Etude de la structure des noyaux non liés $^{7,9}$He et $^{10}$Li

Abstract : The unbound nuclei 7,9He and 10Li have been investigated via the high-energy breakup of beams of neutronrich nuclei (8He, 11Be and 14B). The decay-energy spectra were reconstructed from coincident measurements of the charged fragments (6,8He and 9Li) with a [DELTA]E-E telescope (CHARISSA) and the neutrons with the DEMON array. A theoretical approach based on the sudden approximation was used to model the reactions populating the unbound final states. The calculated decay-energy spectra were convoluted with the response function of the experimental setup using a simulation developed specifically for the present study and compared with the experimental results. The 10Li system was produced using an 11Be beam and the results confirm the continuation of the inversion of the º1s1/2 and º0p1/2 levels in the N = 7 isotopic chain. The 9He system was produced in two difierent ways with the breakup of 11Be and 14B, and was the most exotic system studied here. In this case, a structure was observed at very low decay energy which very probably corresponds to a virtual s state (as u -2-0 fm). This result suggests that the level inversion also occurs in 9He, but with a much weaker core-neutron interaction than for 10Li (as = -14 ± 2 fm). For the data acquired from the breakup of the 14B beam, the decay energy spectrum exhibits a resonance around Er = 1.2 MeV, which most probably corresponds to an excited 1/2- state in 9He. The 7He system was investigated with three different beams (8He, 11Be and 14B). No evidence for the existence of the proposed low-lying (Er » 1 MeV) spin-orbit partner (1/2-) of the ground state (3/2-) could be found.
Document type :
Physique Nucléaire Théorique [nucl-th]. Université de Caen, 2007. Français
Contributor : Sandrine Guesnon <>
Submitted on : Tuesday, January 22, 2008 - 3:32:25 PM
Last modification on : Wednesday, July 1, 2015 - 1:09:00 AM
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  • HAL Id : tel-00212214, version 1



H. Al Falou. Etude de la structure des noyaux non liés $^{7,9}$He et $^{10}$Li. Physique Nucléaire Théorique [nucl-th]. Université de Caen, 2007. Français. <tel-00212214>




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