Transmission electron microscopy observation of cross-sectional specimens prepared by focused ion beam milling method have been applied to study the deep radiation damage and depth profile of point defects generated during ion irradiation in Cu–1 mass%Co alloy specimens by means of coherent precipitates. The specimens were irradiated at a temperature range of 250 to 500°C by 4 and 0.6 MeV self Cu ions to a dose of 0.3 dpa. The damage range has been observed at depths well beyond that expected from ion damage range calculations.