Mass Movement: A 50-Ton Magnet's 3,200-Mile Journey

By truck, by crane and by barge, a 15-meter-wide particle physics apparatus is now making its way around Florida and up the Mississippi River to its new home.

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By truck, by crane and by barge, a 15-meter-wide particle physics apparatus is now making its way around Florida and up the Mississippi River to its new home. The enormous magnet, known as the Muon g–2 ring (pronounced "gee minus two"), is moving from Brookhaven National Laboratory in Upton, N.Y., to Fermi National Accelerator Laboratory near Chicago. In the photo workers load the ring from a specially adapted truck onto a barge at the Smith Point Marina on Long Island.

The ring stores subatomic particles called muons. Although similar to electrons in that they are negatively charged, muons are much heavier but exist for only 2.2 millionths of a second. The ring holds muons from a particle accelerator in a uniform magnetic field, providing ideal conditions for physicists to observe the particles and their magnetic orientation.

In the photograph the ring itself is wrapped in white plastic and supported by a large, red stabilizing frame. The ring weighs only 15.5 metric tons on its own, but the added frame contributes another 30 metric tons.


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Although transporting the ring is no easy task, its relocation should allow physicists to examine the behavior of muons more carefully than ever before. The ring was originally constructed at Brookhaven, but Fermilab has recently developed a particularly intense beam of muons that should improve on previous muon measurements. If it deviates from physicists’ predictions, the way that muons respond to the magnetic field could provide new insight into the quantum world. Fermilab plans to begin the Muon g–2 experiment in 2016.

—Sophie Guterl

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