Alternating Gradient Synchrotron

The Alternating Gradient Synchrotron was built on the innovative concept of the alternating gradient, or strong-focusing, principle, developed by Brookhaven physicists. This breakthrough concept in accelerator design allowed scientists to accelerate protons to energies that would have been otherwise unachievable. The AGS became the world's premiere accelerator when it reached its design energy of 33 billion electron volts (GeV) on July 29, 1960.

The Alternating Gradient Synchrotron under construction, 1957.

Until 1968, the AGS was the highest energy accelerator in the world, slightly higher than its 28 GeV sister machine, the Proton Synchroton at CERN, the European laboratory for high-energy physics. While today's newest accelerators can reach energies in the trillion electron volt region, the AGS has earned researchers three Nobel Prizes and today serves as the injector for Brookhaven's Relativistic Heavy Ion Collider. It also remains the world's highest intensity high-energy proton accelerator, used to search for new physics. The AGS and its accompanying Booster accelerator are the only U.S. heavy ion accelerators suitable for experiments to determine the biological effects of space radiation.

One of the most famous early detectors used at the AGS to study sub-atomic phenomena was the 80-inch bubble chamber. When the first photograph of particle interactions was made in June 1963, the 80-inch bubble chamber was the largest such detector in the world. The most famous discovery made at this detector was by a team of researchers led by future Laboratory director Nicholas Samios. In 1964, this team discovered the omega-minus particle, which was previously only theorized to exist. This finding supported the first attempt by physicists to organize the increasingly long list of subatomic particles into an orderly pattern, similar to that used to arrange chemicals in the periodic table.

Later, another detector, the 7-foot bubble chamber, began routine operations in 1974. The following year, the 7-foot chamber was used to discover the charmed baryon, a particle composed of three quarks, one of which was the "charmed" quark. This result helped physicists confirm a new member of the quark family.

Three discoveries made at the AGS -- the muon-neutrino, CP violation and the J particle -- each captured the Nobel Prize in physics.

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Did you know?

Three discoveries made at the AGS -- the muon-neutrino, CP violation and the J particle -- captured the Nobel Prize in physics. More...

Tracks formed by particles traveling through the AGS' 80-inch bubble chamber detector were photographed by cameras which looked through a 1,500 pound, polished glass window--the largest piece of lens-quality glass ever cast. 

Some have found the images recorded in bubble chambers to be not only scientifically beautiful, but visually as well. Details...

Theoretical Event

The 7-foot bubble chamber used at the AGS was the first particle detector of its type in which the chamber through which the particles passed was surrounded by a superconducting magnet.

Other Accelerators


Alternating Gradient Synchrotron

National Synchrotron Light Source

Relativistic Heavy Ion Collider