Because of their low penetration depth electrons are well suited to investigate metallic surfaces. One method to determine elements or impurities on a surface is Auger electron spectroscopy (AES), relying on the Auger effect and the low penetration depth of the electrons. Moreover, the interaction of electron beams with the free electron cloud in a metal allows excitation of plasmons. These plasmons are a collective motion of the free electrons and their energy, the so-called plasmon energy is determined with electron energy loss spectroscopy (EELS). Beside the physics of electron-matter interaction, knowledge about ultra-high vacuum technology, the Lock-In concept and the application of basic fitting routines are necessary for this experiment.