CERN says atom smasher back in action in spring

[October 18, 2008]  GENEVA (AP) -- Damage to the world's largest atom smasher caused by a bad electrical connection will take much of the planned winter shutdown to repair, but it will be back in action as planned next spring, a spokesman for the operator said Friday.

The massive electromagnets deep underground appear to have escaped damage, said spokesman James Gillies of CERN, the European Organization for Nuclear Research.

But damage to insulation and other parts around 29 of the magnets will likely require that they be brought to the surface for repair, Gillies told The Associated Press.

The failure of a single electrical connection in the Large Hadron Collider caused the equipment to shut down just nine days after the machine's launch with great fanfare Sept. 10.

CERN scientists had already determined that one connection out of 10,000 was badly soldered, causing electrical resistance that led to the fault, but it has taken until now for the supercooled equipment to warm up enough so that experts could examine it and decide what needed to be fixed.

It had already been decided that it was impossible to get the machine up and running again before the annual maintenance time starts in November to save expenses when electricity costs are high.

It takes a month to warm the collider gradually to room temperature from its operating temperature at near absolute zero, colder than outer space. Once the repairs are made, it will take another month to recool it.

The collider uses superconductivity - the ability of some metals to conduct electricity without any resistance in the extreme cold - to operate the electromagnets, which guide the beams of protons until the particles collide with each other.

The shattering of the protons in the collisions helps scientists to understand better how they are made and how they make up everything and everyone in the universe.

The failure was caused by an electrical arc that punctured an enclosure holding the liquid helium used to keep the collider cold, said a CERN statement. Some six tons of helium leaked out as a result, three times as much as originally thought.

The remaining 114 tons of liquid helium in the collider was unaffected by the leak, said Gillies.

He said CERN has enough spares to make any needed replacements of the equipment, but that the repairs will take the whole winter.

"We'll be pretty busy," Gillies said.

He said the costs of the repairs had yet to be determined, but that CERN would be able to cover them out of its budget and that it wouldn't have go to the 20 European member countries to ask for more funds.

The examination also found that the fault sent a "soot-like dust" into the firehose size pipes through which the beams of protons are guided at nearly the speed of light.

The pipes, which are supposed to be completely empty with an extreme vacuum inside so that nothing will obstruct the proton beams, will have to be cleaned, but technicians think they can do that in place inside the 27-kilometer (17-mile) circular tunnel under the French-Swiss border.

Plans are now to put proton beams back into the collider by May or June, he said.

Gillies said technicians have been taking steps to make sure such a problem doesn't develop again.

One thing they have been doing is examining their computer records to see if there were any signs of trouble that would have warned that a problem was developing, he said.

It appears that minuscule fluctuations in the temperature of the helium may have provided a signal. If that is determined to be the case, computer software can be designed to detect such changes in the future and shut down the machine before it is damaged, Gillies said.

He was asked what would happen if the CERN had a similar problem next summer that would shut down the system for another six months.

"What we've got to do is make sure we don't get another one like this," Gillies said.

CERN Director-General Robert Aymar issued a statement that he was "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."

The US$10 billion collider was started before a global audience on Sept. 10, with beams of protons being fired around the circuit, first in one direction and then in the other.

[Associated Press; By ALEXANDER G. HIGGINS]

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