by Adrian Cho
After 13 months of repairs and modifications, the world’s largest particle smasher is once again ready to start circulating particles, officials at the European particle physics laboratory, CERN, near Geneva, Switzerland, announced today. The guts of the Large Hadron Collider’s (LHC’s) more than 1700 large superconducting magnets have been cooled with liquid helium to a frigid 1.9 K, and now that the 35,000 metric tons of hardware are cold, physicists can soon resume feeding particles into the machine’s twin rings, says CERN spokesperson James Gillies. “Were back to the more-routine steps that we went through last year,” he says. “So the first injection tests should begin next week.”
The LHC is designed to smash protons together at energies seven times as high as any previous particle collisions in hopes of discovering new particles and even new dimensions of space. The $5.5 billion accelerator broke down last fall just 9 days after physics first passed particles all the way around its two rings, and researchers have been busy fixing it ever since. Physicists are on track to have beams zipping through LHC’s two rings in late November and to collide the counter-circulating beams at a low energy in December. But with many systems to check—including new systems to protect the machine against a repeat of last year’s catastrophe—researcher may not achieve higher energy collisions for data taking until early next year, Gillies says. “There’s still a possibility for December, but more realistically it’s looking like January,” he says. Even then, just to be on the safe side, officials have limited the energy to half of the LHC’s design maximum.
To start collisions at half the LHC's design maximum is not being "on the safe side," for it's nearly four times Fermilab's world record. Safety is now being considered only in relation to the physical instrument and not the environment or planet. Yet in the past year the safety rationales set up by CERN's in-house theorists have been put in serious doubt by some outside physicists. In particular, a recent revised paper by physicist Rainer Plaga, Ph.D. - at http://arxiv.org/abs/0808.1415v3 - disputes CERN's "cosmic ray" safety arguments and argues that these do not rule out the LHC's production of "metastable quantum-black holes" that could release enormous thermonuclear energy potentially devastating CERN and parts of France and Switzerland.
Robert Houston
To start collisions at half the LHC's design maximum is not being "on the safe side," for it's nearly four times Fermilab's world record. Safety is now being considered only in relation to the physical instrument and not the environment or planet. Yet in the past year the safety rationales set up by CERN's in-house theorists have been put in serious doubt by some outside physicists. In particular, a recent revised paper by physicist Rainer Plaga, Ph.D. - at http://arxiv.org/abs/0808.1415v3 - disputes CERN's "cosmic ray" safety arguments and argues that these do not rule out the LHC's production of "metastable quantum-black holes" that could release enormous thermonuclear energy potentially devastating CERN and parts of France and Switzerland.
Robert Houston