Electromagnetic analyses of the GEM detector magnet system for SSC

The magnet system for the Superconducting Super Collider (SSC) Gamma, Electrons and Muons (GEM) detector consists of a single layer, superconducting, split solenoid and two iron forward field shapers (FFS). In addition, major structura components, such as the central detector and FFS support structures and the vacuum vessels, are to be built with magnetic steel. This paper presents the nonlinear, two and three-dimensional electromagnetic analyses which are performed in support of the overall design effort. A detailed axisymmetric, finite element ANSYS model is used to determine the magnetic field distribution in the region of the detector, and the electromagnetic forces acting on the coi and various magnetic steel elements. A 3-D model is developed to capture the magnetic field perturbations produced by asymmetric, magnetic structural elements. The model produces 3-D field maps of the detector volume to evaluate the effects of these asymmetries on the detector resolution. Another 3-D model is used to determine the distribution of magnetic steel plates required to shield the nearby Electronic Rack Room from the coil's fringe field.