PROGRESS IN THE DESIGN OF A SUPERCONDUCTING TOROIDAL MAGNET FOR THE ATLAS DETECTOR ON LHC

The toroidal system consists of three air core superconducting toroids . The barrel toroid covers the. central region over a length of 26 m w ith an inner bore of 9.4 m and an outer diameter of 19,5 m. The two en d cap toroids are inserted in the barrel at each end over a length of 5.6 m with an inner bore of,26 m, Each toroid consists of eight flat c oils assembled around the beam axis and carrying 3 MAt each, The prese nt paper describes the barrel toroid, Features of the design which are presented include the electromagnetic design, field and forces calcul ations, the basic concept of indirectly cooled aluminium conductor and monolithic fully impregnated winding, the description of the alu-allo y mechanical structure, the thermal analysis and the quench protection , Cryogenics principles, cryostat and toroid assembly procedures are s ummarized, Unsymmetric loadings, fault sensing and stability are discu ssed, in relation with the requirements of transparency.