A method for reducing or removing organic and/or inorganic contamination from a vacuum system of imaging and analytical devices, wherein at least a portion of the area of the inner surface of the vacuum space of the vacuum system is provided with a photocatalytic layer, at least a portion of this photocatalytic layer being cooled to a temperature in the range of 0 K to 280 K, whereby the photocatalytic layer is afterwards at least partially irradiated by electromagnetic radiation, which activates a photocatalytic reaction of the photocatalytic layer with the adsorbed gases of the atmosphere of the inner vacuum space of the vacuum system, where this reaction decomposes the contaminants, reducing their concentration and/or the concentration of water in the inner vacuum space of the vacuum system.