Along RHIC's 2.4-mile ring there are four separate experimental detectors housed where the two particle beams intersect. One of these detectors-the Solenoidal Tracker at RHIC, or STAR-is specially designed to track the particles created in each ion collision. This powerful tracking system simultaneously measures various properties of these particles allowing researchers to reconstruct the ion collisions and look for signs of the quark-gluon plasma, or QGP. (The QGP is too short-lived to be detected directly). From these data, scientists hope to gain a fundamental understanding of the microscopic structure of quark-gluon interactions.

The picture at the right is of one of the first full-energy collisions between gold ions as captured by the STAR detector. The tracks provide researchers with almost a 3-D "snapshot" of thousands of subatomic particles produced in the collisions.

This view shows the tracks left by approximately 1000 charged particles after a head-on collision between two gold nuclei in the STAR detector. (photo courtesy of Brookhaven National Laboratory)