Using GODDESS to Probe Nuclear Structure and Constrain Neutron Capture Rates

Chad Ummel, Rutgers University

Photo of Chad Ummel

Experimental measurements of the structure of nuclei near shell closures yield important information for understanding the evolution of nuclear structure away from stability, particularly in regions of the nuclear chart relevant to nuclear astrophysics and stockpile stewardship. Additionally, neutron-capture reaction rates on these nuclei are a sensitive input needed to understand the abundances of isotopes produced in high neutron flux environments. GODDESS (Gamma array-ORRUBA: Dual Detectors for Experimental Structure Studies), a coupling of the Oak Ridge Rutgers University Barrel Array (ORRUBA) of charged-particle detectors to a high-efficiency gamma-ray detector array, has been developed to facilitate both studies1. Measurements of (d,p) and (d,p gamma) reactions with ORRUBA and GODDESS have successfully constrained nuclear level energies and spin-parities, as well as spectroscopic factors necessary for inferring direct neutron capture cross sections. Additionally, a surrogate reaction method has been validated to extract compound (n,gamma) reaction cross sections from (d,p gamma) reaction measurements with GODDESS2. An overview of the capabilities of GODDESS as well as preliminary results from recent experiments will be presented.

1S.D. Pain, et al., Physics Procedia 90, 455 (2017).
2A. Ratkiewicz, et al., Phys. Rev. Lett. 122, 052502 (2019).

Abstract Author(s): Chad Ummel, on behalf of the GODDESS collaboration