Dynamics of recontamination of laser-cleaned metallic surfaces in laser-produced plasma experiments

Natural impurity layers on Ta, W and Au surfaces have been shown to consist essentially of H, C and O atoms. If they are removed locally by a laser prepulse, recontamination occurs within a time scale of several seconds until saturation is reached. Under the high vacuum conditions used, it is found that recontamination is caused by the surface impurity atoms and that the influence of the residual gas can be neglected.