The world's largest particle accelerator will restart at half power in November, physicists in Switzerland announced Thursday. The giant machine broke down last fall, putting the field of high-energy physics on hold.
The Large Hadron Collider, or LHC, is located at CERN, Europe's premier particle physics laboratory near Geneva, Switzerland. The massive machine is nearly 17 miles around and designed to smash ordinary protons together at near the speed of light.
Physicists hope that the debris from those collisions will provide evidence of the Higgs boson, a particle that helps to endow other particles with mass. It could also reveal things such as extra dimensions in the universe or dark matter — a mysterious form of matter that is believed to help hold galaxies together.
Researchers wanted to start colliding particles last year, but on Sept. 19, just nine days after the machine was switched on, it suffered a massive electrical short. Repairs have taken the better part of this year.
The delay has been an inconvenience for thousands of physicists, who were planning sabbaticals and trips to coincide with the first collisions, says Joe Lykken, a theoretical physicist at the Fermi National Accelerator Laboratory (Fermilab) near Batavia, Illinois. "It's very disconcerting for all of us in terms of planning our lives," he says.
Among the hardest hit have been young graduate students who needed data from the collisions for their doctorates. Sarah Lockwitz and her husband, Ben Auerbach, graduate students at Yale University, moved to Geneva to be there for the first data from the LHC.
But as the delays stretched on, they began to worry about finishing their degrees in time. This summer, they decided to move back to Fermilab, which has a smaller, working accelerator. The move has gone well, Lockwitz says. But, she adds, "I don't want to do this a whole lot more often."
The November restart will be a cautious one. The machine will begin running at roughly half of its design energy, far less than some physicists would like, and eventually ramp up to higher energies in 2010. Rolf-Dieter Heuer, CERN's director-general, is confident that the strategy will prevent another breakdown and give the lab time to make safety modifications to the machine. Eventually, he says, "LHC will find something new in particle physics."