Electrical Glitch Delays Large Hadron Collider
for National Geographic News
|September 22, 2008|
Full-power operation of the world's largest atom smasher will be delayed at least two months because of an electrical malfunction.
Twenty years in the making, the Large Hadron Collider (LHC) near Geneva, Switzerland, was designed to investigate dark matter, the big bang, and other mysteries of the early universe. (Interactive: understanding the God particle.)
Operators hurled the first beam of low-energy particles through the collider's 17-mile (27-kilometer) underground track just over a week ago.
The successful test had officials hopeful that they could start smashing opposing beams of particles together in as little as two week's time.
But during a routine test on September 19, an electrical link failed between two of the machine's massive 30-ton superconducting magnets, which guide speeding particles through the track.
"What we know indicates there was a faulty connection between two cables joining two magnets together that warmed up to the point of melting and that resulted in helium being leaked into the tunnel," said James Gillies, a spokesperson for the European Organization for Nuclear Research (CERN), which operates the machine.
No one was hurt during the malfunction, and the problem has been confined to a roughly two-mile (three-kilometer) swath of the track.
"This was actually the final electrical test of the final electrical circuit for qualification for running at high energy," Gillies told National Geographic News.
"This would have been the last hurdle."
Repairs are expected to take at least two months, thus squashing any hope that the LHC will be ready for its official inauguration, set for October 21.
The delay is due to the fact that the collider's operating temperature inside the track is -456.3 degrees Fahrenheit (-271.3 degrees Celsius).
For engineers to fix the problem, the section has to be warmed up, repaired, and cooled back down, a process known as a thermal cycle.
The thermal cycle for the LHC is about two months.
"The thing that went wrong [at the LHC] is not such a big deal," said Mike Harrison, a high-energy physicist at Brookhaven National Laboratories in Upton, New York.
"The actual fix will be a day or two probably," he said. "The problem is you have to warm it up and cool it down again. That's what takes up time."
Harrison added that this kind of delay is just part of the process of getting a particle accelerator ready for business.
He was involved in the design and fabrication of Brookhaven's Relativistic Heavy Ion Collider (RHIC), a smaller version of the LHC that's been in operation since 2000.
"You expect to have probably a couple of thermal cycles as you go through the commissioning process" of a particle accelerator, Harrison said.
CERN's Gillies agreed that "teething troubles" are inevitable with a machine as complicated as the LHC, and that other particle accelerators have faced similar problems.
"It's one of those things you have to be ready for when you start to operate a machine like this," he said.
"It's just more time-consuming with a superconducting machine, where you have a warm-up and a cool-down phase involved with any repair."
The LHC is also scheduled to be shut down in December to reduce electrical costs in the winter, and it is currently unclear whether repairs will be finished before then.
|© 1996-2008 National Geographic Society. All rights reserved.|