The contactless microwave reflectivity technique was used to measure the transient free carrier density following the creation by a pulsed electron accelerator of electron‐hole pairs in arsenic‐doped silicon at 7°K. The experiments were directed at providing supporting evidence for the Auger recombination mechanism postulated by Nelsonet al. as being operative in the decay of excitons bound at neutral donors in silicon. The results contrast distinctly with the results of similar experiments on semiconductors containing isoelectronic traps by showing a strong post excitation conductivity. Differential equations, describing the model of Auger decay and including the important effects of residual acceptors, are formulated and solved numerically. At high excitation levels the theoretical profiles depend weakly on unknown capture cross‐sectional parameters and agree well with the experimental profiles. At lower excitation levels, the predicted profiles have a stronger dependence on the values of the unknown parameters, but, assuming reasonable values, good fits to the experimental data are obtained. It is therefore concluded that conductivity associated with Auger electrons has been observed.