Rutherford-in-Copper-Channel Conductor for the MARCO Solenoidal Detector Magnet

MARCO will be a superconducting solenoid for a new particle physics detector of the upcoming electron ion collider at Brookhaven National Laboratory (NY, USA). The design field at the interaction point is 2.0 T with a nominal current of about 4 kA at 4.5 K. For this magnet, an aluminum-stabilized conductor was considered at the very preliminary design phase. After that, due to the lack of manufacturers able to deal with aluminum extrusion, copper has been chosen as a stabilizer. Thanks to a dedicated design effort, the copper stabilizer and accompanying material choices provided acceptable hadronic interaction length. The conductor is based on an NbTi Rutherford cable that is soldered in a U-shaped copper profile. This article goes through the definition of the conductor cross section according to the project requirements and the supplier capabilities. Its characteristics will be detailed and discussed, in particular the RRR and the yield strength of the copper channel needed for protection and mechanics, respectively. Finally, a proposal on how to make the joint between two conductors is presented.