A beam will finally be circulated. The Large Hadron Collider (LHC) will now be ready to go in September, according to CERN's latest estimate.
The LHC is the world's most powerful particle accelerator, producing beams seven times more energetic than any previous machine, and around 30 times more intense when it reaches design performance, probably by 2010. Housed in a 27-kilometer tunnel, it relies on technologies that would not have been possible 30 years ago. The LHC is, according to the press from CERN, its own prototype.
There have been numerous delays but most in the physics community had regarded previous estimates with caution anyway.(1) Starting up such a machine is not as simple as flipping a switch and commissioning is a long process that starts with the cooling down of each of the machine's eight sectors, a process which had already been delayed.
This is followed by the electrical testing of the 1600 superconducting magnets and their individual powering to nominal operating current. These steps are followed by the powering together of all the circuits of each sector, and then of the eight independent sectors in unison in order to operate as a single machine.
By the end of July, this work was approaching completion, with all eight sectors at their operating temperature of 1.9 degrees above absolute zero (-271°C). The next phase in the process is synchronization of the LHC with the Super Proton Synchrotron (SPS) accelerator, which forms the last link in the LHC's injector chain. Timing between the two machines has to be accurate to within a fraction of a nanosecond.
A first synchronization test is scheduled for the weekend of 9 August, for the clockwise-circulating LHC beam, with the second to follow over the coming weeks. Tests will continue into September to ensure that the entire machine is ready to accelerate and collide beams at an energy of 5 TeV per beam, the target energy for 2008. Force majeure notwithstanding, the LHC will see its first circulating beam on 10 September at the injection energy of 450 GeV (0.45 TeV).
Once stable circulating beams have been established, they will be brought into collision, and the final step will be to commission the LHC's acceleration system to boost the energy to 5 TeV, taking particle physics research to a new frontier.
'We're finishing a marathon with a sprint,' said LHC project leader Lyn Evans. 'It's been a long haul, and we're all eager to get the LHC research programme underway.'
(1) Except for LHC Project Leader Lyn Evans, who had this bizarre statement in June of 2007.
“The low-energy run at the end of this year was extremely tight due to a number of small delays, but the inner triplet problem now makes it impossible,” he said. “We’ll be starting up for physics in May 2008, as always foreseen, and will commission the machine to full energy in one go.”