A joint Fermilab/SLAC publication
Illustration by Sandbox Studio, Chicago

Big move


For a little over a month this summer, a huge electromagnet slowly journeyed from New York to Illinois, offering great photo opportunities along the way.

If you thought you saw a massive electromagnet being motored up the Mississippi River or driven along the Illinois roadways this summer, well, you weren’t imagining things.

Over 35 days in June and July, this fragile ring, made of aluminum and superconducting coils, took an unprecedented 3200-mile journey over land and sea from New York to Illinois. And along the way, it garnered thousands of fans and onlookers, people who followed its trip from Brookhaven National Laboratory to Fermilab.

The electromagnet is the centerpiece of the Muon g-2 experiment, based at Fermilab. It was originally built for a similar experiment at Brookhaven in the 1990s, an experiment that found tantalizing hints of physics beyond what scientists expected. Scientists would like to repeat that experiment using Fermilab’s accelerators, which can generate the most intense beam of muons in the world. The combination of this ultra-intense beam and the super precise electromagnet will allow for more precise measurement of the “wobble” of these short-lived subatomic particles when they are placed in a magnetic field. If the wobble differs from predictions, that could mean that there are as-yet-undiscovered particles out there.

One problem: building a new electromagnet of this quality would cost upwards of $30 million. The solution: transport Brookhaven’s magnet to Fermilab—very, very carefully. The ring would be damaged if it twisted or flexed more than a few millimeters, so it had to remain as flat as possible for the trip.