The energy transferred to a copper surface by bombardment with Xe+, Ar+, and He+ ions with kinetic energies in the range 100-4000 eV has been studied by our group in previous experiments. There were significant experimental uncertainties for that data at energies below about 200 eV. The present investigation overlaps the previous work, extends the energy range to 10 eV, and includes data for Ne+. Particular emphasis is placed on the energy range below 200eV. A specially designed ion source was employed in these experiments. A polycrystalline copper film deposited onto a highly sensitive calorimeter was used as the target material. The results show that the Xe+ ion deposits more than 97% of its energy over the entire range investigated whereas the lighter ions deposit a decreasing fraction of their energy below about 1 keV. The decrease is largest for the lightest ion (He+). In all cases the deposited energy is about or more than 70% of the incident energy. It will be shown that the present results are in agreement with previous measurements for copper and are qualitatively in good agreement with computer calculations using the TRIM.SP code. © 1992 Springer-Verlag.