Eur. Phys. J. A (2004) 22: 5-8
https://doi.org/10.1140/epja/i2004-10078-8

Letter

Observation of bound excited states in ¹⁵B

¹ Institut de Physique Nucléaire, IN2P3-CNRS, F-91406, Orsay Cedex, France
² Institute of Nuclear Research, Pf. 51, H-4001, Debrecen, Hungary
³ NSCL, Michigan State University, MI 48824-1321, East Lansing, USA
⁴ GANIL, B.P. 55027, F-14076, Caen Cedex 5, France
⁵ FLNR, JINR, 141980, Dubna, Moscow region, Russia
⁶ Laboratoire de Physique Corpusculaire, F-14050, Caen Cedex, France
⁷ IFIN-HH, P.O. Box MG-6, 76900, Bucarest-Magurele, Romania
⁸ Nuclear Physics Institute, AS CR, CZ-25068, Rez, Czech Republic
⁹ CSNSM, IN2P3-CNRS and Université Paris-Sud, F-91405, Orsay Campus, France

^* e-mail: domb@atomki.hu

Abstract

The structure of the A/Z = 3 nucleus ¹⁵B has been investigated using the in-beam -spectroscopy technique with a fragmentation reaction of a ³⁶S beam on a ⁹Be target at 77.5 . The fragments were identified and selected by their energy loss and time of flight using the SPEG spectrograph. -ray energies and intensities have been measured in coincidence with the projectile-like fragments. From this information as well as from the -coincidence relationships a level scheme is proposed for ¹⁵B 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.