LHC restart date now June at earliest

The world's most powerful particle accelerator will go live again in June at the earliest, following the fault that shut it down in September.

The European Organization for Nuclear Research (Cern), which runs the Large Hadron Collider (LHC), previously suggested the apparatus would be restarted in April. On Monday, however, it emerged that June would be the earliest possible date for operations to resume fully. It also became apparent that the cost of the repairs alone could be as high as £11m.

The LHC is housed in a 27km-long circular tunnel nestled beneath the Swiss-French border in the Alps. It is designed to shoot streams of particles around the tunnel in opposing directions, smashing them into each other and thereby hopefully discovering more about the origin and nature of matter and the universe.

The particle beams are held on their paths by dipole magnets and focused by quadrupole magnets. These magnets are made of a superconducting material that needs to be cooled by liquid helium to a temperature of 1.9K if it is to avoid overheating and exploding. The LHC was successfully turned on in September but, little more than a week later, an electrical fault caused a helium leak that necessitated the complete shutdown of the machine.

This week, details began to emerge about the cost of the necessary repairs and the likely resumption date for the LHC. Repair time aside, the process will also be slowed down by the fact that the LHC needs to be out of service throughout winter; as it uses roughly the same amount of electricity as all the cantons of Geneva put together, Cern cannot risk power issues at a time when citizens' homes need heating.

"We already said the bare minimum [repair time] included two months to warm up the sector [from its cryogenic state]," a Cern spokesperson told ZDNet UK on Tuesday. "It became clear that there was no way of doing that before we shut down the accelerator complex for winter anyway, so that puts the earliest possible date [for the re-freezing of the LHC to start] in May. When we start up our accelerator complex, getting it up and running again takes a few weeks, so that takes you into June."

Cern's spokesperson said the fault and resulting shutdown had been educational, as "markers" had been identified that show when such an incident is likely to occur. "Those markers would have allowed us to stop [the LHC before the helium leak], had we known where to look," the spokesperson said.

"We're building in additional monitoring and protection systems to make sure this kind of incident won't happen again, and this will take time," Cern's spokesperson added.

Cern's scientists are currently working on a detailed costing and timetable for the necessary repairs and subsequent re-initiation of the LHC, and will present that timetable to the organisation's governing body next month.

"We expect that the repairs and the [installation of additional monitoring systems] will cost us between 10m [£5.6m] and 20m Swiss francs," Cern's spokesperson said. However, because the repairs will eat into Cern's supply of spare parts for the LHC, a second phase of the resumption operation will involve buying more spares, thereby raising the total costs further. "We do have 20 years of running the machine ahead of us," they said.

Cern's spokesperson said that the costs for repairing the LHC and buying new spares would be "accommodated within Cern's annual budget", and the organisation would not be requesting additional funds from European member states for those purposes.