Study of forward accelerated fast electrons in ultrashort Ti Ká sources

The results of an experiment aimed at studying hot electrons emerging from a target rear side in ultrashort laser-based [ ]Ka sources are described. In particular, forward accelerated fast electrons propagating through a Ti foil are found to be emitted in a cone perpendicular to the target surface. The energy of these electrons is estimated as well as their divergence. A comparison of the experimental findings with the results of a PIC simulation is also reported, aimed at identifying the physical processes responsible for the production of this forward propagating electron population.