Current lead
AssigneeKabushiki Kaisha Toshiba
InventorsTakashi Yazawa, Satoshi Yasuda
Life of this patent
Estimating the term…
Abstract
A superconducting magnet is arranged in a helium tank, and the superconducting magnet cooled to a very low temperature by liquid helium in the helium tank is connected to a power source kept at room temperature by a current lead and a current lead. The current leads are constituted by conductors made of copper or a copper alloy having a residual resistivity of 5.times.10.sup.-8 .OMEGA..multidot.m or more. In a helium tank, a persistent current switch, cooled by liquid helium, for connecting the conductor to the conductor, is arranged. The persistent current switch magnetizes the superconducting magnet to a persistent current mode and demagnetizes it from the persistent current mode. The helium tank is arranged in a vacuum housing.
Claims11
A current lead for electrically connecting a superconducting magnet of a permanent current mode to a power supply, with the superconducting magnet cooled to an operating temperature of the superconducting magnet and the power supply kept at room temperature, comprising:
- a conductor having a residual resistivity .rho..sub.0 of not less than 5.times.10.sup.-9 .OMEGA.m, said conductor consisting essentially of pure copper and at least one of another metal and an impurity element, the amount of the at least one of said another metal and the impurity element being controlled to provide said conductor having said residual resistivity of not less than 5.times.10.sup.-9 .OMEGA.m;
- a liquid nitrogen anchor portion which is formed in a part of said current lead and in which said conductor is cooled by liquid nitrogen;
- a gas circulating tube which is formed to surround said conductor and in which helium vapor for cooling said conductor is circulated;
- and
- a bypass tube, arranged at a position corresponding to said liquid nitrogen anchor portion to be separated from said conductor and connected to said gas circulating tube, for bypassing said helium vapor.
A current lead for electrically connecting a superconducting device cooled to a low temperature to a power supply kept at room temperature, said current lead being cooled by a vapor obtained by evaporating liquid helium for cooling a superconducting device, comprising:
- a conductor in which a current flows;
- a gas circulating tube which is arranged to surround said conductor and in which cooling helium vapor is circulated;
- a liquid nitrogen anchor portion which is formed at a portion of said current lead and in which said conductor is cooled by liquid nitrogen;
- and
- a bypass tube which is arranged at a position corresponding to said liquid nitrogen anchor portion to be separated from said conductor and which is connected to said gas circulating tube to bypass said helium vapor.
Dependencies are inferred from the claim text.