Protons were sent deeper than ever before into the world鈥檚 most powerful particle smasher over the weekend. The tests bode well for the official start-up of the accelerator 鈥� the Large Hadron Collider at CERN in Switzerland 鈥� on Wednesday.
Eventually, two beams of protons will be made to collide head-on in the LHC鈥檚 27-kilometre-long loop, potentially producing new particles that could overturn theories about nature鈥檚 most fundamental laws.
But first physicists must perfect the art of injecting protons into the LHC and test whether each beam can be magnetically threaded through the circuit without veering off course and being lost.
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鈥淲e鈥檝e now fired beams through 5/16 of the machine without having to adjust the magnets, which has been a great surprise,鈥� says Steve Myers, head of accelerators and beams at CERN.
At 0500 local time on Saturday morning, a tired shift crew successfully fired a 鈥減ilot鈥� beam of protons 6.6 km around the counter-clockwise beam pipe 鈥� twice as far as was achieved two weeks ago during the last such injection test. It went straight through a detector called LHCb during the test.
For the first time, the beam was then kicked down a 600-metre-long side tunnel into a 1000-tonne block of graphite, concrete and steel designed to absorb the energy of the beam. 鈥淭he beam was not perfectly centred, but it was right on the block,鈥� says machine operator Jorg Wenninger.
Power outage
Shortly after that test, the team located an error in the machine鈥檚 optics that caused the beam to 鈥渟tretch鈥� in the vertical direction, possibly due to a focusing magnet that had been wrongly configured.
But before the problem could be fully resolved, a power outage at 0900 on Saturday caused two of the LHC鈥檚 eight sectors to warm up above 1.9 K (about -271 掳C), the operating temperature of the superconducting bending magnets.
The cryogenic hiccup also meant that a full 鈥渄ry run鈥� of the LHC, during which all eight sectors would have been powered up at the same time without beam, will be postponed until Tuesday.
So instead, the team concentrated on injecting protons in the opposite, or clockwise, direction.
Until now, protons had made their way through 3.3 km, to the end of one of the LHC鈥檚 eight sectors, taking them through a detector called ALICE.
But on Sunday evening, a beam made it all to the way to a concrete stopper 10 km, or three sectors, away on the first shot. That meant that it reached a giant detector called CMS for the first time.
The weekend鈥檚 tests have given machine operators a better feel for the temperament of their 聙2.9 billion new toy, which will operate for at least a decade.
The Large Hadron Collider 鈥� find out more about the world鈥檚 biggest experiment in our cutting-edge special report.
