Electrical joints between superconducting coil modules in the GEM Detector magnet

The GEM Detector magnet at the Superconducting Super Collider is built in two halves each of which is comprised of 12 single layer superconducting coil modules wound on a 19 m mean diameter and joined with a low resistance lap joint employing the superconducting strands and a copper stabilizer. Each joint half is attached to the sheathed, cable-in-conduit conductor end, and assembly of the mating halves is completed in the field. The target resistance per joint is 5 X [10.sup.-10] [Omega] at an operating current of 50 kA. Details of the joint design, its cooling and results of tests on prototypical sub- and full-scale models using superconducting strands are presented.