General Information

Top of Page

Tandem Van de Graaff

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.

Tandem Van de Graaff facility

Click on the image to download a high-resolution version.

Shown in the above cut-away view of the Tandem Van de Graaff facility are the two Van de Graaff electrostatic accelerators (3) and (9) each independently capable of accelerating a wide variety of ion species from external ion sources (2) and (7) through beam switching magnets (4) and (10) into target rooms (11), (12), (13) and (16).  Highest particle energies are achieved in three-stage operation with the first accelerator (3) injecting energetic negative ions through the connecting link (5) directly into the second accelerator (9).  The accelerators are operated from the centrally located control room (15) which has direct access to the accelerator rooms through one of the shielding doors (8).  The mechanical equipment room (1) contains the pumps and compressors necessary to transfer insulating gas from storage tanks (6) to each accelerator pressure vessel.  Laboratory and office space (14) is available for resident and visiting scientific personnel.