Abstract: A lead assembly provides an electrical connection between a magnet coil maintained at low temperature in a boiling liquid bath within a closed container and a power supply terminal maintained at a higher temperature outside of the container. The assembly includes a length of cable which is superconducting at the low temperature and normally conducting at higher temperatures and is disposed within a tube which communicates with the interior of the container so as to vent vapor from the boiling liquid bath out of the container through the tube along the cable to cool the cable to superconducting temperature near the magnet coil. The cable is preferably formed of a plurality of loosely twisted copper-stabilized superconducting strands.

Abstract: A switch comprises a length of superconductive wire having a plurality of normally conductive stabilizing segments thereon.

Abstract: A method and apparatus are provided for protecting a superconducting magnetic energy storage system having a coil from damage caused by a change of state of at least a portion of the coil from superconducting to normal conducting, and the consequent conversion of stored electrical energy to heat. A thermal capacitance is placed in thermal contact with the coil. The thermal capacitance is formed of a substance, such as nitrogen, which is solid at operating pressure at a temperature substantially above the transition temperature of the coil and that vaporizes below the temperature at which the system is damaged. The volume of the substance is sufficient to provide thermal capacity upon vaporization of the substance to dissipate substantially all of the stored energy without permitting the system to overheat.

Abstract: Methods and apparatus are provided for minimizing heat introduced by electrical leads into the cryogenic liquid in which a superconducting magnet is immersed. The electrical leads have normal portions extending from exterior of the cryogenic liquid containment vessel and thereinto and superconducting portions extending vertically downward therefrom and connected to the magnet. Means are provided to lower and raise the level of cryogenic liquid around the superconducting portions of the leads to fully immerse the supercoducting portions during periods of magnet energization and expose selected segments thereof when the magnet is de-energized. When exposed, the non-immersed segments provide a thermal resistance between the normal metal portions and the cryogenic liquid.

Abstract: A dipole electromagnet of especial use for bending beams in particle accelerators is wound to have high uniformity of magnetic field across a cross section and to decrease evenly to zero as the ends of the electromagnet are approached by disposing the superconducting filaments of the coil in the crescent-shaped nonoverlapping portions of two intersecting circles. Uniform decrease at the ends is achieved by causing the circles to overlap increasingly in the direction of the ends of the coil until the overlap is complete and the coil is terminated.