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July 31, 2009

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Big particle collider restart put off again

REPAIRS to two small helium leaks in the world's largest atom smasher will delay the restart of the giant machine another month until November, a spokesman for the operator said yesterday.

James Gillies said an additional setback to the timing could result if some other problem is found, but the European Organization for Nuclear Research is taking pains to make sure it avoids another big shutdown like the electrical failure of September 19.

"Essentially what's happening is we're proceeding with extreme caution," Gillies said. "We have to be absolutely certain that when we switch on this time, it stays switched on."

The organization, which is known as CERN, has nearly finished examining the 10,000 electrical interconnections like the one that failed last September.

Originally CERN said it expected to start test collisions in April, but that startup date has been pushed back several times already, most recently to October. "Decisions will be taken as to whether there are more that need repairing or not within the next couple of weeks," Gillies said.

If a November start holds, it will still take until December for the accelerator in a 27-kilometer circular tunnel under the Swiss-French border to start producing collisions of sub-atomic particles. Only then will physicists be able to probe deeper into the makeup of matter.

They hope the fragments that come off the collisions will show on a tiny scale what happened one-trillionth of a second after the so-called Big Bang, which many theorize was the massive explosion that formed the universe. The theory holds that the universe was rapidly cooling at that stage and matter was changing quickly.

The leaks currently being repaired were found in the system that uses liquid helium to bring the temperature inside the accelerator to near absolute zero, colder than outer space.

CERN expects repairs and additional safety systems to cost about 40 million Swiss francs (US$37 million) over the course of several years, covered by the organization's budget. The overall Large Hadron Collider project costs US$10 billion.


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