Abstract Damage formation in 〈1 1 1〉-oriented CdTe single crystals irradiated with 270 keV Ar ions at fluences ranging from 1.0 × 10 11 to 6.0 × 10 16 cm −2 was investigated in-situ using Rutherford backscattering spectrometry (RBS) in channeling configuration. Irradiation and subsequent analysis were performed at 15 K without changing the target temperature. CdTe is not rendered amorphous even after irradiation with several 10 16 cm −2. Defect profiles calculated from the RBS channeling spectra using the computer code DICADA show the formation of a broad defect distribution which extends much deeper into the crystal than the projected range of the implanted ions. Energy-dependent RBS channeling analysis was used to identify the defects as predominantly uncorrelated displaced lattice atoms.