CERN: damaged atom smasher will restart at half energy, but a new repair pause is needed

CERN: Damaged collider to restart at half energy

GENEVA — When launched to great fanfare nearly a year ago, some feared the Large Hadron Collider would create a black hole that would destroy the world. The world’s largest scientific machine, built at a cost of $10 billion, has worked only nine days and has yet to smash an atom.

The European Organization for Nuclear Research, known as CERN, said Friday it would restart the collider in November at half power under pressure from scientists eager to conduct experiments to unlock secrets of the universe.

But spokesman James Gillies told The Associated Press they would have to shut down yet again next year to finish repairs so that the Large Hadron Collider can operate at full energy of 7 trillion electron volts — seven times higher than any other machine in the world.

CERN has been working since late last year to repair the damage caused by a faulty electrical joint. The breakdown occurred nine days after the spectacular start up of the $10 billion machine last Sept. 10 when beams of subatomic particles were sent around the accelerator in opposite directions.

Fifty-three massive electrical magnets had to be cleaned and repaired after the failure in the 17-mile (27-kilometer) circular tunnel under the Swiss-French border at Geneva.

Tons of supercold liquid helium spilled out of the system, and a sooty residue had to be cleaned out of the tubes that are meant to be pristine, holding a vacuum in which subatomic particles can whiz around the tunnel at near the speed of light at temperatures colder than outer space.

CERN expects repairs and additional safety systems to cost about 40 million Swiss francs ($37 million) over the course of several years, covered by the 20-nation organization’s budget.

The CERN collider emerged as the world’s largest after the United States in 1993 canceled the Superconducting Super Collider being built in Texas. Congress pulled the plug after costs soared, and questions were raised about the value of the science it could produce.

Some people have questioned the cost of the CERN project, but Gillies says all 20 of CERN’s member nations have remained supportive and that four other countries — Cyprus, Israel, Serbia and Turkey — have asked to join. A fifth country — Slovenia — has expressed interest.

Japan, India, Russia and the United States are observer countries that have made sizable contributions to the CERN project.

Scientists have stressed that colliders always have startup problems and say that by running through this winter as planned CERN will be pretty close to schedule.

CERN is now aiming to restart the machine in November with beams of subatomic particles initially running at 3.5 trillion electron volts, or TeV. That’s only half the level the machine was designed for, but it’s still 3 1/2 times higher than the second most powerful accelerator, the Tevatron at Fermilab outside Chicago. During last year’s brief startup phase the CERN collider only operated at half the Fermilab level.

Even as the machine is being calibrated this winter, scientists will be able to conduct experiments, collecting data on the collisions of protons and lead ions in the accelerator.

They hope the higher energy will enable them to see particles so far undetected, such as the elusive Higgs boson, which in theory gives mass to other particles — and objects and creatures — in the universe.

Physicists have used smaller, room-temperature colliders for decades 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 want to answer with CERN’s new collider.

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 scientists 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.

Some skeptics have expressed fears the high-energy collision of protons could imperil the Earth by creating micro black holes — subatomic versions of collapsed stars whose gravity is so strong they can suck in planets and other stars.

CERN and leading physicists dismiss the fears and maintain the project is safe.

The collider’s teething problems are typical of complicated accelerators, but it has been especially frustrating to physicists from around the world, who already have been waiting for years to conduct their experiments on the machine.

Physics students are even more upset because they need data from experiments for their theses.

“It’s very important to get data for students who are on short time scales,” Gillies said. “For career physicists it’s an issue but less of one.”

Gillies told the AP that CERN management decided at the beginning of the year that it would not try to repair all parts of the collider this year.

“Otherwise, we would never have had a beam before halfway through next year,” he said. “So we consciously took the decision that we’ll start up at a lower energy and then we’ll go in when the experiments have got data to get their teeth into and then we’ll do the necessary repairs to get up to 7 TeV then.”

Gillies said CERN experts have examined every one of the 1,600 superconducting magnets and each of the 10,000 electrical splices as well as copper protection to carry away any spillover current to prevent damage to the magnets if they heat up as happened on Sept. 19.

They decided some of the splices need to be repaired before the collider goes to full power, but that they can operate safely up to 5 TeV without further repairs now.

That has been set as the highest energy for the collider before its next shutdown for maintenance, probably in November 2010. Then the further repairs will be made so that the energy level can be ramped up.

“We’ve measured some of the resistance in the copper and it’s higher than it should be,” said Gillies. “It’s very small resistance but it’s there.”

Another problem with the machine is the superconducting magnets, many of which have to be “retrained” to be able to handle energy up to 7 TeV. Training a magnet is done by applying higher and higher energy to each one until they can safely go up to the design level.

In the examination of the collider over the past year it has been found that some of the magnets have somehow become “detrained,” so the process has to be repeated on each of them, Gillies said.

Gillies said he was aware some people have been questioning whether the collider would ever run as planned.

“It’ll work,” he said.

CERN’s director-general, Rolf Heuer, said the collider has been studied very carefully and is much better understood than a year ago.

“We can look forward with confidence and excitement to a good run through the winter and into next year,” Heuer said.

At present CERN’s member states are Austria, Belgium, Britain, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden and Switzerland.