A Superconducting Horizontal Bend Magnet for JLab´s 12 Gev/c Super High Momentum Spectrometer

Collaboration exists between NSCL and JLab to developing the reference design of JLab\´s super high momentum spectrometer (SHMS) horizontal bend magnet. A Superconducting "C"type, superferric dipole magnet that allows the SHMS to reach small forward angles without restricting the SHMS\´s acceptance, degree of motion or range of particle energy is presented. Spatial requirements for the coexistence of the SHMS at forward angles of -5.5deg along with the existing high momentum spectrometer (HMS) at 12deg to the primary beam line give rise to close tolerances on design parameters. The bending of 12 Gev/c particles by 3deg requires an integral field strength up to 2.1 T.m. The current design is "warm-iron" with a nominal yoke length of 600 mm and a minimum pole gap of 350 mm. Choice of superconducting conductor, between surplus re-flattened SSC NbTi Rutherford cable that provides plenty of current margin and cost savings and Nb₃Sn cable, noted for its temperature margin will be highlighted. Coil forces, coil restraint system, energy margins, hot spot and final temperatures, beam radiated heating and superconducting stability will also be presented.