Speaker
Description
The XT03 beamline at HIE ISOLDE provides a versatile station for reaction studies, centred on the SEC chamber, which has hosted numerous experiments during its first decade of operation. Halo nuclei such as ¹¹Li and ¹⁴Be offer a unique opportunity to investigate di neutron correlations and the evolution of shell structure in light neutron rich systems.
The ground state of ¹¹Li contains mixed p, s, and d components, and its low energy continuum shows broad dipole type strength together with narrower resonances at higher excitation energies. However, the lowest resonance near 1 MeV remains poorly constrained. Studies of the N = 7–8 isotonic chains reveal significant shifts of the neutron orbitals, leading to the ½⁺/½⁻ inversion in ¹¹Be and the breakdown of the N = 8 magic number in ¹²Be, highlighting the need for reliable information on the unbound nucleus ¹³Be.
Transfer reactions with radioactive beams in inverse kinematics provide a sensitive probe of these structures. Two neutron transfer from ⁹Li is predicted to populate selectively the ground and low lying excited states of ¹¹Li. At ISOLDE, we investigate (t,p) reactions on ⁹Li and ¹¹Be at 7 MeV/u and 5.4 MeV/u to study the low energy excitations of ¹¹Li and the resonant states of ¹³Be. This contribution presents the SEC setup and the first results from these measurements.
