Monthly Archives: July 2009

Oak Ridge: Where Cyclotrons Still Roam

Lizzie staring into the exposed belly of the Recoil Mass Spectrometer

Lizzie staring into the exposed belly of the Recoil Mass Spectrometer

Initially, we didn’t think we’d have time to visit Oak Ridge – our planned route took us on a comparatively leisurely drive from New York to Chicago with a stop in Pittsburgh for a night. But as the recommendations began to pile up, first from John Haggerty and the other physicists at Brookhaven, then Cindy Kelly of the Atomic Heritage Foundation, we realized that the additional visit to Tennessee would probably be worth it.

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Nuclear Tourism

The only stop on our tour that didn’t directly involve physics research was at the University of Chicago. Today, a statue and plaques sit above the exact spot where Enrico Fermi initiated the first controlled nuclear reaction in 1942 by pushing chunks of uranium into a pile of graphite – essentially the same process used by the Graphite Reactor at Oak Ridge (which you can read about in the Old Headers section or in our upcoming post about the Lab).

While the plaques speak of the “tremendous scientific potential” tapped for the first time by Fermi’s experiment, Henry Moore’s sculpture more somberly combines the forms of a mushroom cloud and a human skull. By the mid 1960s, when the sculpture was commissioned, the terrible power of nuclear reactions had apparently become all too clear.

A closer look at RHIC

A panoramic view of the PHENIX detectors building and counting house. To the left, an entrance to RHICs particle beam ring is visible. When access is required, the enormous concrete slabs that block the entrance are removed with a crane to expose the route into the tunnel.

A panoramic view of the PHENIX detector's building and counting house. To the left, an entrance to RHIC's particle beam ring is visible. When access is required, the enormous concrete slabs that block the entrance are removed with a crane to expose the route into the tunnel.

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven is a medium-to-high-energy machine that plays a unique role in the study of the early universe. While most particle accelerators collide single particles (like protons and antiprotons in the case Fermilab’s Tevatron), RHIC’s main purpose is to collide gold nuclei, each of which contains 79 protons.

Why the additional mass? The results of a proton-antiproton collision usually look something like this:

A proton-antiproton collision at the Tevatron

A proton-antiproton collision at the Tevatron (courtesy of Rockefeller University/CDF)

Gold ion collisions produce tracks like this:

A gold ion collision at RHIC

A gold ion collision at RHIC (courtesy of RHIC, found on Wikipedia)

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