In the lucky drift model for impact ionization, it is assumed that some lucky carriers are accelerated ballistically (i.e. without scattering) to energies above threshold, causing impact ionization. Assume that average relaxation time is 0.05 ps. At approximately what electric fields will 0.1% of the electrons acquire threshold energy in GaAs and in Si? Assume that at high energies the electron mass is the free electron mass.