The science planned for FRIB requires a beam-energy upgrade in order to produce higher intensities of rare isotope beams. A beam-energy upgrade would double FRIB’s primary beam energy from 200 million electron-volts per nucleon (MeV/u) to at least 400 MeV/u for all ions.

Recent news from the world of astronomy announced the discovery of gravitational waves from the merger of two neutron stars. Subsequent observation of the merger site showed it to be a place where vast amounts of heavier elements were created and hint that this is the long-sought-for site of the r-process. The extremely neutron-rich environment is predicted to produce extremely rare isotopes. To make these isotopes, FRIB will benefit from an upgrade of the base production energy.

With the upgraded energy FRIB will be able to:

• Make and study more of the very rare isotopes important for modeling what elements are made in neutron-star mergers
• Compress neutron-rich nuclei to twice their normal density and study how they react. This will provide important information on the neutron-matter equation of state, also important for interpreting the multi-messenger data from the observed neutron-star merger
• Open a new toolbox of nuclear reactions to probe deeper and more cleaning into the structure of the most exotic isotopes

At its July meeting, the FRIB Science Advisory Committee considered the upgrade, was excited about the prospect, and stated that the recent neutron-star merger observation provides a compelling and timely rationale for the upgrade: “Thus, a very strong and exciting scientific justification has emerged recently for a timely energy upgrade of FRIB.”

The science of the upgrade was further endorsed at the 2018 Low Energy Community Meeting in August, where they stated: “We strongly support pursuit of the 400 MeV/u energy upgrade of FRIB.  It will open new scientific opportunities and is timely given the recent neutron-star merger observation.” The scientific community is now preparing a white paper on the opportunities.