RHIC Era Ends: 25 Years of Particle Research at Brookhaven Laboratory

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory conducted its final collisions on February 6, 2026, shortly after 9 AM. As reported by Brookhaven National Laboratory, nearly light-speed oxygen ions collided in the STAR and sPHENIX detectors. After more than 25 years of operation, the particle accelerator's scientific work has come to an end.

RHIC began operation in the summer of 2000 and has worked with ten different atomic species at various energies and configurations during this time. The final run generated the largest dataset of gold-ion collisions as well as proton-proton collisions for spin analyses. Additionally, low-energy fixed-target collisions and oxygen-oxygen interactions were conducted.

The sPHENIX detector alone collected over 200 petabytes of raw data in the last run – more than all previous RHIC datasets combined. This includes 40 billion snapshots of gold-ion collisions. “RHIC is one of the most successful user facilities of the DOE Office of Science and is available to thousands of scientists from across the United States and around the world,” explained Darío Gil, Under Secretary for Science at the U.S. Department of Energy.

The accelerator, with its two 3.8-kilometer-long superconducting rings, generated quark-gluon plasma (QGP) during its operational period, which mimicked the matter shortly after the Big Bang 14 billion years ago. In 2005, the experiments proved that QGP behaves like a perfect fluid. Furthermore, the measurements contributed significantly to the understanding of proton spin.

Space for the Electron-Ion Collider

The end of RHIC also marks the start of its successor, the Electron-Ion Collider (EIC). The new particle accelerator will adopt important components from RHIC, including the ion storage ring and injectors. One of the two rings will be replaced by an electron ring in the existing tunnel.

The EIC project aims to enable precise measurements of quark and gluon distributions in protons and to investigate their contributions to mass and spin. Construction is scheduled to begin in 2026, with the first experiments expected to start in the early 2030s. The U.S. Department of Energy anticipates costs between 1.7 and 2.8 billion U.S. dollars. “We knew that RHIC had to end for EIC to happen. It's a bittersweet moment,” commented Wolfram Fischer, head of the Collider-Accelerator Department at Brookhaven National Laboratory.

CERN is also setting the course for the future

While a particle accelerator in the USA is getting its successor, CERN in Europe is already planning the next generation. According to the feasibility study for the Future Circular Collider, the FCC, with a 91-kilometer-long tunnel and a depth of 200 meters, is set to significantly surpass the current Large Hadron Collider (LHC) with its 27-kilometer circumference.

The LHC itself recently reached a remarkable milestone: the research facility archived over an exabyte of data on more than 60,000 magnetic tapes. The High-Luminosity upgrade of the LHC is expected to increase the data volume tenfold in the future. For the FCC, several billionaires have already committed 860 million euros, including Eric Schmidt, Xavier Niel, and John Elkann.

The first phase of the FCC is designed as an electron-positron collider and will serve as a “Higgs factory.” Later expansion stages plan for proton collisions with energies up to 100 teraelectronvolts – more than seven times the current LHC capacity. The CERN Council is reviewing the complete feasibility study, and construction could begin in the 2040s.

(vza)