Cern has issued its final report (PDF) on the failure of the Large Hadron Collider (LHC), and has said that the device cannot be restarted before June 2009.

The LHC had barely begun operating when a connection between two huge magnets burnt out. This caused a ton of liquid helium to be released, damaging 53 of the magnets which are used to direct the proton stream around the 27km instrument.

"We have a lot of work to do over the coming months, but we now have the roadmap, the time and the competence necessary to be ready for physics by summer," said LHC project leader Lyn Evans.

"We are currently in a scheduled annual shutdown until May, so we are hopeful that not too much time will be lost."

To prevent the same problem happening again, the LHC is to be upgraded with an early warning system for gas leaks. This will mean the installation of 100 miles of cabling and 2,000 electronic sensors at a cost of around $25m (£16m).

"The top priority for Cern today is to provide collision data for the experiments as soon as is reasonably possible," said Cern director-general Robert Aymar. "This will be in the summer of 2009."