Abstract: At least one gas inlet arrangement with several gas outlet openings supplies a working gas and/or a reactive gas to a chamber through a line system with at least one gas source, and at a given gas pressure. The chamber is provided for the treatment of substrates, such as, in particular, by physical or chemical coating processes or by etching processes. The resistance coefficients of the outlet openings are so dimensioned with respect to the sites in the line system at the given gas pressure, that at each outlet opening, a controlled gas flow exits.