“Caracterização de feixes eletrônicos monoenergéticos de baixas energias”

Abstract

In a variety of spectroscopic techniques of electron impact on gaseous samples, it is essential to use electron beams of low energy focused, collimated and monochromatized. The electron beam intensity should be such that it is possible to perform data acquisition in minimal period time, with good statistics. The requirement of electron beam monochromatization ensures to get as much information of a spectrum. It is in the low-energy electron incident that important processes occur, such as distortions in the electron cloud of the target, polarization effects, exchange effects and electron capture. However, it is precisely in this energy range where the experiments are more difficult to run due to the high sensitivity of the incident and scattered electron beam. In this work, we developed first in this country an electron gun for low energies, producing monochromatized electron beams. The electron gun has been carefully characterized in terms of intensity of the incident electron beam and its capacity of monochromatization, reaching values of energy of 0.105 eV and beam intensities up to 280 nA of 170 eV.