Study of the reactions 9Be(n, α)6He and 9Be(n, αα)nn at 14.1 MeV

The differential cross sections for the reactions 9Be(n, α0)6He(g.s.) and 9Be(n, α1)6He* and the α-α particle-correlation spectrum from the 9Be(n, αα)nn reaction have been measured using 14.1MeV neutrons. The measured angular distributions of α-particles were in good agreement with those of Perroud and Sellem at 13.99MeV, and were compared with DWBA calculations. The spectroscopic factors for the cluster transfer reactions on 9Be have been deduced. The observed correlation spectrum implies that this four-body breakup reaction is dominated by a sequential decay process in the measured α-particle energy region. The second and third excited states in 6He have been confirmed to be located at around 3.4MeV and 6.0MeV, respectively. (author)