GENEVA – A bad electrical connection likely caused the malfunction that has sidelined the world's largest atom smasher days after it was launched with great fanfare, a senior scientist said yesterday.
The fault was probably a poor soldering job on one of the particle collider's 10,000 connections, said Lyn Evans, project leader of the Large Hadron Collider at CERN, the European Nuclear Research Organization.
Only one fault in 10,000 isn't bad, “but it cost dearly,” Evans said. It will take at least two months for the repair, meaning the collider cannot be restarted until spring, after its mandatory shutdown due to high electricity costs during the winter.
Evans said he still hasn't been able to examine the damage because the collider is too cold to be opened. The machine operates at extremely cold temperatures to take advantage of superconductivity – the ability of some metals to conduct electricity without any resistance near absolute zero degrees.
It has to be warmed gradually to room temperature over five weeks so that humans can work inside and make repairs, Evans said. Then it will take another five weeks to rechill it.
The collider was started before a global audience Sept. 10, with beams of protons being fired at nearly the speed of light around the collider, first in one direction and then in the other. The electrical fault occurred nine days later.
Before the failure, the plan had been to step up power on the collider so that scientists could start with test collisions of subatomic particles before the winter shutdown. That will have to wait until next April, Evans said.
He said he expected it will then take about a month – until the end of May – to get the machine to high energy.
“It was a hard blow for us,” he said. The failure occurred during the final test of the collider – a large tube running around the circumference of a 17-mile circular tunnel under the Swiss-French border at Geneva. All the other seven sections of the tunnel had passed the test.
CERN specialists have already figured out that a connector between electromagnets failed and heated up, causing a magnet “quench,” or shutdown. It apparently melted a hole in the tube, causing a leak that spilled about a ton of the liquid helium used to chill that section.
The high-energy collisions enable physicists to understand better how the smallest bits of matter – and everything and everyone – are made. They also hope it will take them even closer to the “Big Bang,” which many theorize was the massive explosion that formed the universe.
By colliding protons from the nucleus of hydrogen atoms at high energy, the CERN machine is designed to re-create, on a minuscule scale, a view of what matter looked like in the rapid cooling one-trillionth of a second after the explosion.
