Abstract: A material processing system for processing a work piece is provided. The material processing is effected by supplying a reactive gas and energetic radiation for activation of the reactive gas to a surrounding of a location of the work piece to be processed. The radiation is preferably provided by an electron microscope. An objective lens of the electron microscope is preferably disposed between a detector of the electron microscope and the work piece. A gas supply arrangement of the material processing system comprises a valve disposed spaced apart from the processing location, a gas volume between the valve and a location of emergence of the reaction gas being small. The gas supply arrangement further comprises a temperature-adjusted, especially cooled reservoir for accommodating a starting material for the reactive gas.