Study of the Beta-delayed multiple particle break-up of the 2.43 MeV state in Be-9

Abstract

The aim of this work is to study the β -delayed multiparticle break-up of the 5/2 − state in 9 Be at 2.43 MeV excitation energy. This process is relevant as it has been proposed recently that this level plays a role in the α(αn,γ) 9 Be reaction. This state breaks-up in 2α+n, and sequential as well as direct ("democratic") decay have previously been considered. In our work energy and direction of the two emitted α particles has been measured, while those of the neutron have been reconstructed. The sequential decay is considered using the R-matrix formalism. For the democratic decay the hyper-spherical harmonics functions are used. The different decay processes are compared with the data using the Monte-Carlo method. Our preliminary results indicate that the data is better described when democratic decay is assumed.