The world's most powerful atom smasher on Monday experienced the first collisions of particles, only three days after it was restarted, the European Organization for Nuclear Research
(CERN) said.
"Today the Large Hadron Collider (LHC) circulated two (particle) beams simultaneously for the first time, allowing the operators to test the
synchronization of the beams and giving the experiments their first chance to look for proton-proton collisions," the Geneva-based organization said in a statement.
From early in the afternoon, the two particle beams were made to cross at four points, and the detectors recorded four collisions, it said.
"It's a great achievement to have come this far in so short a time," said CERN Director General Rolf Heuer. "But we need to keep a sense of perspective -- there's still much to do before we can start the LHC physics program."
Housed in a 27-kilometer, circular tunnel at the Swiss-French border near Geneva, the giant machine was designed by scientists to unlock many
secrets of the universe by recreating the conditions immediately after the Big Bang which happened some 13.7 billion years ago.
That can only be done by colliding two beams of particles circulating in opposite directions at close to the speed of light.
The machine was restarted on Friday, after more than one year of repairs. It was first started on Sept. 10, 2008, but suffered a serious
malfunction only nine days later.
The four small-scale collisions came just three days after the LHC restart, demonstrating the excellent performance of the beam control system, said CERN, the world's leading laboratory for particle physics.
Since the start-up, the operators have been circulating beams around the ring alternately in one direction and then the other at the injection
energy of 450 GeV. The beam lifetime has gradually been increased to 10 hours, and on Monday beams have been circulating simultaneously in both
directions, still at the injection energy.
Next on the schedule is an intense commissioning phase aimed at increasing the beam intensity and accelerating the beams. All being well, by Christmas, the LHC should reach 1.2 TeV per beam, and have provided good quantities of collision data for the experiments' calibrations, CERN said.