After overcoming some hurdles, researchers operated the Large Hadron Collider at its highest energy level yet on Tuesday, gathering data after smashing protons into each other.
The huge underground particle accelerator at CERN, the European Organization for Nuclear Research in Geneva, is designed to probe the nature of dark matter, antimatter, and an elusive particle called the Higgs boson, as well as any number of physics issues about how those things relate to the history of the universe.
"We have observed the first collisions [and] lots of beautiful tracks. It's really fantastic," said a representative of one of the LHC's experiments, called Atlas, during a live Webcast of the event. The tracks are produced by particles created when the LHC's protons collide.
A delay set back by about two hours the attempt to push the accelerator to an energy level of 7 trillion electron volts (7 TeV), with two beams each operating at 3.5 TeV. The accelerator has 9,300 superconducting magnets, each cooled to 2 degrees above absolute zero, and a monitoring system detected a problem with one magnet.
However, it appeared the problem was not with one of the magnets, but rather a broader issue with the electrical system that supplies not just the LHC but also other experiments at CERN, representatives on the Webcast said.
The collider was reset, and after one failed attempt to inject protons into the system, a follow-up attempt succeeded, and the accelerator was ramped up to 7 TeV. At about 1 p.m. local time, the researchers started gathering experimental data, and at 1:22 p.m. local time, the beams were stabilized so they could run without active adjustment.
"It's not a turnkey machine. it's no surprise if things don't work on the first or second or third time," said CERN's director general, Robert Aymar, speaking remotely from Japan to reporters.
The accelerator generates two beams of protons that travel at 99.99 percent of the speed of light, whizzing them around an underground ring 26.7 kilometers in circumference. The beams travel in opposite directions, and the actual experiments take place when the protons collide at high energies--ultimately at 14 TeV, with two beams each at 7 TeV. A total of 600 million collisions per second are created, producing a huge quantity of data to capture and process.
The delay left many physicists and others fidgeting as LHC overseers worked to restart the machine so the full-energy collision could take place. But the LHC has been years in planning, construction, and now testing, and some took the longer view.
"We have a lot of work in front of us in the next few years and we can wait a few more minutes," said Philippe Bloch, head of the CERN physics department, during a Webcast of the attempt.
The LHC reached an energy level of 3.5 TeV, half Tuesday's goal, on March 19.
Updated at 4:17 a.m. PDT to reflect success of operation.
Corrected 3:33 a.m. PDT: The story incorrectly characterized the 7 trillion electron volt energy level. That is half the full energy level planned for the accelerator.