Completed in 1970, the Tandem Van de Graaff facility was for many years the world's largest electrostatic accelerator facility. It can provide researchers with beams of more than 40 different types of ions — atoms that have been stripped of their electrons. Ions ranging from hydrogen to uranium are available. The facility consists of two 15-million-volt electrostatic accelerators, each about 24 meters long, aligned end-to-end.
To study heavy ion collisions at high energies, a 700 meter-long tunnel and beam transport system called the Tandem to Booster (TtB) Line were completed in 1986, allowing the delivery of heavy ions from Tandem to the Alternating Gradient Synchrotron (AGS) for further acceleration. At the time, this modification opened an entirely new area of research at the AGS. The TtB also made it possible for the Tandem to serve as the Relativistic Heavy Ion Collider's ion source. Beginning in 2012, the EBIS pre-injector replaced the Tandems as the ion source for RHIC.
One of the new and interesting applications found for the large variety of different beams and energies available at the Tandem is the testing of integrated circuit chips under heavy ion bombardment. By simulating the effects of radiation both in space and on the ground, scientists and engineers from several other laboratories and companies are improving the reliability of computers. For example, NASA used the Tandem in this way to test components of the Mars Pathfinder spacecraft.