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Physics Topics


Capitalizing on the strengths of nine collaborating research universities and the world-class equipment available at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL), the University Radioactive Ion Beam (UNIRIB) consortium is conducting research at the forefront of nuclear physics.

UNIRIB, a division of the Oak Ridge Institute for Science and Education (ORISE), brings together researchers from around the world to study the short-lived, exotic nuclei that are involved in astrophysical processes. UNIRIB researchers participate in many of the nuclear physics experiments carried out at HRIBF.

UNIRIB researchers are presently leading the following physics topics. To view these files, you will need the Adobe Reader, which is available free on the Adobe Support Site.

Fine Structure Studies in Proton Emission (PDF)
The study of fine structure in from the radioative decay mode known as proton emmision allows one to understand the evolution of single particle wavefunctions and deformations beyond the proton drip line. 

Alpha Emission Near 100Sn and the Termination of the rp Process (PDF)
The endpoint of the astrophysical rapid proton (rp) process is determined by the rate of proton capture on successively heavier nuclei. This rate is dependent on the difference in mass of the nuclei involved. By measuring the decays of nuclei near 100Sn, we can calculate where the rp process will stop.

Deviations from U(5) Symmetry in 116Cd (PDF)
The neutron-rich even-even Cd isotopes are often cited as textbook examples of vibrational nuclei and the best examples of U(5) symmetry. Nuclei that are close to the limits of U(5) symmetry would be expected to exhibit harmonically spaced multiphonon states. However, this simple picture is at odds with the experimental data for 116Cd leading to the conclusion that the Cd isotopes are far more complex than previously assumed.

Study of Single Particle States Near the Doubly-closed Shells of 132Sn and 78Ni
Investigations into the low-energy structure of nuclei via their decays around these double shell closures are vital for determining the single particle levels and two body interactions in valence nuclei. By performing experiments in these areas it becomes possible to determine the strength of the shell closure and the validity of theoretical predictions.