We can start counting down to the end of the world again – the Large Hadron Collider is up and running.
CERN reckons it produced its first collisions yesterday, three days after it started firing protons and much sooner than expected.
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 bumped up to 10 hours, and now beams are circulating simultaneously in both directions.
With just one set of particles whizzing in each direction, the beams can be made to cross in up to two places in the ring. First, the beams were made to cross at points 1 and 5, home to the ATLAS and CMS detectors. Later, beams crossed at points 2 and 8, ALICE and LHCb.
“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 programme.”
Beams were first tuned to produce collisions in the ATLAS detector, which recorded its first candidate for collisions at 14:22 yesterday afternoon. Later, the beams were optimised for CMS. In the evening, ALICE had the first optimization, followed by LHCb.
“It was standing room only in the ALICE control room and cheers erupted with the first collisions,” said ALICE spokesperson Jurgen Schukraft. “This is simply tremendous.”
“The tracks we’re seeing are beautiful,” said LHCb spokesperson Andrei Golutvin, “we’re all ready for serious data taking in a few days time.”
The next challenge is to increase the beam intensity and accelerate the beams to the point necessary to recreate the conditions just after the Big Bang. By Christmas, CERN expects the LHC to reach 1.2 TeV per beam, and to have provided plenty of collision data.