We have performed a study of the temperature dependence of the S-parameter on slightly deformed (7%) copper over a temperature range from room temperature (300 K) down to 7 mK, using a (3)He/(4)He dilution refrigerator. The sample used is expected to contain a spectrum of lattice defects with both deep and shallow traps. The data show a decrease of the S-parameter with temperature down to about 1K and a slight increase below 800 mK.