9 May 2016

Magnet coils that fit like a glove

The second coil of the 32 tesla all-superconducting magnet (foreground) will be fitted over the inner-most coil (background). The second coil of the 32 tesla all-superconducting magnet (foreground) will be fitted over the inner-most coil (background). Stephen Bilenky

This week at the lab, we're trying a magnet on for size.

A research magnet is made of a set of coils engineered from a current-carrying material — a fancy version of the electromagnet many kids make in school using a wire, battery and nail. Typically, four or five coils are slid one inside the next like Russian nesting dolls.

This week, we're slipping the second coil of the highly anticipated 32 tesla all superconducting magnet over the inner-most coil, then making any necessary adjustments. Like a good pair of jeans, the fit should be snug but not tight, with a mere millimeter between the two coils.

"Assembling the coils and the entire electrical circuit is an intricate job, and an exiting one," said project leader Huub Weijers. "After almost seven years of development, design, testing and construction of components, the final magnet is taking shape in front of our eyes."

These two coils, which contain about 6 miles of superconducting tape made of the novel, high-temperature superconductor yttrium barium copper oxide (YBCO). But YBCO is only one layer in this magnet. Those coils will soon be nested inside five more of coils made of conventional superconductors, three of niobium-tin and two of niobium-titanium.

The finished, 2.3-ton magnet system, when completed this summer, will join the MagLab’s roster of world-record magnets. At 32 tesla, it will be by far the strongest superconducting user magnet in the world, surpassing the current record of 23.5 tesla.

"It’s a difficult task to work through the many details of a new technology," said the magnet's lead designer Adam Voran, who managed the computer modeling for the project. "But the reward of seeing those meticulous designs being born into a tangible reality is exhilarating."


Photo by Stephen Bilenky / Text by Kristen Coyne.

Last modified on 9 May 2016