Can multiple structures in positron spectra be caused by atomic effects?

In recent experiments at least two structures have been detected in positron spectra from subcritical (total charge Z ≦ 174) heavy-ion collisions at bombarding energies ELab=5.7-5.9 MeV/n. The origin of these structures is unexplained up to now. Atomic effects have already been discussed as a possible source in a previous paper, where a schematic ansatz for the electronic transition matrix elements was employed. Meanwhile numerical calculations for K-vacancy formation also exhibited oscillations in the impact parameter dependence when using this ansatz. In this paper we report on a scaling law describing these oscillations. As a consequence certain subsidiary conditions have to be imposed on our schematic ansatz, which in turn yield a new understanding on eligible atomic sources for multiple structures in the emission spectra of positrons. © 1988 Springer-Verlag.

Duke Scholars

Author Berndt Mueller Physics