Refrigerator cooling-type superconducting magnet

Abstract

Magnetic field attenuation in a persistent current mode operation is prevented, heat generation at a connecting part between the persistent current switch and the superconducting coil, and increase in a cooling temperature of the superconducting coil in a current supplying mode is suppressed to a minimum. The refrigerator cooling-type superconducting magnet J according to the present invention including a superconducting coil (2), a persistent current switch (1) for switch between a persistent current mode and a current supplying mode; a superconducting coil (2), first and second cryogenic refrigerators (3, 4) for respectively cooing the superconducting coil (2) and the persistent current switch (1); a vacuum vessel (10) for housing the super conducting coil (2), the persistent current switch (1), and cooling stages (31, 32, 41, 42) of the first and second cryogenic refrigerators (3, 4), the magnet includes a superconducting wire (5) for connecting the superconducting coil (2) to the persistent current switch (1) and a superconducting bypass line (6) electrically connected in parallel to the superconducting wire along a longitudinal direction, wherein a superconducting critical temperature of the superconducting bypass line (6) is higher than a superconducting critical temperature of the persistent current switch (5).

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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