Stuttgart 2012 – scientific programme

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A: Fachverband Atomphysik

A 21: Poster: Precision spectroscopy of atoms and ions

A 21.6: Poster

Tuesday, March 13, 2012, 16:30–19:00, Poster.V

Electromagnetic decay of nuclei by electron-positron pair conversion — •Nikolay Belov and Zoltan Harman — Max-Plank-Institute for Nuclear Physics, Heidelberg, Germany

The pair production process by γ-emission of nuclei has been investigated for a long time both theoretically and experimentally. But, in all theoretical works only the production of a free electron and positron was described. The case when an electron is "born" in the bound state of atom has been neglected as a relatively small effect.

We investigate this bound-free pair productions for different multipolarities of nuclear γ decay. We use a relativistic description of the electron and positron wave functions as it is necessary for heavy elements. It appeared that the contribution of this bound-free process for bare heavy ions at low γ-energies gives a contribution comparable to the free-free process.

These results for the bound-free pair production in bare or highly-stripped ions could be relevant in astrophysics, in the physics of heavy ion acceleration and in atomic spectroscopy.