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Collider Problems No Surprise To Scientists

Posted on: Monday, 29 September 2008, 08:25 CDT

Scientists say they were more surprised by the overwhelming success of the world's largest atom smasher on its opening day than by the troubles it later developed.

A magnet connection problem will delay the start of experiments for half a year, due to a needed repair to the $3.8 billion accelerator.

Physicists who waited two decades to use the new equipment will now have to wait three more weeks for the damaged section to be warmed up to room temperature.

Yet such glitches are not uncommon according to Michael Harrison, who worked on Fermilab's Tevatron collider and designed and built the United States' other superconducting collider at Brookhaven on Long Island.

He said both machines had similar startup problems.

"You find all kinds of little issues as you start to turn it on and make it work," Harrison said.

Rival operations in the United States watched in awe as CERN launched its new Large Hadron Collider before the world's media. It marked the first time such a startup was made public.

"A huge cheer went up from here," said Judy Jackson, spokeswoman for the Fermi National Accelerator Laboratory outside Chicago, whose Tevatron is losing its title of world's highest-energy collider with the startup of CERN's.

Scientists almost expected the meltdown of a connection between superconducting magnets nine days later at CERN.

It knocked out use of the machine for two months, costing the scientists valuable time to get the machine ready for use on experiments next spring after the usual four-month winter shutdown.

"It's what happens when you start up a big, superconducting machine," said Jackson. "Our impression is that what happened last Friday at CERN caught them more by surprise than it did us."

CERN specialists found a connector between electromagnets failed and heated up, causing a magnet "quench," or shutdown. It melted a hole in the tube, causing a leak that spilled about a ton of liquid helium.

The collider has well-tested systems to protect against quenches in all 9,600 magnets, and they worked, said CERN spokesman James Gillies.  He said the damaged magnets would have to be repaired.

By colliding protons from the nucleus of hydrogen atoms at high energy, the CERN machine aims to recreate, on a minuscule scale, a view of what matter looked like in the rapid cooling one-trillionth of a second after the Big Bang explosion.

For decades now, physicists have used smaller, room-temperature colliders to study the atom.

They once thought protons and neutrons were the smallest components of the atom's nucleus, but the colliders showed that they are made of quarks and gluons and that there are other forces and particles. And they still have other questions about antimatter, dark matter and particle mass they hope they can answer with CERN's new collider.

Brookhaven also had problems with connections between magnets that caused a quench.

"The thing about the LHC was it has not just caused a quench, but there are systems that are supposed to prevent it from melting and dumping helium," Harrison said. "So it was obviously something else that went on as well."

CERN has been getting encouragement from rivals, who stressed startup problems are common.

Jackson said there have been major strides in the making of magnets. She said Fermilab had lots of problems with exploding magnets when it was commissioning its first, room-temperature accelerator four decades ago.

The leading scientist in charge paraphrased Alfred Tennyson's 1854 poem "The Charge of the Light Brigade": "Magnets to the left of us, magnets to the right of us, magnets in front of us volley'd and thunder'd."

"They were blowing up all the time," said Jackson.

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On the Net:

• Large Hadron Collider (CERN)
• US/LHC

Source: redOrbit Staff & Wire Reports

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