Decay spectroscopy of element 115 daughters:280Rg → 276Mt and 276Mt → 272Bh

Forty-six decay chains, assigned to the decay of (288)115, were produced using the Am-243(Ca-48, 3n) (288)115 reaction at the Lawrence Berkeley National Laboratory 88-in. cyclotron. The resulting series of a decays were studied using alpha-photon and alpha-x-ray spectroscopies. Multiple alpha-photon coincidences were observed in the element 115 decay chain members, particularly in the third-and fourth-generation decays (presumed to be (280)Rg and (276)Mt, respectively). Upon combining these data with those from 22 (288)115 decay chains observed in a similar experiment, updated level schemes in (276)Mt and (272)Bh (populated by the alpha decay of (280)Rg and (276)Mt, respectively) are proposed. Photons were observed in the energy range expected for K x rays coincident with the a decay of both (280)Rg and (276)Mt. However, Compton scattering of higher-energy gamma rays and discrete transitions are present in the K x-ray region preventing a definitive Z identification to be made based on observation of characteristic K x-ray energies.