Investigation on the intensity contrast of Kα line emission from laser–matter interactions

Abstract

The intensity contrast and its angular distribution of Kα line emission originated from the difference of angular distributions of Kα and bremsstrahlung emissions from copper foil targets bombarded by electrons similar to the hot electrons generated in laser–matter interactions are investigated by Monte Carlo simulations. For mono-energetic electron incidences, a higher contrast Kα emission is generated at large detection angles relative to the incident electron direction and for higher electron energy. The Kα emission contrast is decreased with the increase in target thickness. When the areal density of targets is fixed, the contrast is almost unchanged with the change of target density and thickness. For incident electrons with a Boltzmann energy distribution, a higher contrast Kα emission can also be generated at large detection angles and for higher electron temperatures, but the contrast is lower compared to that for mono-energetic electron incidences, and it is changed only slightly with the increase in target thickness. These results help to understand the contrast of Kα emissions in previous experiments. Suggestions are proposed for future laser–matter interaction experiments for higher contrast Kα emissions.