the irradiation device for gaseous or liquid substances has at least one high - power radiator with a discharge chamber filled with filling gas . the filling gas contained therein emits radiation under the influence of quiet electrical discharges . the discharge chamber immediately adjoins a treatment chamber whose walls consist throughout of non - metallic material . an electrode pair and an ac source connected to the two electrodes serve to feed the discharge , the coupling of the discharge chamber to the electrodes being performed essentially capacitively . it is even possible , in particular , to treat by means of an irradiation device of such a design corrosive media or media for which extreme degrees of purity are the aim .