Measurement of ³⁹K(³He,αγ)³⁸K to Inform ³⁸K Energy Levels and the ³⁷Ar(p,γ)³⁸K Reaction Rate

The ³⁷Ar(p,γ)³⁸K reaction rate is important within the rp-process reaction network, influencing the final isotopic abundances at the endpoint of nova nucleosynthesis. Currently, there is little experimental information on ³⁷Ar(p,γ)³⁸K. Previous works have focused on ³⁸K(p,γ)³⁹Ca and have not been able to resolve discrepancies between observed and modelled abundances of ³⁹K. The ³⁷Ar(p,γ)³⁸K reaction could be the input needed to resolve these discrepancies. There is also little information on the energies and spin-parities of states in the ³⁸K nucleus; measuring the ³⁹K(³He,α)³⁸K reaction informs on these properties and could help constrain the ³⁷Ar(p,γ)³⁸K reaction rate calculation. The ³⁹K(³He,α)³⁸K reaction was measured at the ATLAS facility with GODDESS, the coupling of the ORRUBA charged particle detector array and GRETINA, a germanium γ-ray tracking detector array. This talk will cover preliminary results from particle-γ coincidences examining the energies and spin-parities of states up to 600 keV above the ³⁷Ar+p threshold of ³⁸K.