As lab experiments go, it don鈥檛 get much bigger than this. The world鈥檚 largest superconducting magnet was switched on for the first time and tested last week at CERN, the particle accelerator facility in Geneva, Switzerland.
The barrel toroid magnet is a major component of CERN鈥檚 Atlas detector. From next year, Atlas will be scouring the debris of protons smashed head-on in the Large Hadron Collider for signs of the Higgs boson, the particle thought to give all other particles their mass. It could also find evidence for supersymmetry, the proposed extension to the standard model of particle physics, and even see hints of extra dimensions.
The magnet is made of eight superconducting coils, each housed in a 26-by-5-metre structure weighing 100 tonnes. First, the entire magnet was cooled down to -269 掳C over a six-week period, and then the current in the superconducting coils was raised in steps, finally reaching a staggering 21,000 amps, 500 amps more than is needed for its intended use.
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During the test, Atlas鈥檚 muon detectors picked up muons from cosmic rays being deflected by the magnetic field. This is a good sign that Atlas will fulfil its promise: when research using the LHC begins next year, these detectors will allow physicists to measure the deflections of muons created in the proton-proton collisions.
鈥淭his is a major step,鈥� says Atlas spokesperson Peter Jenni. 鈥淭here is a certain pride in it, but we know this is not the end yet.鈥�
