CERN announced all tests on the Large Hadron Collider's high-current electrical connectors were completed last week, and that the machine will start operating at half power in November this year. The LHC will initially operate at 3.5 TeV so the operators can gain experience of running the machine safely.
" We've selected 3.5 TeV to start," said CERN's Director General, Rolf Heuer, "because it allows the LHC operators to gain experience of running the machine safely while opening up a new discovery region for the experiments."
Following the incident of 19 September 2008 that brought the LHC to a standstill, testing has focused on the 10,000 high-current superconducting electrical connections like the one that led to the fault. These consist of two parts: the superconductor itself, and a copper stabilizer that carries the current in case the superconductor warms up and stops superconducting, a so-called quench. In their normal superconducting state, there is negligible electrical resistance across these connections, but in a small number of cases abnormally high resistances have been found in the superconductor. These have been repaired. However, there remain a number of cases where the resistance in the copper stabilizer connections is higher than it should be for running at full energy.