Production and qualification of the 60-kA, aluminum-stabilized conductor for the ATLAS B0 coil

For the toroidal ATLAS magnet system, some 90 km of aluminum stabilized conductor are required. The conductor is a Rutherford cable, coextruded with very pure aluminum. The main characteristics of the conductor are: (1) a very large critical current, 60 kA at 5 T and 4.2 K; (2) RRR of the stabilizing aluminum of at least 1000 on the finished conductor; (3) a good bonding between the Rutherford cable and the stabilizer: a shear stress of 20 MPa is required; and (4) 1750 m of unit length. To assure a good quality of the conductor all along the production and to minimize the risk of rejection of such expensive units, a strict quality assurance was established. The paper describes the results of the R&D phase to set all parameters to produce the first two unit lengths necessary for the winding of the B0 coil (a 9 m long model coil of the ATLAS Barrel Toroid). It also describes the control system based on continuous ultrasonic inspection, able to provide images of the cable inside the aluminum that is used to evaluate on line the quality of aluminum to cable bonding.