The world's largest particle collider outside the Swiss city of Geneva will not restart until spring next year after a weekend technical glitch.
The European Organization for Nuclear Research (Cern) said it would take too long to finish announced repairs before the regular winter shutdown and it could not carry out regular maintenance work.
Cern described the delay as a psychological blow.
A helium leak into the tunnel housing the huge machine forced scientists to shut down the Large Hadron Collider (LHC) just ten days after starting it up.
Experts said the most likely cause of the leak was a faulty electrical connection between two of the accelerator's giant magnets.
The collider, situated in a tunnel under the French-Swiss border, was built to stimulate the conditions of the Big Bang, the explosion generally believed to be at the origin of our universe.
Opponents of the experiment say it could result in black holes that suck up the Earth.
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