Muon g-2: The big move

If you live in or around Chicago, chances are good that you've heard about the big move of a giant electromagnet to its new home at Fermilab. The 50-foot ring was designed and constructed at Brookhaven National Lab, on Long Island, in the early 1990s for a Muon g-2 (pronounced gee minus two) experiment going on there. It took data through about 2001, after which the experiment published a bunch of results and shut down. Luckily for the new experiment at Fermilab, it was cheaper to just let it sit around than to disassemble it, so it sat in a very large garage for a little over a decade until it began its journey to the Midwest.

The vast majority of its trip was by barge - around a month spent traveling south along the Atlantic seaboard and all the way around Florida, then up a series of rivers, from the Tombigbee River and the Tennessee to the Ohio River and eventually the Mississippi. It ended its barge trip on the Illinois and eventually the Des Plaines Rivers, and it was unloaded just last weekend (July 21-22) in Lemont. From there, it went on a three-night journey to Fermilab, reaching the site successfully on Friday, July 26th. 

While it is a pretty large piece of equipment, this move would have been fairly straightforward if it hadn't been for the incredible sensitivity of the ring. It's a superconducting coil that is all one piece, so it couldn't be disassembled at all. As if that weren't enough, flexing just 3 millimeters (around a tenth of an inch) out of the plane of the ring could be enough to damage some of the superconducting coils within, which would make the whole magnet essentially an oversized doorstop. This added complication made the ring's "Big Move" an engineering marvel, and Emmert International really rose to the challenge, custom designing a fantastic (bright red) frame to support the ring and transporting it on a hydraulically balanced barge and truck.

Some of the transportation details are pretty neat, too. For instance, the truck trailer that supported the ring had a whopping 64 wheels on 16 independent axles, and those axles could be remotely controlled to help with maneuvering around trees and backing up the truck. That turned out to be very useful, as the ring's route required that the truck back up several highway ramps in order to avoid tollbooths. Oh, and one other fun fact: when it went through an open-road tolling arch, it had just six inches of clearance on either side!

If you're interested in more information about the ring's move, check out its website, complete with twitter feed, pictures, and a map showing its route.

I'm hoping to write some more posts about Muon g-2 in the near future, in particular about what that ring is useful for and some of the cool things that could come out of its use.

If you want to check out other posts on Muon g-2, they can be found here.