Reevaluation of the 22Na(p, γ) reaction rate

Abstract

Understanding the processes which create and destroy 22Na is important for diagnosing classical nova outbursts. Conventional 22Na(p,γ) studies are complicated by the need to employ radioactive targets. In contrast, we have formed the particle-unbound states of interest through the heavy-ion fusion reaction, 12C(12C,n)23Mg and used the Gamma-sphere array to investigate their radiative decay branches. Detailed spectroscopy was possible and the 22Na(p,γ) reaction rate has been re-evaluated. Hydrodynamical calculations incorporating the revised rate indicate a reduction in the yield of 22Na by a factor of four from previous estimates implying a reduction by a factor of two for the maximum detectability distance for 22Na γ rays from novae.