Characteristic X-rays generated by high-intensity laser interaction with solids were investigated and used for determining the resulting hot electron populations. Spectrally as well as spatially resolved data are evaluated for this purpose. The experimental data were compared with Monte Carlo simulations to determine the electron energy distribution and geometric features of the electron beam. These results are in good agreement with PIC simulations. The self-generated low-resistivity channel of the electron beam results in a distinct difference in the generated rear-side X-ray spot when the electron beam propagates in an insulator rather than a metal. Self-generated electric fields prevent electron propagation into the vacuum. This fact is used for demonstrating photopumping of cobalt with copper Kα radiation, an experiment relevant to innershell X-ray laser schemes. The emission of cobalt is compared with that of nickel, which is not photopumped by copper Kα, and is found to be enhanced by a factor of 2.5.