Design and Engineering of an HTS Dipole in the FRIB Fragment Separator

Abstract

One of the challenges in the Facility for Rare Isotope Beams at Michigan State University is the 30 degree bending dipoles in the fragment separator operating in a high radiation environment. It is known that high temperature superconductors (HTS) have a much larger thermal margin due to high critical temperature > 90 K and high upper critical field > 100 T, which allows HTS magnets to operate stably so as to tolerate very high heat loads due to radiation. The HTS dipole magnets will utilize ReBCO conductor technology and operate at 38 K cooled by helium gas. High radiation deposits a large amount of heat into the iron yoke, cryostat, bobbin and HTS coil itself. For certain beams, over-bent particles will hit the cryostat with high intensity in the beam down-stream. Another difficulty is that the dipole coils generate significant Lorentz forces that need to be contained. All of these challenges have been analyzed separately and then integrated to find novel approaches. These approaches have been applied to optimize the magnet structure and enhance the 38 K helium gas cooling system. We present project status and progress of this HTS ReBCO dipole magnets and lay out a plan for magnet manufacturing.