Large Hadron Collider Starting Up
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CERN, the European Organization for Nuclear Research, has announced that the first attempt to circulate a beam in the Large Hadron Collider (LHC) will be made on September 10, 2008. This news comes as the cool down phase of commissioning CERN’s new particle accelerator reaches a successful conclusion, and the synchronization phase is underway. Television coverage of the start-up will be made available through Eurovision.
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, expected by 2010. Housed in a 27-kilometer tunnel, it relies on technologies that would not have been possible 30 years ago. The LHC is, in a sense, its own prototype.
Starting up such a machine is not as simple as flipping a switch. Commissioning is a long process that starts with the cooling down of each of the machine’s eight sectors. 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. This work has been completed, with all eight sectors at their operating temperature of 1.9 degrees above absolute zero (-271C).
The next phase in the process is synchronization of the LHC with the Super Proton Synchrotron (SPS) accelerator, which forms the last link
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in the LHC’s injector chain. Timing between the two machines has to be accurate to within a fraction of a nanosecond. Synchronization of the LHC’s clockwise beam transfer system and the rest of CERN’s accelerator chain has been successfully achieved. Tests began on August 8 when a single bunch of a few particles was taken down the transfer line from the SPS accelerator to the LHC. After a period of optimization, one bunch was kicked up from the transfer line into the LHC beam pipe and steered about three kilometers around the LHC itself on the first attempt. Then the test was repeated several times to optimize the transfer before the operations group handed the machine back for hardware commissioning.
The anti-clockwise synchronization systems will be tested over the weekend of August 22. 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 September 10 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 program underway.”
The first beam event will be webcast through webcast.cern.ch, and distributed through the Eurovision
