Speaker
Francesca Renzi
(KU Leuven Department of Physics and Astronomy Instituut voor Kern-en Stralingsfysica)
Description
The unbound nucleus $^7$He has attracted the interest of several research groups in
recent years. However, despite a significant number of experiments, an
unambiguous information about $^7$He excited states is still lacking, in particular
for the first excited 1/2- state [1-5]. This state is considered the spin-orbit partner of $^7$He ground state. The importance of the spin-orbit interaction in the vicinity of the neutron drip line for shell model calculation highlights the need of additional experimental investigations.
In this talk we will report a measurement performed at the LLN facility using a
$^6$He beam at 16.8 MeV impinging on a highly pure and self-supporting $^9$Be target.
The detection system consisted of two arrays of silicon-strip detectors covering
5-12 degrees and 22-70 degrees in the laboratory system. In these different
angular ranges diverse mechanisms may be predominant. Indeed, the $^7$He states can
be populated via both 1-neutron ($^6$He,$^7$He) and 2-protons ($^6$He,$^8$Be) transfer
reactions. In both cases, thanks to the signature provided by the decay of the
outgoing $^8$Be, the decay energy spectrum for $^7$He was obtained via the resonant
particle spectroscopy technique. The energy spectrum has been analysed combining
an extended Monte Carlo simulation with the R-Matrix theory.
This work will present the spectroscopic information obtained from the decay
energy spectrum for $^7$He.
[1] D. R. Tilley, et al., Nucl. Phys. A 708, 3 (2002)
[2] F. Skaza, et al., Phys. Rev. C 73, 044301 (2006)
[3] G.V. Rogachev, et al., Phys. Rev. Lett. 92, 23 (2004)
[4] N. Ryezayeva, et al., Phys. Lett. B 639, 623 (2006)
[5] A.H. Wuosmaa, et al., Phys. Rev. C 78, 041302 (2008)
Primary author
Francesca Renzi
(KU Leuven Department of Physics and Astronomy Instituut voor Kern-en Stralingsfysica)
Co-authors
Dr
Alain Gillibert
(CEA-SACLAY DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette, France)
Dr
Alain Ninane
(Centre de Recherches du Cyclotron, Chemin du Cyclotron, 2, B-1348, Louvain-la-Neuve, Belgium)
Dr
Alexandre Obertelli
(CEA-SACLAY DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette, France)
Dr
Carmen Angulo
(Centre de Recherches du Cyclotron, Chemin du Cyclotron, 2, B-1348, Louvain-la-Neuve, Belgium)
Dr
Enrique Casarejos
(Centre de Recherches du Cyclotron, Chemin du Cyclotron, 2, B-1348, Louvain-la-Neuve, Belgium)
Dr
Flore Skaza
(CEA-SACLAY DSM/DAPNIA/SPhN F-91191 Gif-sur-Yvette, France)
Dr
Giacomo Randisi
(KU Leuven, Instituut voor Kern- en Stralingsfysica, Belgium)
Dr
Jean-Luc Chavret
(CEA-SACLAY DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette, France)
Dr
Jean-Luc Sida
(CEA-SACLAY DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette, France)
Dr
Juan Cabrera
(Centre de Recherches du Cyclotron, Chemin du Cyclotron, 2, B-1348, Louvain-la-Neuve, Belgium)
Dr
Laurent Nalpas
(CEA-SACLAY DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette, France)
Dr
M. Nigel Orr
(Laboratoire de Physique Corpusculaire, IN2P3-CNRS, ISMRA et Universite’ de Caen, F-14050 Caen Cedex, France)
Prof.
Riccardo Raabe
(KU Leuven, Instituut voor Kern- en Stralingsfysica, Belgium)
Prof.
Roman Wolski
(Flerov Laboratory of Nuclear Reactions, JINR, 141980, Dubna, Russia)
Dr
Sergey Ivanovich Sidorchuck
(Flerov Laboratory of Nuclear Reactions, JINR, 141980, Dubna, Russia)
Dr
Thomas Keutgen
(Centre de Recherches du Cyclotron, Chemin du Cyclotron, 2, B-1348, Louvain-la-Neuve, Belgium)
Dr
Valerie Lapoux
(CEA-SACLAY DSM/DAPNIA/SPhN F-91191 Gif-sur-Yvette, France)
