For estimating the final spatial resolution of lithography using ionizing radiation as a light source, the migration distances of electrons in gamma-irradiated cryogenic organic matrices of polar alcohols and nonpolar methylcyclohexane have been determined by analyzing the transverse and the longitudinal electron spin-echo relaxations of radical pairs generated from the electrons and their counterpart cations. The intrapair distance of the radical pairs does not depend on the concentration of electron scavengers, which indicates that ejected electrons react with scavengers after losing their kinetic energies and being stabilized as trapped electrons. The intrapair distance decreases with increasing the concentration of polar molecules in the matrices, which indicates that charge-dipole interactions with polar molecules play significant roles in the slowing down process of the ejected electrons.