LHC operations after a transformer malfunction in its cooling system allowed a helium leak -- just nine days after . An investigation concluded that the malfunction was caused by a faulty electrical connection between two of the accelerator's magnets.
As a result, the 53 magnets used to accelerate sub-atomic particles around the machine's 17-mile underground tunnel had to be cleaned or repaired. At the time, the repair costs for the $5 billion LHC were expected to top $16 million.
The European Organization for Nuclear Research, or CERN, the organization that built the LHC, announced Monday that it expects the first beams to begin in September, with the first collisions expected by late October.
The delay is the latest in a string of restart dates CERN has announced. CERN had originally expected to have the LHC back online at the beginning of April, following CERN's annual maintenance period. But that target was revised last November to June. Later that month, CERN's head of communications, James Gillies, told ZDNet UK that the new plan was to restart the LHC in late summer.
"The schedule we have now is without a doubt the best for the LHC and for the physicists waiting for data," CERN Director General Rolf Heuer said in a statement. "It is cautious, ensuring that all the necessary work is done on the LHC before we start-up, yet it allows physics research to begin this year."
The LHC, located along the French-Swiss border, is designed to smash beams of protons into each other, test fundamental physics theories, and help understand the nature of matter.
By Steven Musil