Experimental evidence of 2He decay from 18Ne excited states

Two-proton decay from Ne-18 excited states has been studied by complete kinematical reconstruction of the decay products. The Ne-18 nucleus has been produced as a radioactive beam by Ne-20 primary projectile fragmentation at 45 AMeV incident energy on a Be target. The Ne-18 at 33 AMeV incident energy has been excited via Coulomb excitation on a Pb-nat target. The obtained results unambiguously show that the 6.15 MeV Ne-18 state two-proton decay proceeds through a He-2 diproton resonance (31%) and democratic or virtual sequential decay (69%). The quoted branching ratio has been deduced from relative angle and momentum correlations of the emitted proton pairs.