Measurement of the Cross Section of the Astrophysically Significant Reaction 76Se(α,γ)80Kr

The p-nuclei are a group of 35 nuclides on the proton-rich side of the valley stability with A>56, which cannot be produced through either s- or r- processes. Though their exact production method is a matter of debate, one scenario involves consecutive (γ,n) photodisintegrations from r/s seed nuclei. As a branching point in this process, 80Kr is an isotope of interest and in particular, the magnitude of its related (γ,α) reaction rate has a significant impact on the abundance of the related p-nuclide, 78Kr. Determination of the cross section of the reverse kinematic reaction, 76Se(α,γ)80Kr (which is more practical to analyse), can be utilised to more accurately characterise this (γ,α) reaction rate. DRAGON was used to observe this forward reaction at an astrophysical energy. Upon investigation of the data set, no recoils could be identified from the background and steps were taken to calculate an upper-limit on the number of recoils present. From this value an upper-limit on the cross section was calculated, which was found to be significantly lower than the predictions of current theoretical models.