Direct measurement of nuclear cross sections of astrophysical relevance at LUNA: The 22Ne(p,γ)23Na reaction

Most of the elements constituting the universe were produced in stars through a series of nuclear reactions. LUNA performs direct measurements of nuclear cross sections relevant to astrophysics, taking advantage of the low background at LNGS. The 22Ne(p,γ)23Na reaction rate, which belongs to the NeNa cycle of hydrogen burning, has been recently studied. Its rate is still very uncertain because of a lot of resonances lying inside the Gamow window. LUNA discovered three new resonances using two high-purity germanium detectors and considerably improved the existing upper limits on the lower energy resonances using a highefficiency optically-segmented BGO crystal