ATLAS: Argonne Tandem-Linac Accelerator System

ATLAS-— the Argonne Tandem-Linac Accelerator System — helps physicists explore the atom's nucleus

If you're a physicist in search of a beam of pure gadolinium ions at 800 million electron volts, you'll probably end up at ATLAS.

Physicists from all over the world use ATLAS to probe the structure of the atomic nucleus by studying the gamma rays and particles emitted when ion beams smash into targets. The 500-foot-long accelerator is capable of accelerating ions (atoms stripped of one or more electrons) of any element up to uranium to energies as high as 17 million electron volts (MeV) per nucleon — about 15 percent of the speed of light.

The accelerator's flexibility is a strong attraction for researchers interested in nuclear physics. The device offers hundreds of possible beam energies and combinations.

ATLAS is the world's first heavy-ion accelerator to use superconducting elements for beam focusing and acceleration. Its superconducting resonators make possible a continuous beam. Traditional materials would produce too much heat, requiring a pulsed beam.

ATLAS contains 62 such resonators of seven different designs. Each of the resonators in ATLAS is relatively small and independently controlled. This unusual control capability makes it possible for ATLAS to accelerate any ion, regardless of mass.

ATLAS is a national user facility. Physicists from institutions across the United States and more than a dozen foreign countries participate in experiments at the facility. Twice as much time on the machine has been requested as is available.

Today the ATLAS staff is investigating the possibility of accelerating unstable (radioactive) atoms with a new addition to ATLAS called the Rare Isotope Accelerator. Beams of unstable ions would be extremely valuable in a wide range of studies, including nuclear astrophysics - the field that attempts to understand the origin and abundance of the elements that make up all matter in the universe.

For more information about ATLAS, Argonne's physics research, and Argonne's other scientific user facilities, visit the following Web pages:

• ATLAS home page
• Argonne's Physics Division
• Scientific facilities -- National user facilities and other resarch facilities that are available for use by qualified scientists