Design of the Optional Forward Superconducting Dipole Magnet for the FCC-hh Detector

A 4-T, 10-m free bore and 20-m long central solenoid is proposed as the main magnet in the baseline detector for the future circular collider (FCC) hadron-hadron collisions physics program. Besides the 4-T axial magnetic field around the interaction point in the center of the main solenoid, additionally, magnetic field is required in the forward directions. This provides sufficient bending power for particles traveling at small angles from the beam axis as well. Using forward solenoids is the baseline. Here, we present the option of using forward dipole magnets. A previously published design foresaw cone-shaped dipole magnets as well as force and torque balanced. This design, however, evolved to a more practical design, where the cryostat occupies the same space as in the baseline with forward solenoids, meaning that the vacuum vessel dimensions in solenoid and dipole designs are the same.