The LHC magnet interconnections on their home stretch
The work on the interconnections between the magnets in the last remaining octant of the LHC has started two weeks early with respect to the LHC master schedule.
The welders are on their final leg of the LHC marathon. The first brazing of the last octant to be interconnected (between Points 1 and 2) was performed on 4 April.
The 1700 LHC magnets will be interconnected by September 2007. By then, 123,000 connections will have been performed in only two years. 'The early start of the last stretch of magnet interconnections should allow us to compensate for a time slot in the present LHC master schedule smaller than what was previously needed for the interconnections in the other octants,' says Lucio Rossi, Head of the AT Department's Magnets, Cryostats and Superconductors group.
The task of connecting up all the machine components has been a very challenging one. Vacuum systems, superconducting cables, beam screens, cryogenic pipes and thermal and electrical insulations all have to be interconnected, with each individual interconnection requiring about sixty operations. 'By interconnecting the magnets we turn them into a real machine' says Lucio Rossi. 'We introduced new techniques that were not yet standard in industry, including new welding methods for superconducting wires.' The interconnection techniques were developed at CERN and tested using prototype machines on the LHC test string. They were then sent out for tender and technology transfer. For all the teams responsible for the interconnections, the great challenge is to work in parallel with other ongoing activities.
An impressive learning curve can be observed. After the first interconnection performed on 3 May 2005, it took more than one year for the first octant to be finished. The interconnections of the last remaining octant are expected to be finalized within less than 24 weeks. CERN is working in collaboration with the Krakòv Institute of Nuclear Physics (HNINP) and the Franco-Dutch consortium IEG that took responsibility for the interconnection work and for supplying the welding and brazing machines. During this final phase in magnet interconnections, about 200 engineers and technicians, half from CERN and half from the contractor, are working in the LHC tunnel under rather difficult conditions.
