Moving a 15m superconductive ring across the United States

Researchers from 26 institutions around the world are planning a new experiment called Muon g-2 that could influence particle physics.
Researchers from 26 institutions around the world are planning a new experiment called Muon g-2 that could influence particle physics.

The experiment aims at studying the properties of muons, tiny subatomic particles that exist only 2.2 millionths of a second. It  will use a more intense pure beam of muons made possible at the DOE’s Fermi National Accelerator Laboratory (Fermilab), in Illinois.

This is thanks to three 15-m diameter superconducting coils that energise an already existing 700-ton particle storage ring magnet. The coils are similar to those used in medical MRI machines and made of titanium-niobium filaments in a copper matrix surrounded by pure aluminium. Together, these coils produce a 1.45-Tesla magnetic field, around 30 000 times the Earth’s magnetic field. The magnet was shimmed to produce a uniform field that was constant to a few parts per million and was measured to better than 1 part in 10 million, the best ever measurement for a magnet this size.

Formerly based in Brookhaven National Laboratory in New York, plans to reuse the magnet require it to be transported over 5000 km to Illinois, via the tip of Florida, loaded on a special barge and brought up the Mississipi. Then the “700-ton” Swiss watch”, escorted by police and technical experts, travels by truck at night along at 15km/h.

The Muon g-2 storage ring, in its current location at Brookhaven National Laboratory in New York. The ring, which will capture muons in a magnetic field, must be transported in one piece, and moved flat to avoid undue pressure on the superconducting cable inside.

Photo credit: Brookhaven National Laboratory.