  Models for characterization of laser-accelerated electron via its produced
bremsstrahlung are provided for both thin and thick targets. An effective
temperature functional is proposed to overcome the so-called cold and hot
"temperatures" in the emission spectra, which are shown not to describe the
underlying electron energy distribution. In contrast, this functional allows
for identifying the real effect of a hot electron component. A false "heating"
effect due to added noise is also exposed. The models are shown to be in good
agreement with Monte Carlo simulations, as well as in good agreement with other
experimental methods when applied to experimental data.
