Relativistic Heavy Ion Collider, its construction and upgrade

Abstract

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is a colliding beam research facility that is capable of colliding heavy ion beams as heavy as gold initially and uranium recently at a beam energy of 100 GeV/nucleon for ultra-high-energy nuclear physics research. It is also capable of colliding polarized proton beams up to a beam energy of 250 GeV for the spin-physics program. The construction of this facility was completed in initial configuration in 1999, and highly productive experimental programs have been in progress to date. This article describes the construction and initial configuration and performance of the facility, and upgrades of the collider in recent years as well as the variance of the operations mode developed in response to the evolving physics interests. These improvements include a more sophisticated arrangement to improve the proton beam polarization, introduction of a new heavy ion source based on the Electron Beam Ions Source technology, introduction of stochastic cooling of the beams to enhance the collision luminosity, and collisions of heavy ion beams at a beam energy significantly lower than the nominal injection energy.