Speaker
Description
The 37Ar(p,γ)38K reaction plays a critical role in determining the abundances of several stable isotopes at the endpoint of rp-process nucleosynthesis in novae. To inform the astrophysical reaction rate of proton capture on 37Ar and guide any future direct measurements, a better understanding of the 38K energy levels above the 37Ar+p threshold is essential. Experimentally, these excited states of 38K just above the proton threshold may be probed through alternative, experimentally-accessible reactions.
To this end, the 39K(3He,αγ)38K reaction in regular kinematics was measured. The ATLAS accelerator at Argonne National Laboratory provided a beam of 3He at 30 MeV/u, which was incident on an enriched potassium-39 target. Gamma rays and charged particles were detected using the GODDESS system, comprised of the Oak Ridge Rutgers University Barrel Array (ORRUBA) for charged particles, and the Gamma Ray Energy Tracking In-beam Nuclear Array (GRETINA) for gamma rays. The spectroscopy provides information on the excited states of 38K, including those near the proton separation energy of 5.2 MeV. Experimental constraints on the energies and spin-parities of low-spin states in this region, which are of astrophysical importance, as well as their implications for the rp-process, will be discussed.