The early warning system appears to have paid off: Earlier this month engineers identified two other suspect connections before the glitches could cause problems.
Gillies says he wouldn't go so far as to call last fall's malfunction a blessing in disguise, but, he said, it "has taught us how to monitor for similar problems."
Total repair costs will be about 26 to 34 million U.S. dollars, which is "within the CERN budget," Gillies added.
Pushing the Limits
The electrical problems at the LHC are to be expected given its size and complexity, said Tor Raubenheimer, head of accelerator research at the SLAC National Accelerator Laboratory at Stanford University.
"To continue advancing the scientific frontiers of high energy particle physics, each new accelerator pushes the technical limits beyond the existing state-of-the-art, and most have encountered technical difficulties while starting up," Raubenheimer said.
Mike Harrison is the American regional director for the proposed International Linear Collider and a high-energy physicist at Brookhaven National Laboratories in Upton, New York, which operates the Relativistic Heavy Ion Collider (RHIC).
"The fact that they found another couple [faulty joints] does not surprise me," Harrison said. "You expect a very small number of these things."
The RHIC contains about 6,000 splice joints, and two had to be re-soldered when the accelerator first began operations, Harrison said.
The LHC, the largest collider yet built, contains more than 20,000 splice joints. (See photos of the LHC inside.)
Fixing the faulty joints is a relatively simple process that involves heating and removing the old solder and then remaking the connection from scratch, Harrison said.
The fix usually takes less than a day, but it requires heating the machine to room temperature, opening the joint, and then cooling it back down to -456.3 degrees Fahrenheit (-271.3 degrees Celsius)—a process than can take months.
Fortunately, Harrison said, once a bad joint has been fixed, it rarely fails afterward.
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