Comparative study of different wavelengths from IR to UV applied to clean sandstone

The dependency of ablation rate and wavelength is studied by means of an exemplary chosen sort of sandstone in order to determine the cleaning regime and the feasibility of different wavelengths for practical cleaning. Excimer laser radiation KrF, XeCl.and Nd:YAG laser radiation v, 3v. were used for the ablation of the black crust and sandstone in two independent experiments with a constant number of pulses. q2000 Elsevier Science B.V. All rights reserved