Production of 6He and 9Be by radiative capture and four-body recombination

Abstract

In this work we estimate the production rates for the three-body radiative capture processes α + n + n → 6He + γ and α + α + n → 9Be + γ, as well as the four-body recombination reactions α + α + n + n → 6He + α, α + n + n + n → 6He + n, α + α + n + n → 9Be + n and α + α + α + n → BeBe + α. These processes compete as a source of 6He and 9Be. The hyperspherical adiabatic expansion method is used. With this method no assumption is made about the capture mechanism. Both sequential and direct capture are included. The production rates for the radiative and the four-body recombination processes are found to be comparable for a mass density of about 107g/cm3 ( ∼ 1030 neutrons/cm3) and temperatures of a few GK.