[Zurück]

R. Heller, W. Meissl, D. Schrempf, R.A. Wilhelm, D. Winklehner, S. Facsko, F. Aumayr:
"Electron emission statistics of slow highly charged ions during interaction with insulating surfaces";
Poster: 16th International Conference on the Physics of Highly Charged Ions (HCI 2012), Heidelberg/Germany; 03.09.2012; in: "Book of Abstracts, 16th International Conference on the Physics of Highly Charged Ions (HCI 2012)", (2012), S. 54.

The important role of highly charged ions (HCI) as a promising candidate for creation of
nanometer-sized surface structures has been demonstrated in several experiments in recent
years. The underlying physical processes of nano structure creation strongly differ for
different kind of target materials. Nevertheless, the majority of proposed models have one
point in common: They underline the major role of the electrons emitted by the projectile
during HCI neutralization above and below the surface.
Hence, a detailed understanding of the electron emission characteristics becomes more and
more necessary. Experiments observing the electron emission statistics of very slow highly
charged ions have been carried out so far only for metal surfaces [1,2]. For surfaces of
insulators measurements of the total electron emission statistic exist only for moderate ion
velocities between 1 and 5 keV/amu [3].
In this contribution we will present first results of electron emission statistic measurements for
highly charged Xenon ions (q≤44+) impinging on insulating surfaces of CaF2, KBr as well as
LiF at kinetic energies as low as 10 eV!q. This is well within a regime where kinetic electron
emission is not contributing to the total electron emission yield giving us the opportunity to
compare our results with predictions from the classical-over-the-barrier model. Our results
reveal an unexpectedly high electron emission yield on insulators even for lowest velocities.
The effect of projectile energy gain due to image charge acceleration can be derived from the
velocity dependence of the electron yield.