The reaction of triple radiative capture alpha alpha(n,gamma)Be-9 studied in a beta decay of Li-9

A new way of study the reaction of triple radiative capture alpha alpha(n,gamma)Be-9 is demonstrated. At the GSI-ISOL facility, we have measured the gamma decays of excited 1/2(+), 5/2(-) and 1/2(-)states in Be-9, which are strongly populated in the beta decay of Li-9. The respective partial gamma-widths are of astrophysical interest in order to reliably estimate the alpha alpha(n,gamma)Be-9 rates in SN type-II as a possible site of the synthesis of heavy elements in the Universe. The Li-9 nuclei were implanted into a foil viewed by high-granularity arrays of beta and gamma detectors. The gamma-ray spectra were measured in coincidence with the beta-particles by selecting large beta-gamma angles in order to suppress the bremsstrahlung background. For the first time, the gamma-rays from the 1/2(+) and 5/2(-) states in Be-9 were observed in Li-9 decay, with the 1/2(+)-state energy and width measured to be 1689(10) and 224(7) keV, respectively, while the latter transition provided a reference point. The upper limit of the 1/2(-) partial gamma-width is measured to be 7-10(-6) MeV. An improved sensitivity experiment is feasible at facilities with the larger yield of Li-9.