Observation of bound excited states in $^{15}$B

M. Stanoiu (1) , M. Belleguic (1) , Zs. Dombrádi , D. Sohler , F. Azaiez (1) , B.A. Brown , M.J. Lopez-Jimenez (2) , M.G. Saint-Laurent (2) , O. Sorlin (1) , Yu. E. Penionzhkevich , N.L. Achouri (3) , J.C. Angélique (3) , C. Borcea , C. Bourgeois (1) , J.M. Daugas (2) , Francois de Oliveira Santos (2) , Z. Dlouhy , C. Donzaud (1) , J. Duprat (1) , S. Grévy (3) , D. Guillemaud-Mueller (1) , S. Leenhardt (1) , M. Lewitowicz (2) , S.M. Lukyanov , W. Mittig (2) , M.G. Porquet (4) , F. Pougheon (1) , P. Roussel-Chomaz (2) , H. Savajols (2) , Y. Sobolev , C. Stodel (2) , J. Timár

1 IPNO - Institut de Physique Nucléaire d'Orsay
2 GANIL - Grand Accélérateur National d'Ions Lourds
3 LPCC - Laboratoire de physique corpusculaire de Caen
4 CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse

The structure of the A/Z = 3 nucleus $^{15}$B has been investigated using the in-beam $\gamma$ -spectroscopy technique with a fragmentation reaction of a $^{36}$S beam on a $^{9}$Be target at 77.5 MeV. The fragments were identified and selected by their energy loss and time of flight using the SPEG spectrograph. $\gamma$ -ray energies and intensities have been measured in coincidence with the projectile-like fragments. From this information as well as from the $\gamma\gamma$ -coincidence relationships a level scheme is proposed for $^{15}$B up to the neutron separation energy. The experimental results have been interpreted using shell model calculations in the psd valence space. Effects of the weakly bound nature of the valence neutrons have been observed.

Mots clés: Projectile and target fragmentation; gamma transitions and level energies

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

M. Stanoiu, M. Belleguic, Zs. Dombrádi, D. Sohler, F. Azaiez, et al.. Observation of bound excited states in $^{15}$B. European Physical Journal A, 2004, 22, pp.5-8. ⟨10.1140/epja/i2004-10078-8⟩. ⟨in2p3-00023405⟩