CBM Dipole Magnet

Superconducting dipole magnet for the Compressed Baryonic Matter (CBM) experiment at FAIR. The magnet houses the Silicon Tracking System (STS) and provides a magnetic field integral of 1 Tm which is needed to obtain a momentum resolution of ?p/p < 2% for track reconstruction at FAIR beam energies. The magnet gap has a height of 147 cm and a width of 330 cm in order to accommodate the STS detector. The magnet is of the H-type with a warm iron yoke/pole and cylindrical superconducting coils in two separate casings like the SAMURAI magnet at RIKEN. The potted coil uses Nb-Ti wire with a large Cu/SC ratio. The coil case made of stainless steel contains liquid helium for cooling. The vertical force in the coils is about 300 tons. The cold mass is suspended from the room-temperature vacuum vessel by suspension links. Cylindrical support struts compensate for the vertical forces. The energy stored in the magnet is about 5 MJ. The magnet will be self-protecting. However, in order to limit the temperature rise to 120 K in case of a quench, the energy will be dumped in an external resistor.