Internal conversion and summing effects in heavy-nuclei spectroscopy

Internal conversion of low-energy nuclear transitions occurs with a high probability in heavy nuclei. After the emission of the conversion electron, a cascade of X-rays, Auger or Coster-Kronig electrons takes place. In alpha-decay experiments in which the nuclei of interest are implanted into a silicon detector, these atomic processes contribute to the detected energy. To understand the distortions of the a-particle energy spectra, knowledge of the various atomic yields is required. Using state-of-the-art calculations, new atomic yields are computed in Es-99 and compared to those available in the literature. Detailed simulations of the Md-251(101) alpha decay are performed and compared to experimental data. Possible ways to discriminate between the available atomic yields are also discussed. (C) 2008 Elsevier B.V. All rights reserved.