Initial suspicions that a faulty electrical connection between two magnets inside the giant Large Hadron Collider (LHC) caused a helium leak that ultimately shut down the machine have proved correct.

Mechanical damage from the September 19 electrical snafu caused the magnet to release helium into the particle accelerator's 17-mile (27-kilometer) tunnel, the European Organization for Nuclear Research (CERN), which operates the LHC, said today. CERN's investigation confirms its original explanation for the leak.

"This incident was unforeseen," CERN Director General Robert Aymar said in a statement, "but I am now confident that we can make the necessary repairs, ensure that a similar incident cannot happen in the future, and move forward to achieving our research objectives."

But John Conway, a professor of physics at the University of California, Davis, says it's hard to say just how serious a problem the faulty connection is.

"The real question is whether it’s a fundamental design flaw affecting the magnet interconnects or a weak link in one," Conway tells us. "I don’t think they know the original cause of the event. If it’s a design flaw that requires a retrofit of all the magnets, that could be a big deal."

A spokesman for CERN, James Gillies, says engineers don't, in fact, know the ultimate cause of the problem, but insists there's no design flaw. All 10,000 circuit junctions inside the machine passed inspections except for the one that failed, he says. "We know it was literally a solder joint between two cables that failed," Gillies says. "Why it failed we still don’t know. We know it's not a systematic fault."

The $8-billion LHC has battled operational problems since it was turned on September 10: A transformer broke the day after physicists activated the machine, and then the leak occurred barely more than a week later, delaying experiments until next spring. In addition to investigating the malfunction, the LHC will undergo a previously scheduled winter maintenance.

LHC scientists plan to smash protons together to study conditions that preceded the origins of the universe. Read all about their work and the particle accelerator here.

(Image of LHC/CERN)