Relativistic Heavy Ion Collider

Relativistic Heavy Ion Collider
Z22 · CC BY-SA 4.0 · source
Name	Relativistic Heavy Ion Collider
Location	Upton, New York
Coordinates	40°52′39″N 72°53′17″W
Established	1999
Director	Berndt Mueller
Staff	Brookhaven National Laboratory
Operating organization	Brookhaven National Laboratory
Type	Collider
Energy	Heavy ions up to 100 GeV/nucleon, protons up to 250 GeV
Circumference	3.8 miles (6.1 km)
Website	Brookhaven National Laboratory

Contents

Relativistic Heavy Ion Collider is a particle accelerator located at Upton, New York on the campus of Brookhaven National Laboratory built to collide heavy ions and polarized protons at relativistic energies. It enables research connecting Quantum Chromodynamics, Nuclear Physics, High Energy Physics, and Astrophysics by recreating conditions similar to those of the Big Bang and probing phase transitions such as the formation of the Quark–Gluon Plasma. The facility serves a large international community including users from institutions like CERN, Lawrence Berkeley National Laboratory, Fermilab, SLAC National Accelerator Laboratory, and universities worldwide.

Overview

RHIC is a superconducting synchrotron collider designed to investigate strongly interacting matter through collisions of heavy nuclei such as Gold (Au), lighter ions, and polarized proton beams, enabling comparisons to results from Large Hadron Collider experiments and theoretical frameworks like Lattice QCD and Hydrodynamics (physics). The collider supports experiments by collaborations operating large detectors and auxiliary experiments, including teams drawing on expertise from MIT, Princeton University, Columbia University, Yale University, University of California, Berkeley, Stony Brook University, Ohio State University, Brookhaven National Laboratory, and international partners such as RIKEN, CEA Saclay, INFN, and GSI Helmholtz Centre for Heavy Ion Research. RHIC’s mission overlaps with programs at Thomas Jefferson National Accelerator Facility and complements heavy-ion research at CERN’s ALICE (A Large Ion Collider Experiment).

The project originated from accelerator proposals and workshops in the 1980s linked to researchers at Brookhaven National Laboratory and planning by groups including U.S. Department of Energy program managers, with site selection on Long Island influenced by existing infrastructure from projects such as the Alternating Gradient Synchrotron and collaborations with Argonne National Laboratory. Construction during the 1990s involved contractors and scientific teams affiliated with Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Oak Ridge National Laboratory, and international partners, yielding commissioning in 1999 and first collisions in 2000 under leadership that included directors and scientific staff from Brookhaven National Laboratory and advisory input from committees convened by National Science Foundation and DOE Office of Science.

RHIC’s twin-ring layout uses superconducting magnet technology developed with industrial partners and national laboratories, drawing on experience from projects like Tevatron and HERA. The collider features a 3.8-mile circumference and complex injectors including the Tandem Van de Graaff and booster systems, with beam cooling and polarization systems informed by research at Collider Detector at Fermilab and DESY. Its superconducting magnets operate at cryogenic temperatures similar to systems at CERN Large Hadron Collider and employ RF cavities, vacuum systems, and diagnostics built with cooperation from Brookhaven National Laboratory, Fermilab, KEK, GSI Helmholtz Centre for Heavy Ion Research, and vendors experienced from Spallation Neutron Source. Energy ranges enable gold-gold, copper-copper, deuteron-gold, and polarized proton-proton collisions, with flexibility exploited by collaborations including teams from University of Birmingham, University of Tokyo, Seoul National University, University of São Paulo, and University of Melbourne.

The experimental program centers on major detectors: STAR (Solenoidal Tracker at RHIC), PHENIX (Pioneering High Energy Nuclear Interaction eXperiment), BRAHMS (Broad Range Hadron Magnetic Spectrometers), and PHOBOS, with later additions such as sPHENIX and forward detectors developed with partners like Lawrence Berkeley National Laboratory, Brookhaven National Laboratory, MIT, Columbia University, Yale University, University of Michigan, Los Alamos National Laboratory, Jefferson Lab, RIKEN, CEA Saclay, INFN, and CERN. Detector technology includes time projection chambers, calorimeters, magnet systems, silicon vertex detectors, and muon spectrometers based on designs from ALICE, ATLAS, CMS, and LHCb groups, with readout electronics and trigger systems developed alongside institutions such as Oak Ridge National Laboratory and BNL Instrumentation Division. RHIC supports ancillary experiments and beam test facilities serving researchers from Princeton University, Rutgers University, University of California, Davis, University of Texas at Austin, and international laboratories.

Key discoveries at RHIC include evidence for a strongly-coupled Quark–Gluon Plasma exhibiting near-perfect fluidity with low shear viscosity, jet quenching phenomena analogous to observations at CERN LHC, collective flow signatures such as elliptic flow measured by STAR and PHENIX, and constraints on parton energy loss and hadronization mechanisms that inform Lattice QCD and perturbative Quantum Chromodynamics calculations. RHIC results have influenced theoretical developments by researchers at Brookhaven National Laboratory, Berkeley Lab, Columbia University, MIT, University of Illinois Urbana–Champaign, Stony Brook University, Rutgers University, Indiana University, University of Geneva, CEA Saclay, RIKEN, and INFN, and have led to cross-disciplinary impacts in Astrophysics and Cosmology concerning the early universe, neutron star mergers studied by teams at Max Planck Institute for Astrophysics and LIGO Scientific Collaboration. Observations of spin structure in polarized proton collisions have advanced understanding of gluon polarization relevant to work at Jefferson Lab and by collaborations including COMPASS and HERMES.

Operations have been managed by Brookhaven National Laboratory with funding and oversight from the U.S. Department of Energy Office of Science, enabling staged upgrades such as electron cooling demonstrations, the RHIC Beam Energy Scan program, and the transition to sPHENIX, developed with Lawrence Berkeley National Laboratory and university partners. Future plans include integration with proposed facilities like the Electron Ion Collider concept promoted by DOE and scientific roadmaps from panels including the Nuclear Science Advisory Committee and international stakeholders from CERN, RIKEN, INFN, and GSI Helmholtz Centre for Heavy Ion Research, ensuring RHIC’s role in complementing experiments at Large Hadron Collider and informing next-generation accelerators and detector technologies pursued by collaborations across North America, Europe, and Asia.