Construction of the Alternating Gradient Synchrotron (AGS) Booster was begun in 1986 and completed in 1991. The Booster is less than one quarter the size of the AGS. It is used to preaccelerate particles entering the AGS ring, increasing the intensity of the proton beams generated by the AGS.
The Booster also plays an important role in the operation of the Relatavistic Heavy Ion Collider by accepting heavy ions from EBIS or protons from the 200-million electron volt (MeV) Linac. It then feeds them to the AGS for further acceleration and delivery to RHIC. After the installation of the heavy-ion transfer line in 1986, the AGS was capable of accelerating ions up to silicon with its atomic mass of 28. However, due to its superior vacuum, the Booster makes it possible for the AGS to accelerate and deliver heavy ions up to gold with its atomic mass of 197. The Booster also serves as the energetic heavy ion source for the NASA Space Radiation Laboratory. This facility is operated by the Collider-Accelerator Department.