Hobbled LHC shuttered for repairs; 'No big deal' say scientists

Physicists are brushing off problems that led them to shut down the world's largest particle collider for repairs and temporarily halt an $8 billion search for the origins of the universe.

The European Organization for Nuclear Research (CERN) says that it will take at least two months to fix a "large helium leak" into the Large Hadron Collider's 17-mile tunnel. The likely cause of the drip: a faulty electrical connection between two magnets that are supposed to guide the protons in planned particle-collision experiments.

The mishap occurred Friday, a day after CERN admitted that a transformer had broken just hours after the LHC's Sept. 10 launch. The transformer malfunction caused the tunnel to heat up from minus 455.8 degrees Fahrenheit (2 degrees on the Kelvin scale) to minus 451.57 degrees Fahrenheit (4.5 degrees Kelvin). Once scientists replaced the transformer, the cryogenic fluids that keep the tunnel cold brought temperatures down to around minus 459.4 degrees Fahrenheit (zero degrees Kelvin), the optimal temperature for particle collisions, within a week. 

CERN said on Friday that "The LHC is on course for [its] first collisions in a matter of weeks"; just a day later it announced the minimum two-month repair job.

The snafus are "no big deal," theoretical physicist Sean Carroll tells us. The LHC will probe how the universe formed by recreating the conditions following the Big Bang. (Colliding protons at nearly the speed of light may create forms of matter scientists haven’t seen before, a step towards understanding conditions that preceded the universe.)

"When you turn on the world's largest machine there will be glitches, and this is a glitch," says Carroll, of Cal Tech. "The people at the LHC have been very prudent about not pushing faster than they're ready to go, so I have no doubts that they'll fix it. You always want the results sooner rather than later, but we've been waiting literally decades and a two-month delay will not change anything important. I can't imagine this will change anyone's mind about what matters, which are the physics results that will come out of the LHC."

Still, scientists don't want us to mark the days on our calendars before the LHC starts up again. If repairs take longer than two months, "We don’t want people to look at that as type of failure," says Judy Jackson of Fermilab, home to Tevatron, the world's first superconducting collider. (Fermilab scientists are participating in LHC experiments.) The time it takes to warm up the tunnel to temperatures suitable for humans and then back down to zero Kelvin is "a tricky process," she says.

Nor should doomsday predictors take the shutdown as a sign that the LHC will destroy the world, she says.

"Does the fact they had a setback mean they don’t know what they're doing and the LHC will end the universe?" Jackson says. "No. It's impossible that's going to happen. That there's a technical hiccup, even if fairly serious, has no bearing on safety of the machine, the safety of the universe or the people working there.

"It's disappointing, I'm sure, when things happen," he adds, "but there's just one way forward and that's what CERN is doing."

For more on the LHC, see our in-depth report.


(Image of worker inside LHC tunnel by CERN)



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