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Large Hadron Collider Restart Delayed Until September

Ker Than
for National Geographic News
February 10, 2009
 
The Large Hadron Collider (LHC) won't be restarted until late 2009 because repairs to an electrical glitch that occurred last fall are taking longer than expected.

The European Organization for Nuclear Research (CERN), which operates the machine, had initially said the soonest the LHC could resume operations was the spring of 2009. That deadline was later revised to July 2009.

Yesterday CERN confirmed that the first beams of particles will be sent at the end of September, followed by the first collisions in late October.

After a brief winter shutdown, the LHC will start running its planned experiments next year, generating data until the fall of 2010.

CERN officials cite upgrades to safety protocols and issues scheduling helium transport for the extra delay.

Meanwhile, inspections have turned up two more faulty electrical connections like the one that caused last year's accident, although those repairs are not a factor in the delay, said CERN spokesperson James Gillies.

"We can do these repairs in the shadow of other ongoing work," Gillies said.

Poor Soldering

LHC operators successfully fired the first beam of particles around the collider's 17-mile (27-kilometer) circular track last September.

But shortly afterward, poor soldering work on a so-called splice joint linking two of the LHC's magnets created an electrical overload.

The glitch caused tons of supercooled helium to leak into the underground tunnel and damage sensitive equipment.

Since the meltdown, engineers have developed new diagnostic techniques to prevent similar disasters from occurring.

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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