What is HRIBF

What is HRIBF
Holifield Radioactive Ion Beam Facility is operated as a National User Facility for the U.S. Department of Energy, producing high quality beams of short-lived, radioactive nuclei for studies of exotic nuclei and astrophysics research. These nuclei are produced when intense beams of light ions from the Oak Ridge Isochronous Cyclotron (ORIC) strike highly refractory targets. The radioactive isotopes diffuse out of the production target and are ionized, formed into a beam and mass selected. This technique of radioactive ion beam production is known as the isotope separator on-line (ISOL) technique and is illustrated below. The radioactive ion beam is then injected into the 25-MV Tandem, the world's highest voltage electrostatic accelerator.

An operational schematic of the ISOL technique at the HRIBF. Click on the image to see it alone.

HRIBF is the only facility in the world that provides accelerated beams of shortlived, neutron-rich species. Such beams are used with a variety of spectroscopic techniques to explore the structure of exotic nuclei. The resulting information provides invaluable input for nuclear theory as it struggles to develop the unified description of the nucleus. This work, augmented by reaction studies, illuminates the nature of proton and neutron motion in nuclei. Reactions with neutron-rich accelerated beams help us understand the synthesis mechanism of heavy and superheavy nuclei.

Nuclear structure research at HRIBF provides insight into the nature of the force that clusters protons and neutrons into a nucleus. HRIBF tests the limits of nuclear stability using intense beams above the Coulomb barrier and new techniques for detecting the shortest-lived proton-rich nuclei. These nuclei have exotic decay modes such as one- and two-proton emission.

HRIBF produces beams of radioactive nuclei with a wide range of easily variable energies and intensities sufficient to allow some of the first direct measurements of the nuclear reactions that power novae, X-ray bursts, and other stellar explosions. HRIBF's unique combination of high-quality radioactive beams with experimental equipment optimized for astrophysics has enabled high-precision measurements of stellar reactions with radioactive beams.

The unique capabilities of HRIBF allow the determination of how rapidly some isotopes are created in stellar explosions, and how quickly they may be destroyed, through direct measurements of reactions with radioactive beams. These measurements are required to reduce the large uncertainties in the prediction of the synthesis of many nuclides, including long-lived radioisotopes as well as those that comprise our world.

The questions that HRIBF tries to answer are the major questions that drive the field of low-energy nuclear physics:

  • How do protons and neutrons make stable nuclei and rare isotopes?
  • What is the origin of simple patterns in complex nuclei?
  • What are the heaviest nuclei that can exist?
  • When and how did the elements from iron to uranium originate?
  • How do stars explode?
  • What is the nature of neutron star matter?
  • How can our knowledge of nuclei and our ability to produce them benefit the humankind?

A short 1-page description of HRIBF is available:

HRIBF 1-page Flyer (2007) (pdf)
A version of our most recent brochure is available. When printed on 1 sheet of 7.5x17 paper it is designed to fold into 6 sections.
Page 1 (pdf)
Page 2 (pdf)
Be sure to check out our recent science highlights intended for the general public. Links are found on our outreach webpages.

For questions about this page please contact the HRIBF User Liaison.

This file last modified Sunday November 20, 2005