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Sparks finally fly at the LHC

Despite false starts and warm ups, the LHC, a project that began more than 20 years ago, has finally begun to take and analyse data and the champagne is flowing in celebration.

The experiments in the more than £6 billion project, based at the European Laboratory for Particle Physics, CERN, saw collisions at a record energy of 7 tera electron volts (TeV) at 1pm today. In a “gentlemen’s draw” all four experiments appeared to see the particles smashing together and flying out into the detectors at the same time, as the magnets brought the beams together to collide.

Physicists were primed for action from 4am this morning, but the sensitive safety systems, installed in the wake of the machine’s breakdown in 2008, twice aborted the attempt and reset the system before collisions could get underway.

But finally, the moment of truth came on the third attempt.It was communicated to the untrained eye only through the huge cheers erupting from the various control rooms and collaborators across the world, all linked up by webcam. But by 10 minutes later the first visual displays of colliding particles emerged, showing spaghetti strings of flying particles, tracked within 3D images of the detectors.

CERN researchers are still walking around holding laptops showing such displays and cradling them like newborn babies. The director general of CERN has even been beamed in via videoconference from Japan where he says he is eating an evening meal of crisps and wine, proudly displaying a now empty bottle of 1991 vintage red, the year the LHC got its first official go ahead.

But as the head of the CMS experiment, Guido Tonelli, said in the CMS control room just a few moments ago, the celebrations will be quick because what they are marking is that operation is now underway and it’s time for the experiments to get on with what they were designed to do.

There are now around 50 collisions happening per second within the detectors. At seven times the energy of its nearest competitor – the Tevatron at Fermilab in Illinois,US – the LHC is now by far the highest energy accelerator in the world. But,having been running since 1983, Fermilab still wins in the amount of data collected – a crucial factor in finding some of the most highly sought after particles, including the Higgs boson.

The LHC will now run until it gathers one inverse femtobarn(a measurement of the number of particle collisions) and beats that record.This is foreseen for the end of 2011, when the machine will be shutdown for a year of upgrades before, more than likely, we’ll be back to do this all over again at the optimum energy of 14 TeV.