Stop 2: The Particle Racetrack
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If your computer and Internet connection
allow, click at right to see a great 3-D animation of the RHIC
beam traveling through the RHIC complex. If not, it's time to use your imagination. Since you're already shrunk down to atom size, this shouldn't be so hard. First, picture RHIC as a racetrack, but one for particles, not cars! And hold on tight -- this race goes at the speed of light and lasts only a few fractions of a second! |
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The starting line is the The Tandem uses static electricity to remove the cloud of electrons that surrounds each atom. All that's left is the nucleus (plural: nuclei). A bare nucleus can also be called an ion, because its lack of electrons gives it a powerful positive charge. The Tandem creates thousands of bunches of ions, each containing billions of nuclei. The Tandem gives them a boost of energy, then sends them on their way -- a few millionths of a second apart. And they're off! |
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From the Tandem, the bunches of ions enter the Heavy Ion Transfer Line, which carries them on a magnetic field to the Booster. At this point, they're traveling at about 4.6% the speed of light. A powerful and compact circular accelerator, the Booster makes the ions speed up by giving them more and more energy. Just like you can speed up a car by stepping on the gas pedal, the Booster speeds up the ion beam by making a stronger and stronger magnetic field. Since the ions are positively charged, they "surf" forward on the magnetic field, faster and faster. |
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The Booster then feeds the ion beam into the larger ring of the Alternating Gradient Synchrotron, or AGS. By this time, the ions are traveling about 37% the speed of light. As they whirl around and around the AGS, the ions get even more energy -- until they're going 99.7% the speed of light! * *Light travels at 186,000 miles per second, the fastest that anything in the universe can go. Einstein created his theory of special relativity just to describe the bizarre way things act when they're going this fast. That's why RHIC is the Relativistic Heavy Ion Collider! |
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When the ion beam is going nearly as fast as it can, the AGS sends it careering down a long straight pipe called the AGS-to-RHIC Transfer Line. At the end of this line, there's a fork in the road, where sorting magnets separate the ion bunches. If one goes left, the next goes right, and so on. |
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Next stop, RHIC! |
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