The Large Hadron Collider smashed its first proton beams together yesterday, three days after it was restarted following a 14-month shutdown for repairs.
The particle accelerator’s Atlas detector picked up the first signs of a possible collision at 1:22 p.m. GMT, after its two beams were made to cross and crash into one another for the first time.
While the event involved low-intensity beams and will not reveal new physics, it marks an important milestone in the commissioning of the £5 billion "big bang machine". It will also help scientists to calibrate the atom-smasher’s detectors, so that they are ready to operate when it runs at higher energies next year.
The achievement came after scientists successfully circulated beams of particles in both directions around the accelerator’s 17-mile ring in the morning. This made it possible to cross the beams at two places — initially in the Atlas and CMS detectors so they could look out for collisions.
Rolf Heuer, director-general of the CERN particle physics laboratory near Geneva, said: "It’s a great achievement to have come this far in so short a time, but we need to keep a sense of perspective. There’s still much to do before we can start the LHC physics programme."
Scientists later attempted collisions in the LHC’s other two detectors, Alice and LHCb. Steve Myers, CERN’s director of accelerators and technology, said that the first days of resumed operations since the LHC’s restart on Friday had been an "enormous success".
"We have two beams circulating simultaneously in the LHC," he said. "All this bodes very well for the detectors and the project that is in front of us, and will surely lead to new exciting physics discoveries."