Conceptual Design of the JLab Hall D Replacement Solenoid

The 12 GeV upgrade at Jefferson Lab includes plans for a new solenoid that will replace the existing solenoid made with the Large Aperture Superconducting Solenoid (LASS) coils from Stanford Linear Accelerator Center (SLAC). The conceptual design for the replacement solenoid presented here includes the magnetic design, winding arrangement, conductor selection, quench detection, and protection and cooling scheme. The magnetic design implements three separate coils to provide a 3.8 T field parallel to the beam direction and addresses the fringe field requirements of the facility while integrating into the existing iron yoke. The conductor consists of Superconducting Super Collider (SSC) cable (Nb-Ti) soldered into a copper channel stabilizer. The conductor is layer wound the hard way onto individual internal mandrels. The quench protection system implements a dump resistor and switch. Results from a 3-D quench code are provided for quench initiating at different locations. The magnet is conduction cooled by natural circulation of two-phase helium through cooling tubes mounted at the Outside Diameter (OD) of the cold mass.