EGAS41 - Swansea University

41 st EGAS CP 137 Gdańsk 2009
Influence of target surface contamination on experimental UHV
screening energies
N. Targosz-Ślȩczka1 , K. Czerski 1,2 , A. Huke 2 , L. Martin 2 , P. Heide 2 , A.I. Kilic 1 ,
D. Blauth 3 , H. Winter 3
1 Institute of Physics, University of Szczecin, ul. Wielkopolska 15, 70-451 Szczecin, Poland
2 Institut für Atomare Physik und Optik, Technische Universität Berlin, Hardenbergstr. 36,
10623 Berlin, Germany
3 Institut fr Physik, Humboldt-Universitt zu Berlin, Berlin, Germany
The enhanced screening of the nuclear Coulomb potential due to the atomic electrons has
lead been confirmed in many laboratory experiments. The electron screening effect in
astrophysical plasmas can enhance nuclear reaction rates in the interior of stars by many
orders of magnitude.
However, a reliable comparison between experimental data and theoretical predictions
is still ambiguous because of some systematic errors in experiments. The measurements
on deuterium inside metals are heavily affected by the formation of surface contamination
layers under beam irradiation even in ultra-high vacuum (UHV) system.
Here, we present our recent experimental results obtained for deuteron fusion reactions
taking place in the metallic Zr environment and give some rigorous calculations of the
influence of surface contamination layers on UHV experimental data. We thoroughly
analyzed the ion induced chemical surface reaction mechanisms and their influence on the
obtained screening energies. Our investigations show that this process has crucial impact
on the interpretation of the raw experimental data.
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