Close Frenkel pair recombinations were studied using programmed linear heating through substages IB and IC following irradiation at temperatures below 7 K. The resistivity of the platinum specimens was measured semi-continuously during annealing and corrections were made for the temperature coefficient of the resistivity increment due to the defects. This procedure yielded data of high density from which precise recovery curves could be constructed. The activation energies of the recovery processes were derived from the magnitude of the temperature shift at equal fractional recoveries with change in heating rate. Each substage is characterized by a range of energies and the energy spectrum is much broader after ion than after electron irradiations. The attempt frequency that corresponds to the vibrational mode of the interstitial that leads to recombination has also been determined for each substage.