Abstract
Low concentrations of Frenkel pairs are produced in polycrystalline iron and nickel targets during irradiations with 1.9 to 2.5 MeV electrons at 5 or 20 K. During irradiation (and subsequent thermal annealing for the nickel target) we simultaneously measure on the targets the changes of electrical resistivity, and of length with two different linear systems: a capacitive and an inductive device. The measured ratios of relative length to electrical resistivity increases are [(Δl/l)/Δρ]Fc = and [(Δl/l)/Δρ]Nj = 1020 ±120(Ωcm)−1. Values of Frenkel pair formation volumes of ν Fc = 1.35 ± 0.25 and ν Ni = 2.06 ± 0.30 atomic volumes are proposed.