Huge magnetic ring coming to Chicago’s suburbs via the long road

May 13, 2013

Fermilab National Accelerator Laboratory in west suburban Batavia has a very unusual shipment coming this summer: an electromagnetic ring so wide its journey will shut down whole highways.

The ring, which looks like a huge hula-hoop, currently resides at Brookhaven National Laboratory on Long Island, where it’s been used to conduct high-level experiments on tiny subatomic particles called muons.

“We use them to probe the basic underlying structure of particle physics,” said Chris Polly, a Fermilab physicist. “What are the particles out there, how do they interact at the most fundamental level?” But after being created by high-energy interactions between particles, they only exist for about two millionths of a second.

“Right now, there’s muons passing through you,” Polly said. Those muons sometimes come to earth in “showers” produced by high-energy particle collisions in the earth’s atmosphere; countless invisible muons shower down over wide areas. “We sometimes build experiments that are a mile underground just because we’re trying to get away from the muons.”

Despite being common, muons are elusive and difficult to study. Because the miniscule particles exist so briefly before decaying into electrons and neutrinos, they have to be carefully suspended in a magnetic field for observation. That’s where the magic muon ring comes in: the latest in muon experiments requires a very strong magnetic field, and the way to create that field is through a ring that’s fifty feet in diameter, or about four highway lanes wide.

The muon ring’s massive metal casings can be removed, but the ring itself has to stay in one piece and can’t be tilted more than a few degrees. That means its journey to the western suburbs of Chicago this summer will begin with a barge trip down around the tip of Florida, through the Gulf of Mexico and up the Mississippi River to get to Chicago’s waterways. The ring will then get off the boat at Lemont Port to be transported to the Batavia lab using high-tech remote control carts. Between the carts, the ring and the entourage of police officers and scientists, the process is expected to shut down stretches of I-88 and I-355 overnight in July. The entire trip is about 3,200 miles.

Polly’s excited about the ring’s arrival because the previous Muon g-2 (pronounced “g-minus-two”) experiment at the Brookhaven Lab found inconsistencies not predicted by physicists. These anomalous observations could suggest the existence of a previously unknown particle; in other words, the Standard Model of physics could be proven to be incomplete.

The results of the Brookhaven experiment are suggestive but uncertain, mainly because a definitive answer would require 20 to 25 times more data than Brookhaven’s researchers were able to gather with the technology available to them. Fermilab’s advanced accelerator technology, some of which is left over from the now-defunct Tevatron, will allow the the lab to produce the necessary amount of muons for the experiment.

Fermilab broke ground last week on a new experimental lab to accompany the ring, and the ring won’t be ready to experiment with until 2016. At that point, Polly says the experiment is expected to take three to four years to complete. But he says it’s worth the wait.

“It could be a harbinger of new physics,” said Polly. “There could be new particles in the universe.”

The shipping cost for the magnetic donut is 2.5 million dollars, but Fermilab says that’s just a tenth of what it would cost to build a new one.

You can watch a demonstration of the ring’s mode of transportation and follow its actual movement this summer on the Muon g-2 website.

Lewis Wallace is a Pritzker Journalism Fellow at WBEZ. Follow him @lewispants.