Background Free Measurement of the Spectra of Low Energy Electrons Emitted as a Result of Auger Transitions in Metals

TL;DR

This study uses positron annihilation induced Auger electron spectroscopy to obtain background-free spectra of Cu and Au, revealing a low energy tail caused by multi-electron processes during Auger transitions.

Contribution

It introduces a background-free measurement technique for Auger spectra that isolates low energy electrons and uncovers new multi-electron emission phenomena.

Findings

Identification of a low energy tail extending to 0 eV in Auger spectra.

Evidence of multi-electron ejection during Auger transitions.

Elimination of post-collision effects in the spectra.

Abstract

Positron annihilation induced Auger electron spectroscopy was used to obtain Cu and Au Auger spectra that are free of primary beam induced background by impinging the positrons at energy below the secondary electron emission threshold. The removal of the core electron via annihilation in the PAES process resulted in the elimination of post-collision affects. The spectrum indicates that there is an intense low energy tail (LET) associated with the Auger peak that extends all the way to 0 eV. The LET has been interpreted as being due to processes in which the filling of the core by a valence electron results in the ejection of two or more valence electrons which share the energy of the otherwise Auger electron