Level structure of ⁶⁹Se

Excited levels in ⁶⁹Se have been studied using the ⁴⁰Ca(³²S,2pn)⁶⁹Se reaction at 95- and 105-MeV beam energy. γ-rays have been detected with the EUROBALL spectrometer operated in conjunction with the wall and the charged-particle detector array EUCLIDES. New level sequences with positive and negative parities have been identified from n-γγ and n-γγγ coincidences. Spins have been assigned to many of the levels on the basis of angular distribution and directional correlation measurements. Excitation energies of the positive-parity yrast band and the branching ratios of its decay are compared with the predictions of the rigid triaxial rotor plus particle model.