Geneva (Switzerland) - Scientists are gearing up to launch the Large Hadron Collider (LHC) a 17-mile long particle accelerator that debuts with the promise to enable science to look deep into the origins of the universe, providing new insights in matter, space and time. The LHC may very well be the most fascinating science project of our generation.
Particle generators usually boast many superlatives and breathtaking specifications that are difficult to comprehend. One year ago, we published an extensive article on Fermilab’s Tevatron, the world’s most powerful particle accelerator, its vision and its astounding accomplishments. On September 10, CERN’s LHC will replace the Tevatron, located in Batavia, Illinois, as the world’s most powerful particle accelerator and collider, at least until a possible 18 mile long linear collider (ILC or International Linear Collider) may be built in the U.S.
While the particle beams created in the Tevatron top out a maximum energy of just under 1 TeV (1 billion electron volts), the LHC can create beams with up to 7 TeV, translating into a maximum collision energy of 14 TeV when two beams cross. LHC scientists said that their particle beams will travel in bunches of 3000, carrying a total of about 100 billion particles. At 99.9% of the speed of light, the beam will travel the 27 km (17 mile) ring structure consisting of a pipe that runs through 1746 magnets (1232 dipoles, 514 quadrupoles, located 150 - 450 ft below the surface)) 11,745 times per second. The energy level of the beam at 7 TeV is about comparable to an average car that is traveling at 1000 mph. A beam may be active for up to 10 hours, which means that its total distance traveled will be about 6.2 billion miles, which is about twice the distance between Earth and Neptune.
The purpose of the LHC, of course, is to create beam collisions. When colliding, scientists expect about 20 collisions when the 200 billion beam particles cross. However, due to the high speed of the beam and the fact that the LHC will cross the beams 30 times per second, there will be 600 million collisions per second at a rate of 600 MHz on average. The difficult task is not only to manage this extremely high and potentially very destructive energy level, but to also read the results of the particle collisions. However, it is nearly impossible for scientists to capture data of 600 million collisions per second with today’s computing technology.
For the first launch and the remainder of the year, CERN scientists will limit the LHC energy level to 5 TeV. 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. CERN said that the LHC has been prepared for the test for some time: 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, 1.9 K).
The next phase in the process is a 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.
The first launch of the LHC will be webcast on http://webcast.cern.ch