Nuclear Reactions with Short-lived Nuclear Beams

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

The proposed project will involve the study of nuclear reactions utilizing short-lived radioactive nuclear beams (RNBs) together with the development of instrumentation, techniques, and apparatus to facilitate nuclear research in general and RNB studies in particular. Specific experiments will emphasize the investigation of the structure and reaction mechanisms of neutron- and proton-rich nuclei near the limits of nuclear stability. These studies are a continuation of a very successful program to elucidate the unusual effects that the exotic nuclear halo structure, which appears for weakly-bound systems at the limits of stability, has on various nuclear reactions. Another part of the project relates to the synthesis of elements in normal stars, as well as in supernova explosions and other extreme astrophysical environments. As appropriate, the work will be carried out at the University of Notre Dame (UND), Oak Ridge National Lab (ORNL), and possibly at the National Superconducting Cyclotron Laboratory (NSCL) . Finally, the production and properties of Fermium and trans-Fermium isotopes will be studied in collaboration with a group at Texas A&M University (TAMU), and other experiments using heavy-ion reactions at intermediate energies will be carried out. This work will involve the use of the UM BigSol 7T solenoid apparatus, which has been relocated to a dedicated beamline at the TAMU K500 superconducting-cyclotron laboratory and is now operational. Proposed technology development projects include an upgrade of the University of Michigan (UM) dual 6T superconducting solenoid ion-optical system (TwinSol ), presently at UND. Related to this, the construc- tion of an expanded particle-neutron coincidence detector array is proposed. This will upgrade the existing low-energy RNB facility to allow for more detailed studies of nuclear reactions with already-available beams, and for the development and use of new, higher-atomic-number (Z) beams. The proposed research will have an impact on graduate, undergraduate, and high school education, as well as on the development of a technologically- literate work force and the commercial applications of superconducting magnet technology. The project will involve graduate and undergraduate students from the University of Michigan and the University of Notre Dame, together with faculty members and students from several other (primarily undergraduate) schools located in the Midwest, in close proximity to UM and UND. The hands-on training of these students in the use of advanced, state-of-the-art computational methods, nuclear accelerators, radiation detectors, vacuum and cryogenic techniques, and superconducting ion-optical magnetic systems has already had an important impact on the development of a technologically-literate scientific workforce. Several of the graduate students and postdoctoral research associates who worked on this project in the past are currently employed in highly-responsible positions on national-security and medical-physics related projects. Still others hold tenured or tenure-track academic positions, often at primarily-undergraduate institutions with active research participation programs. The current proposal will allow for the continuation of this tradition, and for the initiation of a new pilot program that will involve high-school students from the socioeconomically-challenged New Buffalo, MI school district in physics-related research. This proposed research will also help in the development of instrumentation and techniques, together with future research personnel, that will be needed for the next generation of RNB facilities, and in particular for the planned US-based Rare Isotope Accelerator (RIA) . Finally, the development of precision high- field, large-bore superconducting magnetic solenoids with special design features (such as light-weight, low-loss aluminum cryostats) has had and will continue to have an impact on technology transfer to US-built commercial magnet systems used in a wide variety of important applications.