Speaker
Description
The Electron-Ion Collider (EIC) requires eight solenoid magnets to polarize the spin of the electron beam. These magnets, called SPIN ROTATORS, are categorized as four LONG (6.2 m) and four SHORT (2.5 m). They operate at a peak magnetic field of about 8.5 T with a 100 mm bore diameter. The integrated magnetic field along the axis is the figure of merit for these magnets, being respectively 46.75 Tm for the LONGs and 15.3 Tm for the SHORTs.
This study focuses on multi-physics simulations for magnetism, mechanics, conductor design, and quench protection to optimize these solenoids respect to the required figure of merit. We investigated NbTi and Nb3Sn conductor based solutions for both the SHORT and LONG magnets. A multi-physics optimization platform employing metaheuristic algorithms was utilized to meet the EIC’s requirements. Both solenoids underwent the same optimization routine with tailored target values to address their specifications. The study also aims at finding a design solution that would allow to use the same conductor and to operate at the same temperature for both LONG and SHORT solenoids. The optimization process begins by defining geometrical parameters as well as ranges and conductor characteristics. Then 2D axisymmetric magnetic simulations using Opera are performed to calculate the figure of merit, field values, and inductances. Subsequently, margins based on superconductor quantity, operating point, and several conductor designs are computed. Mechanical studies utilizing homogenized properties based on conductor composition are performed to extract stress values. Finally, adiabatic stability and quench studies compute enthalpy margin and hotspot temperature. Designs are then ranked based on their target values and the optimization process converges towards suitable magnets.
This systematic approach enabled us to identify diverse optimal designs for the EIC’s demanding requirements. The multi-physics simulations and metaheuristic optimization strategy presented here have successfully facilitated the design of efficient and reliable solenoids for electron spin polarization at the EIC.
