Measurement of the current density profile of a pulsed electron beam for surface treatment

The current-density profile is a critical information when predicting or analyzing material surface treatment with electron beams. In this paper, a knife-edge technique was implemented in order to retrieve such profile for a pulsed-glow-discharge electron gun used for metal surface treatment. It was found that the beam has basically two components, one that is focused, and another that remains unfocused (homogeneous). The focused portion develops after the peak current is reached and remains focused for longer periods than predicted by previous models. The obtained profiles where used to determine the energy density (fluence) delivered to the target in order to understand the different patterns obtained for SAE4140 steel samples.