Study of 9He nucleus via the transfer reaction d(8He, p) at 15.4 MeV/n.

15h - LPC Caen - Salle Gilles Iltis

The study of the light neutron-rich nuclei at the limits of stability and beyond is an area of considerable interest as it affords an extreme test of our understanding of nuclear structure. Experimentally, the recent availability of radioactive beams with significant intensities and the development of new high acceptance detection systems have permitted such systems to be explored.

This thesis deals with a study of the structure of the unbound N=7 system 9He via the single-neutron transfer reaction d(8He,p)9He at the SPIRAL1 facility.  The principal goal of the experiment was to clarify the low-lying level structure of 9He, in particular the possible parity inversion of the ground state. The experiment was one of the first to employ the new MUST2 Si array.

Owing to the relatively low statistics in the region of threshold and various backgrounds, no definitive conclusion could be drawn regarding the character of the lowest lying state.  Higher lying states were identified.  Comparison is made with the angular distributions derived for each of the resonances and DWBA and CRC calculations.  For each of the possible spin assignments, spectroscopic factors have been estimated.