Using GODDESS to Constrain Neutron Capture Rates

Chad Ummel, Rutgers University

Photo of Chad Ummel

Neutron-capture reaction rates are a sensitive input needed to understand the abundances of nuclei produced in high-neutron flux environments relevant to both nuclear astrophysics and stockpile stewardship. Due to the short half-lives of many of the isotopes relevant to these studies, direct measurements of their cross sections often are not possible. However, radioactive ion beam facilities make possible the study of many short-lived nuclei via indirect methods. Measurements of (d,p) reactions with the Oak Ridge-Rutgers University Barrel Array (ORRUBA) silicon detector array have successfully constrained 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 measurements1. The coupled GODDESS (Gamma array-ORRUBA: Dual Detectors for Experimental Structure Studies) detectors enable such studies2. An overview of the capabilities of GODDESS as well as preliminary results from the 2019 GODDESS campaign will be presented. 1A. Ratkiewicz, et. al., Phys. Rev. Lett. 122, 052502 (2019). 2S.D. Pain, et. al., Physics Procedia 90, 455 (2017).

Abstract Author(s): Chad Ummel, on behalf of the GODDESS, ORRUBA and GRETINA collaborations