The Large Hadron Collider, the world's biggest and most expensive scientific experiment, will be shut down for at least two months, say scientists at the European Center for Nuclear Research, or CERN, in Geneva.
The shutdown casts into doubt the hopes of CERN physicists to achieve high-energy collisions of protons in the machine before the end of the year.
"It's too early to say whether we'll still be having collisions this year," James Gillies, chief of communications for CERN, said Saturday in an e-mail message.
The laboratory shuts down to save money on electricity during the winter. A gala inauguration party scheduled for Oct. 21 will still take place, Gillies said.
The collider is designed to accelerate the subatomic particles known as protons to energies of seven trillion electron volts, far surpassing any other accelerator on Earth, and bang them together in search of new particles and forces.
After the initial success of threading protons through the machine on Sept. 10, physicists had hoped they could move ahead quickly to low-energy collisions at 450 billion electron volts and then five-trillion-electron volt collisions as early as mid-October.
Several mishaps, including the failure of a 30-ton electrical transformer, have slowed progress since then. In the worst case, on Friday, one of the giant superconducting magnets that guide the protons failed during a test. A large amount of helium, which is used to cool the magnets and keep them near absolute zero, leaked into the collider tunnel.
In a terse statement, the laboratory said that an electrical connection between the magnets had melted because of the high current.
To fix it, engineers will have to warm that section of the tunnel and then cool it down again.
Physicists said such setbacks were an inevitable part of starting up such a large and complicated machine, which has cost $8 billion and taken 14 years to build.
"This is just an unfortunate fact of life when starting up a machine like the LHC," Gillies said.
Researchers, based at Cern, the European centre for particle physics near Geneva, say early results from the Large Hadron Collider (LHC) suggest it could offer the first experimental test for some aspects of string theory.
David Evans, a Birmingham University physicist who works at Cern, said: “The Alice experiment at the LHC may soon be able to make experimental measurements which, for the first time, can be modelled using the techniques of string theory.
“Although the experimental results will not prove string theory to be correct, an accurate prediction would certainly show that the techniques work, could distinguish between different versions of the theory, and perhaps even show whether the theory is going in the right direction.”See The Times Online for the full article: http://www.thesundaytimes.co.uk/sto/news/uk_news/Science/article621207.ece