THE most powerful magnet in the world has been built at the Lawrence
Berkeley National Laboratory in California.
The magnet, which is a superconducting coil made of a niobium-tin alloy, has
a field strength of 13.5 tesla—250 000 times as strong as the Earth’s
magnetic field and 22 per cent more powerful than the previous record holder, a
Dutch magnet constructed in 1995.
A series of such magnets could one day be used by particle physicists to
accelerate and smash particles together with unprecedented energies. “This could
open up a new range of high-energy physics,” says Ron Scanlan, who led the
research team.
Until recently, magnet makers have shied away from niobium-tin because it is
as brittle as glass and impossible to wind into a coil. The Berkeley group got
round this problem by coiling separate strands of niobium and tin—which
are flexible—and then heating them to 680 °C to form the alloy.
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