Layout and Design of the Auxiliary Bus-Bar Line for the LHC Arc Main Cryostat

The superconducting multipole magnets housed in the cold mass of the LHC arc short straight sections, together with the arc dispersion suppressor and matching section quadrupole magnets, will be electrically fed along the 3 km arcs via 600 A and 6 kA superconducting flexible cables. These will be routed into a tube running parallel to the cold masses, placed inside their cryostat [1], from power converters located at each of the 16 arc extremities. The superconducting 53.5 m cable segments will be inserted in the pipeline at machine installation time in the tunnel, thus limiting the number of useless electrical interconnections to the minimum necessary. Cryogenically connected to the 1.9 K superfluid helium vessel of the cold masses at each main quadrupole location, this so-called auxiliary bus-bar tube (EAB) will be thermally and mechanically separated from the magnet main stream. The general layout of the pipeline, its thermo mechanical functional specification and the tight cryogenic, mechanical, electrical, interface and geometrical constraints imposed by the LHC arc cryostat are presented, together with its detailed design.