[en] The number of Frenkel pairs produced per ion was measured at 5 K for various heavy ion irradiations of thin chromium films. Values much lower than those predicted by transport theory were found. The divergence of experimental and theory was correlated with the maximum elastic deposited energy density and the average concentration of Frenkel pairs. For a given ion mass, the rate at which the damage annealed out of the chromium films was dependent on the irradiation energy. The difference between the annealing rates of 20 and 100 keV ion induced damage was most prominent for the heavier masses (I⁺, Br⁺). The presence of unannealed damage at 80K suggest that at least some clustering of defects did occur. For the 20-50 keV/atom range, N⁺ and N₂⁺ ions of equal velocities had the same defect production rate. No difference in the annealing rates of the damage from these two beams was detected. It is speculated, however, that a higher mass atom would have different damage rates (per atom) associated with its monomer and dimer ions of equal velocity