Decay path measurements for the 2.429 MeV state in Be-9: Implications for the astrophysical alpha+alpha+n reaction

Abstract

An experiment was performed at the Australian National University to study the Be-9(Li-6,Li-6)Be-9(*) -> alpha + alpha + n reaction. This experiment was designed to study the breakup of Be-9, in an attempt to quantify the contribution played by the He-5 + alpha and Be-8(2+) + n channels for the low lying excited states. This information is required in order to resolve uncertainties in the alpha + alpha + n -> Be-9 reaction rate in high-energy and neutron-rich astrophysical environments such as supernovae. Angular correlation measurements have been used to deduce that the 2.429 MeV state breaks up almost exclusively via the Be-8(2+) channel. This method of identifying the break-up channel resolves the problem of distinguishing between the Be-8(2+) and He-5(g.s.) channels which are kinetically identical at this excitation energy.

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