The power of a T-REX with one MINIBALL - A low energy transfer study of 10,11,12Be

by Jacob Johansen

Wednesday 4 Jul 2012, 14:30 → 15:10 Europe/Zurich

26-1-0022 (CERN)

Low energy transfer experiments are ideal to probe single particle excitations in nuclei, and thereby study the shell evolution. In this talk, results from a transfer experiment using a 11Be beam incident on a deuteron target will be presented. The aim was to study the mixing of the p- and the sd-shell in both 11Be and 12Be, leading to the inversion of states in the prior and the breaking of the N = 8 magic number in the latter. The analysis showed furthermore interesting effects in the elastic scattering of 11Be on light targets. Effects, presumably caused by the halo structure of 11Be.

The experiment was performed at REX-ISOLDE using the T-REX and MINIBALL setup for charged particle and gamma detection. The setup proved extremely powerful, enabling a distinction between population of bound states with energy differences down to 5keV. This opened for the possibility of studying all bound states in 10,11,12Be separately. Furthermore decay studies of the long lived 0+_2 isomer and the lowest resonance in 12Be were performed using the MINIBALL’s germanium detectors for both gamma and neutron identification. The large angular coverage of the T-REX, from 8 to 150 degrees, along with the light particles in the reaction, enabled a study of the structure of the beam, which help improved the resolution of the calculated excitation spectra.

The focus of the talk will be on the analysis of the experimental data, including the beam diagnostic and the identification of the individual reactions. A short introduction to neutron rich beryllium isotopes and transfer reaction will be given in the beginning, and the final part of the talk will be on the theoretical interpretations of the data.