Three SM-preforms with the same undoped OH-rich core material [1] and different fluorine content in the cladding are produced. From these preforms SM-fibers with different diameter are drawn and characterized by fiber diameter, cut-off wavelength, and effective V-parameter at 850 nm. The fibers are tested under continuous 60Co-irradiation and pulsed irradiation. All measurements are performed at about 850 nm wavelength and room temperature. Due to different power distributions in SM-fibers with different V-parameters, the influence of radiation induced attenuation in the fluorine doped silica cladding is examined and the dependence of this attenuation on the fluorine concentration is shown. In addition MM-fibers with same core material are irradiated as a reference for the core material.