Refrigerator cooling-type superconducting magnet

Abstract

The attenuation of a magnetic field during a permanent current mode operation is prevented, the generation of heat at a coupling portion between a permanent current switch and a superconducting coil is suppressed, and the increase of a superconducting coil cooling temperature in a current supply mode is minimized. A refrigerator cooling-type superconducting magnet (J) is comprised of a superconducting coil (2); a permanent current switch (1) which switches from a permanent current mode to a current supply mode; first and second extremely-low temperature refrigerators (3, 4) which cool the superconducting coil (2) and the permanent current switch (1), respectively; and a vacuum container (10) which stores cooling stages (31, 32, 41, 42) for the superconducting coil (2), the permanent current switch (1), and the first and second extremely-low temperature refrigerators (3, 4). The refrigerator cooling-type superconducting magnet (J) is comprised of a superconducting wire (5) for couplingthe superconducting coil (2) to the permanent current switch (1), and a superconducting bypass wire (6) electrically connected in parallel to the superconducting wire (5) in the longitudinal direction. The superconducting critical temperature of the superconducting bypass wire (6) is higher than the superconducting critical temperature of the permanent current switch (1).

Description

technical field [0001] The present invention relates to a refrigerator-cooled superconducting magnet used in a state cooled by a refrigerator to a superconducting critical temperature or lower. Background technique [0002] In recent years, the use of analysis devices utilizing a strong magnetic field environment has become widespread. For example, in the medical field, there is a magnetic resonance imaging method (Magnetic Resonance Imaging: MRI) that uses electromagnetic waves generated when the nucleus of a hydrogen atom undergoes magnetic resonance to reflect the state of the body. There are already commercially available magnetic field strengths exceeding 3 Tesla. products capable of high-resolution and high-speed inspection. In addition, among the spectroscopic systems using nuclear magnetic resonance (Nuclear Magnetic Resonance: NMR) in relation to biology, a strong magnetic field NMR system exceeding the hydrogen atomic resonance frequency of 1 GHz is being develope...

AI Technical Summary

Problems solved by technology

[0018] In the current supply mode, the cooling body is directly connected from the continuous current switch heated above the superconducting critical temperature to the superconducting coil cooled below the superconducting critical temperature, so the cooling body conducts from the continuous current switch to the superconducting coil There is a big problem with heat conduction maintaining the superconducting state of superconducting coils

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