First experimentally-determined ^93,94,95Sr(n,γ)^94,95,96Sr cross section via the β-Oslo Method

Our understanding of nuetron-induced reactions on nuclei far from stability has far reaching implications for cosmogenic nucleosynthesis and fundamental nuclear phyics. Direct measurement of the radiative-capture cross section is experimentally inaccessible for these short-lived nuclei; however, indirect methods such as the β-Oslo Method enable the experimentally constraint of key nuclear properties that are inputs for reaction-theory calculations.

At Argonne National Laboratory, an experiment was performed to determine the γ-ray strength function (γSF) and nuclear level density (NLD) for ^94,95,96Sr isotopes using high-intensity Californium Rare Isotope Breeder Upgrade beams. Radioactive beams of ^94,95,96Rb β decay to populate highly excited states in ^94,95,96Sr. The γ decay of these states is measured using total absorption spectroscopy. From the measured γ-ray spectra, the γSF and NLD are extracted using the β-Oslo Method. These experimentally-determined nuclear statistical properties significantly reduced the uncertainty in the resulting Hauser-Feshbach calculated neutron-capture reaction rates. The preliminary results of this work include the NLD, γSF, and ^93,94,95Sr(n,γ)^94,95,96Sr cross section. Furthermore, this work will shed light on nuclear structure properties for Sr isotopes, leading to significantly improved predictive reaction modeling.