FRIB400: 400 MeV/u energy upgrade

FRIB will make the majority of the isotopes predicted to be bound available for experiments. These isotopes will allow researchers to understand atomic nuclei and their role in the universe. The tremendous discovery potential of FRIB can be further extended with an energy upgrade of the FRIB linear accelerator to 400 million electron-volts per nucleon (MeV/u) for uranium and to higher energies for lighter ions (FRIB400).

Status

The FRIB400 energy upgrade will double the reach of FRIB along the neutron dripline from Z=30 (zinc) to Z=60 (neodymium) into a region relevant for neutron-star crusts and to allow study of extreme, neutron-rich nuclei such as calcium-68. FRIB400 will expand the scientific impact of harvested isotopes by increasing the available yield of many isotopes by 10 times.

The FRIB science community laid out the scientific opportunities in the FRIB400 whitepaper that was subsequently endorsed at following Low Energy Community Meetings and also as the second resolution of the 2022 Nuclear Structure, Reactions, and Astrophysics Town Hall Meeting. In the 2023 Nuclear Science Advisory Committee Long Range Plan, FRIB400 is explicitly mentioned in the executive summary following Recommendation IV, which calls for investments in additional projects and new strategic opportunities that advance discovery science.

Science FRIB400 will enable

The FRIB400 energy upgrade will expand the already broad scientific reach of FRIB to encompass the full range of science envisioned by the scientific community and articulated in Nuclear Science Advisory Committee Long Range Plans and studies by the National Academies of Sciences, including:

  • Dense nuclear matter can be created and studied up to twice saturation density, critical for multi-messenger astrophysics
  • Significant gains in isotope yields will be realized, nearly doubling the reach of FRIB along the neutron dripline and allowing study of extreme, neutron-rich nuclei
  • In experiments, thicker targets can be used, increasing the luminosity for measurements of nuclei in key regions of the nuclear chart
  • Nuclear reactions can be performed in an energy regime of optimum nuclear transparency, improving their interpretation by reaction theory

The case for the FRIB400 upgrade has been made timely by the dawn of multi-messenger astronomy and the detection of gravitational waves and subsequent follow-up observations of electromagnetic radiation.

In anticipation of the science potential, as early as in the conceptual design stage of FRIB, space was provided in the FRIB tunnel for an energy upgrade of the accelerator to 400 MeV/u for uranium. The upgrade can be implemented with minimal or no interruption of the FRIB science program.

Science community support 

FRIB400 is explicitly mentioned in the executive summary following Recommendation IV of the Nuclear Science Advisory Committee’s (NSAC) A New Era of Discovery: The 2023 Long Range Plan for Nuclear Science (PDF), released in October 2023. NSAC is a federally chartered advisory committee to the U.S. Department of Energy and National Science Foundation. The recommendation calls for investments in additional projects and new strategic opportunities that advance discovery science. Instruments aspired by the community for FRIB, such as the High Rigidity Spectrometer, the Gamma-Ray Energy Tracking Array, the FRIB Decay Station, and the Isochronous Spectrometer with Large Acceptance, feature in the science section of the long range plan.

The FRIB science community laid out the enormous opportunities in the FRIB400 white paper “The Scientific Case for the 400 MeV/u Energy Upgrade of FRIB,” which was subsequently endorsed at the 2019 Low Energy Community Meeting (LECM2019):

The science case for an energy upgrade of FRIB to 400 MeV/u is extremely compelling and would significantly expand the science opportunities at FRIB, as outlined in the FRIB400 whitepaper.