field in an imaging space in which a subject is arranged has been known. In general, a superconducting magnet apparatus included in an MRI apparatus includes a cooling container that is filled with a refrigerant, such as liquid helium, a freezer that cools the refrigerant in the cooling container, and a superconducting coil that is immersed in the refrigerant in the cooling container. The superconducting coil is formed of a superconducting wire and is cooled by the refrigerant and transmits electricity in a state of having shifted to a superconducting state, thereby generating a magnetic field. In recent years, such superconducting magnet apparatuses have been required to efficiently cool a plurality of structures to be cooled while reducing the amount of a refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating an example of a configuration of an MRI apparatus according to a first embodiment; FIG. 2 is a diagram illustrating an example of a superconducting magnet apparatus according to a comparative example of the first embodiment; FIG. 3 is a diagram illustrating an example of the superconducting magnet apparatus according to the first embodiment; FIG. 4 is a diagram illustrating a modification of the superconducting magnet apparatus according to the first embodiment; FIG. 5 is a diagram illustrating an example of a superconducting magnet apparatus according to a second embodiment; FIG. 6 is a diagram illustrating an example of a superconducting magnet apparatus according to a third embodiment; FIG. 7 is a diagram illustrating an example of a superconducting magnet apparatus according to a fourth embodiment; FIG. 8 is a diagram illustrating an example of a superconducting magnet apparatus according to a fifth embodiment; FIG. 9 is a diagram illustrating an example of a superconducting magnet apparatus according to a sixth embodiment; FIG. 10 is a diagram illustrating an example of a superconducting magnet apparatus according to a seventh embodiment; FIG. 11 is a diagram illustrating an example of a superconducting magnet apparatus according to an eighth embodiment. DETAILED DESCRIPTION A superconducting magnet apparatus according to an embodiment includes a superconducting coil, a structure, a refrigerant tank, a heat exchanger, a freezer, a solid heat conductor, and a vacuum container. The superconducting coil is formed of a superconducting wire that forms a magnetic field. The structure is formed of a superconductor and is electrically connected to the superconducting coil. The refrigerant tank stores a refrigerant. The heat exchanger is exposed to the inside of the refrigerant tank. The freezer cools the refrigerant. The solid heat conductor makes direct or indirect thermal connection between the refrigerant tank and the superconducting coil and the structure. The vacuum container seals in the superconducting coil, the structure, the refrigerant tank, the heat exchanger, the freezer, and the solid heat conductor. The superconducting coil or the structure is formed using at least two structures having different operation temperatures or superconducting characteristics for superconduction. With reference to the accompanying drawings, embodiments of a superconducting magnet apparatus and an MRI apparatus according to the present application will be described in detail below. First Embodiment FIG. 1 is a diagram illustrating an example of a configuration of an MRI apparatus according to a first embodiment. For example, as illustrated in FIG. 1, an MRI apparatus 100 includes a static magnetic field magnet 1, a gradient coil 2, a gradient magnetic field power source 3, a whole body radio frequency (RF) coil 4, a local RF coil 5, a transmitter circuitry 6, a receiver circuitry 7, a RF shield 8, a gantry 9, a couch 10, an input interface 11, a display 12, a storage 13, and processing circuitries 14 to 17. The static magnetic field magnet 1 generates a static magnetic field in an imaging space in which a subject S is arranged. Specifically, the static magnetic field magnet 1 is formed into a hollow and approximately cylindrical shape (including one having a cross section that is orthogonal to a center axis and of which shape is elliptic) and generates a static magnetic field in the imaging space that is formed on an inner circumferential side of the static magnetic field magnet 1. The gradient coil 2 is arranged on an inner side of t