The Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU) achieved a pair of milestones recently, delivering the world’s highest heavy-ion beam power and simultaneously accelerating five charge states of particle beams. These milestones further advance FRIB’s commitment to meeting the needs of the scientific community.
On 29 June, scientists succeeded in simultaneously accelerating five charge states of uranium beams to the production target, achieving a record charge-stripping efficiency of above 80 percent across the five states. This achievement secures FRIB’s status as the most powerful heavy-ion accelerator.
The five-charge-state uranium-238 73+,74+,75+,76+,77+ beam was accelerated up to 177 MeV/u to produce 10 kW on target, and achieved a record charge-stripping efficiency of 83 percent across the five charge states. This exceeds the conventional single-charge-state acceleration of approximately 21-percent stripping efficiency. This five-charge-state acceleration at above 80 percent efficiency is needed for the ongoing primary beam intensity increases at FRIB, and is key to FRIB enhancing its capability.
In addition, scientists were successful in delivering a record 22 kilowatt (kW) selenium-82 beam during a test on 16 July, accelerating the beam to 228 mega electron volt/nucleon (MeV/u). The liquid lithium charge stripper was used to boost the charge state of the beam from 17+ to 32+. The charge stripper helps FRIB’s linear accelerator achieve design-goal beam energies beyond 200 MeV/u and beam power up to 400 kW. During the test experiment, the newly commissioned beam-energy feedback system was activated. The system monitored fluctuations in the thickness of the liquid lithium charge stripper and compensated for these effects. It includes a super-conducting accelerating cavity and a bunching cavity upstream of the charge stripper, which correct the beam energy and arrival phase variations, making the beam energy constant after the charge stripper.
These milestones comes just over two years since the start of user operation at FRIB and are part of the progress toward FRIB’s full capability and, longer term, FRIB400. FRIB400 will expand the scientific reach of FRIB to encompass the full range of science envisioned by the scientific community. The scientific community supports FRIB400, and it is mentioned in the Nuclear Science Advisory Committee’s (NSAC) A New Era of Discovery: The 2023 Long Range Plan for Nuclear Science. The FRIB science community laid out the scientific opportunities in the FRIB400 white paper “The Scientific Case for the 400 MeV/u Energy Upgrade of FRIB,” and FRIB400 was recently endorsed at the 2024 Low Energy Community Meeting.
FRIB’s approach to enhancing discover opportunities involves operating safely while anticipating and avoiding adverse events as it increases the primary beam intensity. In July 2023, 10 kW beam operations were tested before moving to 10 kW routine operation in 2024. Following the successful tests, FRIB anticipates implementing a 15 kW routine operation in 2025.
FRIB has developed additional primary beams and energies to increase yields for rare isotope beams. Read more about the specific beam currents by isotope and energy here.
Michigan State University (MSU) operates the Facility for Rare Isotope Beams (FRIB) as a user facility for the U.S. Department of Energy Office of Science (DOE-SC), with financial support from and furthering the mission of the DOE-SC Office of Nuclear Physics. Hosting the most powerful heavy-ion accelerator, FRIB enables scientists to make discoveries about the properties of rare isotopes in order to better understand the physics of nuclei, nuclear astrophysics, fundamental interactions, and applications for society, including in medicine, homeland security, and industry.
The U.S. Department of Energy Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of today’s most pressing challenges. For more information, visit energy.gov/science.