Abstract: In a high-pressure gas discharge lamp, particularly a high-pressure sodium vapor lamp, comprising a tubular discharge vessel being made of a ceramic material and including electrodes and a filling and ceramic plug elements for closing the end regions of the discharge vessel, receiving a current lead-in connecting the electrode with an outer source of supply voltage, wherein at least one of the plug elements is built up with surface elements of different height levels and determining a cold chamber for receiving the metal additive, the distance between the surface of the metal additive and the current lead-in measured as length of the way determined on the surface elements is at least 4 mm.

Abstract: A high-pressure sodium vapor lamp, comprising a hermetically closed tube made of a translucent material of high thermal resistivity as alumina, at least two electrodes arranged in the tube, is filled with noble gas particularly xenon and with vapors of sodium and mercury and/or cadmium under pressure of saturated vapors at the temperature of operating. The quantity of the vapors of mercury and/or cadmium is in the range from 0.5 to 5.0 micromol for each centimeter of length of the discharge arc initiated between the electrodes. The high-pressure sodium lamp with the mentioned quantity of additives is assured a long lifetime of operation.

Abstract: A high-pressure gas discharge light source with high light conversion efficiency and color rendering, having a translucent discharge vessel of high melting point material in which electrodes of high melting point material are suspended and containing a filling of an inert gas or a mixture of inert gases, at least one metal halide and optionally one or more metals in the elemental state under cold conditions, wherein the ratio of the metal to the halogen forming the halide is stoichiometric or greater, and the specific wall load factor is between 25 and 200 W/cm.sup.2 and/or the quantity of the halide or halides is 0.01 to 1 mg per centimeter length of the arc.