Abstract

Low energy electrons (0 – 10+ eV) play an important role in present day science and technology. After a brief presentation of the most important applications and the challenges associated with them, the talk will focus on the understanding of the fundamental mechanism for secondary electron emission and prediction of the secondary electron yield (SEY) based upon it. The question on the availability of fundamental parameters entering the common models is discussed and some approaches to obtain consistent values for important parameters such as the work function, the electron affinity and most importantly, the inelastic mean free path are presented. The second part of the talk will focus on an experimental approach aiming to directly observe the energy and momentum transfer from the primary particle inducing the secondary electron to the ejected secondary electron by measuring the two involved particles in coincidence. In this way it is generally possible to relate the energy loss processes (e.g. plasmon excitation) to the electronic channel of energy dissipation. In the case of HOPG , this turns out to be mediated by both the dielectric response as well as the band structure of the solid. This plasmon decay spectroscopy technique is discussed and first results are presented.